Bran

(BANM, USAN, rINNM)
Synonyms: Crusca; Farelo; Kleie; Salvado; Son.
Cyrillic synonym: Отруби.

💊 Chemical information

Description.

Bran consists of the fibrous outer layers of cereal grains. It contains celluloses, polysaccharides or hemicelluloses, protein, fat, minerals, and moisture and may contain part of the germ or embryo. Bran provides water-insoluble fibre and, depending on the source, may also provide water-soluble fibre (see also Dietary Role, below). It comprises about 12% of the weight of the grain and is a byproduct of flour milling. It is available in various grades.

Pharmacopoeias.

US includes wheat bran.

USP 31

(Wheat Bran). The outer fraction of the cereal grain (comprising the pericarp, seed coat (testa), nucellar tissue, and aleurone layer) derived from Triticum aestivum, T. compactum, T. durum, or other common einkorn and emmer wheat cultivars. It is obtained by milling and processing the whole wheat grain, and is available in a variety of particle sizes depending on the degree of milling. It contains not less than 36% of dietary fibre. It is a light tan powder having a characteristic aroma. Practically insoluble in cold water and in alcohol.

💊 Adverse Effects

Large quantities of bran may temporarily increase flatulence and abdominal distension, and intestinal obstruction may occur rarely.

Colonic atony.

Colonic atony has been reported in patients who had increased their intake of dietary fibre to relieve constipation associated with systemic sclerosis.1
1. Gough A, et al. Dietary advice in systemic sclerosis: the dangers of a high fibre diet. Ann Rheum Dis 1998; 57: 641–2.

Diarrhoea.

A report of diarrhoea induced by a dramatic increase in fibre intake. Reduction of dietary fibre led to a return to normal bowel habit in 2 to 3 days.1
1. Saibil F. Diarrhea due to fiber overload. N Engl J Med 1989; 320: 599.

Intestinal obstruction.

Intestinal obstruction associated with excessive bran intake has been reported.1-3
1. Allen-Mersh T, De Jode LR. Is bran useful in diverticular disease? BMJ 1982; 284: 740
2. Cooper SG, Tracey EJ. Small-bowel obstruction caused by oatbran bezoar. N Engl J Med 1989; 320: 1148–9
3. Miller DL, et al. Small-bowel obstruction from bran cereal. JAMA 1990; 263: 813–14.

💊 Precautions

Bran is contra-indicated in patients with intestinal obstruction or with undiagnosed abdominal symptoms. There is a particular risk of intestinal or oesophageal obstruction if bulk laxatives are swallowed dry; they should be taken with sufficient fluid and should not be taken immediately before going to bed. Wheat bran should be avoided in gluten enteropathies and coeliac disease.

💊 Interactions

Bran may reduce the absorption of some drugs when given together by mouth. Interference with iron, zinc, and calcium absorption has been reported; calcium phosphate may be added to bran to neutralise fytic acid, which can contribute to such interference.

💊 Uses and Administration

The main use of bran is as a bulk laxative and source of dietary fibre in the management of disorders of the gastrointestinal tract such as constipation, especially in diverticular disease; it is also widely used in irritable bowel syndrome, although its value has been questioned. It should always be taken with plenty of fluid. Bran is used as the basis for some breakfast cereals.

Dietary role.

