Dietary Intakes of Glutamic Acid and Glycine Are Associated with Stroke Mortality in Japanese Adults

Background: Dietary intake of glutamic acid and glycine was reported to be associated with blood pressure level. However, the link between intake of these amino acids and stroke has not been studied. Objective: We aimed to examine the association between glutamic acid and glycine intake and the risk of mortality from stroke in a population-based cohort study in Japan. Methods: The analyses included 29,079 residents (13,355 men and 15,724 women) of Takayama City, Japan, who were aged 35–101 y and enrolled in 1992. Their body mass index ranged from 9.9 to 57.4 kg/m. Their diets were assessed by a validated food frequency questionnaire. Deaths from stroke were ascertained over 16 y. Results: During follow-up, 677 deaths from stroke (328 men and 349 women) were identified. A high intake of glutamic acid in terms of a percentage of total protein was significantly associated with a decreased risk of mortality from total stroke in women after controlling for covariates; the HR (95% CI) for the highest vs. lowest quartile was 0.72 (0.53, 0.98; P-trend: 0.03). Glycine intakewas significantly associated with an increased risk of mortality from total and ischemic stroke in men without history of hypertension at baseline; the HRs (95% CIs) for the highest vs. lowest tertile were 1.60 (0.97, 2.51; P-trend: 0.03) and 1.88 (1.01, 3.52; P-trend: 0.02), respectively. There was no association between animal or vegetable protein intake and mortality from total and any subtype of stroke. Conclusion: The data suggest that glutamic acid and glycine intake may be associated with risk of stroke mortality. Given that this is an initial observation, our results need to be confirmed. J Nutr doi: 10.3945/jn.114.201293.