Eating walnuts may help you lose weight, improve your cholesterol, and keep your brain healthy, too.
If you want to lose weight and you also need to lower your level of potentially artery-clogging cholesterol, adding a high-fat snack to your diet doesn’t automatically sound like a great idea. But if the high-fat food is a handful of walnuts, it could be a heart-smart — and waist-slimming — strategy.
University of California San Diego (UCSC) researchers studied 245 overweight and obese women who were randomly assigned to try one of three different diets for a year — a low-fat, higher-carb diet; a low-carb, higher-fat diet; or a walnut-rich, higher-fat and lower-carbohydrate diet. After six months, all the women had lost about eight percent of their body weight.
"One of the surprising findings of this study was that even though walnuts are higher in fat and calories, the walnut-rich diet was associated with the same degree of weight loss as a lower-fat diet," said UCSC researcher Cheryl Rock, PhD.
But those who ate walnuts, about 1.5 ounces a day, experienced other health benefits, in addition to dropping some excess pounds. The women’s LDL (the “bad” cholesterol) declined and their HDL (the “good,” heart-protective type of cholesterol) went up.
What’s more, the women who had the greatest improvement in these markers of cardiovascular health probably needed it the most — they were insulin resistant. Insulin resistance occurs when your body produces insulin but does not use it effectively to keep blood sugar in check. The condition can lead to prediabetes and type 2 diabetes, according to the National Institute of Diabetes and Digestive and Kidney Diseases.
Rock, whose work at UCSD focuses on the role of diet and obesity in the development of cancer, included testing the research participants for insulin resistance because of a potential link between insulin resistance and malignancies. Higher amounts of insulin are more likely to cause cells to lose their ability to regulate growth — a precursor to cancer. And weight loss typically improves insulin resistance.
"Considering the results of this study, as well as previous walnut research on heart health and weight, there's something to be said for eating a handful of walnuts a day,” Rock said.
"In addition to these findings, we hope to explore the effect of walnuts on satiety, as we believe satiety is a critical factor for maintaining weight loss,” she added.
The health benefit of walnuts may also help your brain as well as your heart and waistline. A large study of U.S. adults by University of California at Los Angeles (UCLA) researchers found that eating walnuts may improve memory, concentration and how fast people can process information. These improvements were seen consistently in adults who consumed walnuts, regardless of their age, gender or ethnicity.
"It is exciting to see the strength of the evidence from this analysis across the U.S. population supporting the previous results of animal studies that have shown the neuroprotective benefit from eating walnuts,” said UCLA nutritional epidemiologist Lenore Arab, PhD, who headed the study.
There are numerous ingredients in walnuts that may explain the brain benefits of the nuts — including antioxidants, vitamins, and minerals. Walnuts are also the only nuts that contain a significant amount of alpha-linolenic acid, a plant-based omega-3 fatty acid that has been found to have both heart and brain health benefits.
"It isn't every day that research results in such simple advice — eating a handful of walnuts daily as a snack, or as part of a meal, can help improve your cognitive health," said Arab. “And it's a realistic amount — less than a handful per day (13 grams)."
July 05, 2016
Janet O’Dell, RN