Researchers from the University of Iowa reviewed data from more than 100,000 postmenopausal women
Research published in the Journal of the American Heart Association alleges a diet with higher levels of plant protein is associated with lower risk of premature death in postmenopausal women.
The researchers analysed data from more than 100,000 women aged 50 to 79 who participated in the national Women's Health Initiative study between 1993 and 1998; they were followed through February 2017. Participants completed questionnaires about their diet. During the study period, a total of 25,976 deaths occurred.
Researchers noted the levels and types of protein women reported consuming, divided them into groups to compare who ate the least and who ate the most of each protein. The median percent intake of total energy from animal protein in this population was 7.5% in the lowest quintile and 16.0% in the highest quintile. The median percent intake of total energy from plant protein in this population was 3.5% in the lowest quintile and 6.8% in the highest quintile.
Compared to postmenopausal women who had the least amount of plant protein intake, those with the highest amount of plant protein intake had a 9% lower risk of death from all causes, a 12% lower risk of death from cardiovascular disease and a 21% lower risk of dementia-related death. Conversely, higher consumption of processed red meat was associated with a 20% higher risk of dying from dementia, and higher consumption of unprocessed meat, eggs and dairy products was associated with a 12%, 24% and 11% higher risk of dying from cardiovascular disease, respectively.
Higher consumption of eggs was associated with a 10% higher risk of death due to cancer, however it was also associated with a 14% lower risk of dying from dementia, while higher poultry consumption was associated with a 15% lower risk.
"It is unclear in our study why eggs were associated with a higher risk of cardiovascular and cancer death," said lead study author Wei Bao, an Assistant Professor of epidemiology at the University of Iowa in Iowa City. "It might be related to the way people cook and eat eggs. Eggs can be boiled, scrambled, poached, baked, basted, fried, shirred, coddled or pickled or in combinations with other foods. In the United States, people usually eat eggs in the form of fried eggs and often with other foods such as bacon."
Researchers also noted that substitution of total red meat, eggs or dairy products with nuts was associated with a lower risk of death from all causes.
"It is important to note that dietary proteins are not consumed in isolation, so the interpretation of these findings could be challenging and should be based on consideration of the overall diet including different cooking methods," said Yangbo Sun, co-author of the study, a Postdoctoral Research Scholar at the University of Iowa in Iowa City and currently an assistant professor of epidemiology at the University of Tennessee Health Science Center.
The authors note several limitations to the study including that it was observational, based on self-reported data at the beginning of the study and lacked data on how the proteins were cooked. They concede the findings may not apply to younger women or men.