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.

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Rheumatoid Arthritis and Vitamin D

Vitamin K Deficiency

Vitamin D Deficiency

Vitamin D Supplementation

The Connection Between Vitamin D and Mental Health

Vitamin Malabsorption: A Comprehensive Guide from A to K

Vitamin D and COVID-19

Breastfeeding and Vitamin D

Vitamin D Overdose

Vitamin D Biochemistry

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Latest Vitamin D News and Research

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

Vitamins A and D may support healthier lungs in asthma patients

Higher levels of circulating vitamin A are linked to better lung function in children and adults with asthma, while vitamin D shows similar benefits in adults, including slower biological ageing, finds the first study of its kind, published online in the respiratory journal Thorax.

30 Jun 2026

Children and adults who eat more live microbe-rich foods have healthier diets

French children and adults widely consumed foods likely to contain live microbes, mainly yogurt, unpasteurised cheese, fruits, and vegetables. Higher intake was associated with more nutrient-rich diets and better diet quality scores, but the cross-sectional study cannot prove health benefits.

29 Jun 2026

Brighter daytime light is linked to a lower dementia risk

The study finds that greater exposure to daytime light may lower dementia risk, pointing to light's role in enhancing circadian rhythms and cognitive function.

29 Jun 2026

New calculator predicts statin-related muscle disorder risk

Researchers at the Nuffield Department of Primary Care Health Sciences, University of Oxford, have developed a new calculator that estimates a person's risk of developing serious muscle disorders from statins.

25 Jun 2026

Common genetic difference may increase the risk of severe COVID-19 and lung fibrosis

A genetic difference carried by nearly one in three people may increase the risk of severe COVID-19 and lung fibrosis by disrupting the function of a previously unknown protein, according to a new study.

24 Jun 2026

Hidden protein linked to severe COVID-19 and lung disease risk

24 Jun 2026

Elite athletes with higher vitamin D show healthier lipid profiles

Higher serum 25-hydroxyvitamin D levels were independently associated with lower LDL-C, triglycerides, and lipoprotein(a) in 773 male professional athletes. The cross-sectional study cannot establish causality, but it suggests that vitamin D status may be linked to cardiovascular risk-related lipid markers, even in elite athletic populations.

23 Jun 2026

US adults are taking more supplements as multivitamins lose ground

A 25-year NHANES analysis of 63,442 US adults found that reported dietary supplement use rose from 51% to 60%, with the largest increases among adults aged 65 years and older. Use shifted away from multivitamin-multimineral products and toward vitamins, minerals, botanicals, and nonvitamin nonmineral supplements marketed for immune, anti-inflammatory, gut, skin, and joint health.

16 Jun 2026

Menopausal hormone therapy linked to stronger bone health

Women on menopausal hormonal therapy face a decreased risk of low bone mineral density compared to those not using it, according to a study being presented Sunday at ENDO 2026, the Endocrine Society's annual meeting in Chicago, Ill.

14 Jun 2026

Trial finds prunes do not outperform calcium and vitamin D for male bone density

A one-year randomized trial found that daily prune supplementation did not improve total or lumbar spine bone mineral density in older men susceptible to, or with, osteopenia. Although some bone turnover biomarkers differed between prune and control groups, these changes did not translate into measurable bone density benefits beyond calcium and vitamin D3 supplementation.

11 Jun 2026

Review finds vitamin D lacks disease-modifying effect in rheumatic diseases

A new review from the International Osteoporosis Foundation (IOF) Osteoimmunology Working Group, published in Osteoporosis International, provides a comprehensive evaluation of the role of vitamin D in inflammatory rheumatic diseases.

8 Jun 2026

The best foods for brain health may change as you age

Investigating brain foods, this review highlights dietary influences on cognition and neurodevelopment, while addressing significant gaps in current research.

3 Jun 2026

Study shows mandatory fortification shields infants from vitamin D deficiency

The majority of young children showed good vitamin D status, no child had indications of deficiency, but among some intake was too low. This is the result of a study encompassing over 1,800 infants in Sweden. Foods providing children with vitamin D also contributed to greenhouse gas emissions.

28 May 2026

New study tests vitamin D analog against pancreatic cancer

A small clinical trial led by Dana-Farber Cancer Institute researchers put a Salk Institute idea to the test in patients: that activating the vitamin D receptor can help reshape the protective environment surrounding pancreatic tumors in ways that could make the notoriously difficult-to-treat cancer more vulnerable to therapeutic treatments.

26 May 2026

Outdoor running combats winter vitamin D deficiency better than supplements

An EHU study says that vitamin D supplements can help to strengthen the immune system, but not to improve athletic performance.

25 May 2026

High-dose vitamin D3 in pregnancy may boost children’s memory by age 10

High-dose vitamin D3 supplementation from mid-pregnancy to early postpartum was associated with better verbal and visual memory in children at age 10. The post hoc analysis suggests prenatal vitamin D3 exposure may support selected cognitive functions, although findings require cautious interpretation.

21 May 2026

Phase two clinical trial demonstrates dramatic mobility gains in children with severe fibrous dysplasia

Fibrous dysplasia is a rare skeletal disorder in which normal bone is gradually replaced by weak fibro-osseous tissue, leading to fractures, pain, deformities, and severe mobility impairment. In many patients, diseased bone tissue produces excessive amounts of fibroblast growth factor-23 (FGF23), a hormone that causes phosphate loss through the kidneys.

21 May 2026

$Calcium and vitamin D supplements show limited fracture prevention benefits$

Calcium and vitamin D supplements show limited fracture prevention benefits

Calcium, vitamin D, or combined supplements offer little to no clinically meaningful benefit on fracture and fall prevention in most older people, finds an in-depth review of the latest evidence published by The BMJ today.

20 May 2026