Increased intake of meat was linked to the risk of coronary heart disease, and substituting plant protein for red or processed meat appeared to reduce that risk, in a study from pooled cohorts totaling more than a million persons.
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“We know that red and processed meat intake has been associated with higher risks of fatal coronary heart disease,” said Laila Al-Shaar, PhD, of Penn State University, Hershey. However, very few studies have evaluated substitution of alternative protein sources for red and processed meat in relation to fatal CHD risk, she said.
In a study presented at the Epidemiology and Prevention/Lifestyle and Cardiometabolic Health meeting, Dr. Al-Shaar and colleagues reviewed individual-level data from the Pooling Project of Prospective Studies of Diet and Cancer, which included 16 prospective cohorts totaling 1,364,211 participants. The average age of the participants was 57 years, and 40% were men. Individuals with a history of cancer or cardiovascular disease were excluded. The participants were followed for 7-32 years. Diet was assessed in each cohort using baselines questionnaires, and cases were identified through medical records.
Total red meat included processed meat and unprocessed red meat; animal protein sources included seafood, poultry, eggs, and low- and high-fat dairy products; and plant protein sources included nuts and beans.
The researchers identified 51,176 fatal CHD cases during the study period. After controlling for dietary and nondietary factors, they found that an increase of 100 g per day of total red meat intake was associated with a 7% increased risk of fatal coronary heart disease (relative risk, 1.07).
However, substituting 200 calories (kcal) per day from nuts, low- and high-fat dairy products, and poultry for 200 calories per day from total red meat was associated with a 6%-14% lower risk of fatal CHD, Dr. Al-Shaar added at the meeting sponsored by the American Heart Association.
These associations were stronger when substituting the alternative protein sources for processed meat, especially among women; risk was reduced by 17%-24%, on the basis of 14,888 cases.
The researchers also found that substituting 200 calories per day from eggs for 200 calories per day for total red meat and unprocessed red meat was associated with 8% and 14% higher risk of fatal CHD, respectively; but this substitution of eggs for processed meat was not significant (4%).
“When we did the association by gender, the results were even stronger in women,” said Dr. Al-Shaar. However, “these are very preliminary results” that should be interpreted with caution, and more analysis is needed, she said. “We are planning to include other cohorts with other protein sources such as soy protein,” she noted. However, the results provide additional evidence that consumption of red and processed meat contributes to an increased risk of coronary heart disease, and that substituting some red and processed meat with nuts, dairy products, or poultry may reduce this risk, she concluded.
Women especially benefit from red meat reduction
The study is important because of the continuing interest in various sources of dietary protein intake, Linda Van Horn, PhD, RD, of Northwestern University, Chicago, said in an interview.
“The investigators studied associations of substituting other animal and plant protein sources for total red meat, unprocessed red meat, and processed meat in relation to risk of fatal CHD,” she said.
The researchers found that swapping as little as 200 calories per day of total red meat for nuts, low- or high-fat dairy products, or poultry were associated with a 6%-14% reduced risk of fatal CHD, said Dr. Van Horn. “Alternatively, if those 200 calories per day for red meat were substituted with eggs, they saw as much as 14% higher risk of fatal CHD,” she noted.
The message for both consumers and clinicians is that the findings from this large study support recommendations for plant-based and lean animal sources of protein instead of red and processed meat or eggs, as these sources “offer significantly lower risk for CHD mortality,” Dr. Van Horn said. “This may be especially true for women, but the total population is likely to benefit from this approach,” she said.
Additional research is needed, Dr. Van Horn emphasized. “Prospective lifetime data, starting in utero and over the life course, are needed to better establish recommended dietary patterns at every age and among all ethnicities and diverse socioeconomic groups,” she said.
Dr. Al-Shaar had no financial conflicts to disclose. Dr. Van Horn had no financial conflicts to disclose.