Fibre supplements (also spelled fiber supplements) are considered to be a form of a subgroup of functional

dietary fibre Dietary fiber (in British English fibre) or roughage is the portion of plant-derived food that cannot be completely broken down by human digestive enzymes. Dietary fibers are diverse in chemical composition, and can be grouped generally by the ...

, and in the United States are defined by the

Institute of Medicine The National Academy of Medicine (NAM), formerly called the Institute of Medicine (IoM) until 2015, is an American nonprofit, non-governmental organization. The National Academy of Medicine is a part of the National Academies of Sciences, E ...

(IOM). According to the IOM, functional fibre "consists of isolated, non-digestible

carbohydrate In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or ma ...

s that have beneficial physiological effects in humans". Fibre supplements are widely available, and can be found in forms such as powders, tablets, and capsules. Consumption of fibre supplements may be for: improving dietary intake, lowering blood cholesterol, alleviating irritable bowel syndrome, reducing the risk of

colon cancer Colorectal cancer (CRC), also known as bowel cancer, colon cancer, or rectal cancer, is the development of cancer from the colon or rectum (parts of the large intestine). Signs and symptoms may include blood in the stool, a change in bowel mo ...

, and increasing feelings of

satiety Satiety ( ) is a state or condition of fullness gratified beyond the point of satisfaction, the opposite of hunger. It is a state which induces meal termination.Hetherington, M.Sensory-specific satiety and its importance in meal termination ''Neuro ...

. Excessive fibre intake can lead to fluid imbalance,

dehydration In physiology, dehydration is a lack of total body water, with an accompanying disruption of metabolic processes. It occurs when free water loss exceeds free water intake, usually due to exercise, disease, or high environmental temperature. Mil ...

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. ( ...

deficiencies,

nutrient A nutrient is a substance used by an organism to survive, grow, and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi, and protists. Nutrients can be incorporated into cells for metabolic purposes or excret ...

and drug interactions, and other medical problems.

Rationale for fibre supplement use

The American Dietetic Association recommends that the average adult consume 25 to 38 grams of

per day. However, research has shown that the average American only consumes 14 to 15 grams per day. To reach the recommended amount of fibre, consumption of dietary fibre from foods (e.g. plants, vegetables, legumes, and grains) instead of supplements is preferred because they contain additional beneficial nutrients and non-nutritive components (e.g.

antioxidant Antioxidants are compounds that inhibit oxidation, a chemical reaction that can produce free radicals. This can lead to polymerization and other chain reactions. They are frequently added to industrial products, such as fuels and lubricant ...

s and

phytoestrogens A phytoestrogen is a plant-derived xenoestrogen (see estrogen) not generated within the endocrine system, but consumed by eating plants or manufactured foods. Also called a "dietary estrogen", it is a diverse group of naturally occurring nonstero ...

). Nevertheless, a fibre supplement may be needed to prevent

constipation Constipation is a bowel dysfunction that makes bowel movements infrequent or hard to pass. The stool is often hard and dry. Other symptoms may include abdominal pain, bloating, and feeling as if one has not completely passed the bowel movement ...

when food intake is low, which is the case among inactive elderly. A cereal bran such as psyllium seed husk, or a synthetic fiber such as methylcellulose is often used in this case.

Health claims

Blood cholesterol reduction

Foods that are high in viscous fibres have been found to lower blood cholesterol by binding with

bile acid Bile acids are steroid acids found predominantly in the bile of mammals and other vertebrates. Diverse bile acids are synthesized in the liver. Bile acids are conjugated with taurine or glycine residues to give anions called bile salts. Primary b ...

s. In order to compensate for this,

cholesterol Cholesterol is any of a class of certain organic molecules called lipids. It is a sterol (or modified steroid), a type of lipid. Cholesterol is biosynthesized by all animal cells and is an essential structural component of animal cell mem ...

from the liver may be used to make more bile acids. The products of bacterial fermentation in the colon may also decrease the rate of cholesterol synthesis in the liver. However, research has produced mixed results with respect to whether fibre supplements are as effective as

in reducing blood cholesterol. Two recent studies show nearly opposing results, using fibre-supplemented apple juice containing both the soluble pectin from apples and gum arabic. In the first study, the supplement-enriched juice had no discernible effect on the blood cholesterol levels of 110 hypercholesterolaemic men and women. In the second study, the total and

LDL-cholesterol Low-density lipoprotein (LDL) is one of the five major groups of lipoprotein that transport all fat molecules around the body in extracellular water. These groups, from least dense to most dense, are chylomicrons (aka ULDL by the overall densit ...

levels of mildly hypercholesterolaemic men were lowered. In another study, a dietary supplement consisting of both soluble fibre (guar gum, pectin) and insoluble fibre (soy fibre, pea fibre, corn bran) was found to reduce

for individuals that have mild to moderate hypercholesterolaemia without reducing

