Participants who had the highest intake of nuts, seeds and fruit with seeds did not have a greater risk of diverticulitis than those who consumed the least.Getty Images
Diet has long been implicated in the development of diverticulitis, a painful gastrointestinal disease.
Consuming too little fibre and too much red meat, for example, has been tied to an increased risk of diverticulitis.
It’s also been thought that eating nuts, seeds and corn can trigger the disease, despite a lack of evidence to support this notion.
In fact, a 2008 study challenged this theory after finding no link between nuts, corn and popcorn consumption and diverticulitis risk.
This study, however, was never replicated, it did not include women nor did it account for diet quality, which has been linked to diverticulitis.
Now, a new study conducted in women provides further evidence that eating nuts, seeds and corn does not set off diverticulitis.
Here’s what to know about the study, plus evidence-based diet strategies to help prevent a diverticulitis flare.
Diverticulitis, diverticulosis defined
Diverticulitis arises from diverticulosis, a condition in which small pouches form and bulge through weak spots in the wall of the colon, typically in the lower part of the colon.
These pouches, called diverticula, are common in older adults. Aging weakens muscles in the wall of the large intestine, increasing the risk of diverticulosis. At least 50 per cent of people over age 60 are thought to have the condition.
Most often diverticula aren’t problematic. When they become inflamed and/or infected, however, diverticulitis occurs. (In medical terms, the suffix “itis” means “inflammation of.”)
Symptoms can range from mild to severe and include intense pain, cramping, bloating, nausea, altered bowel habits and diverticular bleeding.
According to the Canadian Society of Intestinal Research, 10 per cent to 25 per cent of people with diverticulosis will develop diverticulitis. After age 50, diverticulitis is more common in women.
The latest research
The study, published May 5 in the journal Annals of Internal Medicine, investigated the relationship between diet, including nut, seed and corn intake, and risk of diverticulitis in 29,916 women aged 35 to 74 years.
Data, including detailed diet information, was collected at study enrolment and afterwards with annual health updates and detailed follow-up questionnaires every two to three years. Participants were followed for an average of 14 years.
In addition to their usual diet, participants were asked specifically about their intake of peanuts, tree nuts, seeds, corn and fruit with edible seeds (strawberries, tomatoes).
The theory goes that undigested particles of nuts, seeds and corn can trigger diverticulitis when they become stuck in diverticula, causing inflammation.
The researchers found no link, however, between nut and seed intake and risk of diverticulitis. Participants who had the highest intake of nuts, seeds and fruit with seeds did not have a greater risk of diverticulitis than those who consumed the least.
Surprisingly, the study found that compared to people whose diets contained very little corn, participants with the highest intake were 14 per cent less likely to develop diverticulitis.
To eliminate the influence of potential diverticulitis risk factors, the researchers accounted for age, regular use of a non-steroidal anti-inflammatory medication, body mass index, alcohol intake, smoking status and diet quality.
High quality diets protective
The researchers also evaluated whether four dietary patterns – the DASH diet, the Healthy Eating Index, the Alternative Healthy Eating Index and the Alternative Mediterranean Diet – were associated with diverticulitis risk.
Higher adherence to all four eating patterns was tied to a lower the risk of diverticulitis. This was true even after the researchers adjusted for fibre intake.
Women whose diets closely matched the DASH diet, for instance, were 22 per cent less likely to develop diverticulitis over the study period compared to those with low DASH diet scores.
Eating a high-quality diet may guard against diverticulitis by dampening chronic inflammation and improving the composition of the gut microbiome. It may also help prevent metabolic factors associated with diverticulitis, such as Type 2 diabetes.
The new study found associations between diet and diverticulitis; it did not prove a direct causal relationship.
Focus on fibre
A low fibre diet is a risk factor for developing diverticulitis.
A 2020 analysis of five studies involving 865,829 participants found that consuming 30 g of fibre each day was associated with a 44 per cent reduced risk of diverticulitis compared to a low fibre intake.
Which foods you get your fibre from seems to matter too.
A 24-year study involving 50,000 women, published in 2019, found that getting more daily fibre from whole fruit – especially apples, pears and prunes – lowered the risk of diverticulitis.
Eating more cereal fibre each day was also protective. This type of fibre is found in bran, oats, whole wheat pasta, brown rice and other whole grains.
Fibre may protect against diverticulitis by preventing constipation and the pressure it exerts in the colon wall. A high fibre diet also has anti-inflammatory effects.
Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on X @LeslieBeckRD
