부산대학교 도서관

There is strong evidence that whole-grain foods protect against heart disease. Although underlying mechanisms and components are unclear, betaine, found at high levels in wheat aleurone, may play a role. We evaluated the effects of a diet high in wheat aleurone on plasma betaine and related measures. In a parallel, single-blinded intervention study, 79 healthy participants (aged 45-65 y, BMI [greater than or equal to] 25 kg/[m.sup.2] incorporated either aleurone-rich cereal products (27 g/d aleurone) or control products balanced for fiber and macronutrients into their habitual diets for 4 wk. Fasting blood samples were taken at baseline and postintervention (4 wk) from participants. Compared with the control, the aleurone products provided an additional 279 mg/d betaine and resulted in higher plasma betaine (P < 0.001 ; intervention effect size: 5.2 [micro]mol/L) and lower plasma total homocysteine (tHcy) (P = 0.010; -0.7 [micro]mol/L). Plasma dimethylglycine and methionine, which are products of betaine-mediated homocysteine remethylation, were also higher (P < 0.001 ; P = 0.027) relative to control. There were no significant effects on plasma choline or B vitamins (folate, riboflavin, and vitamin B-6). However, LDL cholesterol was lower than in the control group (P = 0.037). We conclude that incorporating aleurone-rich products into the habitual diet for 4 wk significantly increases plasma betaine concentrations and lowers tHcy, which is attributable to enhanced betaine-homocysteine methyltransferase-mediated remethylation of homocysteine. Although this supports a role for betaine in the protective effects of whole grains, concomitant decreases in LDL suggest more than one component or mechanism may be responsible. J. Nutr. 140:2153-2157, 2010. doi: 10.3945/jn.110.126961.