Vitamin D has many important jobs in your body. It keeps your bones strong by helping your body absorb calcium and phosphorus, key minerals for bone health. Your muscles use it to move, and nerves need it to carry messages throughout your body.
But many people don’t get enough vitamin D. Find out the best ways to get what you need and whether a supplement might be a good idea for you.
How much vitamin D should you get?
The amount you need depends on your age:
- 600 IU (international units) a day for people ages 1 to 70, including women who are pregnant or breastfeeding
- 800 IU a day for anyone over 70
Some experts think that these recommendations are too low, especially for people who are more likely to get the bone-thinning disease osteoporosis. Ask your doctor how much vitamin D is best for you.
It is possible to get too much vitamin D. Doses above 4,000 IU a day can be harmful for people ages 9 and older. (Children ages 1 to 8 shouldn’t get more than 2,500-3,000 IU.) It’s hard to get that much from food, but it might happen if you take too many vitamin D supplements.
How can you get vitamin D?
Your body makes the nutrient when the sun shines directly on your skin. Just 10 to 15 minutes of sunlight without sunscreen a couple of times a week usually gives you enough vitamin D. But it’s also important to protect your skin, since too much time under the sun’s rays can cause skin cancer. When you’re out in the sun for more than a few minutes, it’s best to wear sunscreen or clothing that covers you up.
So how else can you get this nutrient? A few foods have it naturally, including:
- Fatty fish like salmon, tuna, and mackerel. They’re the best source of vitamin D.
- Beef liver, cheese, and egg yolks
- Mushrooms have a small amount
In the U.S., other foods are fortified with vitamin D, such as:
- Breakfast cereal
- Some orange juice, yogurt, and soy drinks
It’s best to get vitamin D from sunlight and food, but you can also get it in a supplement.
Why do people take vitamin D?
Vitamin D helps the body absorb calcium and phosphorus from the food you eat. So the nutrient is important for people with osteoporosis. Studies show that calcium and vitamin D together can build stronger bones in women after menopause. It also helps with other disorders that cause weak bones, like rickets. If you’re concerned about your bone health, ask your doctor if you should think about taking a supplement.
People who have low levels of vitamin D also may need supplements. That includes those who:
- Are over 50
- Get very little sun
- Have kidney disease or conditions that affect how their bodies absorb minerals
- Have darker skin
- Are lactose intolerant, meaning they can’t digest the sugar in dairy foods
- Are vegan
- Are infants who eat only breast milk
- Those who take certain anticonvulsant drugs
Vitamin D deficiency is also common for people living in the northern parts of the U.S.
Studies have found prescription-strength vitamin D lotions can help people with psoriasis. Researchers have also studied how it affects other conditions from cancer to high blood pressure, but the evidence is unclear.
What are the risks of taking vitamin D?
At normal doses, vitamin D seems to have few side effects. But if you take any medications, be careful — it can interact with many medicines, such as drugs for high blood pressure and heart problems. Ask your doctor if it’s safe for you to take vitamin D supplements.
Too much vitamin D can cause loss of appetite, the need to pee a lot, nausea, and weight loss. High doses of vitamin D can also make you disoriented and lead to bone pain and kidney stones.
Referenced on 22/05/2021
- Institute of Medicine: “Dietary Reference Intakes for Calcium and vitamin D."
- Longe, J., ed. The Gale Encyclopedia of Alternative Medicine, second edition, 2004.
- National Osteoporosis Foundation: “NOF Scientific Statement: National Osteoporosis Foundation's Updated Recommendations for Calcium and Vitamin D3 Intake."
- Natural Standard Patient Monograph: “Vitamin D."
- Office of Dietary Supplements: “Vitamin D."
- WebMD Feature: “Boning up on Calcium."
- National Institutes of Health: “Vitamin D."
- Mayo Clinic: “Vitamin D toxicity: What if you get too much?"