Diverticular disease is when small abnormal pouches form in the bowel wall. This condition has two different classifications.
- Diverticulosis – this is the formation of the pouches in the bowel wall
- Diverticulitis – is the inflammation or infection of these small pouches in the bowel wall
Diverticulosis can be present and remain completely asymptomatic causing no issues at all. However, the issue is when diverticulitis develops.
Diverticulitis may present with abdominal pain, bloating, constipation, diarrhoea, flatulence and/or blood in the faeces.
Management of the active states of diverticular disease often involves antibiotics and a low fibre diet. Occasionally it may also involve surgery for some individuals.
Risk Factors Of Diverticular Disease
Low Fibre Diet
Although low fibre diets are suggested when inflammation is present, a habitually low fibre diet has been linked to an increased risk of developing diverticular disease in the first place.
It is hypothesised that a lack of fibre in one’s diet leads to dry and low bulk stools that require more pressure to move the stool through the colon.
Over time, this increase in pressure may result in the formation of diverticula and progress the disease once formed.
Higher fibre diets on the other hand allow for stools that are of adequate bulk that move through the colon easily.
Diets rich in high fibre plant food such as fruits, vegetables, whole grains, nuts and seeds also positively influence the gut microbiome and reduce inflammation.
In fact, studies have shown that vegetarians with a high fibre intake (>40g per day), are less likely to develop diverticular disease. One study found that 33% of non-vegetarians had diverticular disease compared to 12% of their vegetarian participants.
Data from the Million Women Study support the high-fibre hypothesis and found that fibre from fruits and grains is especially protective.
High Meat Consumption
On the other hand, eating a low fibre diet that is high in meat has been associated with a 3-fold increased risk in developing diverticular disease.
High meat consumption has also stood out as an independent risk factor of diverticular disease irrelevant of fibre intake.
In one study of men, those who were in the highest quintile of meat consumption were 58% more likely to develop diverticular disease. Unprocessed meat such as steak actually had the highest risk potentially due to being cooked at higher temperatures or from larger pieces reaching the intestine undigested.
Other Risk Factors of Diverticular Disease
Advancing age, being overweight and living a sedentary lifestyle have also been linked to an increased risk of diverticular disease.
Nutrition For Diverticulitis & Flare Ups
During episodes of inflammation and/or infection, it is typically recommended that a low fibre be adopted until the flare-up has passed.
This is generally common practice when someone presents in hospital with diverticulitis.
However, the benefits of a low fibre diet for the treatment of acute diverticulitis have not been proven in studies.
Two observational studies showed that an unrestricted diet during an episode of diverticulitis did not increase the rate of complications.
Furthermore, another study found there was no difference between an unrestricted diet and intravenous nutrition in regards to pain score, length of hospital stay or other complications. However, this study was also testing the efficacy of oral and intravenous antibiotics which may have swayed results.
It is interesting to note that general practice recommendations of a low fibre diet haven’t yet been backed up by research. However, you should always follow the advice of your individual care team.
Going on a low fibre diet and potentially a liquid diet, may ease the uncomfortable symptoms associated with diverticulitis as it gives the bowel so time to ‘rest’.
Avoiding Certain Foods – Do You Need To?
Some practitioners suggest that people with diverticular disease avoid certain foods to prevent episodes of diverticulitis.
Namely foods like nuts, seeds, corn and other high fibre foods. The theory is that these small bits of food may get lodged in the small pockets of the bowel lining and lead to infection.
However, this also is not supported by evidence.
In fact, in the Health Professionals Follow-up Study which included over 40,000 men aged between 40 and 75 years old, nuts and popcorn were associated with a reduced risk of diverticulitis.
This is likely because they are higher fibre foods that assist with frequent and easy bowel movements.
So there is no need to avoid any of these types of foods if you have diverticular disease. Instead, the focus should be on eating a range of plant-based foods, limiting meat consumption and having an overall adequate fibre intake of at least 30g per day.
What To Eat To Reduce The Risk of Diverticular Disease
Diverticular disease is associated with a fibre-poor diet that is limited in plant-based whole foods such as fruits, vegetables, whole grains, and legumes.
So in turn, it makes sense to increase your intake of these foods.
Ideally, you want to follow a plant-based diet that is low to moderate in meat consumption and avoid very high consumption of meat products.
There is no evidence to suggest that you need to limit all animal products so eggs and dairy can still be incorporated regularly to meet nutrient requirements including protein.
However, animal products do not contain fibre so a diet that overemphasises animal products and contains minimal plant food is going to inherently be low in fibre unless you are taking a fibre supplement.
To have a fibre intake of 30-40g per day and to nourish your gut microbiome you should be including the following foods regularly:
- Vegetables (eg. tomatoes, potatoes, leafy greens)
- Fruit (eg. bananas, dates, pears, kiwi fruit)
- Legumes (eg. chickpeas, lentils, black beans, soy foods including edamame & tofu)
- Nuts (eg. cashews, almonds, brazil nuts)
- Seeds (eg. flaxseed, pumpkin seeds, chia seeds)
- Wholegrains (eg. wholegrain bread, quinoa, high fibre cereals, brown rice)
These foods should form the basis of your diet, whilst animal products, specifically meat, should be a secondary addition.
Note that if you currently have a fairly low fibre diet (<20g per day). You will want to gradually increase your fibre intake to avoid discomfort. If you suddenly increase your fibre intake it is not uncommon to experience some bloating and flatulence.
In order to reduce the risk of developing a diverticular disease or to avoid an episode of diverticulitis, it is recommended that you:
- Lead an active lifestyle and don’t spend too much time being sedentary
- Maintain or strive for a healthy weight
- Have at least 30g of fibre daily
- Eat a wide range of plant-based foods such as fruit, vegetables, nuts, legumes, seeds and wholegrains
- Limit overall meat consumption and consume more plant based proteins such as legumes and tofu
- Stay hydrated to assist with regular bowel movements
- If you are chronically constipated you may also want to see a doctor or dietitian to assist with maintaining regular bowel movements