An important new study released in the August issue of Diabetes Care shows that replacing carbohydrates with two ounces of nuts, such as peanuts, everyday improves blood glucose control and blood lipids in people with type 2 diabetes.
David Jenkins, MD, PhD, DSc, Principal Investigator and a pioneer in the area of glycemic control for diabetics said, “Nuts, including peanuts, can make a valuable contribution to the diabetic diet by displacing high glycemic index carbohydrates and replacing them with vegetable fats and vegetable proteins which have been shown in the long term to be associated with better cardiovascular health and diabetes prevention.”
Peanuts have more protein than any other nut and are a source of mono and polyunsaturated oils. The paper reports that, “increased proportions of fat and protein, especially of plant origin, may confer metabolic benefits and reduce the risk of developing coronary heart disease and diabetes.”
The study, “Nuts as a Replacement for Carbohydrates in the Diabetic Diet”, was conducted at the University of Toronto. During the study, 117 men and women with type 2 diabetes were randomized into three groups where they received either a full portion of mixed nuts including peanuts, a half portion of both nuts and muffins, or a full portion of muffins. The muffins were made of healthy whole wheat with protein from egg and skim milk powder. Participants’ fasting blood glucose were tested every other week.
After three months, participants receiving the full portion of nuts showed the biggest decrease in glycated hemoglobin (HgA1c), a measure of blood glucose control. The difference was significantly more than the decrease shown in the participants receiving the half portion of nuts and muffins, and in those solely receiving muffins. Peanut and tree nut intake also decreased total cholesterol and bad LDL cholesterol in the blood compared to the other groups. It is notable that reductions in HgA1c and LDL cholesterol were achieved even though the majority of the subjects were already on antihyperglycemic medications and statins that lower cholesterol.
The authors conclude that nuts, such as peanuts, “may be used to increase vegetable oils and protein intake in the diets of type 2 diabetic patients as part of a strategy to improve diabetes control without weight gain.”
The article says that weight maintenance could have occurred in nut eaters for a few reasons including increased resting metabolic rate, enhanced satiety resulting in decreased intake of other foods, or incomplete absorption of energy. Studies done specifically on peanut eaters have demonstrated each of these factors.
This new clinical trial is an important milestone demonstrating glycemic control and builds on an earlier population study published in JAMA in 2006. Researchers at the Harvard School of Public Health concluded, “Our findings suggest potential benefits of higher nut and peanut butter consumption in lowering the risk of type 2 diabetes in women.”
Peanuts are the most commonly eaten nuts in America. Combined with peanut butter, peanuts comprise over two-thirds of U.S. nut consumption according to USDA data. Numerous studies have shown that consumption of peanuts and peanut butter is beneficial in keeping blood glucose stable, improving satiety and decreasing hunger, maintaining weight, and reducing risk of heart disease.
The 2010 U.S. Dietary Guidelines called for Americans to shift towards a more nutrient-dense, plant-based diet. Peanuts, peanut butter and nuts are foods to encourage daily. This may be particularly useful in preventing the onset of diabetes. Diabetes prevalence is growing at a dangerously rapid rate. Worldwide, the number of people with diabetes has increased over 40% since 1980.
The study was funded in part by The Peanut Institute, the International Nut Council, and the Canada Research Chairs Endowment Fund.
The Peanut Institute is a non-profit organization dedicated to supporting nutrition research and educational programs that contribute to healthful lifestyles.