There is no precise definition for the complex mixture of substances known as dietary fibre. It has been defined as plant polysaccharides and lignin resistant to hydrolysis by the digestive enzymes of humans but this covers many substances other than cell-wall and related polysaccharides. Non-starch polysaccharides are the major component of the plant cell wall and are used as an index of dietary fibre. They comprise watersoluble fibres such as pectins, gums, and mucilages and waterinsoluble fibres such as cellulose. Wheat, maize, and rice contain mainly insoluble non-starch polysaccharides whereas oats, barley, and rye have a significant proportion of soluble fibres.1 Because the USA originally included nondigestible animal carbohydrates in the definition of fibre, the Food and Nutrition Board in the USA proposed a new definition of fibre, whereby dietary fibre consists of nondigestible carbohydrates and lignin that are intrinsic and intact in plants, and functional fibre consists of isolated, nondigestible plant or animal carbohydrates that have beneficial physiological effects in humans. Total fibre is the sum of dietary and functional fibre.2 In the UK, dietary reference values (DRV) have been published for non-starch polysaccharides.1 It has been proposed1 that adult diets should contain an average for the population of 18 g daily (individual range 12 to 24 g daily) non-starch polysaccharide from a variety of foods whose constituents contain it as a naturally integrated component. Children should receive proportionately less non-starch polysaccharide according to body size. No evidence exists for benefit of intakes of non-starch polysaccharide in excess of 32 g daily, and therefore there is no advantage in exceeding this amount. In the USA, an adult dietary fibre intake of 20 to 35 g daily has been suggested; children should consume an amount equivalent to their age plus 5 g daily.3
1. DOH. Dietary reference values for food energy and nutrients for the United Kingdom: report of the panel on dietary reference values of the committee on medical aspects of food policy. Report on health and social subject
41. London: HMSO, 1991
2. Standing Committee on the Scientific Evaluation of Dietary Reference Intakes of the Food and Nutrition Board. Dietary Reference Intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein, and amino acids. Washington DC: National Academy Press, 2002/2005. Also available at: http://www.nap.edu/ openbook.php?record_id=10490 (accessed 04/04/08
3. Marlett JA, et al. Position of the American Dietetic Association: health implications of dietary fiber. J Am Diet Assoc 2002; 102: 993–1000. Also available at: http://www.eatright.org/cps/rde/ xchg/ada/hs.xsl/advocacy_10175_ENU_HTML.htm (accessed 28/03/07)

Disease prevention.

