The short answer: you get vitamin D three ways: sunlight on bare skin, food and supplements. In summer, the NHS says sunlight covers most people’s needs, but in winter the sun is too weak far from the equator. The best foods are oily fish such as trout and salmon, UV-exposed mushrooms and fortified milk. Adults need 600 IU a day, or 800 IU from age 71.
Food figures below come from the NIH Office of Dietary Supplements (ODS) and USDA FoodData Central. The Daily Value (DV) for vitamin D is 800 IU (20 mcg).
What does vitamin D do?
Vitamin D helps your body absorb calcium, one of the main building blocks of bone. NIH says your muscles need it to move, your nerves need it to carry messages and your immune system needs it to fight bacteria and viruses. A long-term shortage causes osteomalacia in adults, with bone pain and muscle weakness, and rickets in children.
How do you get vitamin D from the sun?
Your skin makes vitamin D when UVB rays from the sun reach bare skin outdoors. NIH says most people get at least some vitamin D this way, though clouds, smog, older age and darker skin all reduce how much you make.
Three things get in the way:
- Glass. UVB doesn’t pass through windows, so sitting in a sunny room doesn’t help.
- Sunscreen. Harvard’s Nutrition Source says correctly applied sunscreen can cut vitamin D production by more than 90%.
- Covered skin. Clothing that covers most of your skin limits how much you make.
How long is enough? NIH says it’s hard to give a rule, because season, time of day, skin color and other factors change the answer. It notes that some experts suggest about 5 to 30 minutes of sun between 10 a.m. and 4 p.m., daily or at least twice a week, on the face, arms, hands and legs without sunscreen.
Sunburn is the trade-off. UV rays cause skin cancer, so NIH advises SPF 15 or more for more than a few minutes outside. The NHS says never burn and use at least SPF 30. You can’t overdose on vitamin D from the sun, because your skin limits how much it makes.
Can you get vitamin D from the sun in winter?
Usually not if you live far from the equator. Harvard’s Nutrition Source says people in Boston can’t make enough vitamin D from the sun for 4 months of the year, Edmonton in Canada for 5 months and Bergen in Norway for 6.
In the UK, the NHS says most people can make all the vitamin D they need from late March or early April to the end of September. From October to early March, they don’t make enough. That’s why UK government advice is for everyone to consider a daily 10 mcg (400 IU) supplement in autumn and winter.
What foods are high in vitamin D?
Oily fish, cod liver oil and some mushrooms lead the list. NIH says fortified foods provide most of the vitamin D in US diets.
| Food | Portion | Vitamin D (IU) | % DV | Data |
|---|---|---|---|---|
| Cod liver oil | 1 tbsp | 1,360 | 170% | NIH |
| Maitake mushrooms, raw | 1 cup, diced | 786 | 98% | USDA |
| Rainbow trout, farmed, cooked | 3 oz | 645 | 81% | NIH |
| Portabella mushrooms, UV-exposed, grilled | 1 cup, sliced | 634 | 79% | USDA |
| Sockeye salmon, cooked | 3 oz | 570 | 71% | NIH |
| Swordfish, cooked | 3 oz | 566 | 71% | USDA |
| Pink salmon, canned | 3 oz | 465 | 58% | USDA |
| Atlantic salmon, farmed, cooked | 3 oz | 447 | 56% | USDA |
| Pacific mackerel, cooked | 3 oz | 388 | 49% | USDA |
| White mushrooms, UV-exposed, raw | ½ cup, sliced | 366 | 46% | NIH |
| Halibut, cooked | 3 oz | 196 | 25% | USDA |
| Smoked salmon (chinook) | 1 oz | 194 | 24% | USDA |
| Herring, cooked | 3 oz | 182 | 23% | USDA |
| Sardines, canned in oil | 1 can (3.75 oz) | 178 | 22% | USDA |
| Rockfish, cooked | 3 oz | 156 | 19% | USDA |
| Soy, almond or oat milk, fortified | 1 cup | 100 to 144 | 13 to 18% | NIH |
| Tilapia, cooked | 1 fillet | 131 | 16% | USDA |
| Milk, 2%, fortified | 1 cup | 120 | 15% | NIH |
| Orange juice, fortified | 1 cup | 100 | 12% | USDA |
| Breakfast cereal, fortified with 10% DV | 1 serving | 80 | 10% | NIH |
| Yogurt, low-fat vanilla, fortified | 6 oz | 80 | 10% | USDA |
| Margarine, fortified | 1 tbsp | 60 | 8% | USDA |
| Egg, scrambled | 1 large | 44 | 6% | NIH |
| Beef liver, braised | 3 oz | 42 | 5% | NIH |
| Light tuna, canned in water | 3 oz | 40 | 5% | NIH |
| Cod, cooked | 3 oz | 39 | 5% | USDA |
| Cheddar cheese | 1½ oz | 17 | 2% | NIH |
USDA rows are worked out from USDA’s per-100g figures and portion weights. Fortified foods and mushrooms vary a lot, so check the label.
