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Oat avenanthramides: Acute bioavailability in older adults when administered in an oat bran muffin containing high endogenous avenanthramides

F. COLLINS (1), D. L. McKay (2), O. Chen (2), J. B. Blumberg (2)
(1) Eastern Cereals and Oilseeds Research Centre, Agric & Agri-Food Canada, Ottawa, ON, Canada; (2) Antioxidants Research Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, U.S.A.
Cereal Foods World 56:A17
http://dx.doi.org/10.1094/CPLEX-2011-1005-01W

Avenanthramides (AV) represent the major soluble phenolics present in the oat kernel and normally occur at concentrations between 25 and 100 ppm in most material. We have shown that both purified AV and concentrated AV mixtures have anti-atherogenic and anti-inflammatory activity in IL-1β-stimulated human aortic endothelial cell cultures, suggesting they may have similar effects in vivo if they are sufficiently bioavailable. Based on our previous studies, the bioavailability of pure AV in humans is only about 1% of an acute oral dose, and therefore an oat with about 2,000–4,000 ppm total AV would be required to be physiologically relevant. After developing a proprietary oat malting and abrasion milling process we produced an oat bran ingredient with 3,000–3,500 ppm total AV to meet the requirement. This bran was incorporated (30% by weight) into a 60-g bran muffin which contained about 45 mg total AV after baking. We then conducted a placebo-controlled, crossover study using these muffins to determine the acute AV bioavailability and pharmacokinetics in 10 healthy adults, age 50–70 years with BMI of 18.5–29.9. After a 2-day run-in period following a diet free of oat products, subjects consumed either a muffin made with the enriched oat bran or a placebo muffin, with a 1-week washout period between each intervention. Blood AV levels of the six major AV were determined at specified time points before and up to 24 h after muffin consumption. Preliminary results from six subjects indicate the maximal plasma concentration (C_max) and time to reach C_max (T_max) of these AV were 32.0 ± 16.1 ng/mL at 1.9 ± 0.4 h, respectively, with marked variation between subjects. Data suggesting that AV in this new innovative food source (malted oat bran) are indeed bioavailable in healthy older adults and the potential relevance of these findings to human cardiovascular health will be discussed.