In the news: Pro-Inflammatory Diet Ups Risk of Crohn’s; Call for Zinc & COVID-19 Research

Dietary Pattern a Risk Factor for Crohn’s

Crohn’s disease is a chronic inflammatory disorder in which the immune system attacks the GI tract. According to the National Institute of Diabetes and Digestive and Kidney Diseases, Crohn’s is becoming more common in the US and in other developed countries. The incidence is increasing in developing nations as well.

The exact cause of Crohn's disease is unknown, but studies suggest that it is a multifactorial condition attributable to a combination of environmental and immune factors, as well as alterations in the gut microbiome, in genetically susceptible individuals.

A newly published analysis of three large prospective cohorts provides evidence that a pro-inflammatory eating pattern may also be a factor in the development of Crohn’s, though not ulcerative colitis (1).

In the study, researchers from Massachusetts General Hospital and Harvard Medical School used dietary data collected at multiple time points from nearly 167,000 women and 42,000 men who participated in the Nurses’ Health Study I and II, and the Health Professionals Follow-up Study.

Self-reported Crohn’s and ulcerative colitis cases were confirmed by medical record review. Empirical dietary inflammatory pattern (EDIP) scores were calculated to evaluate dietary inflammatory potential and the risk of developing Crohn’s and ulcerative colitis. The EDIP score has been shown to reflect circulating inflammatory biomarkers.

Over 4,949,938 person-years of follow-up, 328 cases of Crohn’s and 428 cases of ulcerative colitis were documented. Compared with participants in the lowest quartile of cumulative mean EDIP scores, those in the highest quartile had a 51% higher risk of Crohn’s.

Compared to those who persistently consumed a low potentially inflammatory diet over time (measured at 2 time points 8 years apart), participants who continually consumed a pro- inflammatory diet – or who shifted from a low to high inflammatory diet – had a 2-fold greater risk of developing Crohn’s.

Comments

While specific foods have previously been linked to a higher risk of inflammatory bowel disease, this study is the first to underscore the importance of an overall anti-inflammatory dietary pattern on the risk of developing Crohn’s. The Mediterranean diet which has been linked to many general and ocular health benefits, has been shown to have a high anti-inflammatory potential.

Call to Study Zinc for COVID-19 Preventative

Writing in the American Journal of Ophthalmology, an international team from the Netherlands, UK and US, make a case for studying oral zinc as a potential prophylactic treatment for those at risk for COVID-19 (2).

The authors point out experimental data suggesting that zinc may inhibit the interaction of the corona-virus (SARS-CoV-2) S protein spike and the ACE2 receptor, which is critical for viral entry into host cells.

The anti-viral effects of zinc against rhinoviruses is briefly discussed, with the effects thought to be due to enhanced immune cell function and/or the ability of zinc to interfere with the binding of these viruses to cells.

Serum zinc levels can be low in the elderly – a group particularly vulnerable to COVD-19. Given that a vaccine is likely at least a year away, the authors call for more research into zinc, possibly assessing whether there is a difference in progression of respiratory disease between AREDS2 users and non-users in the AREDS2 trial.

The article can be accessed in full at: https://www.ajo.com/article/S0002-9394(20)30213-0/fulltext.

References

1. Chan Han Lo, et al. Dietary inflammatory potential and risk of Crohn's Disease and Ulcerative Colitis. Gastroenterol. Epub May 7, 2020.
2. McPherson SW, et al. Editorial. Investigate oral zinc as a prophylactic treatment for those at risk for COVID19. Am J Ophthalmol. Article in Press May, 25, 2020