Nine months of daily vitamin D3 supplementation significantly increased adiponectin and lowered resistin in vitamin D-deficient postmenopausal women, suggesting that correcting deficiency may favorably influence metabolic signaling after menopause.
By yourNEWS Media Newsroom
Daily vitamin D3 supplementation produced significant changes in two hormones associated with metabolic health in a randomized clinical trial involving vitamin D-deficient postmenopausal women, adding to research examining the nutrient’s potential role beyond its established importance for bones and muscles.
The trial included 160 women between ages 50 and 65 who had gone through menopause and were deficient in vitamin D. Researchers randomly assigned 80 participants to receive 1,000 international units of vitamin D3, or cholecalciferol, each day and 80 to receive a placebo for nine months.
Researchers concentrated on adipokines, signaling proteins produced largely by fat tissue that can influence inflammation, insulin sensitivity and other metabolic processes.
Two of the most significant changes involved adiponectin and resistin.
After nine months, adiponectin increased 18.6% among women receiving vitamin D3, while resistin declined 32.4%. Researchers found statistically significant differences between the vitamin D and placebo groups at the end of the intervention.
Adiponectin is generally associated with greater insulin sensitivity and healthier regulation of glucose and fat metabolism. Lower concentrations are frequently seen in people with obesity, insulin resistance and other forms of metabolic dysfunction.
Resistin has been associated with inflammatory activity and impaired metabolic regulation, although its role in human disease is complex and cannot be reduced to a single measurement.
The simultaneous increase in adiponectin and reduction in resistin led investigators to conclude that vitamin D supplementation was associated with a more favorable adipokine profile among the postmenopausal women studied.
The intervention also substantially changed participants’ vitamin D status.
Average blood concentrations of 25-hydroxyvitamin D, the primary measurement used to evaluate vitamin D status, increased from 15.0 nanograms per milliliter to 27.5 nanograms per milliliter in the supplementation group, representing a 45.4% increase.
Women taking the placebo moved in the opposite direction. Their average levels declined from 16.9 to 13.8 nanograms per milliliter, an 18.5% decrease during the nine-month study period.
The findings are potentially significant for women after menopause because metabolic changes frequently accompany the hormonal transition.
Changes in estrogen levels can coincide with shifts in body composition, including greater abdominal fat accumulation, while age-related changes can affect insulin sensitivity, blood pressure, cholesterol and cardiovascular risk.
Adipose tissue itself is increasingly understood as more than a storage site for body fat. It functions as an endocrine organ, producing hormones and signaling molecules that communicate with the liver, muscles, pancreas, immune system and other tissues.
Adiponectin and resistin are part of that signaling network.
The trial therefore did not simply examine whether taking vitamin D increased blood vitamin levels — an expected outcome of supplementation. Researchers investigated whether correcting deficiency was accompanied by measurable changes in biological signals involved in metabolic regulation.
Their results suggest that it was.
The study does not establish, however, that taking 1,000 IU of vitamin D3 prevents diabetes, produces weight loss or reduces cardiovascular events.
It measured changes in biomarkers rather than long-term clinical outcomes. The participants were also specifically postmenopausal women with vitamin D deficiency, meaning the findings cannot automatically be applied to women who already have adequate vitamin D levels, younger women or men.
The results nevertheless fit into a broader body of research examining connections between vitamin D and glucose metabolism.
Vitamin D receptors are present in numerous tissues involved in metabolic regulation, including pancreatic beta cells, skeletal muscle and adipose tissue. A 2025 scientific review described several pathways through which vitamin D could potentially influence insulin secretion, glucose uptake, inflammation and insulin sensitivity.
Researchers have also repeatedly observed an association between low vitamin D levels and Type 2 diabetes.
One systematic review cited in the 2025 analysis found vitamin D deficiency in approximately 64% of people with Type 2 diabetes across 54 studies involving more than 38,000 participants. Such findings show an association, however, and do not demonstrate that vitamin D deficiency itself causes diabetes.
Clinical trials examining supplementation have produced more nuanced results.
Some meta-analyses have reported improvements in fasting blood glucose, HbA1c or measures of insulin resistance among certain populations receiving vitamin D, particularly people who begin with deficiency or metabolic abnormalities. Other studies have found smaller or no significant effects on particular metabolic outcomes. Researchers continue to examine whether benefits depend on baseline vitamin D status, dose, duration and the metabolic health of participants.
That distinction is important because correcting a deficiency is not the same as taking increasingly large vitamin D doses in hopes of obtaining additional metabolic benefits.
Estimates of vitamin D deficiency in the United States also vary considerably depending on the blood concentration used to define deficiency.
An analysis of U.S. National Health and Nutrition Examination Survey data from 2001 through 2010 estimated that 28.9% of adults had vitamin D levels below 50 nanomoles per liter under the threshold used in that study. More recent analyses using different definitions have produced different prevalence figures, making it misleading to treat 29% as a single universally accepted current deficiency rate.
Vitamin D remains best established for its role in calcium absorption, skeletal health and normal muscle function. The body obtains it through several routes, including sunlight exposure, food and supplements.
Food sources include fatty fish such as salmon, trout and sardines, egg yolks and foods fortified with vitamin D, including many dairy products and plant-based alternatives.
Sunlight can stimulate vitamin D production in the skin, but the amount produced varies considerably according to season, latitude, skin pigmentation, age, clothing, time spent outdoors and other factors.
Vitamin D also functions within a much larger nutritional and metabolic system.
Magnesium participates in hundreds of enzymatic reactions, including processes involved in glucose and energy metabolism. Zinc has roles in insulin storage and signaling, while B vitamins participate in numerous cellular and metabolic pathways. Gut bacteria and dietary patterns can also influence inflammation and metabolism.
Those relationships do not mean combining supplements automatically improves hormone balance or prevents metabolic disease. The vitamin D trial evaluated vitamin D3 by itself and therefore cannot establish benefits from magnesium, B vitamins, zinc, probiotics or other supplements.
Lifestyle factors remain central to metabolic health after menopause.
Regular physical activity, resistance training, adequate sleep, maintaining a healthy body composition, avoiding tobacco and eating a nutrient-dense diet can affect insulin sensitivity, cardiovascular health and muscle and bone preservation.
For women with vitamin D deficiency, the new findings add another potential reason to correct inadequate levels.
After nine months of 1,000 IU of vitamin D3 daily, women in the trial not only raised their circulating vitamin D concentrations but also showed an 18.6% increase in adiponectin and 32.4% decrease in resistin — changes researchers described as evidence of an improved adipokine profile.
The results provide evidence of a biological effect, but they stop short of showing that supplementation will prevent diabetes or other metabolic diseases.
Vitamin D supplements are also not reviewed by the Food and Drug Administration for effectiveness before being marketed in the same manner as prescription drugs. Individual needs can differ, and excessive vitamin D intake can cause harmful elevations in blood calcium.
For postmenopausal women concerned about deficiency, measuring 25-hydroxyvitamin D through a blood test can help determine vitamin D status before decisions about supplementation are made.
The trial’s central finding is narrower but potentially important: among women ages 50 to 65 who were already vitamin D deficient, modest daily vitamin D3 supplementation for nine months produced measurable changes in hormones connected with metabolic regulation, strengthening the case for correcting deficiency as part of broader health management after menopause.
Source: Natural News
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