HDL-cholesterol High-density lipoprotein (HDL) is one of the five major groups of lipoproteins. Lipoproteins are complex particles composed of multiple proteins which transport all fat molecules (lipids) around the body within the water outside cells. They are ty ...

or increasing

triglyceride A triglyceride (TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids (from ''tri-'' and ''glyceride''). Triglycerides are the main constituents of body fat in humans and other vertebrates, as w ...

s. Supplements containing extracted insoluble fibre may have an effect on blood lipids that most resembles the effects of dietary fibre. In a more recent randomized, double blind clinical study of 58 hypercholesterolaemic volunteers, an extruded

carob The carob ( ; ''Ceratonia siliqua'') is a flowering evergreen tree or shrub in the Caesalpinioideae sub-family of the legume family, Fabaceae. It is widely cultivated for its edible fruit pods, and as an ornamental tree in gardens and landscap ...

pulp preparation added to daily diet reduced total and

and improved the ratio of HDL:LDL cholesterol in all participants, and also showed a marked reduction in

serum cholesterol Cholesterol is any of a class of certain organic molecules called lipids. It is a sterol (or modified steroid), a type of lipid. Cholesterol is biosynthesized by all animal cells and is an essential structural component of animal cell mem ...

in the women of the study.

Gastrointestinal health

Colorectal cancer

The protective properties of

against

colorectal cancer Colorectal cancer (CRC), also known as bowel cancer, colon cancer, or rectal cancer, is the development of cancer from the colon or rectum (parts of the large intestine). Signs and symptoms may include blood in the stool, a change in bowel m ...

are undisputed. However, not all fibre supplements seem to provide the same defensive effect. A study of 1429 men and women over six months showed that a high-fibre cereal (

wheat bran Bran, also known as miller's bran, is the hard outer layers of Cereal, cereal grain. It consists of the combined aleurone and pericarp. Corn (maize) bran also includes the pedicel (tip cap). Along with cereal germ, germ, it is an integral pa ...

) supplement had no protective effect on recurring colorectal

adenomas An adenoma is a benign tumor of epithelial tissue with glandular origin, glandular characteristics, or both. Adenomas can grow from many glandular organs, including the adrenal glands, pituitary gland, thyroid, prostate, and others. Some adenom ...

. In addition, no significant improvement in the proportion or features of existing colorectal adenomas was observed.

Diverticular disease

Diverticulitis Diverticulitis, specifically colonic diverticulitis, is a gastrointestinal disease characterized by inflammation of abnormal pouches—diverticula—which can develop in the wall of the large intestine. Symptoms typically include lower abdominal ...

is mainly attributed to the low fibre intake typical of the Western diet for which gradual increase dietary fibre over several weeks is common clinical solution. Fibre supplements are again much less effective. One study of 58 men and women with uncomplicated diverticulitis in a double-blind controlled trial concluded that common doses of wheat bran and a psyllium-derived supplement provided relief of constipation only, with no other observable effects.

Irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common gastrointestinal ailment for which dietary soluble fibre is often prescribed as part of a therapeutic solution. As a supplement, partially hydrolysed guar gum (PHGG - completely soluble, fully fermentable) has been shown to be quite effective in clinical trials for decreasing IBS symptoms such as abdominal pain and generally improving quality of life for sufferers well beyond treatment. In addition, PHGG has been shown to have prebiotic properties by acidifying bowel contents and increasing gut microflora. Acacia senegal fiber ( gum arabic - completely soluble, fully fermentable) has also been shown to have a prebiotic effect in the gut, significantly increasing Bifidobacteria and Lactobacilli after 4 weeks of consumption. Acacia ferments very slowly in the gut, and due to its polymeric nature does not disturb osmotic pressure, so it has a good gastrointestinal tolerance (it has no sudden and painful release of gas, and the total gas production is much lower than with FOS, for instance) and does not present any side effects at dosages up to 50 grams per day. Particularly helpful for IBS is that Acacia senegal behaves as a regulator; it is able to reduce diarrhea and reduce constipation. Dietary insoluble fiber has long been shown to exacerbate Irritable Bowel Syndrome symptoms.

Weight management

It has been suggested that the refining of fibre-rich grains has contributed to the

obesity epidemic Obesity has been observed throughout human history. Many early depictions of the human form in art and sculpture appear obese. However, it was not until the 20th century that obesity became common — so much so that, in 1997, the World Heal ...

of Western countries. Whole, dietary forms of fibre are more difficult to ingest and absorb than milled and refined food products. This is because dietary fibre may be able to displace available

calories The calorie is a unit of energy. For historical reasons, two main definitions of "calorie" are in wide use. The large calorie, food calorie, or kilogram calorie was originally defined as the amount of heat needed to raise the temperature of on ...

and

nutrients A nutrient is a substance used by an organism to survive, grow, and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi, and protists. Nutrients can be incorporated into cells for metabolic purposes or excret ...

