No Meat or Dairy Question

A Prospective Study of Red and Processed Meat Intake in Relation to Cancer Risk

Posted 02/11/2008

Amanda J. Cross; Michael F. Leitzmann; Mitchell H. Gail; Albert R. Hollenbeck; Arthur Schatzkin; Rashmi Sinha
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Abstract and Introduction

Abstract

Background: Red meat and processed meat have been associated with carcinogenesis at several anatomic sites, but no prospective study has examined meat intake in relation to a range of malignancies. We investigated whether red or processed meat intake increases cancer risk at a variety of sites.
Methods and Findings: The National Institutes of Health (NIH)-AARP (formerly the American Association for Retired Persons) Diet and Health Study is a cohort of approximately 500,000 people aged 50-71 y at baseline (1995-1996). Meat intake was estimated from a food frequency questionnaire administered at baseline. Cox proportional hazards regression was used to estimate hazard ratios and 95% confidence intervals within quintiles of red and processed meat intake. During up to 8.2 y of follow-up, 53,396 incident cancers were ascertained. Statistically significant elevated risks (ranging from 20% to 60%) were evident for esophageal, colorectal, liver, and lung cancer, comparing individuals in the highest with those in the lowest quintile of red meat intake. Furthermore, individuals in the highest quintile of processed meat intake had a 20% elevated risk for colorectal and a 16% elevated risk for lung cancer.
Conclusions: Both red and processed meat intakes were positively associated with cancers of the colorectum and lung; furthermore, red meat intake was associated with an elevated risk for cancers of the esophagus and liver.

Introduction

Much of the global variation in cancer incidence has been attributed to environmental influences, including dietary preferences. Not only does meat intake vary substantially around the world, but diets high in red or processed meats have been associated with carcinogenesis at a variety of anatomic sites. The evidence to support a positive association between meat intake and carcinogenesis is based on an assortment of research ranging from laboratory studies^[1-3] to observational epidemiology.^[4-8]

Thus far, the majority of epidemiologic meat research has focused on the more prevalent cancers, particularly colorectal cancer. The most recent meta-analysis of prospective studies of meat and colorectal cancer reported significantly elevated summary relative risks (RRs) for both red meat (RR = 1.28; 95% confidence interval (CI) = 1.15-1.42) and processed meat (RR = 1.20; 95% CI = 1.11-1.31) in the highest versus lowest category of intake.^[9] To date, findings for other major cancers-such as prostate, breast, lung, and pancreatic cancer-are less consistent. Prospective data for rarer cancers are sparse, and most epidemiologic studies of less-commonly occurring cancers are restricted to case-control studies, for which investigations of dietary associations are difficult, because of the potential for recall bias.^[10]

We prospectively investigated red and processed meat intake in relation to cancer incidence in a cohort of approximately half a million men and women enrolled in the National Institutes of Health (NIH)-AARP (formerly known as the American Association for Retired Persons) Diet and Health Study. This study's large size facilitated the investigation of comparatively rare cancers that have not yet been prospectively investigated.

Red-Meat Eaters Risk Colon Cancer

Jan. 11, 2005 -- Bad news for beef eaters: Red meat really does increase your risk of colon cancer.

It's not exactly news. Many studies suggest that people who eat the most meat get the most cancer. Now a huge, 20-year study from the American Cancer Society confirms these findings. The bottom line: Those who eat the most red meat -- beef and/or pork and/or processed meat products -- get colon cancer 30% to 40% more often than those who eat these foods only once in a while.

The news is particularly bad for those who favor lots of lunchmeats, hot dogs, and sausages. Eating lots of these processed foods raises colon cancer risk by 50%, reports Marjorie L. McCullough, ScD, senior epidemiologist at the American Cancer Society in Atlanta. McCullough and colleagues report the findings in the Jan. 12 issue of The Journal of the American Medical Association.

"The bottom line is that the people who were eating the most red meat had higher colon cancer risk than those eating the least," McCullough tells WebMD. "Very few of these lower-risk people ate no red meat. It is not that we are saying people can never have red meat. But this shows it is important to limit the amount of red meat you eat."

The researchers collected detailed information on the diets of nearly 150,000 men and women aged 50 to 74 living in 21 U.S. states. They collected data in 1982 and 1992-1993, and followed them through the end of August 2001. In that time, 1,667 of the study participants developed colon cancer.

The study accounted for factors that are known to increase colon cancer risk, such as smoking, being overweight, little physical activity, alcohol use, age, and low fiber intake as well as factors known to decrease risk, such as daily aspirin use.

How Much Red Meat Is Safe to Eat?

The findings are sobering, given the amount of red meat Americans love to eat.

"For Americans, estimates of per capita red-meat consumption come out to a little more than 5 ounces per day," McCullough says. "That is a little higher than the highest level of red-meat consumption in this study."

