Last updated by Dr Sarah Brewer on
I’d love to follow a more plant-based diet, but the slightest whiff of sizzling bacon or roasting lamb reduces my breaking strain to that of a gnat. Why do the crunchy bits on a BBQ fillet taste so good if they’re really so harmful?
When meat is charred, chemicals known as heterocyclic amines (HCAs) are produced. The longer the meat is cooked, and the higher the temperature, the more HCAs are generated. This is the most popular explanation for observations that high intakes of barbecued, fried and roasted red meat are associated with an increased risk of certain cancers, including those of the stomach, bowel and pancreas. Processed meats such as smoked bacon, sausages and ham have also been linked with an increased risk of cancer as salting, curing, smoking or adding chemical preservatives increase the level of potential carcinogens such as HCAs, polycyclic aromatic hydrocarbons and nitrosamines.
This all seems to make horrible sense, but none of these hypotheses completely explain the link between eating meat and cancer risk, leaving scientists to regularly propose additional mechanisms or refine their theories.
So what’s a meat lover to do? Especially when the World Cancer Research Fund advises that those of us who enjoy red meat (beef, pork, lamb, goat etc) should have less than 500g (18 oz) a week, very little of which (if any) should be processed. Their ultimate goal is to get population average intakes down to no more than 300g (11 oz) per person per week.
I’m happy to eat fish, have one or two veggie days a week, and already replace half the meat in a recipe with chestnut mushrooms, grated carrots and courgettes. My chilli is more non carne than con carne – but I do love a nice, juicy steak. Is red meat really as bad as its reputation?
The bad news is not as bad as it looks
Most studies comparing omnivores with those following a plant-based diet have focussed on meat as the missing factor and assigned any observable differences to its consumption.
A scientific analysis published in the European Journal of Clinical Nutrition argues that what meat-eaters are failing to eat is probably more important. Those eating the most meat also tend to eat the least fruit, the least vegetables, the least wholegrains and fewer nuts and seeds than those with low meat intakes. That means their diet contains fewer of the plant-based nutrients that are known to protect against certain cancers such as isoflavones, lignans, flavonoids and glucosinolates to name a few.
Many people who follow a plant-based diet also have an admirable lifestyle and tend to avoid smoking and excess alcohol, exercise regularly and select wholefoods rather than processed ready-meals. When these factors are accounted for, along with age, calorie intake and education, any link between eating red meat and risk of cancer becomes less scary. In fact, the latest update, looking at all the science, concluded that the association between red meat consumption and bowel cancer is best described as weak ‘with an inability to disentangle effects from other dietary and lifestyle factors, lack of a clear dose-response effect, and weakening evidence over time.’
An important question is – do vegetarians live longer than meat eaters? Research from Oxford University suggests that, in a British population at least, mortality rates are similar between vegetarians and non-vegetarians. If vegetarians are dying less from some causes, they are probably dying more from others, perhaps associated with raised homocysteine levels, platelet stickiness and low intakes of vitamin B12 or omega-3s although, as always, more research is needed.
What’s the work-around?
Where does this leave those of us who dream of a tasty rib-eye? The best advice I could find is that for each 100g of grilled meat you eat, you should also eat 200g of vegetables, either grilled or as a side salad. Seems easy enough. In fact, I can definitely do that. What about you?
Image credits: The Rock Garden – my favourite Guernsey Steak House.