Benefits were seen especially in participants with lower overall diet quality
A new study published in the journal Nutrients has found that consuming mixed tree nuts as part of a calorie-restricted weight loss diet may lead to a reduction in the gut microbiome metabolite trimethylamine N-oxide (TMAO), a novel cardiovascular disease risk factor.
Researchers compared the effects of mixed tree nuts and pretzels on levels of TMAO as part of a 12-week hypocaloric weight loss diet. A total of 95 overweight or obese participants were randomly assigned to one of two groups: a group that ate 1.5 ounces (43 grams, a large handful) of mixed tree nuts each day, or a group that ate a calorie-matched portion of pretzels each day. At baseline and at 12 weeks, plasma samples were collected and analyzed, and nutritional data were collected via dietary recall.
The nut group saw significant weight loss and reductions in plasma TMAO levels. Notably, participants with lower baseline diet quality, as assessed via the Healthy Eating Index (HEI) score, experienced a greater reduction in TMAO when consuming mixed tree nuts compared to pretzels. These findings suggest that including mixed tree nuts as part of a calorie-restricted diet may confer additional cardiovascular benefits, particularly for individuals with poorer overall dietary habits.
The International Tree Nut Council Nutrition Research and Education Foundation (INC NREF) provided funding for this study.
Lei, O., Yang, J., Kang, H. H., & Li, Z. (2025). Impact of a 12-Week Hypocaloric Weight Loss Diet with Mixed Tree Nuts vs. Pretzels on Trimethylamine-N-Oxide (TMAO) Levels in Overweight Adults. Nutrients, 17(13), 2137.