People who ate more fish, chicken, and turkey than red meat had a lower colon cancer risk than those who preferred beef and pork.

"Those consuming higher amounts of poultry and fish, especially for the long term, had about a 30% lower risk of developing colon cancer compared to those who did not eat much poultry and fish," McCullough says. "People who had red meat two to three times as often as white meat had about a 50% higher risk of developing colon cancer."

So how much red meat is too much? Burger lovers, fasten your seat belts. In the study, high red meat consumption was 3 ounces a day for men and 2 ounces for women. That's right. Barely enough daily hamburger to cover your palm raises cancer risk.

More "Food for Thought"

Dana Farber August 19, 2008: Eating a lot of red meat during adolescence may increase the risk of breast cancer among premenopausal women, a new study reports. The findings are based on a study published in a recent issue of Cancer Epidemiology, Biomarkers and Prevention conducted by Dana-Farber oncologist Lindsay Frazier, MD, Sc M, and colleagues at the Harvard School of Public Health and Harvard Medical School.

Red meat consumption during adulthood has been previously shown to spur hormone-fueled breast cancer in women ages 26 to 46. The new study is the first prospective study to show a connection between a diet high in red meat during adolescence and the development of pre-menopausal breast cancer.

ScienceDaily (Apr. 8, 2007) - Eating red meat increases a woman's chance of developing breast cancer, according to new research from the University of Leeds. The findings are most striking for post-menopausal women - those with the highest intake of red meat, the equivalent to one portion a day (more than 57 grams) - run a 56 per cent greater risk of breast cancer than those who eat none.

Researchers at the University's Centre for Epidemiology and Biostatistics have been tracking the eating habits and health of more than 35,000 women for the past seven years, and their latest findings are published in the British Journal of Cancer.

AP  Wed., Feb. 7, 2007  Women who ate more than 1½ servings of red meat per day were almost twice as likely to develop hormone-related breast cancer as those who ate fewer than three portions per week, one study found. The meat study was published in Monday's Archives of Internal Medicine. The women who ate more red meat were more likely to smoke and be overweight, but when the researchers took those factors into account, they still saw that red meat was linked with an increased risk of breast cancer.

Washington Post, Tuesday, November 14, 2006; Page A01: Younger women who regularly eat red meat appear to face an increased risk for a common form of breast cancer, according to a large, well-known Harvard study of women's health. Those who consumed the most red meat had nearly twice the risk of those who ate red meat infrequently. The study, published yesterday in the Archives of Internal Medicine, is the first to examine the relationship between consumption of red meat and breast cancer in premenopausal women, and the first to examine the question by type of breast cancer. (See below)

Archives of Internal Medicine Vol. 166 No. 20, November 13, 2006: Greater red meat intake was strongly related to elevated riskof breast cancers that were estrogen and progesterone receptorpositive but not to those thatwere estrogen and progesterone receptor negative

 Iza-

You quoted: "The take-home message for postmenopausal women is that limiting dietary fat is unlikely to reduce their risk for breast cancer," lead study author Dr. Esther H. J. Kim told Reuters Health.

This is because the BC-fat link is for ER negative tumors.  The majority of BC in postmenopausal is ER+.

American Society of Clinical Oncology annual meeting, Orlando, Florida, May 16, 2005.)

"Postmenopausal women who ate a low-fat diet were less likely to get a recurrence of breast cancer than those who ate a standard diet. This is the first time a large randomized clinical trial has shown that a low-fat diet can reduce the chance of breast cancer coming back."

And from the San Antonio Breast Cancer Symposium (2006):  SAN ANTONIO, Dec. 16 -- A diet with 20% of calories from fat, or less, may help reduce risk of breast cancer recurrence, particularly for women with hormone-receptor-negative disease, according to a large trial.

Among more than 2,400 women with early breast cancer followed for 5.8 years, there were 22% fewer deaths for those on the low-fat diet, although this difference was not significant, said Rowan T. Chlebowski, M.D., Ph.D., of Harbor-UCLA Medical Center in Torrance, Calif. But it was significant for a subset with estrogen-receptor-negative disease.

The randomized, prospective trial comparing a low-fat diet with a normal diet was presented at the San Antonio Breast Cancer Symposium and published simultaneously in the Journal of the National Cancer Institute.

If women lower their fat intake (expressed as a percentage of their overall diet), that automatically means they up their intake of something else. Since we all seem to agree that a healthy diet also needs to be low in carbs, I am assuming this means more protein (again, I am talking about percentages here). Given that there also seems to be general consensus that soy is not a good idea in general, and particularly among women with estrogen-positive breast cancer, and also given that highly-processed foods such as fake meats are unhealthy in many ways, it does look like upping traditional sources of protein (as a percentage of one's diet) might be the way to go.

(We all know what traditional sources of protein are)

To aid to the original question:

Kale... Big calcium supplier. I add it to all my leafy green salads.