Effects of oat and wheat cereals on endothelial responses.

BACKGROUND: This study was undertaken to determine the effects of month-long whole grain oat and wheat cereal supplementation on endothelial function following a fatty meal as measured by brachial artery reactivity studies. METHODS: Fifty healthy adult subjects underwent brachial artery reactivity studies before and after a high-fat meal along with alpha-tocopherol (vitamin E), oats, or a comparable bowl of wheat cereal and were again tested after the high-fat meal following month-long supplementation with oat or wheat cereal in a random crossover with interim washout. RESULTS: In the acute phase, the fatty meal attenuated the hyperemic brachial artery flow response when administered concurrently with wheat cereal (-13.4%; P = 0.02), whereas hyperemic flow was maintained by concurrent administration of either oatmeal or alpha-tocopherol. Following month-long supplementation, postprandial peak flow (wheat +3.88 +/- 5.62%; oat -10.78 +/- 7.15%), and peak diameter (wheat -1.40 +/- 0.96%; oat -0.86 +/- 0.88%) did not differ from preprandial values. Oat and wheat treatments did not differ when directly compared. CONCLUSIONS: Month-long, daily supplementation with either whole-grain oat or wheat cereal may prevent postprandial impairment of vascular reactivity in response to a high-fat meal.

Acute effects of oats and vitamin E on endothelial responses to ingested fat.

OBJECTIVE: To assess the effects of oats and vitamin E on endothelial function following a high-fat meal in healthy adults as measured by brachial artery reactivity studies (BARS). METHODS: A total of 25 men and 25 women (N=50) were recruited from a community population to participate in this randomized, crossover study. All subjects were free of known vascular disease, and female subjects were postmenopausal. Subjects underwent BARS before and after a high-fat meal (50 gm fat) on three occasions 1 week apart, one each with vitamin E 800 IU, oatmeal containing 3 gm beta-glucan, or a comparable bowl of wheat cereal serving as a placebo, in random sequence. The ultrasonographer was blinded to treatment status. RESULTS: Endothelial function, as measured by brachial artery peak flow during one minute of post-occlusive hyperemia, declined significantly from baseline when the high-fat meal was consumed with the wheat cereal (-13.4%; p=0.02). There was no difference in brachial artery flow change before and after a high-fat meal with oats (+0.37%; p=0.77) or a high-fat meal with vitamin E (+1.87%; p=0.42). No significant differences in flow-mediated vasodilation before and after the high-fat meal were detected among the three supplements. CONCLUSIONS: Endothelial dysfunction induced by acute fat ingestion in healthy adults is apparently prevented by concomitant ingestion of oats or vitamin E, but not wheat. Nutrient distribution and meal composition may have important implications for cardiovascular health.