Satiety-boosting mechanism found in walnuts
Fiber, protein, brain boosting omega-3 fatty acids, what’s not to love about walnuts? Past research has linked eating nuts with a variety of benefits including reduced risk of breast and colon cancer, improved stress management, heart health, and now new research has revealed how the brain responds to their satiating qualities.
Researchers at Beth Israel Deaconess Medical Center (BIDMC) in Boston, MA designed a double-blind, placebo controlled study to zone in on how walnut consumption helps squash food cravings. Participants reported feeling full while including walnuts in the diet, and brain imaging results may have revealed the mechanism responsible.
As published in Diabetes Obesity and Metabolism, ten participants with obesity were recruited to live in a controlled environment for two- five day sessions, allowing researchers to observe food and beverage intake accurately, avoiding a major drawback of many observational studies. During one session, participants received a daily smoothie with 48g (or 1 serving according to the American Diabetes Association) of ground walnuts. They received a similar smoothie during their other five day stay, minus the walnuts. Both tasted exactly the same and neither researchers nor participants knew the contents of the smoothie at any time.
At the end of each five day period, participants completed a Visual Analog Scale (VAS) which measured their feelings of hunger, appetite and fullness. They were also shown a variety of images from inedible items to low calorie foods to highly calorific and desirable foods like hamburgers and desserts while braining imaging was in progress.
Walnut eaters reported feeling less hungry via VAS, plus they had increased activity in the right insula of the brain while viewing desirable foods. Placebo drinkers did not record this activity. The insula is thought to be involved in functions like self-awareness, perception and cognitive control, making these findings especially interesting for researchers as it indicates that participants were paying more attention to food choices, while reporting less hunger though visually stimulated. In other words, walnuts could help minimize compulsions to eat calorific foods. This is exciting because it provides a measureable framework for future studies regarding weight control and satiety.
Imagine having a nut or two to help you make better food choices? If you’re interested in adding walnuts to your meals to tamp down your appetite, try our Baby Lettuces with Green Apple, Walnuts and Dried Cranberries salad.
Published October 1, 2017