There have been two warnings in a little over a month about the dangers of eating lots of red meat. The first, a huge European study, suggested a strong link with bowel cancer, and now a smaller British study has found a powerful association with the inflammatory bowel condition Crohn's disease.
Now consider this puzzle. Mormons and Seventh-Day Adventists lead similar lifestyles - they don't smoke, they don't drink and they go to church. But there is a key dietary difference: Mormons eat meat while most Seventh-Day Adventists are vegetarians.
If red meat is a major cause of bowel cancer, then Mormons ought to have higher rates of the disease. But they do not.
Some commentators think this demolishes the claims of scientists who would have us cut down on meat-eating. It doesn't - but it does highlight the difficulty of establishing clear causes. There are only two really significant causes of cancer - smoking and getting older. Everything else pales into insignificance by comparison. With lesser causes, such as red meat, other mitigating factors play a greater role - genetic inheritance, exercise, other elements in the diet.
So how should the average meat-eater respond to the latest research? The warning on red meat is worth heeding because of the place animal flesh plays in the typical Western diet. You do not need to eat steak three times a day to notch up a surprising tally in grams of red meat. The simplest advice, therefore, is not to abandon meat but to think more like a vegetarian - not a pulse-promoting obsessive, but one who cheats with an occasional bacon butty or steak and chips.
As a counter to the evidence from the Mormons and Seventh-Day Adventists, it is worth noting that bowel-cancer rates have risen sharply among the Japanese as they have adopted a Western diet.
Last month's study was the largest ever conducted into the health effects of Europe's passion for meat. Called the European Prospective Investigation into Cancer and Nutrition (Epic), and funded by the UK Medical Research Council and Cancer Research UK among others, it involved 500,000 Europeans in 10 countries whose diets were monitored for five years. The results, published in the Journal of the National Cancer Institute, showed that those who ate two portions a day of red meat - beef, lamb, pork, veal and their processed varieties, ham and bacon - had a third higher risk of developing bowel cancer than those who ate one portion a week.
The high-risk group were eating more than 160 grams of red meat a day - equivalent to two large beef burgers (80 grams each). The average Briton eats 93 grams of red meat a day according to British Meat, allowing it to claim that there was no reason for most people to change their habits. "If you eat meat you are not going to get cancer," a spokesman said.
It is a fair claim. Man has been eating red meat for millennia. But aside from the fact that we live longer now - long enough to develop cancer - we also probably eat more meat than our ancestors. Red meat is also high in fat, which increases the risk of heart disease, providing an added reason to cut down.
In many parts of the world, and in some Mediterranean countries, meat is regarded as a relish or a treat, with the bulk of the meal coming from carbohydrates and vegetables. In contrast, a modern office worker grabbing a bacon sandwich to start the day (two rashers at 30 grams each), eating sausages for lunch (two at 40 grams each) and lamb chops in the evening (80 grams) can quickly ramp up his or her red meat quotient without going near a Big Mac or a steak and chips.
The study showed that the effects of meat-eating were lessened among those who ate plenty of fibre in the form of vegetables and fruit. Those who ate fish every other day also cut their risk.
Doctors believe up to two-thirds of bowel cancers could be prevented by changes in diet and lifestyle. But there is no magic bullet as there is with lung cancer (by cutting out smoking). Defeating bowel cancer will require a multi-pronged approach - changing aspects of diet and lifestyle (especially smoking and drinking, which also contribute to bowel cancer) across a wide front.
The second, smaller study published last week, by researchers at the University of East Anglia, followed the diets and lifestyles of 218 patients over two years and found a 40 per cent increased risk of Crohn's disease among meat-eaters.
The Food Standards Agency has asked its food safety advisers to examine the findings and consider what further research may be necessary. But the agency reiterated its advice that red meat had a place in a balanced and varied diet because it was a good source of iron, zinc, B vitamins and protein. It also pointed out that as we typically eat meat with vegetables and potatoes, we get the fibre that protects against bowel cancer. Maintaining levels of iron is a priority for women, who lose the mineral with each monthly period, and are at risk of anaemia.
About 35,000 cases of bowel cancer are diagnosed each year in the UK, with men slightly more likely to get the disease than women. It is the third most common cancer in men - after cancers of the lung and prostate - and the second most common in women after breast cancer.
Any measure that can reduce this toll without adversely affecting quality of life has to be worth thinking about. If it is right to revere the roast beef of Old England - it is worth saving it for special occasions.Reuse content