Jump to content

Dietary fiber

From Wikipedia, the free encyclopedia
(Redirected from Soluble Fibre)

Foods rich in fibers: fruits, vegetables and grains
Wheat bran has a high content of dietary fiber.

Dietary fiber (fibre in Commonwealth English) or roughage is the portion of plant-derived food that cannot be completely broken down by human digestive enzymes.[1] Dietary fibers are diverse in chemical composition and can be grouped generally by their solubility, viscosity and fermentability which affect how fibers are processed in the body.[2] Dietary fiber has two main subtypes: soluble fiber and insoluble fiber which are components of plant-based foods such as legumes, whole grains, cereals, vegetables, fruits, and nuts or seeds.[2][3] A diet high in regular fiber consumption is generally associated with supporting health and lowering the risk of several diseases.[2][4] Dietary fiber consists of non-starch polysaccharides and other plant components such as cellulose, resistant starch, resistant dextrins, inulins, lignins, chitins, pectins, beta-glucans, and oligosaccharides.[1][2][3]

Food sources of dietary fiber have traditionally been divided according to whether they provide soluble or insoluble fiber. Plant foods contain both types of fiber in varying amounts according to the fiber characteristics of viscosity and fermentability.[1][5] Advantages of consuming fiber depend upon which type is consumed.[6] Bulking fibers – such as cellulose and hemicellulose (including psyllium) – absorb and hold water, promoting bowel movement regularity.[7] Viscous fibers – such as beta-glucan and psyllium – thicken the fecal mass.[7] Fermentable fibers – such as resistant starch, xanthan gum, and inulin – feed the bacteria and microbiota of the large intestine and are metabolized to yield short-chain fatty acids, which have diverse roles in gastrointestinal health.[8][9][10]

Soluble fiber (fermentable fiber or prebiotic fiber) – which dissolves in water – is generally fermented in the colon into gases and physiologically active by-products such as short-chain fatty acids produced in the colon by gut bacteria. Examples are beta-glucans (in oats, barley, and mushrooms) and raw guar gum. Psyllium – soluble, viscous, and non-fermented fiber – is a bulking fiber that retains water as it moves through the digestive system, easing defecation. Soluble fiber is generally viscous and delays gastric emptying which in humans can result in an extended feeling of fullness.[2] Inulin (in chicory root), wheat dextrin, oligosaccharides, and resistant starches[11] (in legumes and bananas) are soluble non-viscous fibers.[2] Regular intake of soluble fibers such as beta-glucans from oats or barley has been established to lower blood levels of LDL cholesterol.[2][4][12] Soluble fiber supplements also significantly lower LDL cholesterol.[13][14][15]

Insoluble fiber – which does not dissolve in water – is inert to digestive enzymes in the upper gastrointestinal tract. Examples are wheat bran, cellulose, and lignin. Coarsely ground insoluble fiber triggers the secretion of mucus in the large intestine providing bulking. However, finely ground insoluble fiber does not have this effect and instead can cause a constipation.[2] Some forms of insoluble fiber, such as resistant starches, can be fermented in the colon.[16]

Definition

[edit]

Dietary fiber is defined to be plant components that are not broken down by human digestive enzymes.[1] In the late 20th century, only lignin and some polysaccharides were known to satisfy this definition, but in the early 21st century, resistant starch and oligosaccharides were included as dietary fiber components.[1][17] The most accepted definition of dietary fiber is "all polysaccharides and lignin, which are not digested by the endogenous secretion of the human digestive tract".[18] Currently, most animal nutritionists are using either a physiological definition, "the dietary components resistant to degradation by mammalian enzymes", or a chemical definition, "the sum of non-starch polysaccharides (NSP) and lignin".[18]

Types and sources

[edit]
water-insoluble dietary fibers
Nutrient Food additive Source/Comments
β-glucans (a few of which are water-soluble)
   Cellulose E 460 cereals, fruit, vegetables (in all plants in general)
   Chitin — in fungi, exoskeleton of insects and crustaceans
Hemicellulose cereals, bran, timber, legumes
   Hexoses — wheat, barley
   Pentose — rye, oat
Lignin — stones of fruits, vegetables (filaments of the garden bean), cereals
Xanthan gum E 415 production with Xanthomonas-bacteria from sugar substrates
Resistant starch Can be starch protected by seed or shell (type RS1), granular starch (type RS2) or retrograded starch (type RS3)[16]
   Resistant starch — high amylose corn, barley, high amylose wheat, legumes, raw bananas, cooked and cooled pasta and potatoes[16]
water-soluble dietary fibers
Nutrient Food additive Source/Comments
Arabinoxylan (a hemicellulose) — psyllium[19]
Fructans replace or complement in some plant taxa the starch as storage carbohydrate
   Inulin — in diverse plants, e.g. topinambour, chicory, etc.
Polyuronide
   Pectin E 440 in the fruit skin (mainly apples, quinces), vegetables
   Alginic acids (Alginates) E 400–E 407 in Algae
      Sodium alginate E 401
      Potassium alginate E 402
      Ammonium alginate E 403
      Calcium alginate E 404
      Propylene glycol alginate (PGA) E 405
      agar E 406
      carrageenan E 407 red algae
Raffinose — legumes
Polydextrose E 1200 synthetic polymer, c. 1 kcal/g

Contents in food

[edit]
Children eating fiber-rich food

Dietary fiber is found in fruits, vegetables and whole grains. The amounts of fiber contained in common foods are listed in the following table:[20]

Fiber content of some common food
Food group Serving mean Fibermass per serving
Fruit 120 mL (0.5 cup)[21][22] 1.1 g
Dark green vegetables 120 mL (0.5 cup) 6.4 g
Orange vegetables 120 mL (0.5 cup) 2.1 g
Cooked dry beans (legumes) 120 mL (0.5 cup) 8.0 g
Starchy vegetables 120 mL (0.5 cup) 1.7 g
Other vegetables 120 mL (0.5 cup) 1.1 g
Whole grains 28 g (1 oz) 2.4 g
Meat 28 g (1 oz) 0.1 g

Dietary fiber is found in plants, typically eaten whole, raw or cooked, although fiber can be added to make dietary supplements and fiber-rich processed foods. Grain bran products have the highest fiber contents, such as crude corn bran (79 g per 100 g) and crude wheat bran (43 g per 100 g), which are ingredients for manufactured foods.[20] Medical authorities, such as the Mayo Clinic, recommend adding fiber-rich products to the Standard American Diet because it is rich in processed and artificially sweetened foods, with minimal intake of vegetables and legumes.[23][24]

Plant sources

[edit]

Some plants contain significant amounts of soluble and insoluble fiber. For example, plums and prunes have a thick skin covering a juicy pulp. The skin is a source of insoluble fiber, whereas soluble fiber is in the pulp. Grapes also contain a fair amount of fiber.[25]

Soluble fiber

[edit]

Found in varying quantities in all plant foods, including:

Insoluble fiber

[edit]

Sources include:

Supplements

[edit]

These are a few example forms of fiber that have been sold as supplements or food additives. These may be marketed to consumers for nutritional purposes, treatment of various gastrointestinal disorders, and for such possible health benefits as lowering cholesterol levels, reducing the risk of colon cancer, and losing weight.

