Snacking on Nuts Daily May Reduce Metabolic Syndrome Risk Factors, New Study Shows

Pictured recipe: Rosemary-Garlic Pecans

What holiday party doesn’t have a bowl of nuts available to nosh on? Seriously, before you could buy pre-shelled nuts, a nutcracker wasn’t just a ballet.

While nuts tend to get a bad rap due to their fat and sodium content, the truth is that most of the fat in nuts is heart-healthy unsaturated fat and the sodium is added during processing (plus, there are several no-salt-added varieties available). 

Evidence suggests regularly eating nuts may improve cholesterol levels, help you lose weight and might even reduce your risk of colon cancer. 

And now, a new study published on December 9, 2023, in Nutrients suggests eating nuts can reduce the risk of metabolic syndrome in young adults. 

Metabolic syndrome is a cluster of risk factors that increases one’s risk of disease, including heart disease, stroke and diabetes. According to the National Heart, Lung and Blood Institute, about 1 in 3 adults in the U.S. has metabolic syndrome, which is characterized by having three or more of the following:

• A large waist circumference
• High blood pressure
• High blood sugar levels
• High blood triglycerides
• Low HDL (“helpful”) cholesterol

The good news is that metabolic syndrome can be prevented—and potentially treated—through lifestyle changes. And nuts might be a key factor to help you get there. 

How the Study Was Conducted

Researchers at Vanderbilt University recruited 84 young adults, ages 22-26, each with at least one risk factor for metabolic syndrome. The participants were randomly split into two groups—one group was instructed to replace their normal high-added-sugar, high-carb snacks with tree nuts and received snack packs of mixed nuts that included unsalted raw cashews, pistachios, hazelnuts, macadamia nuts, pecans, almonds and walnuts. 

The other group was instructed to eat snacks high in carbohydrates. They received snack packs similar to the nut snack packs in terms of calorie, protein, fiber and sodium content. These packs included unsalted pretzels, graham crackers, animal crackers and Nutri-Grain/granola-type bars.  

Participants were counseled on basic nutrition, including portion sizes, and received menus that were based on the 2020-2025 Dietary Guidelines for Americans. The number of calories each group ate was about the same to make the comparisons between each group at the end of the study more valid. 

Participants also wore accelerometers, which are devices that record activity levels. This, too, was to increase the validity of the final comparisons between groups.

Baseline data was collected at the beginning of the study—blood pressure, BMI, waist circumference, cholesterol and triglyceride levels and blood sugar levels—and again at the end of the study. Based on this information, each participant received a metabolic syndrome score, which graded their level of risk for getting metabolic syndrome. 

What the Study Found

At the end of the 16-week study period and after all the information was collected, researchers found that certain metabolic syndrome-related numbers improved in the nut intervention group. Specifically:

• Waist circumference was reduced in females.
• Blood insulin levels improved in males.
• The ratio of triglycerides to HDL cholesterol improved by about 11% in both males and females.
• Metabolic syndrome scores improved significantly with a 67% reduction for females and a 42% reduction in males. 

The study authors concluded that daily consumption of tree nuts can have a positive effect on metabolic syndrome risk factors, including waist circumference, lipid biomarkers (e.g., triglycerides and cholesterol) and insulin sensitivity—all without restricting calories.

The Bottom Line

As long as you don’t have a tree nut allergy, swapping your high-carb snacks with nuts may influence your health in a positive direction. Just be sure to mostly eat raw or roasted nuts, preferably with little to no added oils or salt. Too much salt might elevate blood pressure, which can increase the risk of heart disease, diabetes and more over time. 

Unlike high-added-sugar snacks that send your blood sugar soaring before the impending crash, snacking on nuts can also help stabilize blood sugar levels and keep you full and satisfied until your next meal. 

Just note that a serving size of nuts is about 1 ounce. That’s about 14 walnut halves, 18 whole cashews or 49 pistachios. 

Of course, nuts aren’t a magic bullet, but they can be an important part of a balanced, variety-filled diet that includes plenty of whole grains, lean protein, fruits, vegetables and dairy (if you eat it).   

But diet isn’t the only thing that can influence disease risk. Other lifestyle habits that contribute to reducing metabolic syndrome risk include physical activity, managing sources of stress and getting plenty of quality sleep.