Vitamin D: Why it matters and how to get enough
5/19/2026 by Tasneem Abdel-Karim M.B.B.S.
What is vitamin D?
Vitamin D is sometimes called the "sunshine vitamin" because your body makes it when sunlight hits your skin. It helps your body absorb calcium, keeps your bones strong and supports your immune system. Low vitamin D levels are common — affecting over 1 billion people worldwide — and can lead to weak bones, fatigue and a higher risk of infections.
Who is at risk for low vitamin D?
You may be more likely to have low vitamin D if you:
- Spend most of your time indoors.
- Live in a northern climate with limited winter sunlight.
- Have darker skin.
- Are overweight.
- Follow a strict vegetarian or vegan diet.
Where can you get vitamin D?
You can get vitamin D from these sources:
- Sunlight. About 10–15 minutes of midday sun on your arms and legs a few times a week can help, but this varies by season and skin tone.
- Foods. Fatty fish, such as salmon, tuna and mackerel, egg yolks, fortified milk, fortified orange juice and fortified cereals are good sources.
- Supplements. Vitamin D3 (cholecalciferol) supplements are widely available over the counter.
How much vitamin D do you need?
These are the recommended daily doses of vitamin D:
- Children ages 1–18 — 600 IU daily; up to 1,000–2,000 IU may be recommended.
- Adults ages 19–70 — 600 IU daily.
- Adults over 70 — 800 IU daily.
- Pregnant women — At least 600 IU daily. Your clinician may recommend more.
Talk to your healthcare team before starting any supplement, especially at higher doses. A simple blood test can check your vitamin D level and help guide the right amount for you.
Tasneem Abdel-Karim M.B.B.S., is a third-year pediatric resident in Community Pediatric and Adolescent Medicine at Mayo Clinic in Rochester, Minnesota. Special interests include pediatric endocrinology and bone health.