Soluble fiber

[edit]

Soluble fiber supplements may be beneficial for alleviating symptoms of irritable bowel syndrome, such as diarrhea or constipation and abdominal discomfort.[27] Prebiotic soluble fiber products, like those containing inulin or oligosaccharides, may contribute to relief from inflammatory bowel disease,[28] as in Crohn's disease,[29] ulcerative colitis,[30][31] and Clostridioides difficile,[32] due in part to the short-chain fatty acids produced with subsequent anti-inflammatory actions upon the bowel.[33][34] Fiber supplements may be effective in an overall dietary plan for managing irritable bowel syndrome by modification of food choices.[35]

Insoluble fiber

[edit]

One insoluble fiber, resistant starch from high-amylose corn, has been used as a supplement and may contribute to improving insulin sensitivity and glycemic management[36][37][38] as well as promoting regularity[39] and possibly relief of diarrhea.[40][41][42] One preliminary finding indicates that resistant corn starch may reduce symptoms of ulcerative colitis.[43]

Inulins

[edit]
Main article: Inulin

Chemically defined as oligosaccharides and occurring naturally in most plants, inulins have nutritional value as carbohydrates, or more specifically as fructans, a polymer of the natural plant sugar, fructose. Inulin is typically extracted by manufacturers from enriched plant sources such as chicory roots or Jerusalem artichokes for use in prepared foods.[44] Subtly sweet, it can be used to replace sugar, fat, and flour, is often used to improve the flow and mixing qualities of powdered nutritional supplements, and has potential health value as a prebiotic fermentable fiber.[45]

As a prebiotic fermentable fiber, inulin is metabolized by gut flora to yield short-chain fatty acids (see below), which increase absorption of calcium,[46] magnesium,[47] and iron.[48]

The primary disadvantage of inulin is its fermentation within the intestinal tract, possibly causing flatulence and digestive distress at doses higher than 15 grams/day in most people.[49] Individuals with digestive diseases have benefited from removing fructose and inulin from their diet.[50] While clinical studies have shown changes in the microbiota at lower levels of inulin intake, higher intake amounts may be needed to achieve effects on body weight.[51]

Vegetable gums

[edit]

Vegetable gum fiber supplements are relatively new to the market. Often sold as a powder, vegetable gum fibers dissolve easily with no aftertaste. In preliminary clinical trials, they have proven effective for the treatment of irritable bowel syndrome.[52] Examples of vegetable gum fibers are guar gum and gum arabic.

Activity in the gut

[edit]

Many molecules that are considered to be "dietary fiber" are so because humans lack the necessary enzymes to split the glycosidic bond and they reach the large intestine. Many foods contain varying types of dietary fibers, all of which contribute to health in different ways.

Dietary fibers make three primary contributions: bulking, viscosity and fermentation.[53] Different fibers have different effects, suggesting that a variety of dietary fibers contribute to overall health. Some fibers contribute through one primary mechanism. For instance, cellulose and wheat bran provide excellent bulking effects, but are minimally fermented. Alternatively, many dietary fibers can contribute to health through more than one of these mechanisms. For instance, psyllium provides bulking as well as viscosity.

Bulking fibers can be soluble (e.g. psyllium) or insoluble (e.g. cellulose and hemicellulose). They absorb water and can significantly increase stool weight and regularity. Most bulking fibers are not fermented or are minimally fermented throughout the intestinal tract.[53]

Viscous fibers thicken the contents of the intestinal tract and may attenuate the absorption of sugar, reduce sugar response after eating, and reduce lipid absorption (notably shown with cholesterol absorption). Their use in food formulations is often limited to low levels, due to their viscosity and thickening effects. Some viscous fibers may also be partially or fully fermented within the intestinal tract (guar gum, beta-glucan, glucomannan and pectins), but some viscous fibers are minimally or not fermented (modified cellulose such as methylcellulose and psyllium).[53]

Fermentable fibers are consumed by the microbiota within the large intestines, mildly increasing fecal bulk and producing short-chain fatty acids as byproducts with wide-ranging physiological activities. Resistant starch, inulin, fructooligosaccharide and galactooligosaccharide are dietary fibers which are fully fermented. These include insoluble as well as soluble fibers. This fermentation influences the expression of many genes within the large intestine,[54] which affect digestive function and lipid and glucose metabolism, as well as the immune system, inflammation and more.[55]

Fiber fermentation produces gas (majorly carbon dioxide, hydrogen, and methane) and short-chain fatty acids. Isolated or purified fermentable fibers are more rapidly fermented in the fore-gut and may result in undesirable gastrointestinal symptoms (bloating, indigestion and flatulence).[56]

Dietary fibers can change the nature of the contents of the gastrointestinal tract and can change how other nutrients and chemicals are absorbed through bulking and viscosity.[3][57] Some types of soluble fibers bind to bile acids in the small intestine, making them less likely to re-enter the body; this in turn lowers cholesterol levels in the blood from the actions of cytochrome P450-mediated oxidation of cholesterol.[17]

Insoluble fiber is associated with reduced risk of diabetes,[58] but the mechanism by which this is achieved is unknown.[59] One type of insoluble dietary fiber, resistant starch, may increase insulin sensitivity in healthy people,[60][61] in type 2 diabetics,[62] and in individuals with insulin resistance, possibly contributing to reduced risk of type 2 diabetes.[38][37][36]

Not yet formally proposed as an essential macronutrient, dietary fiber has importance in the diet, with regulatory authorities in many developed countries recommending increases in fiber intake.[3][57][63][64]

Physicochemical properties

[edit]

Dietary fiber has distinct physicochemical properties. Most semi-solid foods, fiber and fat are a combination of gel matrices which are hydrated or collapsed with microstructural elements, globules, solutions or encapsulating walls. Fresh fruit and vegetables are cellular materials.[65][66][67]

  • The cells of cooked potatoes and legumes are gels filled with gelatinized starch granules. The cellular structures of fruits and vegetables are foams with a closed cell geometry filled with a gel, surrounded by cell walls which are composites with an amorphous matrix strengthened by complex carbohydrate fibers.
  • Particle size and interfacial interactions with adjacent matrices affect the mechanical properties of food composites.
  • Food polymers may be soluble in and/or plasticized by water.
  • The variables include chemical structure, polymer concentration, molecular weight, degree of chain branching, the extent of ionization (for electrolytes), solution pH, ionic strength and temperature.
  • Cross-linking of different polymers, protein and polysaccharides, either through chemical covalent bonds or cross-links through molecular entanglement or hydrogen or ionic bond cross-linking.
  • Cooking and chewing food alters these physicochemical properties and hence absorption and movement through the stomach and along the intestine[68]

Upper gastrointestinal tract

[edit]

Following a meal, the stomach and upper gastrointestinal contents consist of

Micelles are colloid-sized clusters of molecules which form in conditions as those above, similar to the critical micelle concentration of detergents.[70] In the upper gastrointestinal tract, these compounds consist of bile acids and di- and monoacyl glycerols which solubilize triacylglycerols and cholesterol.[70]

Two mechanisms bring nutrients into contact with the epithelium:

  1. intestinal contractions create turbulence; and
  2. convection currents direct contents from the lumen to the epithelial surface.[71]

The multiple physical phases in the intestinal tract slow the rate of absorption compared to that of the suspension solvent alone.

  1. Nutrients diffuse through the thin, relatively unstirred layer of fluid adjacent to the epithelium.
  2. Immobilizing of nutrients and other chemicals within complex polysaccharide molecules affects their release and subsequent absorption from the small intestine, an effect influential on the glycemic index.[71]
  3. Molecules begin to interact as their concentration increases. During absorption, water must be absorbed at a rate commensurate with the absorption of solutes. The transport of actively and passively absorbed nutrients across epithelium is affected by the unstirred water layer covering the microvillus membrane.[71]
  4. The presence of mucus or fiber, e.g., pectin or guar, in the unstirred layer may alter the viscosity and solute diffusion coefficient.[69]

Adding viscous polysaccharides to carbohydrate meals can reduce post-prandial blood glucose concentrations. Wheat and maize but not oats modify glucose absorption, the rate being dependent upon the particle size. The reduction in absorption rate with guar gum may be due to the increased resistance by viscous solutions to the convective flows created by intestinal contractions.

Dietary fiber interacts with pancreatic and enteric enzymes and their substrates. Human pancreatic enzyme activity is reduced when incubated with most fiber sources. Fiber may affect amylase activity and hence the rate of hydrolysis of starch. The more viscous polysaccharides extend the mouth-to-cecum transit time; guar, tragacanth and pectin being slower than wheat bran.[72]

Colon

[edit]

The colon may be regarded as two organs,

  1. the right side (cecum and ascending colon), a fermenter.[73] The right side of the colon is involved in nutrient salvage so that dietary fiber, resistant starch, fat and protein are utilized by bacteria and the end-products absorbed for use by the body
  2. the left side (transverse, descending, and sigmoid colon), affecting continence.

