Effects of some cereal brans and textured vegetable protein on plasma lipids.

The hypothesis that dietary fiber lowers serum cholesterol was tested in 10 healthy men, 19 to 54 years old, who ate a mixed diet similar to the diets of many American adult maks. that contained 16% of calories as protein (70% from animal). 4tYC as fat (PIS = 0.3), 44% as carbC'hydrate (9% of calories as sucrose) and 3 g of crude fiber. The energy intake ranged from 2700 to 3500 kcal adjusted to their height and weight. Weight and fitness were held constant. After 30 days of equilibration on the basal diet, they ate 26 g of either 50ft white wheat bran, corn bran (CB), soybean hulls (SH), textured vegetable protein, or hard red spring wheat bran (HRS) for periods of 28 to 30 days each in no particulai sequence. Each fiber ',.1."a.s f~d to fOUf to S!X subjects. The dietary fiber contents of soft white wheat bran, CB, SH, and HRS were: 44. 92, 87. and 51,?,c. respectively. Mean daily fecal weight increased (P ~ 0.0 I) from 72.4 to 144. 68 to 128, and S1 to IS! g when CB, SH, and HRS were fed respectively. No effects were noted with soft white wheat bran or textured vegetable protein. Total plasma cholesterol decreased 12% with HRS (P ~ 0.05) and 14.0% with SH (P ~ 0.05). Low density lipoprotein cholesterol decreased 21% with HRS (P ~ 0.05). High density lipoprotein cholesterol did not change with any of the dietary fiber sources nor did the ratio of high density lipoprotein cholesterol to total cholesterol. Some triglyceride lo',;,'ering effect ,vas seen with all sources of dit:tary fiber {P.$ O.Ol}. The~e was d significant direct l correlation between the area under the oral glucose tolerance cur,es and the levels of total cholesterol (r = 0.57, P ~ 0.0001) and low density lipoprotein cholesterol (r = 0.49, P~ 0.0007), and between fasting plasma glucose and triglycerides (r = 0.32, P~ 0.03). Results were replicated when subjects were fed the same fiber source on t,,'o occasions at 2 to 4 month intervals. Am. J. Clin. Nutr. 32: 580-592. 1979.