Submitted to: Acarology International Congress Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2003
Publication Date: 5/1/2003
Citation: Behall, K.M., Scholfield, D.J., Hallfrisch, J.G. 2003. Plasma lipids fractions of moderately hypercholesterolemic men after consumption of controlled diets containing of three levels of b-glucan from whole wheat/brown rice or barley. Netherlands. Acarology International Congress Proceedings. Interpretive Summary: n/a
Technical Abstract: Cardiovascular disease remains a major problem in the US even though fat intake has declined in response to recommendations of health organizations. Soluble fiber has been recognized as beneficial in decreasing blood glucose levels and other cardiovascular risk factors. Consumption of oats, high in soluble fiber, has been recognized as beneficial in decreasing blood cholesterol levels. Barley also contains high amounts of soluble fiber but is not consumed or utilized as extensively as oats in the US diet. This study investigated whether consumption of barley would reduce cardiovascular risk factors similarly to consumption of other soluble fiber sources such as oats. After human study protocol review and approval, 18 moderately hypercholesterolemic men (23-45 body mass index; 28-62 y) initially consumed a Step 1 diet to adjust the subjects to a lower fat, higher fiber diet than is typically consumed by the U.S. population. Three diets with equal total dietary fiber were fed for 5 weeks each. Diets contained either low levels of soluble fiber, or 3 g or 6 g of soluble fiber from barley/2800 kcal day. Foods (containing the major fiber sources) that varied between the diets were made with whole wheat or brown rice (low soluble fiber), whole wheat, brown rice and barley (mid soluble fiber) or only barley (high soluble fiber). Total lipids and glucose were determined enzymatically and lipid subclass fractions were measured by nuclear magnetic resonance spectroscopy. Large, intermediate and small very low density lipoprotein and low density lipoprotein (LDL) lipoprotein fractions did not significantly differ by dietary treatments. Large LDL showed a trend (P=0.0604) toward improved lower levels with the higher fiber intake. The mean number of LDL particles significantly decreased when whole grains were incorporated into the diet, especially after the high barley diet (12% decrease). LDL mean size remained in the high risk range after all diets. No significant difference due to dietary treatment was observed in the intermediate and large high density lipoprotein (HDL) fractions. The levels of small HDL were significantly lower with the higher fiber intake but was not grain specific. Data previously reported from this study found that fasting glucose levels were significantly lower after all three high grain diets than pre-study levels; the three high grain diets were not significantly different. Insulin levels before and at the end of each diet period were not significantly different. Significant reductions in total lipids, compared to pre-study levels, were previously reported. Total cholesterol was significantly lower (14%, 15% and 21%, low, mid and high soluble fiber diets respectively), while total cholesterol/HDL cholesterol ratio was significantly lower after the low and high soluble fiber diets compared to pre-study values. Overall the subjects' cardiovascular risk factors improved with decreased total cholesterol, LDL (especially large particle number) and total cholesterol/HDL cholesterol ratio; the higher soluble fiber intake having the greatest affect on total and LDL cholesterol.