The presence of bacteria in the colon produces an 'organ' of intense, mainly reductive, metabolic activity, whereas the liver is oxidative. The substrates utilized by the cecum have either passed along the entire intestine or are biliary excretion products. The effects of dietary fiber in the colon are on

  1. bacterial fermentation of some dietary fibers
  2. thereby an increase in bacterial mass
  3. an increase in bacterial enzyme activity
  4. changes in the water-holding capacity of the fiber residue after fermentation

Enlargement of the cecum is a common finding when some dietary fibers are fed and this is now believed to be normal physiological adjustment. Such an increase may be due to a number of factors, prolonged cecal residence of the fiber, increased bacterial mass, or increased bacterial end-products. Some non-absorbed carbohydrates, e.g. pectin, gum arabic, oligosaccharides and resistant starch, are fermented to short-chain fatty acids (chiefly acetic, propionic and n-butyric), and carbon dioxide, hydrogen and methane. Almost all of these short-chain fatty acids will be absorbed from the colon. This means that fecal short-chain fatty acid estimations do not reflect cecal and colonic fermentation, only the efficiency of absorption, the ability of the fiber residue to sequestrate short-chain fatty acids, and the continued fermentation of fiber around the colon, which presumably will continue until the substrate is exhausted. The production of short-chain fatty acids has several possible actions on the gut mucosa. All of the short-chain fatty acids are readily absorbed by the colonic mucosa, but only acetic acid reaches the systemic circulation in appreciable amounts. Butyric acid appears to be used as a fuel by the colonic mucosa as the preferred energy source for colonic cells.

Cholesterol metabolism

[edit]

Dietary fiber may act on each phase of ingestion, digestion, absorption and excretion to affect cholesterol metabolism,[74] such as the following:

  1. Caloric energy of foods through a bulking effect
  2. Slowing of gastric emptying time
  3. A glycemic index type of action on absorption
  4. A slowing of bile acid absorption in the ileum so bile acids escape through to the cecum
  5. Altered or increased bile acid metabolism in the cecum
  6. Indirectly by absorbed short-chain fatty acids, especially propionic acid, resulting from fiber fermentation affecting the cholesterol metabolism in the liver.
  7. Binding of bile acids to fiber or bacteria in the cecum with increased fecal loss from the entero-hepatic circulation.

One action of some fibers is to reduce the reabsorption of bile acids in the ileum and hence the amount and type of bile acid and fats reaching the colon. A reduction in the reabsorption of bile acid from the ileum has several direct effects.

  1. Bile acids may be trapped within the lumen of the ileum either because of a high luminal viscosity or because of binding to a dietary fiber.[75]
  2. Lignin in fiber adsorbs bile acids, but the unconjugated form of the bile acids are adsorbed more than the conjugated form. In the ileum where bile acids are primarily absorbed the bile acids are predominantly conjugated.
  3. The enterohepatic circulation of bile acids may be altered and there is an increased flow of bile acids to the cecum, where they are deconjugated and 7alpha-dehydroxylated.
  4. These water-soluble form, bile acids e.g., deoxycholic and lithocholic are adsorbed to dietary fiber and an increased fecal loss of sterols, dependent in part on the amount and type of fiber.
  5. A further factor is an increase in the bacterial mass and activity of the ileum as some fibers e.g., pectin are digested by bacteria. The bacterial mass increases and cecal bacterial activity increases.
  6. The enteric loss of bile acids results in increased synthesis of bile acids from cholesterol which in turn reduces body cholesterol.

The fibers that are most effective in influencing sterol metabolism (e.g. pectin) are fermented in the colon. It is therefore unlikely that the reduction in body cholesterol is due to adsorption to this fermented fiber in the colon.

  1. There might be alterations in the end-products of bile acid bacterial metabolism or the release of short chain fatty acids which are absorbed from the colon, return to the liver in the portal vein and modulate either the synthesis of cholesterol or its catabolism to bile acids.
  2. The prime mechanism whereby fiber influences cholesterol metabolism is through bacteria binding bile acids in the colon after the initial deconjugation and dehydroxylation. The sequestered bile acids are then excreted in feces.[76]
  3. Fermentable fibers e.g., pectin will increase the bacterial mass in the colon by virtue of their providing a medium for bacterial growth.
  4. Other fibers, e.g., gum arabic, act as stabilizers and cause a significant decrease in serum cholesterol without increasing fecal bile acid excretion.

Fecal weight

[edit]

Feces consist of a plasticine-like material, made up of water, bacteria, lipids, sterols, mucus and fiber.

  1. Feces are 75% water; bacteria make a large contribution to the dry weight, the residue being unfermented fiber and excreted compounds.
  2. Fecal output may vary over a range of between 20 and 280 g over 24 hours. The amount of feces egested a day varies for any one individual over a period of time.
  3. Of dietary constituents, only dietary fiber increases fecal weight.

Water is distributed in the colon in three ways:

  1. Free water which can be absorbed from the colon.
  2. Water that is incorporated into bacterial mass.
  3. Water that is bound by fiber.

Fecal weight is dictated by:

  1. the holding of water by the residual dietary fiber after fermentation.
  2. the bacterial mass.
  3. There may also be an added osmotic effect of products of bacterial fermentation on fecal mass.

Effects of fiber intake

[edit]

Preliminary research indicates that fiber may affect health by different mechanisms.

Effects of fiber include:[1][2]

  • Increases food volume without increasing caloric content to the same extent as digestible carbohydrates, providing satiety which may reduce appetite (both insoluble and soluble fiber)
  • Attracts water and forms a viscous gel during digestion, slowing the emptying of the stomach, shortening intestinal transit time, shielding carbohydrates from enzymes, and delaying absorption of glucose,[1][77] which lowers variance in blood sugar levels (soluble fiber)
  • Lowers total and LDL cholesterol, which may reduce the risk of cardiovascular disease[1] (soluble fiber)
  • Reduces blood pressure, being negatively associated with all-cause and cardiovascular mortality,[78][79] and may prevent the development of cardiovascular disease in offspring[80]
  • Regulates blood sugar, which may reduce glucose and insulin levels in diabetic patients and may lower risk of diabetes[1][81] (insoluble fiber)
  • Speeds the passage of foods through the digestive system, which facilitates regular defecation (insoluble fiber)
  • Adds bulk to the stool, which alleviates constipation (insoluble fiber)
  • Balances intestinal pH[82] and stimulates intestinal fermentation production of short-chain fatty acids.[1]

Fiber does not bind to minerals and vitamins and therefore does not restrict their absorption, but rather evidence exists that fermentable fiber sources improve absorption of minerals, especially calcium.[83][84][85]

Research

[edit]

As of 2019, preliminary clinical research on the potential health effects of a regular high-fiber diet included studies on the risk of several cancers, cardiovascular diseases, and type II diabetes.[2][4]

High-fiber intake is associated with a decreased risk of breast cancer, colon cancer and lower mortality.[86][87][88][89]

Dietary recommendations

[edit]

European Union

[edit]

According to the European Food Safety Authority (EFSA) Panel on Nutrition, Novel Foods and Food Allergens, which deals with the establishment of Dietary Reference Values for carbohydrates and dietary fibre, "based on the available evidence on bowel function, the Panel considers dietary fibre intakes of 25 g per day to be adequate for normal laxation in adults".[90][91]

United States

[edit]

Current recommendations from the United States National Academy of Medicine (NAM) (formerly Institute of Medicine) of the National Academy of Sciences state that for Adequate Intake, adult men ages 19–50 consume 38 grams of dietary fiber per day, men 51 and older 30 grams, women ages 19–50 to consume 25 grams per day, women 51 and older 21 grams. These are based on three studies observing that people in the highest quintile of fiber intake consumed a median of 14 grams of fiber per 1,000 Calories and had the lowest risk of coronary heart disease, especially for those who ate more cereal fiber.[2][92][3]

The U.S. Academy of Nutrition and Dietetics (AND) reiterates the recommendations of the NAM.[93] A 1995 research team's recommendation for children is that intake should equal age in years plus 5 g/day (e.g., a 4-year-old should consume 9 g/day).[94][95] The NAM's current recommendation for children is 19 g/day for age 1–3 years and 25 g/day for age 4–8 years.[2] No guidelines have yet been established for the elderly or very ill. Patients with current constipation, vomiting, and abdominal pain should see a physician. Certain bulking agents are not commonly recommended with the prescription of opioids because the slow transit time mixed with larger stools may lead to severe constipation, pain, or obstruction.

