Vitamin D

Vitamin D is a nutrient that the body needs in small amounts to function and stay healthy. Vitamin D helps the body use calcium and phosphorus to make strong bones and teeth. It is fat-soluble (can dissolve in fats and oils) and is found in fatty fish, egg yolks, and dairy products. Skin exposed to sunshine can also make vitamin D. Not enough vitamin D can cause a bone disease called rickets. It is being studied in the prevention and treatment of some types of cancer. Also called cholecalciferol.

What is Vitamin D?

Vitamin D is a fat-soluble vitamin that is important for strong bones, muscles, and general good health.

The Role of Vitamin D in Hormonal Balance

Sun Exposure - Positive and Negative Effects

Dangers of Vitamin Deficiency During Pregnancy

Vitamin D and Type 2 Diabetes

Vitamin D and Cancer

Rosacea and Vitamin D

Vitamin D Overdose

Breastfeeding and Vitamin D

Vitamin D Supplementation

Vitamin D Deficiency

The Connection Between Vitamin D and Mental Health

See more featured articles »

Vitamins: An Overview

Can Vitamin D Prevent Asthma Attacks?

Rheumatoid Arthritis and Vitamin D

Vitamin D Biochemistry

Vitamin K Deficiency

Taking Calcium and Vitamin D for Osteoporosis

Vitamin Malabsorption: A Comprehensive Guide from A to K

Vitamin D and COVID-19

Latest Vitamin D News and Research

CT scans linked vitamin D levels to fat within muscles after bariatric surgery

Researchers followed 113 adults for one year after bariatric surgery and found that those with higher postoperative vitamin D concentrations had less fat infiltration within certain muscles and lower visceral adiposity. They found no significant association between increases in vitamin D and changes in body composition after correction for multiple comparisons, while preoperative vitamin D levels did not independently predict postoperative body composition.

27 Oct 2026

Kidney Week 2026 features late-breaking clinical trials in kidney care

The American Society of Nephrology, has selected the following late breaking clinical trials to be presented in-person at Kidney Week 2026 October 22–25.

24 Oct 2026

Why the same healthy diet may not work the same way for everyone

A review published in Nutrients proposes a seven-pillar precision nutrition framework that combines biological, behavioral, and environmental information to tailor dietary interventions throughout life. The authors identify potential benefits for cardiovascular, respiratory, blood, and sleep health, while emphasizing the need for further clinical trials to establish effective, accessible, and personalized nutritional strategies.

20 Oct 2026

Could eating whey protein before meals help reduce blood sugar spikes?

A narrative review of 57 randomized trials found that milk and dairy products have inconsistent effects on long-term blood sugar control in adults with type 2 diabetes or prediabetes. Whey protein consumed before meals more consistently reduced short-term blood sugar spikes, but further research is needed to establish whether these benefits persist over time.

19 Oct 2026

Women with low bone density reported less pain after taking pine bark extract

A randomized clinical trial involving 67 women with osteopenia or stable osteoporosis found that three months of Pycnogenol® supplementation improved self-reported bodily pain and vitality scores compared with placebo. However, overall disease-specific quality of life did not significantly improve, and the six-month findings were insufficient to establish long-term benefits or safety.

15 Oct 2026

Younger postmenopausal women may not get enough calcium

A small Italian study examined whether women facing heightened bone-loss risks are getting enough calcium from their diets, with particular attention to breast cancer patients receiving endocrine therapy.

6 Oct 2026

$Vitamin B12 deficiency was linked to higher fracture hazard after 50$

Vitamin B12 deficiency was linked to higher fracture hazard after 50

A study links abnormal vitamin B12 levels to fracture risk, highlighting a complex relationship beyond simple deficiency in middle-aged and older adults.

2 Oct 2026

GLP-1s linked to nutritional deficiencies in children

Children prescribed GLP-1 medications for weight loss, prediabetes, or type 2 diabetes are at risk for nutritional deficiencies – diagnosed in nearly one in six patients (16.8%) within the first year – according to a new study published in the journal Childhood Obesity.

