The objective of this study was to determine the hypocholesterolemic effects of whole meal rye and white wheat breads in healthy humans with elevated serum cholesterol concentrations, and the changes in plasma glucose and insulin concentrations during rye and wheat bread periods. The subjects were 18 men and 22 women with baseline serum cholesterol concentration of 6.4+/-0.2 mmol/L. The study design was a 2x4-wk crossover trial during which each subject randomly consumed rye and wheat breads (20% of daily energy) as part of their usual diet for 4 wk. The bread periods were separated by a 4-wk washout period. Blood samples (after fasting) were collected on two consecutive days at the beginning and end of the bread periods. Serum total cholesterol decreased by 8% (P = 0.002) in men but was not significantly altered in women during the rye bread period. The wheat bread period did not affect any of the variables studied. Analysis of the serum lipids in tertiles of rye bread consumption confirmed the reduction in total cholesterol (P = 0.048) in men and revealed the reduction in LDL cholesterol (P = 0.032); both were dependent on the amount of rye bread consumed (-2, -14 and -10% in total cholesterol and 0, -12 and -12% in LDL cholesterol). Neither rye nor wheat bread influenced the concentrations of glucose and insulin. In conclusion, rye bread is effective in reducing serum total and LDL cholesterol concentrations in men with elevated serum cholesterol. Good compliance with consuming a relatively large amount of rye bread in the usual diet indicates that rye bread offers a practical dietary means of reducing serum cholesterol in men.