Snacking on tree nuts may reduce risk for metabolic syndrome in young adults

Key takeaways:

• Consuming tree nuts between meals reduced metabolic syndrome scores by 67% in men and 42% in women.
• Tree nuts were also linked to improvements in triglycerides and TG/HDL ratios.

Young adults who consumed tree nuts as snacks had a lower risk for metabolic syndrome than those who did not, as well as improvements in waist circumference, visceral fat and blood insulin levels, a study found.

Tree nuts have previously been reported to have benefits in several health outcomes, including risk reductions for CVD and all-cause mortality.

According to Kate Sumislawski, RD, a registered dietician from Vanderbilt University Medical Center, and colleagues, “the overall prevalence of [metabolic syndrome] has increased to 21.3% among American healthy young adults.”

“While there is no one optimal diet for preventing [metabolic syndrome], dietary macronutrient intake, particularly the amount of saturated fat consumed, is a key factor in the development of obesity and insulin resistance,” they wrote in Nutrients.

The researchers noted that tree nuts are a key source of mono- and polyunsaturated fats, and thus aimed to compare their impact on metabolic syndrome risk as a snack.

The randomized controlled trial consisted of 84 adults aged 22 to 26 years who had BMIs between 24.5 and 34.9 kg/m² and at least one metabolic risk factor at baseline.

Over 16 weeks, participants consumed either 1 oz of unsalted mixed tree nuts or 1 oz of typical carbohydrate snacks twice a day. Both snacks had the same amount of protein, calories, fiber and sodium, according to a press release.

Sumislawski and colleagues found that, compared with those who ate typical carbohydrate snacks, women who ate tree nuts had a:

• reduced waist circumference (mean difference [MD] = –2.2 ± 0.73 cm); and
• trend toward reduced visceral fat (MD = –5.27 ± 13.05 cm²).

Meanwhile, men who ate tree nuts had reduced blood insulin levels (MD = –1.14 ± 1.41 mIU/L).

Tree nut consumption also had a significant effect on triglycerides (TG) and TG/HDL ratios in men and women, with an approximate 11% reduction in TG/HDL ratios vs. consumption of carbohydrate snacks.

These health effects may have contributed to a reduction in metabolic syndrome scores, which were reduced by 67% in women and 42% in men who consumed tree nuts vs. those who consumed carbohydrate snacks, according to Sumislawski and colleagues.

The researchers noted that tree nuts did not significantly impact weight or BMI, which is in contrast to concerns about tree nuts causing weight gain because their dietary fat content.

“Given the widespread prevalence of metabolic syndrome and its harmful potential for the development of diabetes and cardiovascular diseases, it is imperative that practical and feasible therapeutic strategies be adopted,” they concluded. “Future investigation could be conducted in subgroups of the young adult population such as athletes as well as populations with chronic disease states including prediabetes, type 2 diabetes, and cardiovascular diseases.”

References:

• Study shows tree nuts as snacks reduces metabolic syndrome risk in millenials. https://www.eurekalert.org/news-releases/1011166. Published Dec. 14, 2023. Accessed Dec. 14, 2023.
• Sumislawski K, et al. Nutrients. 2023;doi:10.3390/nu15245051.