New York, March 19 : Women who ate slightly more than the recommended daily amount of protein were significantly less likely to develop atrial fibrillation (AFib), a dangerous heart rhythm disorder that can lead to stroke and heart failure, say researchers.
"Women with the lowest protein intake -- which was roughly equivalent to the current recommended daily amount of protein in the US -- had the highest incidence of AFib, and eating a little more was protective, even after taking into account other factors that can predispose someone to develop AFib," said the study's lead author Daniel Gerber from Stanford University in the US.
"This modifiable risk factor for AFib may be a fairly easy way for women to potentially lower their risk," Gerber added.
According to the researchers, protein is an important part of women's diets, especially as they age, because it can help prevent frailty and loss of bone mass and lean muscle mass.
Current US guidelines recommend consuming 0.8 grams of protein per kilogram of bodyweight, which for a 140-pound person is about 51 grams per day.
The analysis of over 99,000 postmenopausal women (median age of 64 years) from the Women's Health Initiative Randomised Controlled Trials and Observational Study found that those who ate 58-74 grams of protein a day were 5-8 per cent less likely to develop AFib, but there seemed to be a ceiling effect after eating more than 74 grams, at which point the benefit was no longer statistically significant.
Of the nearly 100,000 women in the study, 21,258 (21.3 per cent) developed new AFib during the average 10-year follow up period.
Researchers excluded women with existing heart rhythm issues and had a two-year run-in period to be sure women didn't have any signs of occasional AFib.
They assessed protein intake using a food questionnaire, and these reports were adjusted using validated urine tests to confirm how much protein was consumed.
The women were then grouped into four quartiles based on protein intake (below 58 g/day, 58-66 g/day, 66-74 g/day and below 74 g/day) and then assessed for new cases of AFib.
The average protein intake was 60 grams/day, with women who ate between 58 and 74 grams a day having significantly less risk of AFib.
This relationship remained even after adjusting for age, ethnicity, education and other cardiovascular conditions and risk factors such as body mass index, physical activity, tobacco and alcohol use, high blood pressure, high cholesterol, diabetes, coronary and peripheral artery disease and heart failure.
Interestingly, women typically underestimated their daily protein intake by about 10 grams and caloric intake by 600-700 calories, which speaks of the need for more nutritional awareness and education, researchers said.
"Based on our findings, it seems that eating more protein may not only help strengthen women physically, but it may also have cardiovascular benefits in terms of reducing AFib and related death, strokes and heart failure," Gerber said.
The research is scheduled to be presented at the American College of Cardiology's Annual Scientific Session Together with World Congress of Cardiology on March 28-30 in the US.