Vitamin D and metabolic
4 papers in the library, strongest Preliminary.
Graded Preliminary · A one-time survey of 1,668 older adults; because everything was measured at once, it cannot show which factor comes first.
Papers 4
- Vitamin D and Exercise Tied to Fewer Stacked Heart RisksPreliminaryn = 1,6682026International journal of environmental health researchOlder adults in South Korea with more vitamin D in their blood less often had several heart and metabolic risk factors at once. The same was true for those who met the guideline for aerobic activity. People with both were the least likely to have this cluster of risks. The data came from a national health survey in 2023. It covered 1,668 people aged 65 or older who lived at home. Having at least three of five such risk factors counted as a cluster, which applied to just over a third. Compared with people below 20 nanograms of vitamin D per milliliter of blood who did not meet the activity guideline, those at 20 or more who did meet it had the cluster less often. The analysis accounted for social background, smoking, alcohol, place of residence and body weight. Vitamin D and activity were each linked to the result on their own. The researchers found no sign that the two boost each other. The key limit: everything was measured at a single point in time. So the study cannot say whether more vitamin D or more activity actually lowers these risks. No vitamin D supplement was tested.
- Vitamin D Reduced Liver Fat in Rats on a Snack-Heavy DietPreliminary2026The Journal of nutritional biochemistryRats that grew fat on a diet of snack-style food had less fat in their livers when they also got vitamin D. Their blood sugar control improved too. Their livers made less sugar than those of untreated obese rats. Fatty liver is often linked to low vitamin D, so the researchers tested whether giving it changes anything. The rats ate a so-called cafeteria diet for 60 days, modeled on fattening human eating habits. A comparison group ate normal chow. The diets then continued for five more weeks. During that time, some animals in each group received vitamin D once a week through a tube into the stomach. The treated obese rats ate less and gained less weight. Their bodies responded better to insulin. In the liver, genes for inflammation signals were less active, while genes for defense against harmful oxygen compounds were more active. All of these results come from rats. This study did not test whether vitamin D does the same for people with fatty liver. The authors see therapeutic potential, which would still need to be checked in human studies.
- Diabetes Plus Low Vitamin D Tied to More Muscle Loss in Old AgePreliminaryn = 7,5202026The journal of nutrition, health & agingOlder people with diabetes who also had low vitamin D in their blood more often had age-related muscle loss in an English group. Muscle loss here meant a weak grip together with low estimated muscle mass. Across all participants, though, there was no clear link once other factors were taken into account. Researchers looked at data from 7,520 people aged 50 or older in the US and England, each examined once. Low vitamin D meant 50 nanomoles per liter or less. In England, people with diabetes and low levels had muscle loss more often than people without diabetes and higher levels. The US group pointed the same way, but the result was not clear. The team also gave vitamin D3 to rats made artificially old and diabetic. Those rats gripped harder, and their muscles held about 72 percent less fat than rats lacking vitamin D. The authors call the human findings suggestive, not confirmatory. Because everyone was measured only once, it is unclear which came first: low vitamin D or weak muscles. Whether vitamin D protects people with diabetes from muscle loss was not tested; supplements were given only to rats.
- Older Adults With More Vitamin D Have Less DiabetesPreliminaryn = 1,3242026Journal of diabetes and metabolic disordersIn people aged 60 and older, vitamin D levels were tied to blood sugar. Those with more vitamin D in their blood were less likely to fall into a worse diabetes category. This held even after many other influences were taken into account. The researchers examined 1,324 older adults at a single point in time. Their average age was just under 70, and slightly more than half were women. Trained interviewers asked about exercise and smoking. The team measured weight, waist size and blood pressure, plus fasting blood sugar and vitamin D. About one in four had too little vitamin D. Around 29 percent had diabetes, and another 23 percent had prediabetes, an early stage of it. The authors say the results support awareness programs about vitamin D for older adults. But the study cannot show that vitamin D changes blood sugar. All values come from one moment, so it is unclear which came first. No vitamin D supplement was tested.
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