On average, North Americans consume less than 50% of the dietary fiber levels recommended for good health. In the preferred food choices of today's youth, this value may be as low as 20%, a factor considered by experts as contributing to the obesity levels seen in many developed countries.[96] Recognizing the growing scientific evidence for physiological benefits of increased fiber intake, regulatory agencies such as the U.S. Food and Drug Administration (FDA) have given approvals to food products making health claims for fiber. The FDA classifies which ingredients qualify as being "fiber", and requires for product labeling that a physiological benefit is gained by adding the fiber ingredient.[97] As of 2008, the FDA approved health claims for qualified fiber products to display labeling that regular consumption may reduce blood cholesterol levels – which can lower the risk of coronary heart disease[98] – and also reduce the risk of some types of cancer.[99]

Viscous fiber sources gaining FDA approval are:[2]

Other examples of bulking fiber sources used in functional foods and supplements include cellulose, guar gum and xanthan gum. Other examples of fermentable fiber sources (from plant foods or biotechnology) used in functional foods and supplements include resistant starch, inulin, fructans, fructooligo saccharides, oligo- or polysaccharides, and resistant dextrins, which may be partially or fully fermented.

Consistent intake of fermentable fiber may reduce the risk of chronic diseases.[100][101][102] Insufficient fiber in the diet can lead to constipation.[103]

United Kingdom

[edit]

In 2018, the British Nutrition Foundation issued a statement to define dietary fiber more concisely and list the potential health benefits established to date, while increasing its recommended daily minimum intake to 30 grams for healthy adults.[104][1]

The use of certain analytical methods to quantify dietary fiber by nature of its indigestin ability results in many other indigestible components being isolated along with the carbohydrate components of dietary fiber. These components include resistant starches and oligosaccharides along with other substances that exist within the plant cell structure and contribute to the material that passes through the digestive tract. Such components are likely to have physiological effects.

Diets naturally high in fiber can be considered to bring about several main physiological consequences:[1]

Fiber is defined by its physiological impact, with many heterogenous types of fibers. Some fibers may primarily impact one of these benefits (i.e., cellulose increases fecal bulking and prevents constipation), but many fibers impact more than one of these benefits (i.e., resistant starch increases bulking, increases colonic fermentation, positively modulates colonic microflora and increases satiety and insulin sensitivity).[16][11] The beneficial effects of high fiber diets are the summation of the effects of the different types of fiber present in the diet and also other components of such diets.

Defining fiber physiologically allows recognition of indigestible carbohydrates with structures and physiological properties similar to those of naturally occurring dietary fibers.[1]

Fermentation

[edit]

The Cereals & Grains Association has defined soluble fiber this way: "the edible parts of plants or similar carbohydrates resistant to digestion and absorption in the human small intestine with complete or partial fermentation in the large intestine."[105]

In this definition, "edible parts of plants" indicates that some parts of a plant that are eaten—skin, pulp, seeds, stems, leaves, roots—contain fiber. Both insoluble and soluble sources are in those plant components. "Carbohydrates" refers to complex carbohydrates, such as long-chained sugars also called starch, oligosaccharides, or polysaccharides, which are sources of soluble fermentable fiber. "Resistant to digestion and absorption in the human small intestine" refers to compounds that are not digested by gastric acid and digestive enzymes in the stomach and small intestine, preventing the digesting animal from utilizing the compounds for energy. A food resistant to this process is undigested, as insoluble and soluble fibers are. They pass to the large intestine only affected by their absorption of water (insoluble fiber) or dissolution in water (soluble fiber). "Complete or partial fermentation in the large intestine" describes the digestive processes of the large intestine, which comprises a segment called the colon within which additional nutrient absorption occurs through the process of fermentation. Fermentation occurs through the action of colonic bacteria on the food mass, producing gases and short-chain fatty acids. These short-chain fatty acids have been shown to have significant health properties.[106] They include butyric, acetic (ethanoic), propionic, and valeric acids.

As an example of fermentation, shorter-chain carbohydrates (a type of fiber found in legumes) cannot be digested, but are changed via fermentation in the colon into short-chain fatty acids and gases (which are typically expelled as flatulence).

According to a 2002 journal article,[100] fiber compounds with partial or low fermentability include:

fiber compounds with high fermentability include:

Short-chain fatty acids

[edit]
Main article: Short-chain fatty acid

When fermentable fiber is fermented, short-chain fatty acids (SCFA) are produced.[18] SCFAs are involved in numerous physiological processes promoting health, including:[106]

SCFAs that are absorbed by the colonic mucosa pass through the colonic wall into the portal circulation (supplying the liver), and the liver transports them into the general circulatory system.

Overall, SCFAs affect major regulatory systems, such as blood glucose and lipid levels, the colonic environment, and intestinal immune functions.[108][109]

The major SCFAs in humans are butyrate, propionate, and acetate, where butyrate is the major energy source for colonocytes, propionate is destined for uptake by the liver, and acetate enters the peripheral circulation to be metabolized by peripheral tissues.[citation needed]

FDA-approved health claims

[edit]

The FDA allows manufacturers of foods containing 1.7 g per serving of psyllium husk soluble fiber or 0.75 g of oat or barley soluble fiber as beta-glucans to claim that regular consumption may reduce the risk of heart disease.[12]

The FDA statement template for making this claim is:

Soluble fiber from foods such as [name of soluble fiber source, and, if desired, name of food product], as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease. A serving of [name of food product] supplies __ grams of the [necessary daily dietary intake for the benefit] soluble fiber from [name of soluble fiber source] necessary per day to have this effect.[12]

Eligible sources of soluble fiber providing beta-glucan include:

  • Oat bran
  • Rolled oats
  • Whole oat flour
  • Oatrim
  • Whole grain barley and dry milled barley
  • Soluble fiber from psyllium husk with purity of no less than 95%

The allowed label may state that diets low in saturated fat and cholesterol and that include soluble fiber from certain of the above foods "may" or "might" reduce the risk of heart disease.

