Eating mixed tree nuts helps reduce cardiovascular risk: Research

Researchers discovered that eating a variety of tree nuts, including almonds, Brazil nuts, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios, and walnuts, enhanced tryptophan metabolism in overweight and obese persons in a study published online this week in the journal Nutrients. Serotonin, a neurotransmitter, and cardioprotective tryptophan metabolites increased in particular.

In a recent study, UCLA researchers found that eating 1.5 ounces of tree nuts per day (rather than pretzels) for 24 weeks of weight loss and maintenance resulted in weight loss, higher satiety, lower diastolic blood pressure, and lower heart rate. Tryptophan (present in tree nuts) has been linked to an increased risk of cardiovascular disease (CVD).

It is metabolised in the gut, producing a variety of bioactive metabolites that are crucial in immunological control and the prevention of chronic diseases such as diabetes and cardiovascular disease. The current study investigated whether tree nut snacks, when consumed as part of a hypocaloric diet, may alter the gut microbiome, leading in higher amounts of cardio-protective tryptophan microbial metabolites.

Plasma and stool samples were obtained from 95 overweight or obese patients and analysed for tryptophan metabolites and gut flora in the current investigation.  “We’ve known for a long time that tree nuts can help decrease CVD risk, and these findings provide some possible explanations,”

Lead researcher, Zhaoping Li, MD, PhD, Professor of Medicine and Chief of the Division of Clinical Nutrition at UCLA said, “We discovered some new associations between tryptophan metabolites and blood pressure, heart rate, and satiety in overweight/obese subjects, suggesting a broader impact of tryptophan metabolism in overall health, including cardiovascular health.”

Another intriguing finding was a considerable increase in blood serotonin levels (60.9 percent and 82.2 percent increase from baseline at weeks 12 and 24, respectively) in individuals who fed mixed tree nuts during both the weight loss and weight maintenance periods.”This is the first time we’ve seen mixed tree nut consumption associated with an increase in serotonin levels in the body,” explained Dr Li.

“While more research is needed, this is exciting since serotonin can have an important impact on mood and overall mental health.” According to studies, people acquire roughly 25% of their calories from snacks each day, with a major share coming from desserts, sugar-sweetened beverages, sweets, and salty nibbles.

“Replacing just one of those snacks with 1.5 ounces of tree nuts may help improve overall health and reduce the risk for various chronic diseases,” according to Maureen Ternus, M.S., R.D.N, Executive Director of the International Tree Nut Council Nutrition Research & Education Foundation.