Nuts are known for their health benefits, but a new study, led by David Katz from the Yale-Griffin Prevention Research Center, shows that eating a handful of walnuts every day also improves blood vessel function and lowers LDL cholesterol levels, thus lowering the risk of developing type 2 diabetes overall.
Walnuts are a good source of essential fatty acids. However, some people avoid them because of their fat content. Can the nutritional benefits of walnuts outweigh the fact that they are high in calories?
"We know nuts are really nutritious, but they're really loaded with calories. So the question was, if we tell people to eat nuts every day, will they over time start to gain weight? And will the weight gain over time start to offset the metabolic benefits that come from the high-quality nutrition of nuts?" Katz said, according to Live Science.
To answer these questions, the researchers recruited 31 men and 81 women aged 25 to 75 years old. They were randomly assigned into two groups. The first group was given dietary counseling to control their calorie intake, while the second group was not given such advice. In each of the two groups, some were given two ounces of walnuts in addition to their daily diet, while some were not.
This setup was followed for six months. The study participants were then given a 12-week break, after which they switched places so that those who did not have dietary counseling now received it, and those who were not given walnuts were now given two ounces of the nuts to add to their daily diet.
The researchers found that consumption of walnuts improved the participants' blood vessel function no matter which dietary counseling they were given. Additionally, walnuts did not affect blood pressure and HDL cholesterol levels negatively. A handful of walnuts added to the participants' daily diet also made their waistlines smaller, particularly when they were given dietary counsel to control calorie intake.
"So even if you don't talk to people about [making room in their diet] for these calories, they seem to do pretty well," Katz said. "They don't gain weight. But on the other hand, you may be able to augment those benefits if you do provide some counseling about how to make room for those calories."
The study, funded by the California Walnut Commission, was published online in the Nov. 23 issue of the journal BMJ Open Diabetes Resource and Care.