, requires more time for chewing (thereby slowing intake rate and inducing

), and reduces the efficiency of absorption in the

small intestine The small intestine or small bowel is an organ in the gastrointestinal tract where most of the absorption of nutrients from food takes place. It lies between the stomach and large intestine, and receives bile and pancreatic juice through the p ...

. Supplemental forms of fibre have been shown to potentially assist weight management by increasing

, decreasing the absorption rate of starches and sugars, and binding to lipids in the small intestine thereby reducing serum

s and

chylomicron Chylomicrons (from the Greek χυλός, chylos, meaning ''juice'' (of plants or animals), and micron, meaning ''small particle''), also known as ultra low-density lipoproteins (ULDL), are lipoprotein particles that consist of triglycerides (85 ...

. Powdered guar gum, a soluble fibre, was shown to be associated with a significantly lower energy intake in obese subjects who ingested a non-restricted diet over one week, when the same participants did not consume the fibre supplement. A similar reduction of energy intake through fibre supplementation was observed in another study. A dose of guar gum was administered to normal-weight and obese participants. A 10% reduction of energy was observed in the normal subjects, and a 30% reduction of energy for obese subjects. Fibre supplementation has also been indicated to assist compliance to low-calorie diets, as indicated through decreased feelings of hunger and increased ratings of

. Other soluble fiber forms such as glucomannan have also been studied in relationship to blood sugar and fat digestion in obese patients.

Side effects

Abruptly adding elevated amounts of fibre to the diet too quickly can lead to intestinal gas,

diarrhea Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin wi ...

, abdominal bloating, cramping, and

. It is therefore better to regulate and moderate daily fibre intake. If increased fibre intake is desired, gradually increasing the amount over a few days allows the natural

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

in the

gastrointestinal tract The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organ (biology), organs of the digestive syste ...

to adjust to the change. Drinking 1- 2 L of water every day can prevent some uncomfortable symptoms by making the stool soft and bulky. The risk of intestinal obstruction from insoluble fiber in susceptible individuals, fluid imbalance leading to

and mineral deficiencies may increase if more than 50 g of fibre is ingested per day. For this reason, individuals who decide to suddenly double or triple their fibre intake are often advised to double or triple their water intake. In addition, excessive intake of non-fermentable fibre (typically in supplemental form) may lead to mineral deficiencies by reducing the

absorption Absorption may refer to: Chemistry and biology * Absorption (biology), digestion **Absorption (small intestine) *Absorption (chemistry), diffusion of particles of gas or liquid into liquid or solid materials *Absorption (skin), a route by which ...

or increasing the

excretion Excretion is a process in which metabolic waste is eliminated from an organism. In vertebrates this is primarily carried out by the lungs, kidneys, and skin. This is in contrast with secretion, where the substance may have specific tasks after lea ...

s, especially when mineral intake is too low or when mineral needs are increased such as during

pregnancy Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occurs by sexual intercourse, but ca ...

lactation Lactation describes the secretion of milk from the mammary glands and the period of time that a mother lactates to feed her young. The process naturally occurs with all sexually mature female mammals, although it may predate mammals. The proces ...

, or

adolescence Adolescence () is a transitional stage of physical and psychological development that generally occurs during the period from puberty to adulthood (typically corresponding to the age of majority). Adolescence is usually associated with the t ...

. Excessive fibre intake can also contribute to nutrient and drug interactions. For example,

antidepressant Antidepressants are a class of medication used to treat major depressive disorder, anxiety disorders, chronic pain conditions, and to help manage addictions. Common side-effects of antidepressants include dry mouth, weight gain, dizziness, hea ...

medications, diabetes medications, carbamazepine,

-lowering medications and

penicillin Penicillins (P, PCN or PEN) are a group of β-lactam antibiotics originally obtained from ''Penicillium'' moulds, principally '' P. chrysogenum'' and '' P. rubens''. Most penicillins in clinical use are synthesised by P. chrysogenum using ...

. According to figures from Public Health England (PHE), most Brits aren’t getting enough fiber from their diets. Findings from the latest National Diet and Nutrition Survey reveal that the average Brit consumes 18g of fiber each day, however, this is significantly below the recommended intake of 30g.

Common supplements

S=Soluble, I=Insoluble C=Capsule/Tablet, P=Powder

References

External links

Oregon State Univ. Micronutrient Information Center - Fiber
{{DEFAULTSORT:Fibre Supplements Dietary supplements