Shifting to a plant-based diet may be key to better cardiometabolic health

A systematic review and meta-analysis of prospective studies demonstrate that switching from animal-based (AB) to plant-based (PB) foods conferred cardiometabolic improvements.

“Our findings indicate that a shift from AB (eg, red and processed meat, eggs, dairy, poultry, butter) to PB (eg, nuts, legumes, whole grains, olive oil) foods is beneficially associated with cardiometabolic health and all-cause mortality,” said the researchers.

“The substitution of red and processed meat with nuts, legumes, and whole grains reduced the risk of total cardiovascular disease (CVD), coronary heart disease (CHD), type 2 diabetes (T2D), and all-cause mortality with moderate certainty of evidence (CoE),” they continued.

Substituting 50 g of processed meat with about 10–50 g of nuts per day led to a lower incidence of total CVD, CHD, T2D, and all-cause mortality (summary hazard ratios [SHRs], 0.73, 0.87, 0.78, and 0.79, respectively). With legumes (50 g/day) or whole grains (30 g/day) as substitutes, the SHRs for total CVD incidence were 0.77 and 0.64, respectively. [BMC Med 2023;21:404]

There was a lower incidence of T2D when red meat (50 g/day) was replaced with nuts (10 g/day; SHR, 0.92) or whole grains/cereals (11–30 g/day; SHR, 0.90), and when poultry (50 g/day) was swapped with whole grains (30 g/day; SHR, 0.87).

The risk of all-cause mortality also dropped when red meat was traded off with nuts (SHR, 0.93) and whole grains (SHR, 0.96), and when processed meat was replaced with nuts (SHR, 0.79) and legumes (SHR, 0.91).

There was also moderate CoE for the association between the replacement of eggs (one/day) with nuts (10–28 g) and a lower incidence of total CVD, T2D, and all-cause mortality (SHRs, 0.83, 0.82, and 0.85, respectively).

Trading off 5 g of butter with the same amount of olive oil daily led to a reduced risk of total T2D (SHR, 0.94), CVD (SHR, 0.96), and all-cause mortality (SHR, 0.94).

Furthermore, replacing dairy with nuts (SHR, 0.94) or legumes (SHR, 0.90) was tied to a lower risk of all-cause mortality.

All 37 studies included in the meta-analyses were prospective cohort studies, with no randomized controlled trials included. Mean follow-up duration was 19 years.

Processed meat contains saturated fatty acids and compounds that promote oxidative stress and chronic low-grade inflammation, which have all been tied to increased CVD and T2D risk. [J Am Heart Assoc 2021;10:e019814; Eur J Nutr 2019;58:2639-2647; BMJ 2017;357:j1957; Curr Diab Rep 2018;18:100]. Conversely, PB foods have been known for their health benefits owing to their antioxidant and anti-inflammatory properties. [Am J Med 2015;128:229-238; Adv Nutr 2019;10:205-218]

The findings suggest that cutting down AB food consumption (especially meat) and increasing PB food intake simultaneously contribute to the observed beneficial associations with cardiometabolic health, the researchers said. “Thus, a change in dietary habits towards an increment of PB products appears to be important for cardiometabolic health.”

Further investigation is warranted to validate the findings and evaluate new associations, with focus on meat and dairy replacement products as there are no studies to date on these food products which, according to the investigators, have rapidly increased in popularity of late.

Also, as dairy products were mostly treated as one group, they called for more research on the substitution of subtypes of dairy products with PB foods.