Findings of a study demonstrating that diets high in peanuts, peanut butter and peanut oil are as effective as olive oil in protecting against heart disease and are more heart healthy than very low fat diets were announced today at the Experimental Biology annual meeting in San Francisco.
In the study, conducted by researchers at The Pennsylvania State University and the University of Rochester in New York, 22 healthy subjects with slightly elevated blood cholesterol levels consumed five diets — low fat, olive oil, peanut/peanut butter, peanut oil, and typical American — for four weeks each.
Results show that the peanut/peanut butter, peanut oil and olive oil diets (all low in saturated fat and cholesterol and high in monounsaturated fat), which lowered total and LDL cholesterol and triglycerides levels, did not lower the beneficial HDL cholesterol levels. The low fat diet did lower LDL cholesterol levels but also lowered HDL cholesterol and increased triglyceride levels.
Compared to the typical American diet, subjects consuming the diet enriched with peanuts and peanut butter experienced a 11% reduction in total blood cholesterol levels and a 14% reduction in LDL cholesterol levels. HDL cholesterol levels did not change. When the subjects consumed the diet enriched with peanut oil, their blood cholesterol levels had similar heart healthy changes. The olive oil enriched diet did not affect blood cholesterol levels any differently — total cholesterol levels were decreased by 11%, LDL cholesterol decreased by 15% and HDL cholesterol levels remained unchanged.
Subject’s total cholesterol and LDL cholesterol levels were also lowered after the low fat diet by approximately the same amount as compared to the peanut/peanut butter and olive oil diets. However, subjects’ HDL cholesterol levels, or the so-called “good” cholesterol, decreased about 4 percent while on the low fat diet. The low fat diet was the only diet that increased triglyceride levels when compared to the typical American diet. The other three diets lowered triglyceride levels.
This timely study adds a significant piece to the ongoing fat debate centering around how the type of fat in the diet affects blood lipids and heart disease risk. Numerous studies have shown that higher fat diets rich in mono- and polyunsaturated fats are more protective against heart disease than very low fat diets.
Dr. Penny Kris-Etherton, Distinguished Professor of Nutrition at Penn State University notes that, “What is important about these findings is that we have another food option beyond olive oil — peanuts, peanut butter and peanut oil — for increasing monounsaturated fats in the diet. These options may be preferrable than low fat diets for some individuals. Inclusion of peanut products will add variety, flexibility and eating satisfaction to heart healthy diet planning.”
According to Dr. Tom Pearson, Kaiser Professor, Department of Community and Preventive Medicine at the University of Rochester, and a co-investigator on this study, “The positive effects from peanuts and peanut products may go beyond their content of beneficial fatty acids. The antioxidant Vitamin E, folic acid, phytochemicals, fiber, vitamins, minerals and plant protein may all somehow contribute to heart disease protection.”
Reaping these heart disease protective benefits from the peanuts/peanut butter and peanut oil diets was not difficult. Test subjects, who maintained their weight throughout the research study, included small amounts of peanut products into their daily diets. For example, small amounts of peanut butter were added to a bagel in the morning with a small serving of peanuts as an afternoon snack. Peanut oil was used in salad dressings.
The Peanut Institute is a non-profit organization that supports nutrition research and develops educational programs to encourage healthful lifestyles.