A number of studies have suggested that a diet high in protein is beneficial for health, boosting metabolism, and aiding weight loss. For older women, however, a high-protein diet may be more harmful than helpful; researchers suggest it may raise their risk of heart failure, particularly if the majority of protein comes from meat.
Heart failure occurs when the heart is no longer able to pump enough oxygen-rich blood around the body to support other organs.
According to the Centers for Disease Control and Prevention (CDC), around 5.7 million American adults have heart failure, and in 2009, heart failure contributed to around 1 in 9 deaths in the United States.
A diet high in fat, cholesterol, and sodium is known to raise the risk of heart failure, but according to study co-author Dr. Mohamad Firas Barbour, of Brown University Memorial Hospital of Rhode Island, and colleagues, a diet high in protein may be just as harmful.
The researchers recently presented their findings at the American Heart Association's Scientific Sessions 2016, held in New Orleans, LA.
Protein is found in foods such as meat, poultry, dairy products, seafood, beans, peas, and nuts, and it is considered essential for healthy bones, muscles, and skin.
While some studies have suggested a diet high in protein may aid weight loss by suppressing appetite, other research has cited the downfalls of a high-protein diet.
Such studies claim animal-derived proteins are more to blame for negative health implications than plant-derived proteins, and the new research is no exception.
Heart failure risk higher for women who eat more meat protein
The researchers came to their findings by analyzing data of 103,878 postmenopausal women aged 50-79 years who were part of the Women's Health Initiative (WHI).
As part of the survey, participants were required to complete a food frequency questionnaire that assessed their daily intake of around 125 different food items between 1993-1998. The researchers looked at subjects' total daily protein intake, as well as the total amount of daily protein consumed from meat and vegetables.
- Fatigue, shortness of breath, and weight gain with swelling in the stomach, feet, legs, or ankles may be signs of heart failure
- Around 50 percent of people with heart failure die within 5 years of diagnosis
- Heart failure costs the U.S. around $30.7 billion annually.
The researchers note that self-reported dietary data can be inaccurate, so they also used biomarker data to get a more reliable indication of participants' protein intake. This involved assessing subjects' urinary nitrogen and doubly labeled water levels - a measure of metabolism.
All women were free of heart failure at study baseline, and heart failure development was monitored until 2005.
A total of 1,711 of the women in the study developed heart failure, the team reports.
Compared with women who had low total protein intake, those who had a higher total protein intake were found to be at much greater risk of heart failure. The risk was greater among women who consumed most of their protein from meat.
The researchers did uncover an association between high intake of vegetable proteins and lower risk of heart failure, but when the team accounted for body mass index (BMI), this result was not statistically significant.
The team warns that the findings should be interpreted with caution and further research is required, but they do suggest a high-protein diet may be linked to heart failure.
"Higher calibrated total dietary protein intake appears to be associated with substantially increased heart failure risk while vegetable protein intake appears to be protective, although additional studies are needed to further explore this potential association."
Dr. Mohamad Firas Barbour
"Heart failure is highly prevalent, especially in postmenopausal women; therefore, a better understanding of nutrition-related factors associated with heart failure is needed," adds Dr. Barbour.