Amino acids in a high protein diet may reduce the risk of stroke

A high protein diet, such as beef, poultry and eggs, is the main dietary source of cysteine intake Dr Susanna C Larsson and colleagues at the Karolinska Institute in Stockholm wrote in the journal stroke that in some studies, a high protein diet was associated with lower blood pressure and stroke risk, and this new study may explain this association Women with the highest levels of cysteine in their diet had a 21% reduced risk of stroke compared with women with the lowest levels of amino acids in their diet "Our findings further suggest that dietary cysteine intake at least partially accounts for our previous study that total protein and animal protein intake are associated with a reduced risk of stroke," the researchers wrote Protein diet and blood pressure Data on the relationship between protein diet and hypertension are still confusing A meta analysis published in 2012 found that higher protein intake was associated with a significant decrease in systolic and diastolic blood pressure, similar to the results reported in a 2014 study at Boston University School of medicine Participants in the study included those aged 30 to 54 in the Framingham Offspring Study High protein and high cellulose intake reduced the risk of hypertension by 59% Other studies, including seven control trials and 32 observational studies published in the 2014 meta-analysis, have shown that a vegetarian based, low protein diet is associated with reduced blood pressure A recent study by Larsson and colleagues in 2012 found an inverse relationship between higher protein intake and stroke risk in women with hypertension "In this study, we evaluated the previous hypothesis that cysteine intake is inversely related to stroke risk," they said Only cysteine was negatively correlated with stroke risk This prospective cohort Swedish study, based on a population of 34250 women who underwent mammography, used data to identify 1751 stroke cases during a 10.4-year follow-up period The intake of cysteine was assessed by food frequency questionnaire, and participants also provided BMI data, smoking history and other related lifestyle factors Women with the lowest quartile cysteine intake (703 mg / day) tend to be older, have a higher BMI, are less likely to be current smokers, and are more likely to have a history of hypertension or diabetes After adjusting for other stroke risk factors and total protein intake, we found a significant negative correlation between cysteine intake and all stroke risks Research findings: The relative risk of all stroke variables was 0.79 (95% CI 0.65-0.97; P = 0.04) The relative risk of cerebral infarction was 0.82 (95% CI 0.65-0.97; P = 0.12), and that of cerebral hemorrhage was 0.54 (95% CI 0.29-1.03; P = 0.08) Other amino acids, including proline and arginine, were not independently associated with stroke risk The potential limitations of the study cited by the researchers lie in the fact that the frequency of food intake and lifestyle questionnaires are self filled But they point out that based on prospective study designs, measurement errors in assessing amino acid intake are unlikely to be related to conclusions They further pointed out that because the study was observational, it could not prove causality Previous studies have explored the relationship between amino acid intake and stroke risk, but no protective effect of cysteine diet on blood pressure has been found "We observed a negative correlation between the dietary intake of cysteine and the risk of stroke," the researchers concluded Our results further suggest that cysteine may at least partially account for previous reports of a negative correlation between protein intake and stroke risk in animals These results need to be confirmed by other prospective studies and randomized trials "