Dietary glycine and blood pressure: the International Study on Macro/Micronutrients and Blood Pressure
ABSTRACT BACKGROUND: Available data have indicated independent direct relations of dietary animal protein and meat to the blood pressure (BP) of individuals. OBJECTIVE: In this study, we aimed to assess whether BP is associated with the intake of dietary amino acids higher relatively in animal than in vegetable protein (alanine, arginine, aspartic acid, glycine, histidine, lysine, methionine, and threonine). DESIGN: The study was a cross-sectional epidemiologic study that involved 4680 persons aged 40-59 y from 17 random population samples in the People's Republic of China, Japan, the United Kingdom, and the United States. BP was measured 8 times at 4 visits; dietary data (83 nutrients and 18 amino acids) were from four 24-h dietary recalls and two 24-h urine collections. RESULTS: Dietary glycine and alanine (the percentage of total protein intake) were considered singly related directly to BP; with these 2 amino acids together in regression models (from model 1, which was controlled for age, sex, and sample, to model 5, which was controlled for 16 possible confounders), glycine, but not alanine, was significantly related to BP. Estimated average BP differences associated with a 2-SD higher glycine intake (0.71 g/24 h) were 2.0-3.0-mm Hg systolic BP (z = 2.97-4.32) stronger in Western than in East Asian participants. In Westerners, meat was the main dietary source of glycine but not in East Asians (Chinese: grains/flour and rice/noodles; Japanese: fish/shellfish and rice/noodles). CONCLUSION: Dietary glycine may have an independent adverse effect on BP, which possibly contributes to direct relations of animal protein and meat to BP.
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ABSTRACT: Cysteine could potentially lower the risk of stroke through antihypertensive and antioxidant effects. Our aim was to evaluate the hypothesis that cysteine intake is inversely associated with stroke incidence. We used data from the Swedish Mammography Cohort, a population-based prospective cohort of 34 250 women who were free of cardiovascular disease and cancer and had completed a food-frequency questionnaire about diet and other risk factors for stroke in the autumn of 1997. Stroke cases were identified by linkage of the study population with the Swedish Inpatient Register and the Swedish Cause of Death Register. Relative risks (RR) with 95% confidence intervals, adjusted for potential confounders, were estimated by using Cox proportional hazards regression model. We ascertained 1751 incident cases of stroke during 10.4 years of follow-up. Dietary cysteine intake (mean, 635 mg/d) was inversely associated with stroke risk. The multivariable RR of total stroke comparing the highest with the lowest quintile of cysteine intake was 0.79 (95% confidence interval, 0.65-0.97; P for trend=0.04). The corresponding RR was 0.82 (95% confidence interval, 0.65-1.03; P for trend=0.12) for cerebral infarction and 0.54 (95% confidence interval, 0.29-1.03; P for trend=0.08) for intracerebral hemorrhage. Dietary intake of other amino acids showed no independent (after adjustment for cysteine intake) association with stroke risk. These findings suggest that dietary cysteine intake may be inversely associated with risk of stroke. http://www.clinicaltrials.gov. Unique identifier: NCT01127698. © 2015 American Heart Association, Inc.Stroke 02/2015; DOI:10.1161/STROKEAHA.114.008022 · 6.02 Impact Factor
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ABSTRACT: Dietary intakes of glutamic acid and glycine have been reported to be associated with blood pressure. However, the link between intakes of these amino acids and stroke has not been studied. We aimed to examine the association between glutamic acid and glycine intakes and the risk of mortality from stroke in a population-based cohort study in Japan. 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(2). Their diets were assessed by a validated food frequency questionnaire. Deaths from stroke were ascertained over 16 y. 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 intake was 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. The data suggest that glutamic acid and glycine intakes may be associated with risk of stroke mortality. Given that this is an initial observation, our results need to be confirmed. © 2015 American Society for Nutrition.Journal of Nutrition 04/2015; 145(4):720-8. DOI:10.3945/jn.114.201293 · 4.23 Impact Factor