By Craig Weatherby
Scarfing hot dogs, baloney, pepperoni, and salami often seems to be a bad idea.
Another very large population study links diets high in processed meats to early death.
The analysis also showed that such diets raise the risk of cancer and cardiovascular disease.
People who ate more than 5.7 ounces (160 grams) of processed meat a day were 44 percent more likely to die within 13 years than those eating two-thirds of an ounce (20 grams) of processed meat or less daily.
To put this into practical terms, two sausages plus a slice of bacon add up to about 5.7 ounces of processed meat.
Bolstering the credibility of the team's conclusion, a person's risk of premature death from any cause rose with the amount of processed meat eaten.
While high consumption of red meat was linked to a 14 percent higher risk of early death, that association vanished after the authors adjusted the results for possible measurement errors.
Those who ate no more than two-thirds of an ounce (20 grams) of processed red meat daily (i.e., five ounces or 140 grams per week) showed no increase in death risk.
The researchers attributed the safety of moderate intake of processed red meat to the fact that red meat is high in certain nutrients, such as B vitamins.
Earlier studies have linked heavy consumption of red meats and processed red meats to health risks.
Last year, a Harvard team reported the results of two studies, which affirmed the findings of prior ones:
“Red meat consumption is associated with an increased risk of total, cardiovascular disease (CVD), and cancer mortality. Substitution of other healthy protein sources for red meat is associated with a lower mortality risk.” (Pan A et al. 2012)
What are red and processed meats?
The study authors defined processed meat as red meat preserved by smoking, curing, salting or adding preservatives, including ham, bacon, pastrami, salami, chorizo, pepperoni hot dogs, and some sausages.
Red meat (beef, lamb, and pork) and minced red meats count as processed meat only if they have been preserved with salt or chemical additives.
And they stressed that moderate consumption or red meat is not inherently unhealthful, noting that it is a good source of protein, iron, zinc, and B vitamins, especially vitamin B12.
Study links processed meat to risk of early death
The authors analyzed data from a study that involved 448,568 men and women from ten countries, who were followed for an average of 13 years … the European Prospective Investigation into Cancer and Nutrition or EPIC (Rohrmann S et al. 2013).
The EPIC participants – who were between 35 and 69 years old – had no history of cancer, stroke, or heart attacks. The study authors had access to the volunteers' body mass indices and self-reported diets and lifestyles.
As an epidemiological study, this data analysis cannot prove a cause-effect relationship between dietary habits and health outcomes.
And measuring the effect of meaty diets on health is made harder by the “confounding” effect of lifestyle factors (smoking, drinking, stress, activity levels) on health.
For example, vegetarians often have healthier lifestyles than meat-eaters, and they're less likely to smoke or be overweight, while being more physically active.
Men and women in the EPIC study who ate the most processed meat also ate the least fruits and vegetables and were more likely to smoke.
Men who ate a lot of meat also tended to drink more alcohol than average. Only studies as large as this one provide enough statistical power to isolate the effects of eating processed meat from other lifestyle factors.
Critically, the link between processed meats and risk of early death remained after the authors adjusted the data to account for other major risk factors such as overweight, smoking, low activity levels, and others.
While it is possible that the results were skewed by the influence of other confounding factors, this study's findings fit with those of many similar ones.
And a study by the World Cancer Research Fund, published in 2007 and confirmed in 2011, provided strong evidence that diets high in processed meats raises the risk of bowel cancer (Chan DS et al. 2011).
The organization estimates that there would be 4,000 fewer cases of bowel cancer annually if people ate less than 10g (one-third ounce) of processed red meat per day.
Bernstein AM, Sun Q, Hu FB, Stampfer MJ, Manson JE, Willett WC. Major dietary protein sources and risk of coronary heart disease in women. Circulation. 2010 Aug 31;122(9):876-83. doi: 10.1161/CIRCULATIONAHA.109.915165. Epub 2010 Aug 16.
BioMed Central Limited (BCL). Processed meat linked to premature death. March 5, 2013. Accessed at http://www.alphagalileo.org/ViewItem.aspx?ItemId=129056&CultureCode=en
Chan DS, Lau R, Aune D, Vieira R, Greenwood DC, Kampman E, Norat T. Red and processed meat and colorectal cancer incidence: meta-analysis of prospective studies. PLoS One. 2011;6(6):e20456. doi: 10.1371/journal.pone.0020456. Epub 2011 Jun 6.
Pan A, Sun Q, Bernstein AM, Schulze MB, Manson JE, Stampfer MJ, Willett WC, Hu FB. Red meat consumption and mortality: results from 2 prospective cohort studies. Arch Intern Med. 2012 Apr 9;172(7):555-63. doi: 10.1001/archinternmed.2011.2287. Epub 2012 Mar 12.
Rohrmann S et al. Meat consumption and mortality - results from the European Prospective Investigation into Cancer and Nutrition. BMC Medicine, 2013; 11 (1): 63 DOI: 10.1186/1741-7015-11-63
Sinha R, Cross AJ, Graubard BI, Leitzmann MF, Schatzkin A. Meat intake and mortality: a prospective study of over half a million people. Arch Intern Med. 2009 Mar 23;169(6):562-71. doi: 10.1001/archinternmed.2009.6.