24 Sep 2026

GLP-1 medications place children at risk for nutritional deficiencies

21 Sep 2026

Working shifts may change more than your sleep schedule

A cross-sectional analysis of 1,814 Japanese workers found that shift work was associated with lower raw seafood intake and shorter sleep patterns in both sexes, while female shift workers also consumed less milk and dairy products. Total energy intake was similar between work groups, but male shift workers were more likely to consider preference and convenience when choosing foods, highlighting potentially important differences in dietary quality and lifestyle rather than calorie intake.

8 Sep 2026

Probiotics for mental health? A new review finds promising signals and major gaps

This narrative review examines how psychobiotics may influence anxiety, depression, bipolar disorder, and schizophrenia through gut-brain pathways involving neurotransmitters, inflammation, immune regulation, gut barrier function, and stress signaling. Specific Lactobacillus and Bifidobacterium strains showed encouraging effects, but wide differences in strains, doses, populations, and study designs currently limit clinical translation.

28 Aug 2026

Sunlight, blood sugar and diabetes: a new study finds an intriguing connection

Higher short-term ambient UVA exposure was associated with modestly lower blood glucose levels, particularly during winter, in a large UK Biobank analysis. Separately, more frequent solarium use, used as a proxy for habitual sunlight exposure, was associated with a lower hazard of type 2 diabetes, although the observational findings do not establish causality.

27 Aug 2026

Study links lower vitamin D to mood and cognitive health in adults over 85 with diabetes

Researchers studying 188 adults aged 85 years or older with type 2 diabetes found the lowest serum 25(OH)D concentrations among those with both depressive symptoms and mild cognitive impairment. Lower levels remained associated with having both conditions after adjustment for selected factors, but the cross-sectional study cannot establish causation or a benefit from supplementation.

3 Aug 2026

Siemens Healthineers launches an industry-leading menu for core lab capillary testing on Atellica analyzers with claims for 24 assays

Siemens Healthineers announced today that it has launched capillary testing on the Atellica CH, IM, and CI Analyzers after receiving CE-mark for 24 capillary blood testing claims, an advancement for capillary testing that offers clinical labs greater confidence in test results and higher throughput.

From Siemens Healthineers 24 Jul 2026

Study tests chronotype’s liver link and finds no significant association

Researchers found no significant association between chronotype and FibroScan-derived liver fat or stiffness in 119 medication-naïve adults with overweight or obesity. The exploratory findings cannot exclude smaller effects, particularly for fibrosis, and require confirmation in larger longitudinal studies.

21 Jul 2026

Vitamin D falls short as an add-on treatment for endometriosis

An eight-week randomized trial of 66 women found that adjunctive vitamin D did not significantly or meaningfully improve endometriosis pain or quality of life compared with placebo during dienogest therapy. The results do not support routine short-term adjunctive supplementation, although the brief trial and absence of post-treatment vitamin D measurements leave longer-term effects uncertain.

19 Jul 2026

Evidence does not support universal vitamin D supplementation to prevent preterm birth

Announcing a new article publication in BIO Integration. Preterm birth complications are among leading causes of mortality in neonates and children under 5 years of age worldwide.

15 Jul 2026

High physician knowledge scores linked to lower healthcare costs

Patients whose physicians scored higher in the first year of the American Board of Internal Medicine's (ABIM) Internal Medicine Longitudinal Knowledge Assessment (LKA) were significantly less likely to receive low-value healthcare services, which cumulatively cost the U.S. healthcare system an estimated $100 billion each year.

13 Jul 2026

Dutch study shows why plant-based eating can miss key nutrients

A Dutch dietary modeling study found that replacing major animal-based protein sources with plant-based substitutes reduced protein, EAA, vitamin, and mineral intake across age groups. Older adults, adolescents, children, and women were especially vulnerable to shortfalls, highlighting the need for planned substitutions, fortified foods, and age-specific dietary guidance.

3 Jul 2026

Plant-based diets offer heart benefits but may require supplements

A study reveals unsupplemented vegan diets in Northeast China lead to micronutrient deficiencies, despite benefits for body composition and cholesterol levels.

2 Jul 2026