High red meat intake a risk factor for an inflamed gut: Harvard study
The study found the highest level of red meat intake was related to a 58% increased risk of developing diverticulitis, when compared with the lowest levels of consumption.
With each daily serving an 18% increased risk was correlated. This risk reached a high at six servings per week and was particularly strong for unprocessed red meat, such as steak.
Replacing one daily portion of meat with fish or poultry lowered risk by 20%.
Study criteria
A follow-up study, involving nearly 46,500 men, used a food frequency questionnaire (FFQ) to ascertain how often, on average, they had eaten standard size portions of red meat, including processed meat; poultry; and fish, over the preceding year.
These men, aged 40 to 75 when they joined the study between 1986 and 2012, were monitored for this 26 year period, in which 764 of them developed diverticulitis.
After taking account of potentially influential factors, such as lifestyle and medication, total red meat intake was associated with heightened diverticulitis risk.
“We observed that unprocessed red meat, but not processed red meat, was the primary driver for the association between total red meat and risk of diverticulitis,” the study’s authors observed.
“Unprocessed meat is usually consumed in larger portions, which could lead to a larger undigested piece in the large bowel and induce different changes in colonic microbiota.
“In addition, higher cooking temperatures used in the preparation of unprocessed meat may influence bacterial composition or proinflammatory mediators in the colon.”
The researchers pointed to previous observations that higher red meat consumption correlates to an increase in C-reactive protein and ferritin, substances that could promote inflammation.
The substances’ relationship to heart disease/stroke and diabetes were also well-established with research indicating their role in the chronic inflammation characteristic of these conditions.
Besides dietary fibre, the role of other dietary factors in the prevention of diverticulitis has previously been underexplored.
Fibre’s role in diverticulitis risk has been the subject of a number of European studies.
A recent UK population-based cohort study found that risk of diverticular disease was 31% lower among vegetarians or vegans compared with meat eaters.
Diverticulitis dossier
Diverticulitis is a digestive condition that affects the large intestine (colon). Here small bulges develop in the intestine’s lining that become inflamed or infected.
It is often described as a 'Western disease' because cases are high in Europe and North America and comparatively low in African and Asian countries.
Genetic and dietary influences are thought to explain this observation along with a relatively low dietary fibre intake in Western countries.
Individuals aged 50-70 who consume high-fibre foods (25g a day) were found to have a 40% lower chance of suffering complications of diverticular disease.
Study limitations
The significance of this result was a feature of this study that the team could not develop on.
The limited number of people consuming a vegetarian diet meant the team were unable to estimate the substitution effect of a vegetarian dish.
Other limitations of the study were its observational nature that restricted any firm conclusions to be drawn regarding cause and effect.
The British Society of Gastroenterology has estimated that between one-third and a half of the population of Western Europe will get diverticula in the colon during their lifetime.
The likelihood of having the condition increases as a person gets older. Less than one person in 20 has the condition before the age of 40, rising to a quarter by 60 years of age and two-thirds by the age of 85.
Source: Gut
Published online ahead of print: doi:10.1136/gutjnl-2016-313082
“Meat intake and risk of diverticulitis among men.”
Authors: Andrew Chan et al.