As discussed in FDA regulation 21 CFR 101.81, the daily dietary intake levels of soluble fiber from sources listed above associated with reduced risk of coronary heart disease are:

  • 3 g or more per day of beta-glucan soluble fiber from either whole oats or barley, or a combination of whole oats and barley
  • 7 g or more per day of soluble fiber from psyllium seed husk.[110]

Soluble fiber from consuming grains is included in other allowed health claims for lowering risk of some types of cancer and heart disease by consuming fruit and vegetables (21 CFR 101.76, 101.77, and 101.78).[12]

In December 2016, the FDA approved a qualified health claim that consuming resistant starch from high-amylose corn may reduce the risk of type 2 diabetes due to its effect of increasing insulin sensitivity. The allowed claim specified: "High-amylose maize resistant starch may reduce the risk of type 2 diabetes. The FDA has concluded that there is limited scientific evidence for this claim."[111] In 2018, the FDA released further guidance on the labeling of isolated or synthetic dietary fiber to clarify how different types of dietary fiber should be classified.[112]

See also

[edit]

References

[edit]
  1. ^ a b c d e f g h i j k l m "Dietary fibre". British Nutrition Foundation. 2018. Archived from the original on 26 July 2018. Retrieved 26 July 2018.
  2. ^ a b c d e f g h i j k l m "Fiber". Linus Pauling Institute, Oregon State University. March 2019. Retrieved 3 February 2021.
  3. ^ a b c d e Dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein, and amino acids (2005), Chapter 7: Dietary, Functional and Total Fiber. US Department of Agriculture, National Agricultural Library and National Academy of Sciences, Institute of Medicine, Food and Nutrition Board. 2005. doi:10.17226/10490. ISBN 978-0-309-08525-0.
  4. ^ a b c Veronese N, Solmi M, Caruso MG, et al. (March 2018). "Dietary fiber and health outcomes: an umbrella review of systematic reviews and meta-analyses". The American Journal of Clinical Nutrition. 107 (3): 436–444. doi:10.1093/ajcn/nqx082. PMID 29566200.{{cite journal}}: CS1 maint: overridden setting (link)
  5. ^ Institute of Medicine (2001). Dietary Reference Intakes, Proposed Definition of Dietary Fiber. Washington, D.C.: Institute of Medicine Press. p. 25. ISBN 978-0-309-07564-0.
  6. ^ Gallaher DD (2006). "8". Present Knowledge in Nutrition (9 ed.). Washington, D.C.: ILSI Press. pp. 102–110. ISBN 978-1-57881-199-1.
  7. ^ a b Institute of Medicine (2001). Dietary Reference Intakes: Proposed Definition of Dietary Fiber. Washington, D.C.: National Academy Press. p. 19. ISBN 978-0-309-07564-0.
  8. ^ Bedford A, Gong J (June 2018). "Implications of butyrate and its derivatives for gut health and animal production". Animal Nutrition. 4 (2): 151–159. doi:10.1016/j.aninu.2017.08.010. PMC 6104520. PMID 30140754.
  9. ^ Cummings JH (2001). The Effect of Dietary Fiber on Fecal Weight and Composition (3 ed.). Boca Raton, Florida: CRC Press. p. 184. ISBN 978-0-8493-2387-4.
  10. ^ Ostrowski MP, La Rosa SL, Kunath BJ, et al. (April 2022). "Mechanistic insights into consumption of the food additive xanthan gum by the human gut microbiota". Nature Microbiology. 7 (4): 556–569. doi:10.1038/s41564-022-01093-0. hdl:11250/3003739. PMID 35365790. S2CID 247866305.{{cite journal}}: CS1 maint: overridden setting (link)
  11. ^ a b Keenan MJ, Zhou J, Hegsted M, et al. (March 2015). "Role of resistant starch in improving gut health, adiposity, and insulin resistance". Advances in Nutrition. 6 (2): 198–205. doi:10.3945/an.114.007419. PMC 4352178. PMID 25770258.
  12. ^ a b c d FDA/CFSAN A Food Labeling Guide: Appendix C Health Claims, April 2008 Archived 12 April 2008 at the Wayback Machine
  13. ^ Jovanovski E, Yashpal S, Komishon A, et al. (1 November 2018). "Effect of psyllium (Plantago ovata) fiber on LDL cholesterol and alternative lipid targets, non-HDL cholesterol and apolipoprotein B: a systematic review and meta-analysis of randomized controlled trials". The American Journal of Clinical Nutrition. 108 (5): 922–932. doi:10.1093/ajcn/nqy115. ISSN 1938-3207. PMID 30239559.
  14. ^ Ho HV, Jovanovski E, Zurbau A, et al. (May 2017). "A systematic review and meta-analysis of randomized controlled trials of the effect of konjac glucomannan, a viscous soluble fiber, on LDL cholesterol and the new lipid targets non-HDL cholesterol and apolipoprotein B". The American Journal of Clinical Nutrition. 105 (5): 1239–1247. doi:10.3945/ajcn.116.142158. ISSN 1938-3207. PMID 28356275.
  15. ^ Ghavami A, Ziaei R, Talebi S, et al. (1 May 2023). "Soluble Fiber Supplementation and Serum Lipid Profile: A Systematic Review and Dose-Response Meta-Analysis of Randomized Controlled Trials". Advances in Nutrition. 14 (3): 465–474. doi:10.1016/j.advnut.2023.01.005. ISSN 2161-8313. PMC 10201678. PMID 36796439.
  16. ^ a b c d Lockyer S, Nugent AP (2017). "Health effects of resistant starch". Nutrition Bulletin. 42: 10–41. doi:10.1111/nbu.12244.
  17. ^ a b Anderson JW, Baird P, Davis RH, et al. (April 2009). "Health benefits of dietary fiber" (PDF). Nutrition Reviews. 67 (4): 188–205. doi:10.1111/j.1753-4887.2009.00189.x. PMID 19335713. S2CID 11762029.{{cite journal}}: CS1 maint: overridden setting (link)
  18. ^ a b c Jha R, Mishra P (April 2021). "Dietary fiber in poultry nutrition and their effects on nutrient utilization, performance, gut health, and on the environment: a review". Journal of Animal Science and Biotechnology. 12 (1): 51. doi:10.1186/s40104-021-00576-0. PMC 8054369. PMID 33866972.
  19. ^ Fischer MH, Yu N, Gray GR, et al. (August 2004). "The gel-forming polysaccharide of psyllium husk (Plantago ovata Forsk)". Carbohydrate Research. 339 (11): 2009–17. doi:10.1016/j.carres.2004.05.023. PMID 15261594.
  20. ^ a b "Search, USDA Food Composition Databases". Nutrient Data Laboratory. USDA National Nutrient Database, US Department of Agriculture, Standard Release 28. 2015. Archived from the original on 22 April 2019. Retrieved 18 November 2017.
  21. ^ U.S. Government Printing Office—Electronic Code of Federal Regulations Archived 13 August 2009 at the Wayback Machine
  22. ^ U.S. Food and Drug Administration—Guidelines for Determining Metric Equivalents of Household Measures
  23. ^ Bloomfield HE, Kane R, Koeller E, et al. (November 2015). "Benefits and Harms of the Mediterranean Diet Compared to Other Diets" (PDF). VA Evidence-based Synthesis Program Reports. PMID 27559560.
  24. ^ "Nutrition and healthy eating: Fiber". Mayo Clinic. 2017. Retrieved 18 November 2017.
  25. ^ Stacewicz-Sapuntzakis M, Bowen PE, Hussain EA, et al. (May 2001). "Chemical composition and potential health effects of prunes: a functional food?". Critical Reviews in Food Science and Nutrition. 41 (4): 251–86. doi:10.1080/20014091091814. PMID 11401245. S2CID 31159565.
  26. ^ Alvarado A, Pacheco-Delahaye E, Hevia P (2001). "Value of a tomato byproduct as a source of dietary fiber in rats" (PDF). Plant Foods for Human Nutrition. 56 (4): 335–48. doi:10.1023/A:1011855316778. PMID 11678439. S2CID 21835355.
