Steam cooking significantly improves in vitro bile acid binding of beets, eggplant, asparagus, carrots, green beans, and cauliflower☆

Abstract 

Cholesterol-lowering potential of foods and food fractions have been evaluated by determining their bile acid–binding potential. Reducing bile acid recirculation lowers cholesterol by reducing fat absorption and use of cholesterol to synthesize bile acid. Secondary bile acids increase the risk of cancer. Bile acid–binding potential is related to lowering the risk of heart disease as well as cancer prevention. Previously, we have reported bile acid binding by several uncooked vegetables. However, most vegetables are consumed after cooking. How cooking would influence in vitro bile acid binding of various vegetables was investigated using a mixture of bile acids secreted in human bile under physiologic conditions. Eight replicate incubations were conducted for each treatment simulating gastric and intestinal digestion, which included a substrate only, a bile acid mixture only, and 6 with a substrate and bile acid mixture. Cholestyramine (a cholesterol-lowering, bile acid–binding drug) was the positive control treatment, and cellulose was the negative control. Relative to cholestyramine, in vitro bile acid binding on a dry matter basis was, for beets, 18%; okra, 16%; eggplant, 14%; asparagus, 10%; carrots, 8%; green beans, 7%; cauliflower, 6%; and turnips, 1%. These results point to the significantly different (P ≤ .05) health-promoting potential of these vegetables (from highest to lowest, beets, okra, eggplant, asparagus, carrots and green beans, cauliflower, turnips) as indicated by their bile acid binding on a dry matter basis. Steam cooking significantly improved in vitro bile acid binding of beets, eggplant, asparagus, carrots, green beans, and cauliflower compared with previously observed bile acid–binding values for these vegetables uncooked. Inclusion of steam-cooked beets, okra, eggplant, asparagus, carrots, green beans, and cauliflower in our daily diet as health-promoting vegetables should be encouraged. These vegetables, when consumed regularly, may lower the risk of premature degenerative diseases (heart disease and cancer), improve public health, and advance human nutrition research.

Keywords: In vitro, Bile acid binding, Beets, Okra, Eggplant, Asparagus, Carrots, Green beans, Cauliflower, Turnips