Not everyone has diverticula, but the majority of people will develop them with age. These small, bulging pouches form in the wall of the colon and become increasingly common over time. More than 30% of U.S. adults between ages 50 and 59 have them, and that number climbs past 70% for people older than 80. Among younger adults, diverticula are less common but not rare, and rates have been rising in recent decades.
How Common Diverticula Are by Age
Diverticula are relatively uncommon before age 40, though they do occur. After 50, prevalence rises sharply with each decade. By the time people reach their 80s, having diverticula is more the norm than the exception. The condition of simply having these pouches is called diverticulosis, and it’s one of the most common findings on routine colonoscopies in older adults.
Where you live and what you eat also matter. In Western countries, prevalence ranges from about 5% to 45% across all age groups, with some nations approaching 40%. In parts of Asia and Africa with traditionally high-fiber diets, rates have historically been well below 1%. That gap has been narrowing, though. As countries adopt more Western-style eating patterns, their diverticulosis rates have climbed in parallel.
Why Diverticula Form
The colon wall isn’t uniformly thick. There are natural weak spots where blood vessels pass through the muscle layer, and these are the points where diverticula tend to push outward. Two factors drive this process: pressure building up inside the colon and the wall itself becoming less resilient.
A low-fiber diet plays a central role. Fiber adds bulk to stool and helps it move through the colon with less effort. Without enough fiber, the colon has to squeeze harder to push smaller, firmer stool along. That increased pressure, repeated over years and decades, gradually forces the lining of the colon to bulge outward through those weak spots. Meanwhile, the colon wall naturally loses some of its structural integrity with age, making it easier for pouches to form. Once a diverticulum exists, it doesn’t go away on its own.
Where They Typically Appear
In people of European descent, diverticula most often develop in the sigmoid colon, the last S-shaped segment on the lower left side of the abdomen just before the rectum. This section is narrower than the rest of the colon and generates higher internal pressure, making it especially vulnerable. In people of Asian descent, diverticula more commonly form in the first part of the colon, up in the upper right area of the abdomen. This difference affects where symptoms show up if complications ever develop.
Most People Never Have Symptoms
Having diverticula is usually a silent condition. The vast majority of people with diverticulosis never know they have it unless the pouches show up on imaging done for another reason. Diverticulosis by itself requires no treatment.
The concern is diverticulitis, which happens when one or more of those pouches becomes inflamed, typically from a bacterial infection trapped inside. Older estimates put the lifetime risk of progressing from diverticulosis to diverticulitis at 10% to 25%, but more recent research suggests the actual rate is closer to 5%. When diverticulitis does occur, it typically causes significant pain (usually in the lower left abdomen), fever, and changes in bowel habits.
What Raises Your Risk
Diet is the most well-studied factor. People who eat a vegetarian diet with high fiber intake, around 40 grams per day or more, have lower rates of diverticulosis overall. Diets high in red meat and fat are associated with higher incidence. Beyond diet, several other factors play a role:
- Body weight: Higher BMI is consistently linked to greater risk of both diverticulosis and diverticulitis, regardless of genetic background.
- Physical activity: Regular exercise is associated with lower risk.
- Smoking: Adds to the likelihood of developing complications.
- Genetics: Research using polygenic risk scores has confirmed that genetic predisposition contributes independently. Some people are simply more prone to developing diverticula based on inherited traits affecting connective tissue or colon structure.
Both lifestyle and genetics matter, and they appear to compound each other. A person with higher genetic risk who also carries excess weight faces a greater chance of complications than either factor alone would predict.
The Nuts and Seeds Myth
For years, people with diverticula were told to avoid nuts, seeds, and popcorn. The thinking was that small, hard particles could lodge inside a pouch and trigger inflammation. This advice persisted for decades, but there is no evidence to support it. No specific foods have been shown to trigger diverticulitis attacks, and no special diet has been proven to prevent them. The restriction has been dropped from current guidelines, so there’s no reason to avoid these foods if you have diverticulosis.
Living With Diverticula
If you’ve been told you have diverticulosis, the most practical thing you can do is eat a fiber-rich diet. This won’t reverse existing pouches, but it reduces the pressure inside your colon and may lower the odds of new ones forming or existing ones becoming inflamed. Fruits, vegetables, whole grains, and legumes are all good sources. Staying physically active and maintaining a healthy weight further reduce your risk of complications.
Diverticulosis itself is not a disease that needs monitoring or medication. It’s an anatomical change that becomes part of aging for most people, particularly in countries with Western-style diets. The key distinction is between having diverticula, which is common and harmless, and developing diverticulitis, which is relatively uncommon and treatable when it does happen.