Results from a recent study showed that both processed and unprocessed red meat consumption increased both all cause, and cause specific, mortality rates in middle aged and older adults.
The mechanism by which red meat can cause physiological harm is not fully understood but it is assumed that the iron from meat based sources (or heme iron), nitrate and nitrite each adversely affect physiological health.1 While iron is a necessary part of the diet, too much can do more harm than good. In fact, excess heme iron consumption has been associated with increased risk for cardiovascular disease and certain cancers.1 Nitrate and nitrites that occur naturally in dietary sources, such as vegetables, are considered beneficial.1 However, evidence shows the artificial addition of nitrate and nitrites during the process of curing meats to be associated with increased risk for cancer.1
Results from a recent population based cohort study were published in the British Medical Journal (BMJ) by A. Etemadi, et al in 2017. The study examined the influence meat consumption has on mortality rates in 51-70 year olds from diverse ethnicities. Diet surveys were collected over 16 years using NIH-AARP Diet and Health survey that included over 500,000 participants from the US. All participants were AARP members living in Atlanta, Georgia; Detroit, Michigan; California, Florida, Louisiana, New Jersey, North Carolina, or Pennsylvania. The survey assessed portions and frequency intake of total red meat (including beef, pork, liver), white meat (including chicken, turkey, tuna) and processed meat intake (such as bacon, hotdogs, and sausage).
- When comparing the highest versus lowest meat consumption, there was
an increase in all-cause mortality risk associated with red meat intake (HR 1.26, 95% confidence)
- This increase was associated with both processed and unprocessed red meat consumption
- Heme iron and nitrate/nitrite were estimated from dietary survey responses and were shown to contribute independently to the increased risk of all cause mortality by 20-24% and 37-72%, respectively
- Using the same comparison, the study also saw a clear reduction in all-cause mortality risk with increased white meat consumption
Why is this Clinically Relevant?
- High red meat consumption increases all-cause mortality regardless of processed or unprocessed status
- Added nitrites and nitrates increased all-cause mortality
- Reducing red meat consumption may have a positive impact on mortality rates
- Increasing white meat consumption, may decrease all-cause morality rates
1 Etemadi A, Sinha R, Ward MH, et al. Mortality from different causes associated with meat, heme iron, nitrates, and nitrites in the NIH-AARP Diet and Health Study: population based cohort study. BMJ. 2017;357:j1957.