Replacing red meat with vegetables could reduce mortality, CHD risk

Two US-based prospective studies presented at the recent EPI Scientific Sessions 2020 suggested that replacing animal-based foods with plant-based ones could reduce mortality and cardiovascular disease (CVD) risk.

The first study included 37,233 adults (mean age 50 years) with 24-hour dietary recall data from eight NHANES* cycles spanning 1999 to 2014. A total of 4,866 deaths occurred over 297,768 person-years of follow up, including 849 and 1,068 deaths due to heart disease and cancer, respectively.

There was no apparent association between higher total animal protein intake with total mortality. In contrast, a higher intake of plant protein was associated with a lower risk of total mortality (hazard ratio [HR], 0.73, 95 percent confidence interval [CI], 0.61–0.88 comparing highest with lowest intake quintile; p_trend<0.001). [EPI Lifestyle 2020, abstract P510]

This reduced mortality with higher plant protein intake applied to heart disease (HR, 0.71, 95 percent CI, 0.48–1.05) and cancer (HR, 0.74, 95 percent CI, 0.53–1.04) mortality.

The effect was more pronounced when 5 percent daily energy from total animal protein was substituted with that from plant protein (HR, 0.49, 95 percent CI, 0.32–0.74 [total mortality]; HR, 0.51, 95 percent CI, 0.28–0.95 [heart disease mortality]; and HR, 0.53, 95 percent CI, 0.28–1.00 [cancer mortality])**.

Additionally, replacing 2 percent of energy from unprocessed red meat, processed meat, and dairy, and 1 percent energy from seafood with that percentage from plant protein was also tied to reduced total mortality risk (HR, 0.74, 0.68, 0.74, and 0.86, respectively).

Study lead author Dr Zhilei Shan from the Harvard TH Chan School of Public Health, Boston, Massachusetts, US, noted that merely cutting red meat out of the diet may be insufficient.

“[I]t’s also about what you choose to eat in place of red meat. Healthy plant proteins like nuts, legumes, and whole grains contain more than just protein – they include other beneficial nutrients such as healthy fats, antioxidant vitamins, minerals, and phytochemicals … which have been associated with lower risk of chronic diseases such as diabetes, CVD, and some cancers,” he said.

Reduced CHD risk with plant foods

Participants in the second study were 43,259 men with no history of cancer or CVD enrolled in the Health Professionals Follow up Study from 1986 to 2012. Dietary intake was ascertained from food frequency questionnaires updated every 4 years. A total of 4,148 incidents of coronary heart disease (CHD) occurred over 932,968 person-years of follow-up, of which 1,680 resulted in death.

Every one serving/day increase in red meat intake was associated with an elevated risk of CHD, be it total red meat (adjusted*** [adj]HR, 1.08, 95 percent CI, 1.01–1.14) or processed red meat (adjHR, 1.13, 95 percent CI, 1.03–1.22). [EPI Lifestyle 2020, abstract P512]

Substituting one serving/day of total red meat with one of nuts, legumes, soy, whole grains, or dairy led to a 10–47 percent reduced risk of CHD. Moreover, the risk of fatal CHD was almost halved by substituting red meat with whole grains (48 percent reduction) and was reduced by 17 percent by substituting red meat with nuts.

“Our findings suggest that even partial replacement of red meat with healthy, plant-based sources of protein could substantially reduce rates of CHD in the US,” said study lead author Dr Laila Al-Shaar, also from the Harvard TH Chan School of Public Health. However, Al-Shaar and co-authors cautioned that the findings in this Caucasian majority, male-only population may not extend to more diverse populations.