Diet high in red meat linked to inflammatory bowel condition

Eating large amounts of unprocessed meat has been linked to an increased risk of getting an inflammatory bowl condition, according to a new study.

Researchers analysed information about the diets of more than 46,000 men in the US, of whom 764 developed the condition, called diverticulitis, over a period of 26 years. Those who ate the highest amounts of red meat had a 58 per cent higher chance of getting the disease compared to those who consumed the least, the study found.

However the scientists, from Harvard Medical School and other leading academic and medical institutions in Boston, said it was unclear how red meat might affect the disease.

Saying further research was required, they suggested it might affect the bacteria in the gut, which in turn could alter the immune system and irritate the gut lining.

The link was stronger for unprocessed than processed red meat, which the researchers speculated could be because higher cooking temperatures used in the latter reduced the effect.

A statistical correlation is not conclusive evidence of a cause and it could be because of other habits common among red-meat eaters.

The researchers said those in their sample tended to smoke more, take less vigorous exercise and eat less fibre. And those who ate more fish and poultry instead also usually smoked less and exercised harder. But the scientists said the link persisted despite taking these potentially significant factors into account.

Writing in the journal Gut, the scientists said: “We found that intake of red meat, particularly unprocessed red meat, was associated with an increased risk of diverticulitis.

“Substitution of unprocessed red meat with poultry or fish may reduce the risk of diverticulitis.

"Our findings may provide practical dietary guidance for patients at risk of diverticulitis, a common disease of huge economic and clinical burden.

“The mechanisms underlying the observed associations require further investigation.”

In the US, diverticulitis results in more than 200,000 hospital admissions a year at an annual cost of $2bn (£1.6bn).

According to the NHS website, the disease produces small bulges or pockets in the lining of the intestine, which can cause lower abdominal pain and make people feel bloated.

This less serious form is known as diverticulosis and some people do not have any symptoms.

Full-blown diverticulitis can result in severe abdominal pain, especially on the left side, a fever and diarrhoea or frequent bowel movements.

The NHS suggests a high-fibre diet “can often ease symptoms” of the milder form of the disease while antibiotics can be used to treat the more serious version.

“People aged 50-70 who eat a high-fibre diet (25g a day) have a 40 per cent lower chance of admission to hospital with complications of diverticular disease – compared to others in their age range with the lowest amount of dietary fibre,” the website adds.

However Dr Carrie Ruxton, of the UK's Meat Advisory Panel, said: “This is yet another exercise where a large observational study is milked to produce statistical links between diet and reported disease 25 years later.

"It is highly unlikely that the results represent a real causal link between red meat and diverticulitis, particularly as the association was not seen in processed meat, which tends to be higher in fat and salt than fresh red meat.

"Indeed, the authors themselves noted that 'pathways through which red meat consumption may influence risk of diverticulitis are yet to be established'.

“The best way to lower the risk of diverticulitis and diverticular disease is to boost fibre intakes significantly to 30g per day, as recommended by the Scientific Advisory Committee on Nutrition.

"Current intakes in the UK are less than 20g. Lean red meat, around five times a week in modest amounts, can be a nutritious part of a high-fibre diet”.