Association of ultra-processed food intake with risk of inflammatory bowel disease: prospective cohort study
Authors: Narula N et al
Citation: BMJ. 2021;374:n1554
A prospective study of 116,087 adults across 21 low, middle, and high income countries from seven geographical regions (Europe and North America, South America, Africa, Middle East, south Asia, South East Asia, and China), who completed food frequency questionnaires at least every 3 years for a median follow-up of 9.7 years (range 8.9-11.2 years). After adjustment for potential confounding factors, higher intake of ultra-processed food was associated with a higher risk of incident IBD (hazard ratio 1.82, 95% confidence interval 1.22 to 2.72 for ≥5 servings/day and 1.67, 1.18 to 2.37 for 1-4 servings/day compared with <1 serving/day, P=0.006 for trend). Different subgroups of ultra-processed food, including soft drinks, refined sweetened foods, salty snacks, and processed meat, each were associated with higher hazard ratios for IBD.
Gut-microbiota-targeted diets modulate human immune status
Authors: Wastyk HC et al
Citation: Cell. 2021;S0092-8674(21)00754-6. doi:10.1016/j.cell.2021.06.019.
A 17-week prospective randomized study (n=18/arm) of high fiber and high fermented food diets evaluated by -omics measurements of microbiome and host and extensive immune profiling, found specific diet-related effects. The high fiber diet increased microbiome carbohydrate active enzymes with stable microbial diversity, while high fermented food diet increased microbial diversity and decreased inflammatory markers, highlighting the potential for benefit by coupling them together, utilizing immune and microbiome profiling for individual insight.
Long-term dietary patterns are associated with pro-inflammatory and anti-inflammatory features of the gut microbiome
Authors: Bolte LA et al
Citation: Gut.. 2021;70(7):1287-1298. doi:10.1136/gutjnl-2020-322670.
The relationship between 173 dietary factors and the microbiome across four cohorts (CD, UC, IBS, and the general population of 1425 individuals) is examined. Authors identify dietary patterns that consistently correlate with groups of bacteria with shared functional roles in health and disease. Processed foods and animal-derived foods were consistently associated with higher abundances of Firmicutes, Ruminococcus species of the Blautia genus, and endotoxin synthesis pathways. The opposite was found for plant foods and fish, which were positively associated with short-chain fatty acid-producing commensals and pathways of nutrient metabolism.
The role of precision nutrition in the modulation of microbial composition and function in people with inflammatory bowel disease
Authors: Sasson AN, Ingram RJM et al
Citation: Lancet Gastroenterol Hepatol.. 2021;S2468-1253(21)00097-2. doi:10.1016/S2468-1253(21)00097-2.
The authors review the role of dietary patterns, their influence on the structure and function of the gut microbiome, and their effects on inflammation and immunity in individuals with inflammatory bowel disease. A recommended food pyramid for patients with IBD is provided suggesting optimal intake of dietary food groups based upon the combined results of dietary intervention trials. The authors propose future design of microbiome targeted dietary interventions utilizing metabolic, genomic, and microbial profiles to develop precision nutrition for the management of IBD.
Low-fat, high-fiber diet reduces markers of inflammation and dysbiosis and improves quality of life in patients with ulcerative colitis
Authors: Fritsch J et al
Citation: Clin Gastroenterol Hepatol.. 2021;19(6):1189-1199.e30. doi:10.1016/j.cgh.2020.05.026.
A parallel crossover study of 17 patients with UC in remission or mild disease were randomized to either a low fat (10% of calories) high fiber diet for 4 weeks, or 4 weeks of improved standard American diet (iSAD) (35-40% of calories from fat with increased fruits, vegetables and fiber) followed by 2 week washout and crossover. Both study diets were healthier than patient's baseline diet. Compared to baseline, both diets significantly improved quality of life scores. Only the low-fat high fiber diet significantly reduced serum amyloid A concentration. CRP decreased numerically in the low-fat high fiber diet, but did not reach statistical significance. Intestinal dysbiosis was reduced in the low-fat high fiber diet measured by significant increases in F. prausnitzii and decreases in Actinobacteria with significant increases in acetate (an anti-inflammatory metabolite) found in fecal samples.