High plant protein intake inversely associated with CVD, dementia mortality in older women
Dietary protein from different sources was associated with varying risk for CVD mortality and death from dementia or cancer among older women, according to research published in the Journal of the American Heart Association.
In addition, the partial substitution of plant protein for animal protein was associated with lower risk for all-cause, CVD and dementia mortality among postmenopausal women, researchers reported.
“Not all protein is the same. Increasing plant protein intake or partially substituting animal protein with plant protein may lower the risk of death from CVD,” Wei Bao, MD, PhD, assistant professor in the department of epidemiology in the college of public health at the University of Iowa, told Healio. “This study comprehensively examined the association of all major types of protein sources with the risk of death from all causes and specific causes. Of note, to our knowledge, this is the first study to report the association of major animal and plant protein sources with the risk of death from dementia.
“Current dietary guidelines on dietary proteins mainly focus on the total amount of protein intake,” Bao said. “Our findings support the need for consideration of protein sources, in addition to the amount of protein intake, in future dietary guidelines.”
For this analysis, researchers included 102,521 postmenopausal women from the Women’s Health Initiative study from 1993 to 1998 who were followed through February 2017 to evaluate the effect of the source of dietary protein on all-cause and cause-specific mortality.
Plant vs. animal protein intake
Compared with the lowest quintile of plant protein consumption, the highest quintile of consumption was associated with reduced risk for all-cause mortality (HR = 0.91; 95% CI, 0.86-0.96), CVD mortality (HR = 0.88; 95% CI, 0.79-0.97) and dementia mortality (HR = 0.79; 95% CI, 0.67-0.94).
Compared with low consumption of processed red meat, high consumption was associated with elevated risk for all-cause mortality (HR = 1.06; 95% CI, 1.01-1.1), the researchers wrote, noting a similar trend with eggs (HR = 1.14; 95% CI, 1.1-1.19).
Researchers observed that compared with low consumption, high consumption of the following was linked to elevated risk for CVD mortality: unprocessed red meat (HR = 1.12; 95% CI, 1.02-1.23), eggs (HR = 1.24; 95% CI, 1.14-1.34) and dairy (HR = 1.11; 95% CI, 1.02-1.22).
Moreover, high egg consumption was associated with elevated cancer mortality (HR = 1.1; 95% CI, 1.02-1.19), and high processed red meat consumption was associated with higher dementia mortality (HR = 1.2; 95% CI, 1.05-1.32) compared with low consumption of either. In contrast, compared with low consumption, high consumption of poultry (HR = 0.85; 95% CI, 0.75-0.97) and eggs (HR = 0.86; 95% CI, 0.75-0.98) was associated with lower risk for dementia mortality.
“It is unclear in our study why eggs were associated with a higher risk of cardiovascular and cancer death,” Bao said in a press release. “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. Although we have carefully accounted for many potential confounding factors in the analysis, it is still difficult to completely tease out whether eggs, other foods usually consumed with eggs, or even nondietary factors related to egg consumption, may lead to the increased risk of cardiovascular and cancer death.”
Substituting animal for plant protein
In a secondary analysis, researchers found that substituting 5% of energy from animal protein with plant protein was associated with reduced risk for all-cause mortality (HR = 0.86; 95% CI, 0.81-0.91), CVD mortality (HR = 0.78; 95% CI, 0.7-0.87) and dementia mortality (HR = 0.81; 95% CI, 0.68-0.97). However, the 5% substitution was not associated with change in cancer mortality.
“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,” Sun said in the release.
For more information:
Wei Bao, MD, PhD, can be reached at firstname.lastname@example.org.