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Nuts May Reduce Heart Disease Risk & Increase Serotonin, New Study Says

Tree nuts can lower the risk of heart disease factors, as well as give you a mood boost.
FACT CHECKED BY Samantha Boesch

If we told you there's a delicious food that's great for anti-aging, reducing inflammation, and weight loss, you might think that we've found a magically transformative treat. That is partially true, but you may be surprised to find out that we're referring to nuts. A great option if you're looking for a way to add a crunchy texture to your next meal or a simple snack to grab on the go, a new study has found that nuts may also be able to reduce the risk factors associated with heart disease and increase the amount of serotonin in your body.

The study that was recently published in Nutrients used data that had been collected during an earlier study, which found that opting for a daily snack of 1.5 ounces of tree nuts—such as walnuts, almonds, cashews, hazelnuts, macadamia nuts, pecans, pine nuts, pistachios, and Brazil nuts—as opposed to pretzels, led to weight loss and satisfied appetite as well as a decrease in both blood pressure and heart rate. The cause is thought to be the tryptophan found in nuts, which metabolizes once it reaches the gut and results in bioactive metabolites that help the body's immune regulation related to potential heart disease.

In the recent study, researchers wanted to find out if eating tree nuts along with a low-calorie diet affected both the gut and the number of tryptophan metabolites. Noting that there was, indeed, a positive outcome on tryptophan metabolites, lead researcher, Zhaoping Li, MD, PhD, professor of medicine and chief of the Division of Clinical Nutrition at UCLA, noted (via EurekAlert!), "We've known for a long time that tree nuts can help decrease CVD risk, and these findings provide some possible explanations."

Li added, "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."

hands pouring jar of nuts and dried fruit

Beyond that, the second study found that blood serotonin levels increased by 60.9% after 12 weeks of eating nuts and 82.2% by the 24th week. Li commented on the discovery, saying, "This is the first time we've seen mixed tree nut consumption associated with an increase in serotonin levels in the body. While more research is needed, this is exciting because serotonin can have an important impact on mood and overall mental health."

When it comes to the findings, Dana Ellis Hunnes, PhD, MPH, RD, senior clinical dietitian with UCLA Medical Center, assistant professor at UCLA Fielding School of Public Health, and author of Recipe For Survival from Cambridge University Press, tells Eat This, Not That!, "I'm not surprised based on previous findings that are available on the cardiovascular and metabolic benefits of eating walnuts."

Hunes notes that "This study continues to lend credence to the idea that not all fats are bad, and that some are actually healthy and protective. And also, that plant protein sources are healthy and protective as well."

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mixed nuts in a wooden bowl

"In addition to being a source of good fats and fiber, research has also found that consuming a selection of different nuts can help reduce platelet aggregation, which means they're less likely to form blood clots, one of the leading causes of a heart attack or stroke," Dan Gallagher, RD, registered dietitian with Aegle Nutrition, tells Eat This, Not That! "Regular intake of nuts is also linked with increases in levels of serotonin, the 'happiness hormone,' making them an effective way for people to boost their mood naturally."

Gallagher points out that, "For most people, incorporating some kind of nut into their diets can easily provide all of these health benefits, with hazelnuts and walnuts typically providing the greatest benefits."

On the other hand, Gallagher tells us, "Unfortunately, however, individuals who have nut allergies must forego these potential benefits, as exposure is dangerous. Instead, they should focus on other healthy sources such as sunflower seeds and avocados."

Desirée O
Desirée O is a freelance writer who covers lifestyle, food, and nutrition news among other topics. Read more about Desirée
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