Tuesday, October 20, 2015

DOES RED MEAT CAUSE CANCER? (Mr Roger Leicester)

With so much focus once again on red meat and cancer, it’s time to dust off SACN’s 2010 Iron and Health report [1] and put things back into perspective.

An exhaustive review of the literature in 2010 by the government’s Scientific Advisory Committee on Nutrition (SACN)[2]  concluded that eating up to 70g of red meat daily does not pose a risk for colorectal cancer. SACN noted difficulties in interpreting the inconsistent evidence base saying: “it is not possible to quantify the amount of red and processed meat that may be associated with increased colorectal cancer risk because of limitations and inconsistencies in the data”.

In fact there is no evidence showing that lean, red meat has any causal relationship with the initiation of cancers.

Avoiding red meat in the diet is not a protective strategy against cancer.  Results from many studies show a very weak association between high red meat consumption and increased risk of cancer.  These include the large EPIC study, of which there is a British cohort, has found similar rates of bowel / colorectal cancer in vegetarians and meat-eaters [3].  Other studies have also shown no association between red meat intake and risk of other types of cancer including prostate [4], and breast cancer [5].

Many studies have attempted to show a link between red meat consumption and cancer but many are poorly designed, using food frequency questionnaires and lacking the use of urinary biomarkers as indicators of red meat intakes.  In fact, the interdependency of food consumption with other dietary and lifestyle factors, socioeconomic characteristics, clinical variables, and genetic traits makes it difficult to isolate the independent effects of a specific food or food group, such as meat intake, on disease risk.

Cancer specialist, Professor Karol Sikora has noted that those people who enjoy eating red meat should continue to do so; he adds: "We have created a nightmare situation of confusing messages based on very little evidence. Eating red meat in the context of a balanced diet should really not be viewed as a problem. Yes, avoid a high calorie, high fat diet - but by all means enjoy that steak.”

Follow the SACN guidance
Instead of the knee jerk reaction of eating less red meat, we have excellent guidance from SACN which advises that people who eat more than 90g red meat daily should lower their intakes to an average of 70g. Given changes to meat consumption over the past decade, average intakes are now 71g suggesting that most people don’t need to change their meat consumption.



References
[2] SACN (Scientific Advisory Committee on Nutrition) (2011). Iron and Health. http://www.sacn.gov.uk/pdfs/sacn_iron_and_health_report_web.pdf
[3] Keys T et al. (2014) Cancer in British vegetarians: updated analyses of 4998 incident cancers in a cohort of 32,491 meat eaters, 8612 fish eaters, 18,298 vegetarians, and 2246 vegans. Am J Clin Nutr 100(suppl): 378S–85S.
[4] Rohrmann, S., et al. (2015). "Intake of meat mutagens and risk of prostate cancer in a cohort of U.S. health professionals." Cancer Epidemiol Biomarkers Prev.   
[5] Alexander, D et al (2010)” A review and meta-analysis of red and processed meat consumption and breast cancer.” Nutr Res Rev 23(2): 349-365

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