A new study published in Nutrients assessed whether snacks of mixed tree nuts as part of a hypocaloric diet modified the gut microbiome, leading to an increase in levels of cardio-protective microbial metabolites of tryptophan (Trp), an essential amino acid found in tree nuts.
As part of a randomized, controlled, parallel, two-arm study, 95 overweight/obese individuals were instructed to consume either mixed tree nuts or pretzels daily as part of a hypocaloric weight loss diet for 12 weeks followed by an isocaloric weight maintenance program for an additional 12 weeks. Plasma and fecal samples were collected and evaluated for Trp metabolites by liquid chromatography–mass spectrometry and for gut microbiota by sequencing of the 16S rRNA gene.
The findings suggest that consumption of mixed tree nuts affected host and microbial metabolism of Trp. The study discovered some new associations between Trp metabolites and blood pressure, heart rate and satiety in overweight/obese subjects, suggesting a broader impact of Trp metabolism on host health, including cardiovascular health.
This study was co-funded by the International Tree Nut Council Nutrition Research & Education Foundation (INC NREF).
Yang, J., Lee, R., Schulz, Z., Hsu, A., Pai, J., Yang, S., Henning, S. M., et al. (2023). Mixed Nuts as Healthy Snacks: Effect on Tryptophan Metabolism and Cardiovascular Risk Factors. Nutrients, 15(3), 569. MDPI AG.