Elderly adults need to maintain muscle mass for optimal health(2). However, most lose muscle mass as they age and are less efficient at using dietary protein to build muscle. Making matters worse, older adults typically eat less protein than younger adults despite studies in the general population showing they should be eating more.
Little is known about the impact of low versus high protein intake in patients with heart failure, a condition that increases with age. Around one in ten 70-year-olds has heart failure(3). Heart failure is a serious medical condition where the heart does not pump blood around the body as well as it should. This means that the blood does not deliver sufficient oxygen and nutrients to the body to allow it to work normally.
This study investigated the association between protein intake and survival in 2,281 patients with heart failure in the BIOSTAT-CHF study, which was conducted in 11 countries in Europe(4). The average age of patients in this analysis was 68 years and 27% were female. Daily protein intake was estimated from urine urea excretion, corrected for urine creatinine and body mass index (BMI) using a validated formula. Patients were divided into four groups according to the amount of protein they consumed, and then the association with mortality was assessed.
The median protein intake was 53 grams per day, ranging from 40 grams in the lowest quartile to 70 grams in the highest. At the end of the median 21 month follow up period, 31% of patients in the lowest quartile of protein intake (40 grams or less per day) had died compared to 18% of patients in the highest quartile of protein intake (70 grams or more per day) (p<0.001).
After adjusting for multiple confounders, including age and renal function, patients in the lowest quartile of protein intake had a 46% higher risk of death than those in the highest quartile of protein intake (hazard ratio 1.46; 95% confidence interval 1.01–2.12; p=0.045).
Koen Streng, study author and PhD student, University Medical Centre Groningen, the Netherlands, said: “We observed that in patients with heart failure, a higher protein intake is independently associated with better survival. The study did not look at causes for this link, but it is likely that dietary protein builds muscle mass which is beneficial for health in these patients.”
“A randomised controlled trial is needed to determine a recommended amount of daily protein intake for patients with heart failure,” he said.