COMMENTARY

Avoid Inflammatory Diets to Combat Diverticulitis

David A. Johnson, MD

Disclosures

March 05, 2020

This transcript has been edited for clarity.

Hello. I'm Dr David Johnson, professor of medicine and chief of gastroenterology at Eastern Virginia Medical School in Norfolk, Virginia.

We all deal with diverticulitis in our patients. One of the first questions I get from my patients is, "What can I do to prevent it?" We're aware that the dietary restrictions on nuts and seeds have since been debunked as not being evidence-based. But there is growing recognition that diverticulitis may be an inflammatory process rather than just an infectious process. The American Gastroenterological Association Institute Guideline addresses this change by recommending that perhaps these patients should be put on clear liquids alone and observed, unless there is a suggestion of a more invasive type of complication of diverticulitis, in which case they would of course require antibiotics.

Yet the question remains: What should we do from a dietary standpoint if taking away the nuts and seeds doesn't really work?

New Data Linking Inflammatory Diets With Diverticulitis

A fascinating new analysis from the Health Professionals Follow-Up Study gives us some potential answers by looking at the association between diet, circulating markers of inflammation, and the risk of developing diverticulitis. Investigators assessed four decades of data in approximately 46,000 men initially free of diverticulitis, with nearly 1 million patient-years among them. Of these participants, 1100 went on to develop diverticulitis.

Investigators performed a nested case-control cohort study to look at prediagnostic markers of inflammation. They specifically looked at C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor (TNF)-receptor superfamily member 1B. Although CRP is something that we sometimes monitor in diverticulitis, the other two markers are not routinely assessed; I certainly don't look at either in these patients.

Next, investigators applied a diet questionnaire validated in the Nurses' Health Study and the Health Professionals Follow-Up Study, called the empirical dietary inflammatory pattern score. They specifically looked at the inflammatory potential of 39 different types of food groups. These are all listed in the article, which I encourage you to read.

The snapshot summary is that the negative effects related to the development of diverticulitis were observed with those foods you would expect: high-sugar drinks (eg, colas containing high-fructose corn syrup), organ meat, red meat, processed meat, and the dietary fats. Conversely, the positive effects were seen with green leafy and dark-yellow vegetables. Interestingly, the positive effects were also seen for wine and beer, as well as for coffee, tea, and high-fiber foods.

As noted, investigators followed these subjects over a considerable time period. The mean time from the initial blood draw to when they developed diverticulitis was approximately 7 years. This is important, as it nullifies concerns that the study design would lead to recall bias or reverse causation, because it was not looking at anything other than routine monitoring over a long period of time.

Regarding the markers of inflammation, investigators found that having CRP in the highest quintile produced a relative risk for diverticulitis of 1.85 times compared with the lowest quintile. For IL-6, it was a little higher, at 2.04 times. The TNF-receptor superfamily member 1B didn't seem to measure up and was therefore not considered relevant.

This becomes additionally important when we consider that these same inflammatory markers are also linked to cardiovascular disease. Therefore, when you start to talk with your patients about these inflammatory markers—CRP in particular—it is worth noting that their elevation also relates to cardiac disease.

Talking to Your Patients About Diet

This study helps us recognize that long-term exposure to low-grade chronic inflammation is associated with the onset of diverticulitis, and diet may well be a predisposing factor. As a result, it may be advisable to begin talking to our patients about dietary intake and the risk of developing diverticulitis.

Although diets with higher inflammatory potential have certainly been associated with inflammatory conditions like cardiovascular disease and colorectal cancer, this hasn't led to a clear intervention. We can simply say, "You had an elevated CRP and IL-6, so let's place you on a low-inflammatory diet and see how you do." I would caution you that the Level 1 evidence is not quite there, but this prospective trial does offer lots of good data.

The conclusion, in my mind, is that a diet with a higher inflammatory profile has the potential to upregulate inflammatory cytokines/chemokines that may be predisposing to recurrent diverticulitis. And this low-grade complication of inflammation may be not only for diverticulitis but for other disease states as well.

When I talk to these patients, I do start talking to them about possibly minimizing their intake of things like sugary beverages, organ meat, red meat, and processed meat, and increasing fiber and green leafy and dark-yellow vegetables. I think we have a reasonable evidence chain to support that intervention. And, certainly, if we don't talk about this diet information early on, we may have to do it years later when our patients with recurrent diverticulitis ask us how to prevent it. If you don't talk about diet with patients now, what are you leaving on the therapeutic table?

Even though the Level 1 evidence is not there yet, this is going to change my practice. In particular, I'm going to start monitoring CRP in patients with complicated diverticulitis. I don't think I can get IL-6 passed by insurance companies, and certainly not the TNF biomarker. However, I think the CRP may be a reasonable thing to emphasize for these patients, especially as it relates to other disease states such as cardiovascular disease and colorectal cancer.

I look forward to some prospective randomized data on this topic, but that may be a long time in coming. To me, it's sound enough to make an intervention right now, and these diets make sense.

This is Dr David Johnson. Thanks for listening.

David A. Johnson, MD, a regular contributor to Medscape, is professor of medicine and chief of gastroenterology at Eastern Virginia Medical School in Norfolk, Virginia, and a past president of the American College of Gastroenterology. His primary focus is the clinical practice of gastroenterology. He has published extensively in the internal medicine/gastroenterology literature, with principal research interests in esophageal and colon disease, and more recently in sleep and microbiome effects on gastrointestinal health and disease.

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