A Handful of Pistachios Can Decrease Glycemic Response

Kate Johnson

December 06, 2011

December 6, 2011 (Dubai, United Arab Emirates) — A couple of handfuls of pistachio nuts eaten with a high-glycemic meal such as pasta can do wonders for postprandial glucose and insulin levels, especially in people with metabolic syndrome, according to new research presented here at the International Diabetes Federation (IDF) World Diabetes Congress 2011.

The study, sponsored by the Western Pistachio Association, Fresno, California, included 20 patients with metabolic syndrome (12 women; average age, 54 years) and an average body mass index of 37.5 kg/m2, reported lead investigator Cyril W.C. Kendall, PhD, from the University of Toronto, Ontario, Canada.

In an expansion of research recently published by his group (Eur J Clin Nutrition. 2011;65:696-702), Dr. Kendall described how pistachios (84 g) were served to fasting patients, either alone or in combination with white bread (50 g) or white bread with butter and cheese.

Venous and finger-prick blood sampling was used to assess glucose and insulin responses over 3 hours, as well as glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide-1 (GLP-1) and ghrelin.

The study found that when carbohydrates were consumed with pistachios there was a blunted postprandial glycemic response, suggesting a beneficial effect for patients with the metabolic syndrome.

A previous paper published by the group showed the glycemic response to meals of rice and pasta was similarly blunted by pistachio nuts, and the response approached statistical significance with instant mashed potatoes.

"These data demonstrate that the addition of pistachios to foods with high available carbohydrate content reduces the overall glycemic impact of the foods studied [parboiled rice, pasta, white bread, and mashed potatoes], despite increasing the overall available carbohydrate content," the authors wrote.

But Dana Dabelea, MD, PhD, associate professor at the Colorado School of Public Health, Aurora, and moderator of the session at which the findings were presented, said she is not convinced.

"I'm not convinced by what I've seen because I've seen comparisons to certain food groups that I wouldn't normally associate with pistachios, like pasta and potatoes. It's difficult to select the best reference group," she told Medscape Medical News.

"We're looking at mechanisms," Dr. Kendall responded in an interview. "Nuts have healthy protein and healthy fats and they're low in available carbohydrate, so hopefully they're replacing available carbohydrate, which tends to have a high glycemic index in North America. The effects are quite modest, but these are some of the mechanisms by which nuts — and pistachios in particular — help to improve glycemic control."

The study was sponsored by the Western Pistachio Association, Fresno, California. Dr. Kendall is a co-investigator on an unrestricted grant from the Coca-Cola Company and has served on the scientific advisory board and received research support, travel funding, consultant fees, or honoraria from Pulse Canada, Barilla, Solae, Unilever, Hain Celestial, Loblaws Inc., Oldways Preservation Trust, the Almond Board of California, the International Nut Council, Paramount Farms, the California Strawberry Commission, the Canola and Flax Councils of Canada, and Saskatchewan Pulse Growers. He also receives partial salary funding from research grants provided by Unilever, Loblaws, and the Almond Board of California. Dr. Dabelea has disclosed no relevant financial relationships.

International Diabetes Federation (IDF) World Diabetes Congress 2011. Abstract # O-0479. Presented December 6, 2011.


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