Iran: Consuming probiotic yogurt (PY) and vitamin D-fortified yogurt is shown to be a promising approach during calorie restriction in a recent study published in Food Science & Nutrition.
The study showed that in healthy individuals undergoing a low-calorie diet, a daily intake of 100 g PY or vitamin D-fortified yogurt over ten weeks improved the anorectic hormone GLP-1 without a change in ghrelin.

The World Health Organization (WHO) defines obesity as the excess storage of fat arising from an imbalance between energy intake and energy expenditure (EE). Obesity predisposes the affected individuals to numerous medical conditions such as type 2 diabetes, cardiovascular disease, sleep apnea, and hyperlipidemia, imploding a substantial financial burden on the healthcare system.
The primary therapeutic intervention for obesity control has always been lifestyle modification, including dietary interventions combined with exercise. However, some studies have shown that weight loss may be linked with biological adaptations, including gradual gut peptide secretion changes, which start an impaired cycle with progressively worsening appetite regulation that promotes overfeeding. Glucagon-like peptide-1 (GLP-1) and peptide Tyrosin-Tysrosin (PYY) are anorexigenic hormones that increase satiety, likely through a delay of gastric emptying. Ghrelin is the only described peripheral orexigenic peptide.
Manipulation of macronutrient composition of the diet and energy restriction are the main approaches used by individuals looking to lose weight. In cases where such strategies are employed, endocrine and appetite regulators of satiety, such as gut peptides, are all deeply affected. The gut microbiota-brain axis controls energy homeostasis by affecting central satiety and gut peptides.
Against the above background, Shima Hajipoor, School of Nutritional Sciences and Food Technology Kermanshah University of Medical Sciences, Kermanshah, Iran, and colleagues aimed to investigate the synergistic effect of probiotics and vitamin D in yogurt matrix can modulate this effect.
For this purpose, the researchers conducted a randomized, double-blind, placebo-controlled trial including 140 obese adults. They were randomly allocated into four groups:
Regular yogurt plus low-calorie diet
Vitamin D-fortified yogurt plus low-calorie diet
PY plus low-calorie diet
Probiotic and vitamin D co-fortified yogurt plus low-calorie diet
All groups were motivated to increase their physical activity. The researchers measured GLP-1, PYY, anthropometric variables, ghrelin, fasting blood sugar (FBS), insulin, physical activity, dietary intake, and 1,25(OH)2 D3 before and after ten weeks.
The study led to the following findings:
The difference between groups for GLP-1 after ten weeks was significant after adjusting for baseline GLP-1 and protein intake as confounders.
Probiotic yogurt showed the most prominent effect size (ES) on GLP-1 and FBS compared with others.
A pairwise comparison of yogurts effect sizes on GLP-1 showed a significant difference in group 1 vs. group 2, group 1 vs. group 3, and group 1 vs. group 4.
Vitamin D-fortified yogurt had the most significant effect on the serum level of vitamin D, showing a substantial difference between RY and PY.
"Intake of vitamin D-fortified yogurt and PY is a promising approach during calorie restriction," the researchers wrote in their study. "The results indicate a promising approach for controlling the effect of negative energy balance during diet therapy on gut hormones."
Reference:
Hajipoor, S., Hekmatdoost, A., Pasdar, Y., Mohammadi, R., Alipour, M., Rezaie, M., Nachvak, S. M., Balthazar, C. F., Sobhiyeh, M. R., Mortazavian, A. M., & Cruz, A. G. (2022). Consumption of probiotic yogurt and vitamin D-fortified yogurt increases fasting level of GLP-1 in obese adults undergoing low-calorie diet: A double-blind randomized controlled trial. Food Science & Nutrition, 10, 3259–3271. https://doi.org/10.1002/fsn3.2816