Rye Bread Decreases Serum Cholesterol Levels In Hypercholesterolemic Men

Nutrition Research Newsletter, March, 2000

Multiple studies have proven the inverse relationship between the consumption of dietary fiber and heart disease. Of all available sources of fiber, cereal fiber has been shown to have the most beneficial effect. It is thought that water-soluble, viscous fiber is protective due to the ability of the material to bind bile acids in the small intestine, allowing the acids to be excreted in the feces. Also, short-chain fatty acids produced through the fermentation of fiber in the colon may also reduce serum cholesterol further through the inhibition of cholesterol synthesis in the liver. Oat fiber is likely the most studied cereal fiber due to its hypocholesterolemic properties. The beta-glucans found in oats allows for a modest reduction of serum cholesterol in individuals with normal cholesterol and a larger reduction in those individuals with hypercholesterolemia. Wheat fiber does not appear to alter serum cholesterol and is therefore commonly used as a control diet in research pertaining to this matter. To date, the effect of the cereal rye on cholesterol levels is unknown. The fiber content of rye consists of 60% arabinoxylan, 15% cellulose, and 9% beta-glucans.

Recently, researchers investigated the effect of rye bread, incorporated into the diet, on serum cholesterol levels. The study utilized 18 men and 22 women with elevated serum cholesterol values as subjects in this crossover designed trial. The subjects randomly consumed a diet of either 20% of daily calories as wheat breads or 20% of daily calories from rye breads for a four-week period. A four-week washout period was observed and then subjects consumed the alternate diet for four weeks. Fasting serum cholesterol values were obtained on two consecutive days at the beginning and at the end of each diet period.

As expected, the wheat bread had no effect on serum cholesterol levels. Neither wheat nor rye bread was found to alter serum glucose or insulin concentrations. It was found that in men, the consumption of rye bread reduced total and LDL cholesterol values significantly. Both the reductions in LDL and total cholesterol were dependent upon the amount of rye bread consumed. It can be concluded that rye bread is effective in lowering serum total and LDL cholesterol concentrations in hypercholesterolemic men. However, it appears that large amounts of rye bread, such as the 20% of daily energy intake used in this study, must be consumed in order to see the beneficial effects.

K. Leinonen, K. Poutanen, H. Mykkanen, Rye Bread Decreases Serum Total and LDL Cholesterol in Men with Moderately Elevated Serum Cholesterol, J. Nutr. 130:164-170 (February 2000) [Correspondence: Katri S. Leinonen, Dept. of Clinical Nutrition, University of Kuopio, FIN-70211 Kuopio, Finland.]