(dailyRx News) Nuts are rich in fiber and protein, but also can be high in fats, leaving people to wonder if they should be part of a healthy diet.
A research team recently reviewed published studies and concluded that long-term consumption of nuts was tied to lower weight gain and obesity.
These researchers also found a lower risk of type 2 diabetes in people who ate nuts regularly over many years.
This study was conducted by Chandra L. Jackson, PhD, MS, and Frank B. Hu, MD, PhD, MPH, both from the Department of Nutrition at the Harvard School of Public Health.
The researchers reviewed published studies on the association between nut consumption, weight gain and obesity. They also analyzed studies done on the relationship between nut consumption and type 2 diabetes.
Patients with type 2 diabetes have high blood sugar and resistance to the bodys ability to use insulin, a hormone that usually decreases blood sugar.
Several studies have shown an association between eating nuts and weight change.
An eight-year study of 51,188 women aged 20 to 45 showed that those who ate nuts two or more times a week gained an average of 11 pounds during the study, while those who did not eat nuts gained an average of 12 pounds.
A study of 120,877 women and men found that during a four-year period of the study, each extra daily serving of nuts they ate was associated with about a weight loss of a half pound. In comparison, for every additional daily serving of potato chips people added to their diet during that same time period, the participants gained over a pound and a half.
A study done in Spain on 8,865 men and women found that those who ate nuts two or more times a week had a 31 percent lower risk of gaining weight than those people who never ate nuts.
Studies have also shown that eating nuts may protect against developing type 2 diabetes.
One study that lasted 16 years found that women who ate nuts five times a week or more had a 36 percent lower risk of developing type 2 diabetes than women who never or almost never ate nuts.
A study on walnut consumption found that for every two servings of nuts the women added to their diet per week, there was a 21 percent decrease in risk of type 2 diabetes compared to the risk if added nuts were not eaten.
The authors explained that there could be several reasons for the link between nut consumption and lower body weight. Since nuts are high in fiber and protein, people who eat them feel full faster so may not eat as much. Additionally, the fats in nuts increase a process in the body called oxidation, which decreases fat accumulation.
Nuts are also rich in vitamins and minerals, and the authors felt these nutrients may have contributed to the link with lower rates of type 2 diabetes and may also be helpful in preventing other chronic diseases.
Because weight gain is generally very gradual and difficult to detect and combat, small diet and lifestyle changes such as the replacement of less healthy food items (eg, red or processed meats, refined-grain products) with nuts and other healthy foods to avoid increased caloric intake can make a big difference and present a tremendous opportunity for obesity and chronic disease prevention, the authors wrote.
This study was published in the June issue of the American Journal of Clinical Nutrition.
Funding for this project was provided by the National Institutes of Health.
Dr. Hu disclosed receiving research funding from the California Walnut Commission, who had no role in the conduct of this study.