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Oats so healthy: a rich source of dietary fibre

Aisling Aherne
BSc PhD RNutr
Freelance Nutrition Consultant

In order to promote good nutrition and healthy eating, dietary guidelines have been recommended for the general population.(1) One of these recommendations states that adults should consume 18g of dietary fibre (nonstarch polysaccharides) on a daily basis, with an individual range of 12-24g of fibre.(1) This recommendation is based on the health benefits associated with eating a naturally fibre-rich diet and is made in terms of obtaining fibre from various food sources.(2)

Dietary fibre
Food sources of dietary fibre include wholegrains, fruit, vegetables and legumes. Fibre can be classified into two subgroups: soluble and insoluble. Foods high in insoluble fibre include wheat cereals, wholewheat breads, wheat bran, as well as certain fruit and vegetables. Insoluble fibre has an important role in normal bowel function and can also aid body weight maintenance.
Oatmeal, breads and other foods made with rolled oats, oatbran or whole oat flour, and hot and cold breakfast cereals containing whole oats are sources of dietary soluble fibre.(3) Other sources include legumes, vegetables and fruit. Oats provide one of the richest sources of the dietary soluble fibre beta-glucan, as well as supplying protein of relatively good quality and significant quantities of vitamins and minerals.(4)
 
Health benefits of oats
In addition to their nutritional attributes, fibre-rich foods such as oats exert a number of physiological effects that may be beneficial in the prevention or improvement of pathophysiological conditions, including gastrointestinal function, body weight maintenance, glycaemic control and lipid metabolism.(4-6)

Lipid-lowering effects
There have been many reports on the cholesterol-lowering effects of oats.(7-9) Based on a meta-analysis of ten trials, Ripsin et al concluded that the daily consumption of soluble dietary fibre from oat products can cause a modest reduction in blood cholesterol levels.(10) In 1997 the US FDA authorised food companies to use a health claim based on these and other findings, which states: "Soluble fibre from foods such as oat bran, rolled oats or oatmeal, and whole oat flour, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease." Although the cholesterol-lowering effects are small, they are significant.(10,11) In addition to their cholesterol-lowering properties, oats have also been shown to exert other beneficial cardiovascular effects.

Glycaemic control
Soluble fibre from oats when consumed as part of a healthy, balanced diet can improve glycaemic control in both patients with type 2 diabetes and healthy individuals.(12,5) The major benefits to glycaemic control may be attributable to the beta-glucan fraction of oats.(13) However, the mechanism of action, and extent, in improving glycaemic control is unclear.

Body weight
Epidemiological data suggest that fibre-rich diets can aid in weight maintenance and/or prevent weight gain.(14) Including both soluble and insoluble fibre in the diet reduces hunger and increases satiety, which can therefore reduce the risk of overeating.
A healthy, balanced diet is a diet that provides the right amount of nutrients, and energy, needed for optimal health in the right proportions.(15) The consumption of oats as part of a healthy, balanced diet can be encouraged in order to achieve the right amount of soluble fibre in the diet. Consuming a variety of foods is the key to obtaining a wide range of nutrients and hence good nutrition.

References

  1. Dietary reference values for food energy and nutrients for the UK. London: HMSO; 1991.
  2. Englyst HN, Hudson GJ. In: Garrow JS, et al, editors. Human nutrition and dietetics. London: Harcourt; 2002. p. 61-76.
  3. Available from URL:  http://www.cfsan.fda.gov/~lrd/tpoats.html
  4. Welch RW. Br J Biomed Sci 1994;51:260-70.
  5. Ha TKK, et al. Eur J Clin Nutr 1998;52:467-81.
  6. Diabet Med 2003;20:786-807
  7. Available from URL: http://www.quakeroatmeal.com/healthpros/LIB/RA_Articles.cfm
  8. Truswell AS. Eur J Clin Nutr 2002;56:1-14.
  9. Available from URL: http://www.americanheart.org
  10. Ripsin CM, et al. JAMA 1992;267:3317-25.
  11. Brown L, et al. Am J Clin Nutr 1999;69:30-42.
  12. Brand JC, et al. Diabetes Care 1991;14:95-101.
  13. Wood PJ, et al. Br J Nutr 1994;72:731-43.
  14. Kirk TR. Proc Nutr Soc 2000;59:349-50.
  15. Buttriss J, et al. Nutrition: a handbook for community nurses. London: Whurr; 2001.