Nuts, peanuts, and peanut butter are mostly fat. Several decades of indoctrination has taught us to avoid them. We have been taught to cut back on the fat we eat to avoid getting fat and developing diabetes.
I remember when I was first diagnosed with diabetes eight years ago. I took a record of everything that I ate to my nutritionist at the VA Clinic in Santa Barbara. She went through it carefully and circled all the no-no's in my diet. They were invariably anything that was high in any sort of fat.
There are good fats as well as bad fats.
Now, our understanding of the differences among the four main types of fat has become much more sophisticated. For this we are much indebted to the Harvard School of Public Health and particularly to Associate Professor Frank Hu of the department of nutrition.
MEDLINE has abstracts of 93 of his publications since 1994. Two of the most important earlier for which Professor Hu was a co-author were "Dietary fat intake and risk of type 2 diabetes in women" in the June 2001 issue of the American Journal of Clinical Nutrition and "Diet and risk of Type II diabetes: the role of types of fat and carbohydrate" in the July 2001 issue of Diabetologia.
The first of these studies concluded that "total fat and saturated and monounsaturated fatty acid intakes are not associated with risk of type 2 diabetes in women, but that trans fatty acids increase and polyunsaturated fatty acids reduce risk." The second concluded, "Our findings indicate that a higher intake of polyunsaturated fat and possibly long-chain n-3 fatty acids could be beneficial, whereas a higher intake of saturated fat and trans-fat could adversely affect glucose metabolism and insulin resistance."
We know now from these and other studies that there are good fats as well as bad fats. Now, Professor Hu and his associates have gone on to study specific high-fat foods in "Nut and peanut butter consumption and risk of type 2 diabetes in women." They report their most interesting findings in the November 27, 2002, issue of JAMA, the journal of the American Medical Association.
Women in the study who reported that they eat at least five ounces of peanuts and peanut butter a week reduced their risk of developing type 2 diabetes by 21 percent compared to those who rarely or never ate them. The researchers also found that women in the study who frequently ate tree nuts (almonds, walnuts, pecans, pistachios, cashews, and others) reduced their risk for type 2 diabetes 27 percent compared to women in the study who rarely ate them.
The 27 percent reduction in the chances of getting diabetes is "pretty substantial," Dr. David Jenkins, a professor of nutrition at the University of Toronto, told HealthScout News. Dr. Jenkins studies the health benefits of nuts and is famous for creating the glycemic index in 1981.
How does the 5 ounces per week that offer such substantial benefits compare to what we eat on the average? It's a lot more.
According to U.S. Department of Agriculture reports and Census Bureau population estimates, the average American eats just one-fourth of an ounce of tree nuts and 2 and one-half ounces of peanuts a week, 45 percent of which is peanut butter.
The researchers tracked 83,818 women in the Nurses' Health Study for 16 years. These women, none of whom had a history of diabetes, cardiovascular disease, or cancer, completed food-frequency questionnaires about every four years between 1980 and 1996. The questionnaires included information on their nut, peanut, and peanut butter consumption.
Oil-roasted mixed nuts are 57 percent fat, of which 33 percent is monounsaturated, 11 percent polyunsaturated, and 9 percent saturated, according to the USDA National Nutrient Database. Dry-roasted peanuts are 50 percent fat, of which 25 percent is monounsaturated, 16 percent polyunsaturated, and 7 percent saturated, according to that source.
Peanuts are part of the legume family and are not true nuts. Nevertheless, Professor Hu and his associates were not surprised that peanuts had the same effect as nuts. Both nuts and peanuts are rich in the healthy types of fats and are a good source of antioxidant vitamins, protein, and fiber.
The authors admit that they don't know exactly how the specific types of dietary fat affect insulin sensitivity. They do know that nuts and peanuts are rich in fiber and magnesium and have a low glycemic index. Several large studies have found an inverse correlation between nut consumption and the risk of coronary heart disease. That is supported by clinical studies that have shown that diets high in nuts are good for our lipid (cholesterol and triglycerides) levels.
These results "contradict the conventional wisdom that intake of high-fat foods leads to obesity and heart disease," the Harvard researchers conclude. Consequently, they recommend that everyone who seeks to avoid diabetes replace refined grains or red or processed meats with more nuts and peanut butter.
That's well and good for those lucky souls who don't already have diabetes. But what about those of us who now suffer from it, perhaps because we didn't eat enough nuts and peanut butter when we were younger?
The outstanding recent book on how to prevent diabetes, Gretchen Becker's Stop Diabetes, is about the minimizing the risk of developing diabetes. But as I read it I was struck by the fact that the 50 simple steps she recommends would seem to apply equally to those of us who already have it.
Ms. Becker says she agrees. "The same strategies to keep blood glucose levels down before you have diabetes are the same as those you want to use after you are diagnosed," she wrote me. "The main difference, I think, is that a person simply at risk can have a chocolate sundae every now and then without having blood glucose levels go through the roof. A person already diagnosed has to be stricter. To me, that's one reason to take care before you get the disease. Giving up 'treats' 90 percent of the time may ensure that you'll be able to have them 10 percent of the time for the rest of your life."
This article originally appeared on mendosa.com, January 2003
David Mendosa is a freelance journalist and consultant specializing in diabetes and lives in Boulder, Colorado. When he was diagnosed with type 2 diabetes in February 1994, he began to write entirely about that condition. His articles and columns have appeared in many of the major diabetes magazines and websites. His own website, David Mendosa’s Diabetes Directory, established in 1995, was one of the first and is now one of the largest with that focus. Every month he also publishes an online newsletter called “Diabetes Update.” He is a co-author of What Makes My Blood Glucose Go Up...And Down? (New York: Marlowe & Co., August 2003).
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