High Intake of Processed Meat Linked to Cancer Deaths

Shelley Wood and Roxanne Nelson

March 11, 2013

Bacon, sausage, and ham are once again being singled out as key culprits driving the association between meat consumption and the world's most common diseases.

One of the largest studies to address this question, published online March 7 in BMC Medicine, found a moderate positive association between processed meat consumption and mortality. This was particularly true for cardiovascular diseases (CVDs), but was also true for cancer.

Over a mean of 12 years, high consumption of processed meat was associated with a near doubling of the risk for all-cause mortality in adults, compared with low consumption. The risk for cancer death was 43% higher and the risk for cardiovascular death was 70% higher in people eating more than 160 g/day of processed meats than in those eating 10.0 to 19.9 g/day.

"The clinical message [is] to limit consumption of processed meat — not every day and not in high amounts," said lead author Sabine Rohrmann, PhD, MPH, head of the Department of Epidemiology and Prevention at the University of Zurich in Switzerland, in an interview.

EPIC data

The new data come from the European Prospective Investigation into Cancer and Nutrition (EPIC) study, which involved 10 countries and almost half a million men and women.

A signal of increased mortality was seen in the highest consumers of red meat in general; however, the risk was much lower with red meat than with processed meats, and lost statistical significance after correction for measurement error, the researchers report. In fact, the high consumption of processed meat was associated with an 18% increased risk for all-cause mortality.

After multivariate adjustment, the consumption of more than 160 g/day of red meat was related to higher all-cause mortality than the consumption of 10.0 to 19.9 g/day (hazard ratio [HR], 1.14; 95% confidence interval [CI], 1.01 to 1.28). The HR was higher for more than 160 g/day of processed meat (1.44; 95% CI, 1.24 to 1.66).

After correction for measurement error, all-cause mortality remained significantly higher only for the consumption of 50 g/day of processed meat (HR, 1.18; 95% CI, 1.11 to 1.25).

A very high consumption of red meat was nonsignificantly associated with increased cancer mortality, but not with deaths caused by CVD or respiratory diseases, diseases of the digestive tract, or any other disease.

As the researchers point out, processed meats tend to contain more saturated fat than unprocessed meat (where the fat is often trimmed off) and more cholesterol and additives (which are part of the smoking or curing process). Some of these are believed to be carcinogenic or precursors to carcinogenic processes.

When the researchers re-examined the association between processed meat intake and cancer risk using the lowest consumption category (0.0 to 9.9 g/d) as a reference, they observed a statistically significantly increased risk for cancer mortality in people who consumed 80.0 to 159.9 g/day (HR, 1.12; 95% CI, 1.01 to 1.24). There was also a nonsignificantly increased risk in the highest consumption category (HR, 1.19; 95% CI, 0.93 to 1.51).

"Another factor is the salt in processed meat products, which is linked to hypertension — a CVD risk factor," noted Dr. Rohrmann. Heme iron also links meat consumption to CVD risk, "but that's not limited to processed meat," she explained.

Dr. Rohrmann and colleagues point out that the high consumption of processed meat typically goes hand in hand with other unhealthy behaviors, including smoking, low levels of physical activity, and low consumption of fruit and vegetables.

"Overall, we estimate that 3% of premature deaths each year could be prevented if people ate less than 20 g of processed meat per day," she said in a press statement.

What About Red Meat?

Other studies have singled out processed meats as being particularly hazardous to health. Two large long-running American studies have documented the link between meat consumption and CVD and cancer deaths. However, the stronger association with processed meats that Dr. Rohrmann and colleagues found in their European cohort is somewhat at odds with the American data.

A number of studies have examined the link between meat consumption and cancer. For example, one large prospective trial linked the consumption of processed meat to an increased risk for bladder cancer. Another study found that the consumption of red and processed meats increases the risk for colorectal cancer.

"Although we did not find a statistically significant association between unprocessed red meat consumption and mortality in our studies, we would not say that there is definitely no association" between red meat consumption and CVD, Dr. Rohrmann explained.

"Our studies show it that it's okay to eat a moderate amount of meat (300 to 600 g per week), as recommended by many nutrition societies," she said. However, "a balanced vegetarian diet is okay as well," she added.

Significant Association With Processed Meat

In their study, Dr. Rohrmann and colleagues examined the association between risk for early death and the consumption of red meat, processed meat, and poultry. The 448,568 study participants were 35 to 69 years of age, and had no prevalent cancer, stroke, or myocardial infarction, and had complete information on diet, smoking, physical activity, and body mass index.

A total of 26,344 study participants (11,563 men and 14,781 women) died during the median follow-up period of 12.7 years; 5556 died of CVD, 9861 of cancer, 1068 of respiratory diseases, 715 of digestive tract diseases, and 9144 of other causes.

The researchers note that, according to their estimates, "3.3% (95% CI, 1.5% to 5.0%) of deaths could be prevented if all participants had a processed meat consumption of less than 20 g/day."

The consumption of poultry was not related to all-cause mortality.

This research received financial support from the Europe Against Cancer Program of the European Commission; Deutsche Krebshilfe and Deutsches Krebsforschungszentrum, German Federal Ministry of Education and Research; the Danish Cancer Society; the Health Research Fund of the Spanish Ministry of Health, Spanish Regional Governments of Andalucia, Asturias, Basque Country, Murcia and Navarra; ISCIII RCESP exp. C03/09, Spain; Cancer Research UK; Medical Research Council, United Kingdom; Stroke Association, United Kingdom; British Heart Foundation; Department of Health, United Kingdom; Food Standards Agency, United Kingdom; Wellcome Trust, United Kingdom; the Hellenic Health Foundation and the Stavros Niarchos Foundation; Italian Association for Research on Cancer; Italian National Research Council, Fondazione-Istituto Banco Napoli, Italy; Dutch Ministry of Public Health, Welfare and Sports, Netherlands Cancer Registry, LK Research Funds, Dutch Prevention Funds, Dutch ZON (Zorg Onderzoek Nederland), World Cancer Research Fund, Statistics Netherlands; Swedish Cancer Society; Swedish Scientific Council; Regional Government of Skåne, Sweden; Nordforsk the Norwegian Cancer Society; French League against Cancer; National Institute for Health and Medical Research, France; Mutuelle Générale de l'Education Nationale, France; 3M Co, France; Gustave Roussy Institute, France; and General Councils of France. The authors have disclosed no relevant financial relationships.

BMC Medicine. Published online March 7, 2013. Full text