Vitamin D deficiency can be regarded as one of the overgrowing health problem in all of the world. Evidence from a clinical trial suggested a role for probiotic bacteria in increasing vitamin D. However, probiotic's effect is strain specific and this effect should be confirmed about different strains. The objective was to determine if yogurt fortification with probiotic bacteria, Lactobillus acidophilus La‐B5, Bifidobacterium lactis Bb‐12 either alone or in combination with vitamin D can be a complementary treatment for vitamin D deficiency. The end‐points were vitamin D, cardio metabolic lipid profile, anthropometric indices (weight, height, waist, hip, fat mass, lean body mass) and dietary intake. A 10‐week parallel‐group, double‐blind, randomized and controlled trial was conducted on 140 obese men and women. The participants were randomly allocated to receive 100 grams either 1) plain low‐fat yogurt or 2) probiotic yogurt or 3) vitamin D‐fortified yogurt or 4) probiotic and vitamin D cofortified yogurt. All groups received low‐calorie diet. Vitamin D increased significantly in group 4 (p = .008), group 3 (p = .001) and group 1 (p = .012 with no difference between groups. Vitamin D‐fortified yogurt had the most effect size and showed a significant difference versus plain (p = .018) and probiotic yogurt (p = .002). Regarding lipid profile, there were no significant differences between groups. Data from this study does not support the hypothesis that yogurt fortified with probiotic bacteria, Lactobillus acidophilus La‐5 and Bifidobacterium lactis Bb‐12 either alone or in combination with vitamin D might impose any increasing effect on serum level of vitamin D in comparison with vitamin D‐fortified yogurt.

Energy restriction and manipulation of macronutrient composition of the diet are the main approaches that are used by people who aim to lose weight. When such strategies are employed, appetite and endocrine regulators of satiety, such as gut peptides, all are deeply affected. The gut microbiota–brain axis controls energy homeostasis in humans by affecting central satiety and gut peptides. The purpose of this study was to evaluate if the synergistic effect of probiotics and vitamin D in yogurt matrix can modulate this effect. In the double‐blind, randomized, placebo‐controlled trial, 140 obese adults were randomly allocated into four groups: 1) regular yogurt plus low‐calorie diet; 2) PY plus low‐calorie diet; 3) vitamin D‐fortified yogurt plus low‐calorie diet, and 4) probiotic and vitamin D co‐fortified yogurt plus low‐calorie diet. All groups were encouraged to increase their physical activity. Glucagon‐like peptide‐1 (GLP‐1), peptide Tyrosin‐Tysrosin (PYY), ghrelin, anthropometric variables, insulin, fasting blood sugar (FBS), insulin resistance/sensitivity, 1,25(OH)2 D3, dietary intake, and physical activity were measured before and after 10 weeks. The difference between groups for GLP‐1 after 10 weeks was significant after adjusting for baseline GLP‐1 and protein intake as confounders. PY showed the largest effect size (ES) on GLP‐1 (p = 14.2) and FBS (p = 14) compared with others. Pairwise comparison of yogurts effect sizes on GLP‐1 showed a significant difference in group 1 vs. group 2 (p = .001), group 1 vs. group 3 (p = .003), and group 1 vs. group 4 (p = .048). Vitamin D‐fortified yogurt had the largest effect size on the serum level of vitamin D and it showed a significant difference with RY (p = .018) and PY (p = .002). Consumption of vitamin D‐fortified yogurt and PY could be regarded as a promising approach during calorie restriction.