Red Meat and Cancer: What's the Beef?

Laura A. Stokowski, RN, MS

Disclosures

June 20, 2013

In This Article

Meat, Mortality, and Cancer: The Latest Findings

US study. The approach taken by Pan and colleagues[32] to the "red meat question" was to determine whether the increased incidences of cancer and other chronic conditions associated with red meat consumption corresponded with an increase in mortality. Their large-scale, prospective, longitudinal study used 2 cohorts: the Health Professionals Follow-Up Study and the Nurses' Health Study.

First author An Pan describes the study's main findings. "We found that red meat was associated with increased mortality risk, which is consistent with the recent EPIC study,[33] and also several previous studies, such as the NIH-AARP study.[27] Our study also suggests that replacing red meat with other healthy food choices is associated with reduced risk. The association in our study was quite linear, suggesting that there is no threshold effect, the less the better. But we certainly need more studies to confirm this."

A higher intake of red meat was associated with an increased risk for total, cardiovascular, and cancer mortality -- associations that were relatively greater for processed red meat. A strength of this study was that every 4 years, the researchers obtained updated dietary information from participants. In a previous study that found higher intakes of red and processed meat to be associated with higher mortality, dietary intake was assessed only at baseline.[27]

These studies still fail to fully explain the effect of red meat consumption on mortality, but the researchers speculate that some previously identified culprits -- N-nitroso compounds, HCAs, PAHs, or heme iron content -- could be involved, as well as other constituents of meat, such as saturated fat and sodium.

Men and women with the highest intakes of red meat were less likely to be physically active. To answer critics who claim that the study's findings are confounded by such variables, Pan and colleagues "carefully controlled for lifestyle factors (eg, smoking, drinking, physical activity, body mass index, other dietary factors) in our statistical models. The results can be considered as being independent of those factors. Although we may not be able to fully account for all confounding factors, we did not observe significant interactions with those lifestyle factors in our study."

With respect to mortality from different types of cancer, the study was not designed to stratify according to different types of cancer, says Pan. However, "red meat was associated with deaths from several major cancers, such as CRC and lung cancer, but the associations were very modest for breast and prostate cancer."

European (EPIC) study. The meat-mortality connection received more support this year with the publication of the EPIC study,[33] in which a large European cohort (almost a half million individuals) were followed for a median of 12.7 years. A high consumption of processed meat, but not red meat, was related to increased all-cause mortality. The risk for cancer death was 43% higher and the risk for cardiovascular death was 70% higher in people who ate more than 160 g/day of processed meats than in those who ate 10.0-19.9 g/day. The study's most important finding, according to lead author Sabine Rohrmann, "is that mortality increases with increasing amounts of processed meat consumed. We estimate, based on our results, that 3.3% of total mortality is due to high processed meat consumption. This is lower than the preventable fraction that has been calculated from US studies, which reported that about 8% in the Nurses' Health study and 20% in the NIH-AARP cohort was preventable."

An interaction with smoking suggested that mortality was significantly higher in current and former smokers. The study had several other interesting findings. Rather than being associated with zero meat consumption, the lowest mortality rates were found among those who consumed about 10-20 g of processed meat per day (equivalent to eating processed meat once or twice a week.) This, although unexpected, is consistent with previous studies showing that vegetarians and nonvegetarians who eat low amounts of meat have similar mortality rates.

The association between mortality and processed meat consumption was stronger in lean individuals than in obese or overweight individuals. Rohrmann says that this finding is difficult to explain. "We see a statistically significant interaction (eg, different effects by body mass index group), but the risk estimates are not that different. It might just be chance due to small numbers or perhaps, because obesity is a stronger risk factor for mortality than processed meat consumption, we cannot detect the association as clearly." 

The evidence on mortality presented by EPIC also agrees with observations from other analyses that high intakes of red meat and processed meat are associated with chronic diseases such as diabetes, heart disease, and stroke.[34,35]

Comments

3090D553-9492-4563-8681-AD288FA52ACE
Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.
Post as:

processing....