  27. ^ Friedman G (September 1989). "Nutritional therapy of irritable bowel syndrome". Gastroenterology Clinics of North America. 18 (3): 513–24. doi:10.1016/S0889-8553(21)00639-7. PMID 2553606.
  28. ^ Ewaschuk JB, Dieleman LA (October 2006). "Probiotics and prebiotics in chronic inflammatory bowel diseases". World Journal of Gastroenterology. 12 (37): 5941–50. doi:10.3748/wjg.v12.i37.5941. PMC 4124400. PMID 17009391.
  29. ^ Guarner F (April 2005). "Inulin and oligofructose: impact on intestinal diseases and disorders". The British Journal of Nutrition. 93 (Suppl 1): S61-5. doi:10.1079/BJN20041345. PMID 15877897.
  30. ^ Seidner DL, Lashner BA, Brzezinski A, et al. (April 2005). "An oral supplement enriched with fish oil, soluble fiber, and antioxidants for corticosteroid sparing in ulcerative colitis: a randomized, controlled trial". Clinical Gastroenterology and Hepatology. 3 (4): 358–69. doi:10.1016/S1542-3565(04)00672-X. PMID 15822041.{{cite journal}}: CS1 maint: overridden setting (link)
  31. ^ Rodríguez-Cabezas ME, Gálvez J, Camuesco D, et al. (October 2003). "Intestinal anti-inflammatory activity of dietary fiber (Plantago ovata seeds) in HLA-B27 transgenic rats". Clinical Nutrition. 22 (5): 463–71. doi:10.1016/S0261-5614(03)00045-1. PMID 14512034.{{cite journal}}: CS1 maint: overridden setting (link)
  32. ^ Ward PB, Young GP (1997). "Dynamics of Clostridium Difficile Infection: Control Using Diet". Mechanisms in the Pathogenesis of Enteric Diseases. Advances in Experimental Medicine and Biology. Vol. 412. pp. 63–75. doi:10.1007/978-1-4899-1828-4_8. ISBN 978-1-4899-1830-7. PMID 9191992.
  33. ^ Säemann MD, Böhmig GA, Zlabinger GJ (May 2002). "Short-chain fatty acids: bacterial mediators of a balanced host-microbial relationship in the human gut". Wiener Klinische Wochenschrift. 114 (8–9): 289–300. PMID 12212362.
  34. ^ Cavaglieri CR, Nishiyama A, Fernandes LC, et al. (August 2003). "Differential effects of short-chain fatty acids on proliferation and production of pro- and anti-inflammatory cytokines by cultured lymphocytes". Life Sciences. 73 (13): 1683–90. doi:10.1016/S0024-3205(03)00490-9. PMID 12875900.
  35. ^ MacDermott RP (January 2007). "Treatment of irritable bowel syndrome in outpatients with inflammatory bowel disease using a food and beverage intolerance, food and beverage avoidance diet". Inflammatory Bowel Diseases. 13 (1): 91–6. doi:10.1002/ibd.20048. PMID 17206644. S2CID 24307163.
  36. ^ a b Robertson MD, Wright JW, Loizon E, et al. (September 2012). "Insulin-sensitizing effects on muscle and adipose tissue after dietary fiber intake in men and women with metabolic syndrome". The Journal of Clinical Endocrinology and Metabolism. 97 (9): 3326–32. doi:10.1210/jc.2012-1513. PMID 22745235.{{cite journal}}: CS1 maint: overridden setting (link)
  37. ^ a b Maki KC, Pelkman CL, Finocchiaro ET, et al. (April 2012). "Resistant starch from high-amylose maize increases insulin sensitivity in overweight and obese men". The Journal of Nutrition. 142 (4): 717–23. doi:10.3945/jn.111.152975. PMC 3301990. PMID 22357745.
  38. ^ a b Johnston KL, Thomas EL, Bell JD, et al. (April 2010). "Resistant starch improves insulin sensitivity in metabolic syndrome". Diabetic Medicine. 27 (4): 391–7. doi:10.1111/j.1464-5491.2010.02923.x. PMID 20536509. S2CID 27570039.
  39. ^ Phillips J, Muir JG, Birkett A, et al. (July 1995). "Effect of resistant starch on fecal bulk and fermentation-dependent events in humans". The American Journal of Clinical Nutrition. 62 (1): 121–30. doi:10.1093/ajcn/62.1.121. PMID 7598054.
  40. ^ Ramakrishna BS, Venkataraman S, Srinivasan P, et al. (February 2000). "Amylase-resistant starch plus oral rehydration solution for cholera". The New England Journal of Medicine. 342 (5): 308–13. doi:10.1056/NEJM200002033420502. PMID 10655529.
  41. ^ Raghupathy P, Ramakrishna BS, Oommen SP, et al. (April 2006). "Amylase-resistant starch as adjunct to oral rehydration therapy in children with diarrhea". Journal of Pediatric Gastroenterology and Nutrition. 42 (4): 362–8. doi:10.1097/01.mpg.0000214163.83316.41. PMID 16641573. S2CID 4647366.{{cite journal}}: CS1 maint: overridden setting (link)
  42. ^ Ramakrishna BS, Subramanian V, Mohan V, et al. (February 2008). "A randomized controlled trial of glucose versus amylase resistant starch hypo-osmolar oral rehydration solution for adult acute dehydrating diarrhea". PLOS ONE. 3 (2): e1587. Bibcode:2008PLoSO...3.1587R. doi:10.1371/journal.pone.0001587. PMC 2217593. PMID 18270575. Open access icon
  43. ^ James S. "P208. Abnormal fibre utilisation and gut transit in ulcerative colitis in remission: A potential new target for dietary intervention". Presentation at European Crohn's & Colitis Organization meeting, Feb 16–18, 2012 in Barcelona, Spain. European Crohn's & Colitis Organization. Archived from the original on 27 September 2016. Retrieved 25 September 2016.
  44. ^ Kaur N, Gupta AK (December 2002). "Applications of inulin and oligofructose in health and nutrition" (PDF). Journal of Biosciences. 27 (7): 703–14. doi:10.1007/BF02708379. PMID 12571376. S2CID 1327336.
  45. ^ Roberfroid MB (November 2007). "Inulin-type fructans: functional food ingredients". The Journal of Nutrition. 137 (11 Suppl): 2493S–2502S. doi:10.1093/jn/137.11.2493S. PMID 17951492.
  46. ^ Abrams SA, Griffin IJ, Hawthorne KM, et al. (August 2005). "A combination of prebiotic short- and long-chain inulin-type fructans enhances calcium absorption and bone mineralization in young adolescents". The American Journal of Clinical Nutrition. 82 (2): 471–6. doi:10.1093/ajcn.82.2.471. PMID 16087995.
  47. ^ Coudray C, Demigné C, Rayssiguier Y (January 2003). "Effects of dietary fibers on magnesium absorption in animals and humans". The Journal of Nutrition. 133 (1): 1–4. doi:10.1093/jn/133.1.1. PMID 12514257.
  48. ^ Tako E, Glahn RP, Welch RM, et al. (March 2008). "Dietary inulin affects the expression of intestinal enterocyte iron transporters, receptors and storage protein and alters the microbiota in the pig intestine". The British Journal of Nutrition. 99 (3): 472–80. doi:10.1017/S0007114507825128. PMID 17868492.
  49. ^ Grabitske HA, Slavin JL (April 2009). "Gastrointestinal effects of low-digestible carbohydrates". Critical Reviews in Food Science and Nutrition. 49 (4): 327–60. doi:10.1080/10408390802067126. PMID 19234944. S2CID 205689161.
  50. ^ Shepherd SJ, Gibson PR (October 2006). "Fructose malabsorption and symptoms of irritable bowel syndrome: guidelines for effective dietary management". Journal of the American Dietetic Association. 106 (10): 1631–9. doi:10.1016/j.jada.2006.07.010. PMID 17000196.
  51. ^ Liber A, Szajewska H (2013). "Effects of inulin-type fructans on appetite, energy intake, and body weight in children and adults: systematic review of randomized controlled trials". Annals of Nutrition & Metabolism. 63 (1–2): 42–54. doi:10.1159/000350312. PMID 23887189.
