Diverticular Disease & Nuts & Seeds
Question: Dear Dr. Harris, I had a colonoscopy about ten years ago and was told I have diverticular disease (diverticuli) in my colon. At that time, I was told to avoid nuts and seeds to prevent diverticulitis. I hear about all the health benefits of nuts and seeds and wonder if the diverticuli ever heal? How can I get all my SuperFoods if I cannot eat nuts or seeds?
Answer: This is a great question. Diverticular disease of the colon is a common problem and the concern about nuts and seeds causing diverticulitis and diverticular bleeding has been a long-held medical myth. Only over the last few years are gastroenterologists (specialists who deal with the stomach and intestines) changing their advice about what you can eat if you have diverticular disease.
So, what is diverticular disease? Diverticular disease is a broad term referring to any inflammation, infection, or injury to diverticuli (the singular form is diverticulum) in the colon. A diverticulum is a pouch that forms in the colon wall. The pouch forms when the muscles of the colon squeeze against a hard stool. The pressure created in the colon by the digestive musculature squeezing on the hard stool pushes the lining of the colon outward in areas where there are not muscles. Over time, the outward pressure on the colon lining causes permanent pouches (diverticuli) to form in between the colon muscles. The best demonstration of this phenomenon is to squeeze a partially inflated balloon in your hand. Like the colon muscles, your hand cannot cover the entire balloon, so when you squeeze, small pouches of balloon expand between your fingers (also notice that the balloon wall is thinner in these pouches).
Over time, the pouches in the colon become permanent sacs with thin walls. These diverticuli are often associated with small blood vessels, so with injury (from a hard stool) they can bleed, causing blood in the stool or black, tarry stools. A pouch can also fill with stool and become inflamed and infected when the stool cannot empty from the diverticulum. Inflammation and infection in a diverticulum is called diverticulitis. Diverticulitis causes abdominal pain like appendicitis, fever, and constipation. Diverticulitis can become a surgical emergency, and should not be taken lightly. It is important to see a physician immediately if you develop abdominal pain and a fever.
To prevent and treat asymptomatic (no symptoms, problems, or pain) diverticular disease, physicians tend to recommend a higher fiber diet. Fiber tends to bulk up the stool, retain water in the stool, and keep the stool soft. In contrast, a low-fiber diet tends to lead to small, firm stool which lead to diverticular disease. I recommend eating more high-fiber foods like fruits and vegetables and drinking lots of water. Increasing your fiber without increasing water in your diet can actually cause constipation because the fiber needs water to bulk up the stool and keep it soft. I always recommend gradually increasing the amount of daily fiber. Changing too quickly from a low- fiber diet to a very high-fiber diet can cause bloating, gas, and constipation. A more gradual transition is easier for the bowels and colon to accommodate. A diet of SuperFoods is ideal for colon health and preventing diverticular disease.
The concern over nuts and seeds stems from observation, not research. We have all observed undigested parts of seeds and nuts in our stool. In the past, many gastroenterologists were concerned the undigested material could aggravate or even get stuck in a diverticulum. So, physicians often recommended avoiding nuts and seeds to patients with diverticular disease. But, these recommendations were not based on research or medical science.
Only in the past two years, have we begun to realize that avoiding nuts and seeds probably doesn’t make much of a difference to diverticular disease. The health benefits of seeds and nuts have also helped to change physician recommendations. Most recently, a prospective study by the division of gastroenterology at the University of Washington, Seattle, found no association between eating nuts, corn, or popcorn and developing diverticular bleeding or diverticulitis. The study looked at habits of 47,000 male participants in the Health Professions Follow-Up Study (a study started over 20 years ago). Actually, eating popcorn was associated with a protective effect against diverticular problems. Men who ate popcorn at least twice a week had a significantly lower rate of diverticular bleeding or diverticulitis than men who ate popcorn less that once a month. Even better, men who ate nuts at least twice a week also had a lower risk of diverticular complications.
I am recommending that people with diverticular disease eat their SuperFoods, including nuts and seeds. The fiber in the SuperFoods helps the colon and may reduce the chances of getting colon cancer. Most importantly, be sure you get the appropriate colon cancer screenings—ask your doctor if you are up-to-date.
The final word: eating nuts and seeds is okay, just drink lots of water and get enough fiber.
I hope this helps,
Geoffrey R. Harris, MD