Vitamin D

Summary

Vitamins are substances that your body needs to grow and develop normally. Vitamin D helps your body absorb calcium. Calcium is one of the main building blocks of bone. A lack of vitamin D can lead to bone diseases such as osteoporosis or rickets. Vitamin D also has a role in your nerve, muscle, and immune systems.

You can get vitamin D in three ways: through your skin, from your diet, and from supplements. Your body forms vitamin D naturally after exposure to sunlight. However, too much sun exposure can lead to skin aging and skin cancer. So many people try to get their vitamin D from other sources.

Vitamin D-rich foods include egg yolks, saltwater fish, and liver. Some other foods, like milk and cereal, often have added vitamin D.

You can also take vitamin D supplements. Check with your health care provider to see how much you should take. People who might need extra vitamin D include:

• Older adults
• Breastfed infants
• People with dark skin
• People with certain conditions, such as liver diseases, cystic fibrosis and Crohn’s disease
• People who have obesity or have had gastric bypass surgery

NIH: National Institutes of Health Office of Dietary Supplements

NIH Office of Dietary Supplements

Patient Handouts

• 25-hydroxy vitamin D test Medical Encyclopedia
• Calcium, vitamin D, and your bones Medical Encyclopedia
• Hypervitaminosis D Medical Encyclopedia
• Vitamin D Medical Encyclopedia

Women

• Breastfeeding: Vitamin D Centers for Disease Control and Prevention

Related Issues

• Calcium and Vitamin D: Important for Bone Health National Institute of Arthritis and Musculoskeletal and Skin Diseases
• Vitamin D Toxicity: What If You Get Too Much? Mayo Foundation for Medical Education and Research

Clinical Trials

• ClinicalTrials.gov: Vitamin D National Institutes of Health

Start Here

• Digging Into Vitamin D: All About the “Sunshine” Vitamin National Institutes of Health
• Vitamin D Harvard School of Public Health
• Vitamin D National Institutes of Health, Office of Dietary Supplements

Find an Expert

• Find a Nutrition Expert Academy of Nutrition and Dietetics
• Food and Drug Administration Food and Drug Administration
• Food and Nutrition Information Center Food and Nutrition Information Center
• National Institutes of Health, Office of Dietary Supplements National Institutes of Health, Office of Dietary Supplements

Journal Articles

• Vitamin D

Children

• Vitamin D Nemours Foundation

Statistics and Research

• Vitamin D and Cancer Prevention National Cancer Institute
• Vitamin D and Multiple Sclerosis (MS): Is There Any Connection? Mayo Foundation for Medical Education and Research
• Vitamin D Supplements Don’t Reduce Cancer Incidence, Trial Shows National Cancer Institute

Diagnosis and Tests

• Vitamin D Test National Library of Medicine