  52. ^ Parisi GC, Zilli M, Miani MP, et al. (August 2002). "High-fiber diet supplementation in patients with irritable bowel syndrome (IBS): a multicenter, randomized, open trial comparison between wheat bran diet and partially hydrolyzed guar gum (PHGG)". Digestive Diseases and Sciences. 47 (8): 1697–704. doi:10.1023/A:1016419906546. PMID 12184518. S2CID 27545330.{{cite journal}}: CS1 maint: overridden setting (link)
  53. ^ a b c Gallaher DD (2006). Dietary Fiber. Washington, D.C.: ILSI Press. pp. 102–10. ISBN 978-1-57881-199-1.
  54. ^ Keenan MJ, Martin RJ, Raggio AM, et al. (2012). "High-amylose resistant starch increases hormones and improves structure and function of the gastrointestinal tract: a microarray study". Journal of Nutrigenetics and Nutrigenomics. 5 (1): 26–44. doi:10.1159/000335319. PMC 4030412. PMID 22516953.{{cite journal}}: CS1 maint: overridden setting (link)
  55. ^ Simpson HL, Campbell BJ (July 2015). "Review article: dietary fibre-microbiota interactions". Alimentary Pharmacology & Therapeutics. 42 (2): 158–79. doi:10.1111/apt.13248. PMC 4949558. PMID 26011307.
  56. ^ Noack J, Timm D, Hospattankar A, et al. (May 2013). "Fermentation profiles of wheat dextrin, inulin and partially hydrolyzed guar gum using an in vitro digestion pretreatment and in vitro batch fermentation system model". Nutrients. 5 (5): 1500–10. doi:10.3390/nu5051500. PMC 3708332. PMID 23645025. S2CID 233676.
  57. ^ a b Eastwood M, Kritchevsky D (2005). "Dietary fiber: how did we get where we are?". Annual Review of Nutrition. 25: 1–8. doi:10.1146/annurev.nutr.25.121304.131658. PMID 16011456.
  58. ^ "Foods that spike a patient's blood glucose are not what you think". American Medical Association. Retrieved 14 October 2020.
  59. ^ Weickert MO, Pfeiffer AF (March 2008). "Metabolic effects of dietary fiber consumption and prevention of diabetes". The Journal of Nutrition. 138 (3): 439–42. doi:10.1093/jn/138.3.439. PMID 18287346.
  60. ^ Robertson MD, Currie JM, Morgan LM, et al. (May 2003). "Prior short-term consumption of resistant starch enhances postprandial insulin sensitivity in healthy subjects". Diabetologia. 46 (5): 659–65. doi:10.1007/s00125-003-1081-0. PMID 12712245.
  61. ^ Robertson MD, Bickerton AS, Dennis AL, et al. (September 2005). "Insulin-sensitizing effects of dietary resistant starch and effects on skeletal muscle and adipose tissue metabolism". The American Journal of Clinical Nutrition. 82 (3): 559–67. doi:10.1093/ajcn.82.3.559. PMID 16155268.
  62. ^ Zhang WQ, Wang HW, Zhang YM, et al. (March 2007). "[Effects of resistant starch on insulin resistance of type 2 diabetes mellitus patients]". Zhonghua Yu Fang Yi Xue Za Zhi [Chinese Journal of Preventive Medicine] (in Chinese). 41 (2): 101–4. PMID 17605234.
  63. ^ EFSA Panel on Dietetic Products, Nutrition, and Allergies, European Food Safety Authority (2010). "Scientific Opinion on Dietary Reference Values for carbohydrates and dietary fiber". EFSA Journal. 8 (3): 1462. doi:10.2903/j.efsa.2010.1462.
  64. ^ Jones PJ, Varady KA (February 2008). "Are functional foods redefining nutritional requirements?". Applied Physiology, Nutrition, and Metabolism. 33 (1): 118–23. doi:10.1139/H07-134. PMID 18347661. Archived from the original on 11 July 2012.
  65. ^ Hermansson AM. Gel structure of food biopolymers In: Food Structure, its creation and evaluation.JMV Blanshard and JR Mitchell, eds. 1988 pp. 25–40 Butterworths, London.
  66. ^ Rockland LB, Stewart GF. Water Activity: Influences on Food Quality. Academic Press, New York. 1991
  67. ^ Eastwood MA, Morris ER (February 1992). "Physical properties of dietary fiber that influence physiological function: a model for polymers along the gastrointestinal tract". The American Journal of Clinical Nutrition. 55 (2): 436–42. doi:10.1093/ajcn/55.2.436. PMID 1310375.
  68. ^ Eastwood MA. The physiological effect of dietary fiber: an update. Annual Review Nutrition, 1992:12 : 19–35
  69. ^ a b Eastwood MA. The physiological effect of dietary fiber: an update. Annual Review Nutrition. 1992. 12:19–35.
  70. ^ a b Carey MC, Small DM and Bliss CM. Lipid digestion and Absorption. Annual Review of Physiology. 1983. 45:651–77.
  71. ^ a b c Edwards CA, Johnson IT, Read NW (April 1988). "Do viscous polysaccharides slow absorption by inhibiting diffusion or convection?". European Journal of Clinical Nutrition. 42 (4): 307–12. PMID 2840277.
  72. ^ Schneeman BO, Gallacher D. Effects of dietary fibre on digestive enzyme activity and bile acids in the small intestine. Proc Soc Exp Biol Med 1985; 180 409–14.
  73. ^ Hellendoorn EW 1983 Fermentation as the principal cause of the physiological activity of indigestible food residue. In: Spiller GA (ed) Topics in dietary fiber research. Plenum Press, New York, pp. 127–68
  74. ^ Brown L, Rosner B, Willett WW, et al. (January 1999). "Cholesterol-lowering effects of dietary fiber: a meta-analysis". The American Journal of Clinical Nutrition. 69 (1): 30–42. doi:10.1093/ajcn/69.1.30. PMID 9925120.
  75. ^ Eastwood MA, Hamilton D (January 1968). "Studies on the adsorption of bile salts to non-absorbed components of diet". Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism. 152 (1): 165–73. doi:10.1016/0005-2760(68)90018-0. PMID 5645448.
  76. ^ Gelissen IC, Eastwood MA (August 1995). "Taurocholic acid adsorption during non-starch polysaccharide fermentation: an in vitro study". The British Journal of Nutrition. 74 (2): 221–8. doi:10.1079/BJN19950125. PMID 7547839.
  77. ^ Gropper SS, Smith JL, Groff JL (2008). Advanced nutrition and human metabolism (5th ed.). Cengage Learning. p. 114. ISBN 978-0-495-11657-8.
  78. ^ Reynolds A, Mann J (10 January 2019). "Carbohydrate quality and human health: a series of systematic reviews and meta-analyses". Lancet. 393 (10170): 434–445. doi:10.1016/S0140-6736(18)31809-9. PMID 30638909. Retrieved 7 August 2024.
  79. ^ Jama H, Snelson M (12 July 2024). "Recommendations for the Use of Dietary Fiber to Improve Blood Pressure Control". Circulation Research. 135 (4): 537–539. doi:10.1161/CIRCRESAHA.124.324614. PMID 39016011. Retrieved 7 August 2024.
  80. ^ Jama H, Malathi D (2 August 2024). "Maternal Diet and Gut Microbiota Influence Predisposition to Cardiovascular Disease in Offspring". Hypertension. 81 (7): 1450–1459. doi:10.1161/HYPERTENSIONAHA.123.22575. PMID 38586958. Retrieved 7 August 2024.
  81. ^ Food and Nutrition Board, Institute of Medicine of the National Academies (2005). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academies Press. pp. 380–82.
  82. ^ Spiller G, Woods MN, Gorbach SL (27 June 2001). Influence of fiber on the ecology of the intestinal flora; In: CRC Handbook of Dietary Fiber in Human Nutrition. CRC Press. p. 257. ISBN 978-0-8493-2387-4. Retrieved 22 April 2009.
  83. ^ Greger JL (July 1999). "Nondigestible carbohydrates and mineral bioavailability". The Journal of Nutrition. 129 (7 Suppl): 1434S–5S. doi:10.1093/jn/129.7.1434S. PMID 10395614.
  84. ^ Raschka L, Daniel H (November 2005). "Mechanisms underlying the effects of inulin-type fructans on calcium absorption in the large intestine of rats". Bone. 37 (5): 728–35. doi:10.1016/j.bone.2005.05.015. PMID 16126464.
