Eating Processed Meats, but Not Unprocessed Red Meats, May Raise Risk of Heart D

[Guest guest]

Eating Processed Meats, but Not Unprocessed Red Meats, May Raise Risk of

Heart Disease and Diabetes

_http://www.hsph.harvard.edu/news/press-releases/2010-releases/processed-mea

ts-unprocessed-heart-disease-diabetes.html_

(http://www.hsph.harvard.edu/news/press-releases/2010-releases/processed-meats-u\

nprocessed-heart-disease-dia

betes.html)

Boston, MA—In a new study, researchers from the Harvard School of Public

Health (HSPH) have found that eating processed meat, such as bacon, sausage

or processed deli meats, was associated with a 42% higher risk of heart

disease and a 19% higher risk of type 2 diabetes. In contrast, the researchers

did not find any higher risk of heart disease or diabetes among

individuals eating unprocessed red meat, such as from beef, pork, or lamb. This

work

is the first systematic review and meta-analysis of the worldwide evidence

for how eating unprocessed red meat and processed meat relates to risk of

cardiovascular diseases and diabetes.

“Although most dietary guidelines recommend reducing meat consumption,

prior individual studies have shown mixed results for relationships between

meat consumption and cardiovascular diseases and diabetes,†said Renata

Micha, a research fellow in the department of epidemiology at HSPH and lead

author of the study. “Most prior studies also did not separately consider the

health effects of eating unprocessed red versus processed meats.â€

Watch a video of Micha describing the findings:

_http://www.hsph.harvard.edu/multimedia/Video/2010/processedmeat/index.html_

(http://www.hsph.harvard.edu/multimedia/Video/2010/processedmeat/index.html)

The study appears online May 17, 2010, on the website of the journal

Circulation.

The researchers, led by Micha and HSPH colleagues Dariush Mozaffarian,

assistant professor in the department of epidemiology and Wallace,

junior research fellow in the department of epidemiology, systematically

reviewed nearly 1,600 studies. Twenty relevant studies were identified, which

included a total of 1,218,380 individuals from 10 countries on four continents

(North America, Europe, Australia, and Asia).

The researchers defined unprocessed red meat as any unprocessed meat from

beef, lamb or pork, excluding poultry. Processed meat was defined as any

meat preserved by smoking, curing or salting, or with the addition of

chemical preservatives; examples include bacon, salami, sausages, hot dogs or

processed deli or luncheon meats. Vegetable or seafood protein sources were not

evaluated in these studies.

The results showed that, on average, each 50 gram (1.8 oz) daily serving

of processed meat (about 1-2 slices of deli meats or 1 hot dog) was

associated with a 42% higher risk of developing heart disease and a 19% higher

risk

of developing diabetes. In contrast, eating unprocessed red meat was not

associated with risk of developing heart disease or diabetes. Too few

studies evaluated the relationship between eating meat and risk of stroke to

enable the researchers to draw any conclusions.

“Although cause-and-effect cannot be proven by these types of long-term

observational studies, all of these studies adjusted for other risk factors,

which may have been different between people who were eating more versus

less meats,†said Mozaffarian. “Also, the lifestyle factors associated with

eating unprocessed red meats and processed meats were similar, but only

processed meats were linked to higher risk.â€

“When we looked at average nutrients in unprocessed red and processed

meats eaten in the United States, we found that they contained similar average

amounts of saturated fat and cholesterol. In contrast, processed meats

contained, on average, 4 times more sodium and 50% more nitrate

preservatives,â€

said Micha. “This suggests that differences in salt and preservatives,

rather than fats, might explain the higher risk of heart disease and diabetes

seen with processed meats, but not with unprocessed red meats.â€

Dietary sodium (salt) is known to increase blood pressure, a strong risk

factor for heart disease. In animal experiments, nitrate preservatives can

promote atherosclerosis and reduce glucose tolerance, effects which could

increase risk of heart disease and diabetes.

Given the differences in health risks seen with eating processed meats

versus unprocessed red meats, these findings suggest that these types of meats

should be studied separately in future research for health effects,

including cancer, the authors said. For example, higher intake of total meat

and

processed meat has been associated with higher risk of colorectal cancer,

but unprocessed red meat has not been separately evaluated. They also

suggest that more research is needed into which factors (especially salt and

other preservatives) in meats are most important for health effects.

Current efforts to update the United States government’s Dietary

Guidelines for Americans, which are often a reference for other countries

around the

world, make these findings particularly timely, the researchers say. They

recommend that dietary and policy efforts should especially focus on

reducing intake of processed meat.

“To lower risk of heart attacks and diabetes, people should consider which

types of meats they are eating. Processed meats such as bacon, salami,

sausages, hot dogs and processed deli meats may be the most important to avoid,

†said Micha. “Based on our findings, eating one serving per week or less

would be associated with relatively small risk.â€

“Red and Processed Meat Consumption and Risk of Incident Coronary Heart

Disease, Stroke, and Diabetes Mellitus: A Systematic Review and Meta-Analysis,

†Renata Micha, K. Wallace, Dariush Mozaffarian, Circulation, online

May 17, 2010.

For more information:

Todd Datz

617.998.8819

_tdatz@..._ (mailto:tdatz@...)

Visit the HSPH website for the latest news, press releases and multimedia

offerings.

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