title: Phytochemical Pharmacokinetics and Bioactivity of Oat and Barley Flour: A Randomized Crossover Trial.
abstract: While dietary fiber plays an important role in the health benefits associated with whole grain consumption, other ingredients concentrated in the outer bran layer, including alkylresorcinols, lignans, phenolic acids, phytosterols, and tocols, may also contribute to these outcomes. To determine the acute bioavailability and pharmacokinetics of the major phytochemicals found in barley and oats, we conducted a randomized, three-way crossover trial in 13 healthy subjects, aged 40-70 years with a body mass index (BMI) of 27-35.9 kg/m². After a two-day run-in period following a diet low in phytochemicals, subjects were randomized to receive muffins made with either 48 g whole oat flour, whole barley flour, or refined wheat flour plus cellulose (control), with a one-week washout period between each intervention. At the same time, an oral glucose tolerance test was administered. In addition to plasma phytochemical concentrations, glucose and insulin responses, biomarkers of antioxidant activity, lipid peroxidation, inflammation, and vascular remodeling were determined over a 24-h period. There was no significant effect on acute bioavailability or pharmacokinetics of major phytochemicals. Administered concurrently with a glucose bolus, the source of whole grains did not attenuate the post-prandial response of markers of glucoregulation and insulin sensitivity, inflammation, nor vascular remodeling compared to the refined grain control. No significant differences were observed in the bioavailability or postprandial effects between whole-oat and whole-barley compared to a refined wheat control when administered with a glucose challenge. These null results may be due, in part, to the inclusion criteria for the subjects, dose of the whole grains, and concurrent acute administration of the whole grains with the glucose bolus.
authors.affiliation: Nutritional Epidemiology, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston 02111, MA, USA. caleigh.sawicki@tufts.edu.
authors.forename: Caleigh M
authors.initials: CM
authors.lastname: Sawicki
authors.affiliation: Antioxidants Research Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston 02111, MA, USA. diane.mckay@tufts.edu.
authors.forename: Diane L
authors.initials: DL
authors.lastname: McKay
authors.affiliation: Nutritional Epidemiology, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston 02111, MA, USA. nicola.mckeown@tufts.edu.
authors.forename: Nicola M
authors.initials: NM
authors.lastname: McKeown
authors.affiliation: Biostatistics Unit, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston 02111, MA, USA. jerry.dallal@tufts.edu.
authors.forename: Gerard
authors.initials: G
authors.lastname: Dallal
authors.affiliation: Antioxidants Research Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston 02111, MA, USA. oliver.chen@tufts.edu.
authors.forename: C -Y Oliver
authors.initials: C-
authors.lastname: Chen
authors.affiliation: Antioxidants Research Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston 02111, MA, USA. jeffrey.blumberg@tufts.edu.
authors.forename: Jeffrey B
authors.initials: JB
authors.lastname: Blumberg
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D019540:Area Under Curve; D018554:Avena / Q000737:chemistry*; D001682:Biological Availability; D001786:Blood Glucose / Q000032:analysis; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D005433:Flour; D005947:Glucose / Q000008:administration & dosage; D005951:Glucose Tolerance Test; D064368:Healthy Volunteers; D001467:Hordeum / Q000737:chemistry*; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D064209:Phytochemicals / Q000493:pharmacokinetics*; D019518:Postprandial Period / Q000187:drug effects*; D013549:Sweetening Agents / Q000008:administration & dosage; D014908:Triticum / Q000737:chemistry
chemical_list: D001786:Blood Glucose; D007328:Insulin; D064209:Phytochemicals; D013549:Sweetening Agents; D005947:Glucose
keywords: antioxidant; barley; bioactives; oat; phenolic acids; polyphenols; tocols; whole grain