How to Get Enough Vitamin D

Most people ages 1 to 70 need 600 IU (15 micrograms) of vitamin D a day, and adults over 70 need 800 IU (20 micrograms), according to the NIH Office of Dietary Supplements. Few foods are naturally rich in it, so most Americans rely on a mix of fortified foods such as milk, a few natural sources like fatty fish and eggs, and some sunlight. If you’re worried you’re low, a blood test can tell you where you stand.

Why vitamin D matters

Vitamin D helps your body absorb calcium, which makes it essential for building and keeping strong bones. It also plays roles in muscle movement, nerve signaling and the immune system. A long-term shortage can lead to soft, weak bones: rickets in children and osteomalacia in adults. The Dietary Guidelines have listed vitamin D as a nutrient of public health concern because so many Americans fall short through food alone.

How much you need

Age or stage	Recommended daily amount
Birth to 12 months	400 IU (10 mcg)
1–70 years	600 IU (15 mcg)
71 years and older	800 IU (20 mcg)
Pregnant or breastfeeding	600 IU (15 mcg)

These amounts assume minimal sun exposure, which makes them a safe target year-round.

Where to find it in food

Approximate values, based on NIH and USDA FoodData Central figures. Fortified foods vary by product, so check the Nutrition Facts label.

Food	Portion	Approximate vitamin D
Rainbow trout, farmed, cooked	3 oz	about 645 IU
Sockeye salmon, cooked	3 oz	about 570 IU
Mushrooms treated with UV light	½ cup	varies widely, often several hundred IU
Milk, fortified	1 cup	about 100–120 IU
Soy, almond or oat beverage, fortified	1 cup	about 100–145 IU
Breakfast cereal, fortified	1 serving	often about 10% of the Daily Value
Sardines, canned	2 fish	about 45 IU
Egg	1 large	about 45 IU, all in the yolk
Light tuna, canned	3 oz	about 40 IU

Notice the gap between fatty fish and everything else. On days without trout or salmon, reaching 600 IU from food alone is hard, which is why fortified milk, plant beverages and cereals matter so much in the American diet.

Where sunlight fits in

Your skin makes vitamin D when it’s exposed to the sun’s UVB rays. How much you make depends on the season, the time of day, your latitude, cloud cover and smog, your skin pigmentation, your age and whether you’re wearing sunscreen. In much of the northern U.S., the winter sun is too weak for the skin to make much vitamin D for several months of the year.

Because ultraviolet exposure is a major cause of skin cancer, health agencies don’t recommend tanning or a specific “dose” of sun to make vitamin D. Brief, everyday time outdoors is part of life; relying on food and supplements is the safer plan for meeting your needs.

Who is more likely to run low

NIH lists several groups at higher risk:

• Breastfed infants. Breast milk is low in vitamin D, so the American Academy of Pediatrics recommends a daily supplement of 400 IU for breastfed and partially breastfed babies, starting soon after birth. Your pediatrician can guide you.
• Older adults, whose skin makes vitamin D less efficiently.
• People who get little sun, such as those who are homebound or cover most of their skin.
• People with darker skin, since more melanin reduces vitamin D production from sunlight.
• People with conditions that limit fat absorption, such as Crohn’s disease, celiac disease or cystic fibrosis.
• People with obesity or who have had gastric bypass surgery.

Building vitamin D into your week

• Have fatty fish such as salmon, trout or sardines once or twice a week. Our fish and seafood guide explains which kinds are lowest in mercury.
• Use fortified milk or a fortified plant beverage in coffee, oatmeal or smoothies.
• Look for UV-treated mushrooms in the produce section and add them to stir-fries, omelets and pasta.
• Keep eggs on hand for quick breakfasts and lunches.
• Compare cereal labels for vitamin D if you eat cereal regularly.

Vitamin D and calcium work as a team, so it’s worth reading our guide to getting enough calcium alongside this one.

Supplements: ask first

Vitamin D supplements come as D2 and D3, alone or combined with calcium. More is not better: NIH sets the upper limit for adults and children 9 and older at 4,000 IU (100 mcg) a day, and very high intakes can raise blood calcium to harmful levels. Vitamin D can also interact with some medications. If you think you might be low, ask your doctor whether a blood test makes sense and what amount, if any, is right for you.

Putting it together

Plan on fatty fish a couple of times a week, lean on fortified foods the rest of the time, and enjoy the outdoors without counting on it for your vitamin D. If you fall into a higher-risk group, bring it up at your next checkup.