3 Foods to Avoid to Prevent a Diverticulitis Flare-Up—And What to Eat Instead
If you have even the slightest working knowledge of diverticulitis, you've probably heard the "recommendation" to steer clear of any of the following: nuts, seeds, popcorn, corn—basically anything that seems difficult to fully digest, for fear that it will agitate the condition.
Turns out, that's faulty advice. There's no evidence that these foods boost the risk, according to the Cleveland Clinic—in fact, it directly contradicts advice doctors give their patients to prevent the condition in the first place (to eat a healthy, high-fiber diet).
There are, however, a few foods you may want to limit in your diet, either while you're enduring a diverticulitis flare or to avoid one in the future. Here's what we know about the dietary tweaks that may be helpful.
What to know about diet and diverticulitis
A diagnosis of acute diverticulitis means you have one or more little pockets (called diverticula) along the wall of the colon that have become infected or inflamed, says the American Gastroenterological Association (AGA). If it's an uncomplicated case, you'll likely be treated with a special diet. Some people may receive antibiotics.
After a few days of bowel rest (during which you'll follow a liquid or low-fiber diet), people usually start to feel better, according to the AGA. At that point, the goal is to prevent another painful episode. About 20% of people with diverticulitis go on to have a future attack.
Once someone has fully recovered from a diverticulitis attack, "he or she should theoretically be eating a normal, healthy, high-fiber diet," Ryan Warren, RD, CDN, a New York City-based registered dietitian and clinical nutritionist, tells Health.
While there's no surefire way to prevent diverticulitis—indeed, your genes play a significant role, says AGA—the evidence to date suggests that dietary fiber can be protective. According to Harvard Health, a high-fiber diet "will sharply reduce" the risk of developing diverticula in the first place. And if you do develop these little pouches, the chances that they will become inflamed or infected is also reduced, it says.
Recognizing the role that fiber plays, AGA recommends that people with a history of diverticulitis consume a "high-quality diet," which includes foods that are high in fiber, such as fruits, vegetables, whole grains, and legumes.
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Are nuts and seeds really OK to eat if you have diverticulosis (or have had diverticulitis)?
Years ago, doctors worried that small bits of roughage in a person's diet could block and irritate the little sacs that can form along the wall of the colon, leading to diverticulitis. But there was no real evidence to support this theory, says Harvard Health.
A large study published more than a decade ago in JAMA helped to put that myth to rest. Some 47,000 men with no known diverticulitis were followed for 18 years. The study found no increased risk of diverticular complications, including diverticulitis. In fact, nut and popcorn consumption appeared to be slightly protective.
Recently, AGA weighed in: "Nut, corn, and popcorn consumption is not associated with an increased risk of diverticulitis," the medical group noted. Likewise, it added, there's no proof that ingesting seeds, including tiny seeds found in strawberries and blueberries, boosts diverticulitis risk.
As Cleveland Clinic points out, seeds are actually part of a high-fiber diet, which again, is recommended to reduce the risk of diverticulitis.
So what foods should you limit to lower your risk of a diverticulitis flare-up?
To avoid a recurrence (or possibly stave off an initial bout) of diverticulitis, doctors and dietitians recommend a healthy, fiber-rich diet. It doesn't particularly matter which dietary pattern you follow, as long as it includes plenty of vegetables, fruits, and other plant-based foods.
"We encourage our patients to focus on high-quality, nutrient-dense foods that they should be eating," Warren says.
As for foods to eat less of, experts and studies suggest that people limit their intake of:
The evidence is strongest for red meat consumption. One 2018 study published in the journal Gut, involved the health and diet information from roughly 46,000 men over 26 years. The men who consumed the most red meat per week (especially unprocessed red meat like steak) had a 58% greater risk of developing diverticulitis compared to those eating the least amount each week. The study doesn't prove the eating red meat causes diverticulitis, but it does show an association. A person's risk of diverticulitis rose 18% per serving of red meat consumed per day.
Another large study, in Gastroenterology, examined overall dietary patterns, rather than individual foods. A typical Western diet (think: red meat, refined grains, high-fat dairy) was associated with an increased risk of diverticulitis, while something called a "prudent pattern" was tied to a decreased risk.
"The prudent pattern, which is high in fruits and vegetables, low in meat, low in processed foods, low in sweets, low in fat, is beneficial," Lisa Strate, MD, the study's lead author and professor of medicine at the University of Washington in Seattle, tells Health.
On a food-specific basis, Dr. Strate and colleagues concluded that the link between dietary pattern and diverticulitis is primarily due to fiber and red meat intake.
The take home message? It may not be a single food, necessarily, that makes or breaks your risk of diverticulitis. As the authors of a recent systematic review in the journal Nutrients point out, "attention must be focused on the entirety of dietary pattern."
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