  85. ^ Scholz-Ahrens KE, Schrezenmeir J (November 2007). "Inulin and oligofructose and mineral metabolism: the evidence from animal trials". The Journal of Nutrition. 137 (11 Suppl): 2513S–2523S. doi:10.1093/jn/137.11.2513S. PMID 17951495.
  86. ^ Arayici ME, Basbinar Y, Ellidokuz H. (2023). "High and low dietary fiber consumption and cancer risk: a comprehensive umbrella review with meta-meta-analysis involving meta-analyses of observational epidemiological studies". Critical Reviews in Food Science and Nutrition. 28: 1–14. doi:10.1080/10408398.2023.2298772. PMID 38153313.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  87. ^ Yiallourou A, Pantavou K, Markozannes G, Pilavas A, Georgiou A, Hadjikou A, Economou M, Christodoulou N, Letsos K, Khattab E, Kossyva C, Constantinou M, Theodoridou M, Piovani D, Tsilidis KΚ, Bonovas S, Nikolopoulos GK. (2024). "Non-genetic factors and breast cancer: an umbrella review of meta-analyses". BMC Cancer. 24 (1): 903. doi:10.1186/s12885-024-12641-8. PMC 11282738. PMID 39061008.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  88. ^ Oh H, Kim H, Lee DH, Lee A, Giovannucci EL, Kang SS, Keum N. (2019). "Different dietary fibre sources and risks of colorectal cancer and adenoma: a dose–response meta-analysis of prospective studies". British Journal of Nutrition. 122 (6): 605–615. doi:10.1017/S0007114519001454. PMID 31495339.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  89. ^ Arayici ME, Mert-Ozupek N, Yalcin F, Basbinar Y, Ellidokuz H. (2022). "Soluble and Insoluble Dietary Fiber Consumption and Colorectal Cancer Risk: A Systematic Review and Meta-Analysis". Nutrition and Cancer. 74 (7): 2412–2425. doi:10.1080/01635581.2021.2008990. PMID 34854791.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  90. ^ "Scientific Opinion on Dietary Reference Values for carbohydrates and dietary fibre". EFSA Journal. 8 (3): 1462. 2010. doi:10.2903/j.efsa.2010.1462. ISSN 1831-4732.
  91. ^ Maragkoudakis P (20 June 2017). "Dietary Fibre". EU Science Hub. Joint Research Centre. Retrieved 21 December 2019.
  92. ^ Institute of Medicine (2005). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, DC: The National Academies Press. pp. 387–388. doi:10.17226/10490. ISBN 978-0-309-08525-0. Retrieved 8 June 2021.
  93. ^ "Fiber". www.eatright.org. Retrieved 11 October 2019.
  94. ^ Williams CL, Bollella M, Wynder EL (November 1995). "A New Recommendation for Dietary Fiber in Childhood". Pediatrics. 96 (5): 985–988. doi:10.1542/peds.96.5.985. PMID 7494677. S2CID 39644070. Retrieved 7 June 2021.
  95. ^ Wilkinson Enns C, Mickle SJ, Goldman JD (2002). "Trends in Food and Nutrient Intakes by Children in the United States". Family Economics and Nutrition Review. 14 (1): 64. Retrieved 7 June 2021.
  96. ^ Suter PM (2005). "Carbohydrates and dietary fiber". Atherosclerosis: Diet and Drugs. Handbook of Experimental Pharmacology. Vol. 170. pp. 231–61. doi:10.1007/3-540-27661-0_8. ISBN 978-3-540-22569-0. PMID 16596802. S2CID 37892002.
  97. ^ Aubrey A (23 October 2017). "The FDA Will Decide Whether 26 Ingredients Count As Fiber". National Public Radio. Retrieved 19 November 2017.
  98. ^ Health claims: fruits, vegetables, and grain products that contain fiber, particularly soluble fiber, and risk of coronary heart disease. Electronic Code of Federal Regulations: US Government Printing Office, current as of 20 October 2008
  99. ^ Health claims: fiber-containing grain products, fruits, and vegetables and cancer. Electronic Code of Federal Regulations: US Government Printing Office, current as of 20 October 2008
  100. ^ a b Tungland BC, Meyer D (2002). "Nondigestible oligo- and polysaccharides (dietary fiber): their physiology and role in human health and food". Comprehensive Reviews in Food Science and Food Safety. 1 (3): 73–92. doi:10.1111/j.1541-4337.2002.tb00009.x. PMID 33451232.
  101. ^ Lee YP, Puddey IB, Hodgson JM (April 2008). "Protein, fibre and blood pressure: potential benefit of legumes". Clinical and Experimental Pharmacology & Physiology. 35 (4): 473–6. doi:10.1111/j.1440-1681.2008.04899.x. PMID 18307744. S2CID 25086200.
  102. ^ Theuwissen E, Mensink RP (May 2008). "Water-soluble dietary fibers and cardiovascular disease". Physiology & Behavior. 94 (2): 285–92. doi:10.1016/j.physbeh.2008.01.001. PMID 18302966. S2CID 30898446.
  103. ^ "What Is Constipation?". WebMD. 2017. Retrieved 19 November 2017.
  104. ^ Hooper B, Spiro A, Stanner S (2015). "30 g of fibre a day: An achievable recommendation?". Nutrition Bulletin. 40 (2): 118–129. doi:10.1111/nbu.12141.
  105. ^ AACC International. "The Definition of Dietary Fiber" (PDF). Archived from the original (PDF) on 28 September 2007. Retrieved 12 May 2007.
  106. ^ a b Wong JM, de Souza R, Kendall CW, et al. (March 2006). "Colonic health: fermentation and short chain fatty acids". Journal of Clinical Gastroenterology. 40 (3): 235–43. doi:10.1097/00004836-200603000-00015. PMID 16633129. S2CID 46228892.
  107. ^ Drozdowski LA, Dixon WT, McBurney MI, et al. (2002). "Short-chain fatty acids and total parenteral nutrition affect intestinal gene expression". Journal of Parenteral and Enteral Nutrition. 26 (3): 145–50. doi:10.1177/0148607102026003145. PMID 12005453.
  108. ^ Roy CC, Kien CL, Bouthillier L, et al. (August 2006). "Short-chain fatty acids: ready for prime time?". Nutrition in Clinical Practice. 21 (4): 351–66. doi:10.1177/0115426506021004351. PMID 16870803.
  109. ^ Scholz-Ahrens KE, Ade P, Marten B, et al. (March 2007). "Prebiotics, probiotics, and synbiotics affect mineral absorption, bone mineral content, and bone structure". The Journal of Nutrition. 137 (3 Suppl 2): 838S–46S. doi:10.1093/jn/137.3.838S. PMID 17311984.{{cite journal}}: CS1 maint: overridden setting (link)
  110. ^ Soluble Fiber from Certain Foods and Risk of Coronary Heart Disease, U.S. Government Printing Office, Electronic Code of Federal Regulations, Title 21: Food and Drugs, part 101: Food Labeling, Subpart E, Specific Requirements for Health Claims, 101.81 [1] Archived 1 June 2008 at the Wayback Machine
  111. ^ Balentine D (12 December 2016). "Petition for a Health Claim for High-Amylose Maize Starch (Containing Type-2 Resistant Starch) and Reduced Risk Type 2 Diabetes Mellitus (Docket Number FDA2015-Q-2352)" (PDF). Office of Nutrition and Food Labeling, Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration. Retrieved 22 March 2018.
  112. ^ Elaine Watson (14 June 2018). "FDA unveils dietary fibers guidance: Good news for inulin, polydextrose, some gray areas remaining". FoodNavigatorUSA.com. Retrieved 24 June 2019.

Further reading

[edit]
  • Yusuf, K.; Saha, S.; Umar, S. (26 May 2022). "Health Benefits of Dietary Fiber for the Management of Inflammatory Bowel Disease". Biomedicines, 10(6: Novel Therapeutic Approaches in Inflammatory Bowel Diseases 2.0 (special issue)), 1242. doi:10.3390/biomedicines10061242.
[edit]
Wikimedia Commons has media related to Dietary fiber.
Retrieved from "https://wiki.riteme.site/w/index.php?title=Dietary_fiber&oldid=1259714957"