A high dietary intake of red meat is linked to a heightened risk of developing the common inflammatory bowel condition diverticulitis, according to research published online in the journal Gut.
Diverticulitis occurs when the small pockets or bulges lining the intestine (diverticula) become inflamed. It is relatively common, accounting for more than 200,000 hospital admissions every year in the United States at an annual cost of $2 billion.
New cases of the condition are on the rise, particularly among younger people. And around 4 percent of those affected will develop severe or long term complications, such as perforations in the gut wall, abscesses, and fistula (abnormal connections between two hollow spaces).
Yet despite its prevalence and impact, not much is known about what causes diverticulitis, although it has been linked to smoking, the use of non-steroidal anti-inflammatory drugs (NSAIDs), physical inactivity and obesity.
Insufficient dietary fiber intake is also thought to have a role, but few other dietary factors have been explored in any detail.
In a bid to rectify this, the research team from Massachusetts General Hospital assessed the potential impact of total dietary red meat, poultry and fish intake on the risk of developing diverticulitis in nearly 46,500 men, taking part in the Health Professionals Follow-Up Study.
The men were all aged 40 to 75 when they joined the study between 1986 and 2012. Every four years they were asked to state how often, on average, they had eaten standard size portions of red meat, including processed meat; poultry; and fish, over the preceding year.
They were given nine options, ranging from “never” or “less than once a month” to “six or more times a day.”
During the 26-year monitoring period, 764 men developed diverticulitis.
Those who ate higher quantities of red meat tended to use common anti-inflammatory drugs and painkillers more often; they smoked more; and they were less likely to exercise vigorously. Their fiber intake was also lower.
Compared with the lowest levels of consumption, the highest level of red meat intake was associated with a 58 percent heightened risk of developing diverticulitis, with each daily serving associated with an 18 percent increased risk. However, risk peaked at six servings a week.
The association was strongest for unprocessed red meat, and substituting one daily portion of this with fish or poultry was associated with a 20 percent lowered risk.
The overall findings did not seem to be influenced by overweight or age.
Exactly how red meat intake might affect diverticulitis risk is not clear, and further research is required, the authors concluded.
This is an observational study, so no firm conclusions can be drawn about cause and effect, the researchers point out. But they conclude that their “findings may provide practical dietary guidance for patients at risk of diverticulitis, a common disease of huge economic and clinical burden.”
“As we have seen frequently with these type of observational studies, researchers are attempting to make broad conclusions from self-reported intake questionnaires, in this case completed once every four years. This is not a recipe for meaningful results,” according to KatieRose McCullough, director of scientific and regulatory affairs for the North American Meat Institute. “In particular with the diverticulitis study, researchers point out that the condition has been on the rise, but ignore the fact that overall red meat consumption has declined during their study period, which is contradictory to their results. In addition, the inconsistent data between red and processed meat intake raises similar questions given that red meat is most often the primary ingredient in processed products.”
She added that Americans concerned about their health are “best served to follow the advice in the Dietary Guidelines for Americans which shows that red meat can be part of a healthy balanced diet and offers numerous nutrition benefits.”