Dietary tryptophan intake density and the risk of cardiovascular diseases: insights from a prospective cohort study

Tryptophan's metabolic products, serotonin and melatonin, exhibit antioxidant activity and neuroprotective properties, thereby preventing mortality from cardiovascular diseases (CVD). We aim to examine the relationship between dietary tryptophan intake density and the risk of CVD.

A prospective cohort study was conducted in northern Vietnam from 2008 to 2019, which comprises 42,146 participants aged 10 and older. Dietary tryptophan intake density per 1000 kcal was assessed using a validated semi-quantitative food frequency questionnaire. CVD deaths were 348 cases. The mean age was 38.5 years; 48 % were male and 52 % were female. The median follow-up duration was 11.01 years. Hazard ratio and 95 % confidence interval HR (95 % CI) were calculated for the association between dietary tryptophan intake density and mortality risks from CVD. The inverse association between dietary tryptophan intake density, top to bottom quintile, and CVD was seen for the entire study population, HR (95 % CI): 0.59 (0.42, 0.83), and after excluding deaths in the first three years, HR (95 % CI): 0.59 (0.41, 0.86). The results remained after additional adjustment for pack-years of smoking. A similar protective pattern was observed in subgroups with BMI <23 kg/m², smokers, drinkers, and men. The beneficial effect was observed in both young adults and those 65 years or older.

A beneficial effect of dietary tryptophan intake density against the risk of CVD was observed. The findings warrant further research to understand the mechanism and its application in preventing CVD.