Replacing carbs with nuts
The study included 117 people with type 2 diabetes, all being treated with blood sugar-lowering medications, who were following a special diet to help manage their diabetes, reduce cholesterol levels, and lose weight. They were divided into three groups and given supplemental foods to replace some of their regular carbohydrate portions:
one group received a portion of mixed nuts;
the second group received whole-wheat, fruit-sweetened muffins; and
the third group received a half portion of mixed nuts and a half portion of muffins.
The supplemental foods were intended to provide 20 to 30% of each day’s calories. Most participants received 75 grams (2.5 ounces) of nuts, or three muffins, or 37.5 grams (1.25 ounces) of nuts and 1.5 muffins, but exact amounts were determined by the individual calorie requirements of each person.
The nuts were unsalted and mostly raw, with some dry roasted, and included almonds, pistachios, walnuts, peanuts, pecans, hazelnuts, cashews, and macadamias.
Nut eaters tend to be healthier
After three months of eating the supplemental foods, lab tests revealed the following changes:
Hemoglobin A1c, a marker of long-term blood sugar control, improved more in the group eating a full portion of nuts than in the other groups.
Total cholesterol and LDL cholesterol levels fell primarily in people eating the full portion of nuts.
Another marker related to cardiac risk, apolipoprotein B (ApoB) levels, dropped in people eating both the full-portion and half-portion of nuts, though the effect was stronger in people eating the full portion.
There was no significant weight gain or loss in any of the groups.
“Our findings provide a specific food option for individuals with type 2 diabetes who wish to lower the carbohydrate content of their diet,” said lead study author, Dr. David J. A. Jenkins at St. Michael's Hospital in Toronto, Ontario. “Because of their poly- and mono-unsaturated fats and their vegetable protein content, nuts fit well in low-carbohydrate, high-vegetable fat, and high-protein diets, which are increasingly being recognized as protective against heart disease and diabetes.”
The best ways to eat nuts
Why are nuts so good for us? One reason is that the fats they contain are mostly mono- and poly-unsaturated, unlike the fats from animal foods, which are mostly saturated. They contain fiber, vitamin E, and a host of minerals like magnesium and selenium. Nuts are healthiest for us if they are eaten as follows:
- Unsalted. Even though salt is unlikely to diminish the positive effects of nuts on blood sugar and cholesterol levels, too much salt can increase the risks of high blood pressure and stroke.
- Raw or roasted. Roasted nuts are generally cooked at high temperatures that damage their healthy mono- and poly-unsaturated fats. Because eating heat-damaged fats can increase oxidative injuries to cells and tissues in the body, many nutrition experts recommend eating nuts raw. Some scientists, however, have found that roasting can increase the levels of antioxidants in certain nuts. Since researchers have not compared the health benefits of raw versus roasted nuts, and studies show that people who eat roasted nuts experience health benefits, the best advice is to eat them raw or roasted.
- In the right amount. Even though they are really good for us, nuts are high in calories—the average amount used in this study provided 475 calories! Reducing total calorie intake is essential if you need to lose weight, so when you add nuts to your diet, use them in place of foods with a similar or higher number of calories.
(Diabetes Care 2011;34:1706–11)