Whilst emphasising that diet be a part of a multidimensional approach to CD and UC, the team finds a reduction in liver steatosis severity, improved BMI, reduced elevation in inflammatory biomarkers and improved Quality of Life (QoL) after the dietary intervention.
“In contrast to the negative effect of the Western diet, the Mediterranean diet, characterised by the consumption of fruits, vegetables, whole grains, olive oil, red wine, and yogurt, might have positive outcomes in Inflammatory Bowel Diseases (IBD),” the University of Caligari team writes.
“Experimental evidences suggest that Md could contribute to prevent the onset of dysbiosis by sustaining the presence of anti-inflammatory bacterial species.”
Writing in the journal Inflammatory Bowel Diseases, the team say the role of the diet is probably underestimated in IBD clinical management.
They home in on diet as one of the main determinants of human gut microbiota with a misbalanced diet possibly contributing to dysbiosis with multiple effects on the host.
Dysbiosis has been shown to promote intestinal inflammation encouraging the development of adipose tissue, which represents an important source of pro-inflammatory proteins.
In addition, dysbiosis and obesity sustain the accumulation of fat in the liver and the increase of intestinal permeability.
This in turn, promotes the influx of bacterial components such as lipopolysaccharide (LPS) that may promote liver inflammation and fibrosis, as shown in animal models of liver steatosis.
Med diet’s protective effect
The Mediterranean diet is characterised by a high consumption of vegetables, fruits, cereals, nuts, legumes, unsaturated fat such as olive oil, a medium intake of fish, dairy products, wine, a low consumption of saturated fat, meat, and sweets.
Studies have shown an association with reduced inflammation as well as a protective effect in some diseases such as colorectal cancer.
The team began following patients with IBD, both Crohn’s disease (CD) and ulcerative colitis (UC), who followed a Mediterranean diet for six months.
Their body mass index (BMI), body tissue composition, liver steatosis and function, clinical disease activity, and inflammatory biomarkers were collected at baseline (T0) and compared with those obtained after six months (T180) to evaluate the impact of Md.
Out of 142 IBD patients, (84 UC and 58 CD), followed for 6 months, the team found at T180, diet-adherent CD and UC improved BMI (UC −0.42, CD −0.48,) and waist circumference (UC −1.25 centimetres (cm), CD −1.37 cm).
Additionally, the number of patients affected by liver steatosis of any grade was significantly reduced in both groups (UC T0 31 of 84 [36.9%] vs T180 18 of 84 [21.4%]; CD T0 27 of 58 [46.6%] vs T180 18 of 58 [31.0%]) after dietary intervention.
Finally, after 6 months of the diet, fewer UC and CD patients with stable therapy had active disease (UC T0 14 of 59 [23.7%] vs T180 4 of 59 [6.8%]; CD T0 9 of 51 [17.6%] vs T180 2 of 51 [3.0%]) and elevated inflammatory biomarkers.
Additional findings revealed Mediterranean diet improved QoL in both UC and CD, but neither serum lipid profile nor liver function were modified by the diet.
“Our study emphasises the importance of a multidimensional approach in the management of IBD, not limited to the treatment of luminal inflammation but extended to the correction of the nutritional status and liver steatosis,” the team concludes.
The relevance of this approach seems to be remarkable on disease control with a possible drug-sparing effect, on patients’ wellness, and in reducing the risk of other life-threatening conditions, one of which is liver steatosis and its complications.
“Our data support the role of nutritional counselling in the multidisciplinary management of IBD. However, more studies with larger cohorts of patients are needed to improve our knowledge on the relationship between diet and IBD.”
Dr Aline Charabaty, clinical director of the GI division at the Johns Hopkins School of Medicine and director of the IBD Center at the Johns Hopkins-Sibley Memorial Hospital, in Baltimore welcomed the study’s findings adding, “I’m a big fan of the Mediterranean diet. So, I’m excited to see a study that looks at it.
“IBD is more complex than that,” she said in response to earlier studies that tended to look at the impact of single foods on IBD. “We know it’s multifactorial. There’s a genetic component but also an environmental one.”
Dr Charabaty referenced evidence originating from countries that IBD cases were very low in number only to rise as the culture took on Western influences.
“This study is very nicely done, and it mirrors what is known from epidemiological studies,” she said.
Source: Inflammatory Bowel Diseases
Published online ahead of print: doi.org/10.1093/ibd/izaa097
“Multidimensional Impact of Mediterranean Diet on IBD Patients.”
Authors: Fabio Chicco et al.