After following nearly 30,000 women for 15 years,
investigators found that women were more likely to die from
heart disease if they often substituted red meat for
carbohydrates. In contrast, swapping vegetable sources of
protein for carbs appeared to protect women from heart disease.
"Our main finding was that animal compared to vegetable
sources of protein seem to have a different effect on dying
from heart disease," study author Dr. Linda E. Kelemen from the
Mayo Clinic College of Medicine in Rochester, Minnesota told
Reuters Health.
For this reason, she recommended that people who want to
follow high protein diets should stick with vegetable proteins
such as tofu, nuts and peanut butter, or healthier meats like
chicken or fish.
With high protein diets a now-popular eating style, few
studies have examined their long-term health effects, and
whether different sources of protein make a difference, Kelemen
and her team write in the American Journal of Epidemiology.
To investigate, the researchers interviewed 29,017
postmenopausal women about their eating and lifestyle habits,
then followed them for 15 years, noting who died and of what
cause. All of the women were free of cancer, heart disease and
diabetes at the beginning of the study.
The investigators found that women who most often ate
vegetable protein in place of carbohydrates and animal protein
were 30 percent less likely to die of heart disease.
But the more red meat and dairy products women substituted
for carbohydrates, the more their risk of heart disease
increased.
Overall, opting for protein over carbs had no significant
influence on the risk of dying from any cause.
Kelemen explained that it's still unclear why our hearts
like vegetable proteins better than animal proteins. It's
possible that vegetable proteins contain different building
blocks, minerals or antioxidants that are good for our bodies,
Kelemen said. Vegetable proteins could also contain substances
that affect hormones in healthier ways, she added.
"Protein from different sources seems to have different
health effects," she noted. "Long-term adherence to higher
protein intakes without distinguishing between the source of
the protein may increase the risk of dying from heart disease."
SOURCE: American Journal of Epidemiology, February 2005.
