I went out to eat last week and gobbled down a steak. Do not judge me: it was medium-rare and delicious. But just before my steak supper, the British Medical Journal published a study of half a million Americans showing that the risk of dying from cancer, heart disease, stroke, diabetes, infections, kidney disease, liver disease or lung disease all increased with the amount of meat consumed. Did I miss any diseases? Could the villainy of red meat be any clearer? Those people with the highest meat intake doubled their chances of dying from chronic liver disease. How so?
All meat contains heme iron and processed meat has nitrates and nitrites added during curing. The authors of the study hypothesise that these additions cause oxidative stress, which means that our cells are less able to defend themselves from damage by free radicals and age prematurely. Other mechanisms include mutagenic substances in cooked meat that are linked to bowel cancer. In the BMJ, John D Potter, professor of epidemiology at Massey University in New Zealand, further argues that the rainforest destruction and greenhouse gas emissions that are a result of the meat industry are more harmful to the planet than fossil fuels used for transport.
So, is it time to give up red meat and, like our relatives the gorillas, embrace vegetarianism? Or is it OK to be like the ancient Greeks and save it for parties?
The link between red meat and cancer is not new. A WHO working group in 2015 looked at more than 800 studies of the link between red meat and cancer and declared red meat as “probably carcinogenic to humans” (there being not enough evidence) and processed meat as “carcinogenic to humans”. WHO concluded that each 50g portion of processed meat a day increased the chance of bowel cancer by 18%. They also linked it to pancreatic and stomach cancer. The Department of Health suggests we eat a maximum of 70g of meat a day (a cooked breakfast with two sausages and two slices of bacon is around 130g). This latest study, like others, shows that substituting white for red meat reduced the risk of dying from most causes.
So, ideally, we should replace most red meat with white meat or fish. If we must have red meat we should avoid anything processed, keep portions small and not barbecue, as animal studies show that direct heat produces cancer-causing chemicals. Barbecued sausages are therefore wrong on many levels. Studies on humans are tricky because they are based on remembering barbecues of the past. All dietary research is tricky as it is hard to control for other factors that might influence disease. Red meat is a good source of proteins, vitamin B, iron and zinc and your individual risk of any of these conditions is likely to be raised by only a small amount per slab of meat. As usual, it’s about moderation.