Diseases such as colorectal cancer, ischaemic heart disease, diabetes mellitus, and obesity are common in affluent developed countries but occur rarely in rural Africa. This difference in disease patterns has been linked to the low fibre intake in developed countries compared with rural Africans. However, there are many other differences in diet and lifestyle, such as a lower intake of fat, protein, and sugar in rural Africans and less exposure to toxins and pollutants, any of which could contribute to the difference. The excessive consumption of energy-rich foods may be more to blame for diseases of affluence than is deficiency of dietary fibre.1 Results from large prospective cohort studies have been conflicting as to whether there is any reduction in risk of colorectal cancer associated with a high intake of dietary fibre, and have mostly failed to show a reduction in the recurrence rate of colorectal adenomas (although most adenomas do not develop into cancer, and so the relevance of these results is unclear2). A pooled analysis of 13 prospective cohort studies found a significant inverse association between dietary fibre intake and colorectal cancer. However, after adjusting for other risk factors, this association was attenuated and no longer statistically significant. There was some suggestion that intake of dietary fibre from cereals and from whole-grain foods were both associated with a weak reduction in the risk of rectal cancer.3 Some have commented4 that fibre is a broad term encompassing a wide range of organic material, which may have a large number of actions on digestive physiology. Furthermore, there is some concern that the use of fibre supplements is not entirely without harmful effects: it has been pointed out that fermentable fibre substrates can stimulate cell proliferation in the colon.5 However, the role of cell proliferation as a marker for the development of colonic cancer is questioned by some authors.6 A small randomised crossover study7 in patients with type 2 diabetes mellitus suggested that an increased intake of dietary fibre was associated with improved glycaemic control, decreased hyperinsulinaemia, and lower plasma lipid concentrations. In prospective cohort studies, inverse associations were found between whole-grain intake and the risk of type 2 diabetes mellitus;8-11 in some studies, this inverse association persisted for cereal fibre intake,9-11 but in one the protective effect of whole grain could not entirely be explained by fibre content.8 Fibre may act as an obstacle to energy intake by displacing available calories and nutrients from the diet, by increasing satiety, and by decreasing the absorption efficiency of the small intestine. Epidemiological studies support the hypothesis that a higher dietary fibre intake prevents obesity; populations that report higher fibre consumption also demonstrate lower obesity rates.12Weight gain was inversely associated with increases in the intake of whole grains but positively associated with increases in the intake of refined grains, emphasising the importance of distinguishing whole-grain from refined-grain products.13 A large prospective cohort study in men found an inverse association between whole-grain intake and the incidence of coronary heart disease; the finding was even stronger for bran intake. These associations were attenuated, but not eliminated, by adjustment for other risk factors for coronary heart disease.14 There is some suggestion that diets high in fibre may have a moderate effect on blood pressure reduction.15
1. Anonymous. The bran wagon. Lancet 1987; i: 782–3
2. Byers T. Diet, colorectal adenomas, and colorectal cancer. N Engl J Med 2000; 342: 1206–7
3. Park Y, et al. Dietary fiber intake and risk of colorectal cancer: a pooled analysis of prospective cohort studies. JAMA 2005; 294: 2849–57
4. Goodlad RA. Dietary fibre and the risk of colorectal cancer. Gut 2001; 48: 587–9
5. Wasan HS, Goodlad RA. Fibre-supplemented foods may damage your health. Lancet 1996; 348: 319–20
6. Hill MJ, Leeds AR. Fibre and colorectal cancer. Lancet 1996; 348: 957
7. Chandalia M, et al. Beneficial effects of high dietary fiber intake in patients with type 2 diabetes mellitus. N Engl J Med 2000; 342: 1392–8
8. Liu S, et al. A prospective study of whole-grain intake and risk of type 2 diabetes mellitus in US women. Am J Public Health 2000; 90: 1409–15
9. Meyer KA, et al. Carbohydrates, dietary fiber, and incident type 2 diabetes in older women. Am J Clin Nutr 2000; 71: 921–30
10. Fung TT, et al. Whole-grain intake and the risk of type 2 diabetes: a prospective study in men. Am J Clin Nutr 2002; 76: 535–40
11. Montonen J, et al. Whole-grain and fiber intake and the incidence of type 2 diabetes. Am J Clin Nutr 2003; 77: 622–9
12. Slavin JL. Dietary fiber and body weight. Nutrition 2005; 21: 411–18
13. Liu S, et al. Relation between changes in intakes of dietary fiber and grain products and changes in weight and development of obesity among middle-aged women. Am J Clin Nutr 2003; 78: 920–7
14. Jensen MK, et al. Intakes of whole grains, bran, and germ and the risk of coronary heart disease in men. Am J Clin Nutr 2004; 80: 1492–9
15. He J, et al. Effect of dietary fiber intake on blood pressure: a randomized, double-blind, placebo-controlled trial. J Hypertens 2004; 22: 73–80.

💊 Preparations

Proprietary Preparations

Braz.: Fibracap†; Trifibra Mix; Canad.: Novo-Fibre; Fr.: Doses-O-Son; Irl.: Trifyba†; Ital.: Crusken; Malaysia: Fibrosine†; Mex.: Fisiolax†; Neth.: Fiberform; Port.: Infibran; Singapore: Fibrosine; Swed.: Fiberform; Fiberform Mix; Switz.: Fibion†. Multi-ingredient: Arg.: Centella Queen Reductora; Gelax; Gurfi Fibras†; Salutaris; Austral.: Neo-Trim Fibre†; Prochol†; Proslender†; Austria: Herbelax; Fr.: Maxi-Flore; Stimulance; Ital.: Bio Fibralax Bi-Attivo; Ecofibra; Levoplus; Plurilac; Resource Benefiber; Sedastip; Stimulance; Mex.: Psilumax; NZ: Stimulance; Pol.: Magnezytki; Otrebuski; Port.: Stimulance†; Venez.: Senokot con Fibra†.
Published December 05, 2018.