Published: March 30, 2012
Reviewed by Robert Jasmer, MD; Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, RN, BC-ADM, Nurse Planner
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A Middle Eastern yogurt drink known as "doogh" and fortified with vitamin D was found to decrease inflammatory markers in people with type 2 diabetes, researchers found.
Those who drank the doogh fortified with vitamin D, or vitamin D plus calcium, had decreased levels of highly sensitive C-reactive protein and several interleukin proteins, among other markers of inflammation, reported Tirang Neyestani, PhD, of Beheshti University of Medical Sciences in Tehran, Iran, and colleagues.
In addition, those drinking the fortified concoctions had significantly higher levels of adiponectin, they reported online in the Journal of Clinical Endocrinology and Metabolism.
Adiponectin is a hormone known to have anti-inflammatory properties and to regulate the metabolism of glucose. A 2009 review of the literature found that higher levels of adiponectin were associated with a lower risk of type 2 diabetes (JAMA 2009; 302(2): 179-188).
Neyestani and colleagues noted that animal studies have shown vitamin D to have a beneficial effect in various autoimmune disorders. These researchers also reported last year the positive effect vitamin D has in diabetics on endothelial biomarkers (BMC Medicine 2011; 9:125) and on glycemic control (Am J Clin Nutr 2011; 93: 764-771), again using fortified doogh.
However, they said that the evidence in humans showing this particularly unique effect of vitamin D is scarce.
In this study, researchers conducted a double-blind, randomized, controlled trial over 12 weeks in 90 patients with type 2 diabetes. Participants were randomized equally either to plain doogh, doogh fortified with vitamin D, or doogh fortified with vitamin D and calcium.
Baseline characteristics between the groups were similar, with an age range of 30 to 60. Participants drank two bottles of the liquid yogurt per day. The average body mass index was 29 kg/m2
"The prevalence of overweight and obesity is escalating in Iran," Neyestani told MedPage Today via email. "Moreover, obesity and abdominal adiposity have a close association with development of type 2 diabetes; in other words, most cases of type 2 diabetes are overweight or obese."
Both groups with fortified drinks showed significant improvement of vitamin D status at the end of 12 weeks, "confirming high bioavailability of vitamin D in doogh," researchers said.
The inflammatory markers that significantly decreased at the end of 12 weeks were C-reactive protein, interleukin(IL)-1 beta, IL-6, fibrinogen and retinol binding protein (RBP)-4.
"This is the first study to show that vitamin D with or without extra calcium resulted in a significant decrease in these particular inflammatory biomarkers, as well as an increase in adiponectin and RBP-4," Neyestani and colleagues concluded.
Vitamin D studies of healthy people have typically not shown beneficial effects. "It is possible that the immunomodulatory effect of vitamin D can be more clearly observed when the immune system is stimulated," they said.
The findings, however, are not inconsistent with animal studies, they noted.
"Our study showed for the first time that adiponectin, a substance secreted by fat tissue that has an anti-inflammatory effect, increased when calcium and vitamin D-fortified doogh was consumed," said Neyestani.
Unlike vitamin D, calcium can be obtained through diet, mostly dairy products. Vitamin D, however, has very limited food sources.
"People usually do not have sufficient direct sun exposure for many reasons, including cultural, as women in Iran are veiled since age 9, Neyestani told MedPage Today. "In Iran, this problem is more complicated by the fact that there is no fortification program at the time. We therefore must rely mostly on vitamin D supplementation for now."
A limitation of the study was that three-quarters of participants were deficient in vitamin D, and that longer-term studies need to be done to adequately capture all vitamin D-dependent functions.
The work was funded by the National Nutrition and Food Technology Research Institute at Shahid Beheshti University of Medical Sciences in Tehran, Iran.
The authors reported they had nothing to disclose.
The authors reported they had nothing to disclose.
From the American Heart Association:
Antioxidant Vitamin Supplements and Cardiovascular Disease
Primary source: Journal of Clinical Endocrinology and Metabolism
Source reference:
"Improvement of vitamin D status via daily intake of fortified yogurt drink either with or without extra calcium ameliorates systemic inflammatory biomarkers, including adipokines, in the subjects with type 2 diabetes" J Clin Endocrinol Metab 2012; DOI: 10.1210/jc.2011-3465.
Source reference:
"Improvement of vitamin D status via daily intake of fortified yogurt drink either with or without extra calcium ameliorates systemic inflammatory biomarkers, including adipokines, in the subjects with type 2 diabetes" J Clin Endocrinol Metab 2012; DOI: 10.1210/jc.2011-3465.
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