NIH says almost all US milk is fortified with about 120 IU per cup, and many plant milks are too. Cheese and ice cream usually aren’t. Some breakfast cereals are fortified with vitamin D, and choosing one from our list of high-fiber foods gets you fiber at the same time.
How much vitamin D do you need a day?
Adults need 600 IU (15 mcg) of vitamin D a day up to age 70, and 800 IU (20 mcg) from age 71, according to NIH.
| Life stage | Recommended per day | Upper limit per day |
|---|---|---|
| Children 1 to 3 years | 600 IU (15 mcg) | 2,500 IU (63 mcg) |
| Children 4 to 8 years | 600 IU (15 mcg) | 3,000 IU (75 mcg) |
| Children 9 to 18 years | 600 IU (15 mcg) | 4,000 IU (100 mcg) |
| Adults 19 to 70 | 600 IU (15 mcg) | 4,000 IU (100 mcg) |
| Adults 71 and older | 800 IU (20 mcg) | 4,000 IU (100 mcg) |
| Pregnant or breastfeeding | 600 IU (15 mcg) | 4,000 IU (100 mcg) |
The upper limit covers everything combined: food, drinks and supplements.
Whether you need a supplement, and how much, is a question for your doctor or pharmacist. Vitamin D is fat soluble, so NIH says it’s best absorbed with a meal or snack that contains some fat.
Vitamin D also interacts with some medicines. NIH says steroids such as prednisone can lower vitamin D levels, orlistat can reduce absorption, and vitamin D supplements may affect how statins or thiazide diuretics work. Don’t stop or change a medicine because of this. Tell your doctor or pharmacist about any supplement you take.
Who is most likely to have low vitamin D?
People who get little sun on their skin are most likely to run low. NIH says almost 1 in 4 people in the US have blood levels that are too low or inadequate for bone and overall health. Groups at higher risk include:
- people who rarely go outside or keep most of their skin covered
- people with darker skin, who make less vitamin D from the same sun
- older adults, because the skin’s ability to make vitamin D declines with age
- people with Crohn’s disease, celiac disease, ulcerative colitis or other conditions that limit fat absorption
- people with obesity or who have had gastric bypass surgery
- breastfed babies, since breast milk alone doesn’t provide enough
Cleveland Clinic says low vitamin D in adults may cause fatigue, bone pain, muscle weakness, aches or cramps, and mood changes, though many people have no symptoms. If tiredness is your main problem, our guide to why you might always be tired walks through the other common causes. Our guide to vitamin D deficiency symptoms covers the signs in more detail.
Should you get your vitamin D level tested?
Most people don’t need a routine test. Cleveland Clinic says doctors don’t usually order routine checks, but test people with symptoms, risk factors or certain conditions. MedlinePlus adds low bone density, weight-loss surgery and kidney or liver disease to the reasons.
The test measures 25-hydroxyvitamin D in your blood. NIH says levels of 20 ng/mL (50 nmol/L) or above are adequate for most people, below 12 ng/mL (30 nmol/L) are too low, and above 50 ng/mL (125 nmol/L) are too high and might cause problems.
How much vitamin D is too much?
For adults, NIH and the NHS both set the daily upper limit at 4,000 IU (100 mcg). Too much almost always comes from supplements, never from the sun.
Very high blood levels can cause nausea, vomiting, muscle weakness, confusion, pain, loss of appetite, dehydration, a lot of urination and thirst, and kidney stones, NIH says. If you take vitamin D and notice these signs, contact your doctor.
What should you do next?
Plan oily fish such as trout, salmon or sardines into two meals this week, and check whether your milk or plant milk is fortified. On a sunny day, a short walk outdoors with your arms bare counts, as long as you don’t burn. If you’re rarely outside or have a gut condition, ask your doctor whether a test makes sense. Vitamin D matters for bones, and our guide to what to eat during menopause covers calcium and vitamin D together. B12 is the other common shortfall; our list of foods high in B12 has the numbers. For 4 weeks of high-protein meals with grocery lists, see The Menopause Meal Plan.
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Quick questions
Can you get vitamin D through a window?
No. The UVB rays your skin needs to make vitamin D don’t pass through glass, NIH says, so sitting by a sunny window won’t raise your vitamin D. You need sunlight directly on bare skin outdoors. Clouds, smog and sunscreen also reduce how much vitamin D your skin can make.
Can you get vitamin D with sunscreen on?
Some, but much less. Harvard’s Nutrition Source says correctly applied sunscreen can reduce vitamin D production by more than 90%. Even so, NIH still advises sunscreen of SPF 15 or more for anything beyond a few minutes outdoors, because UV rays cause skin cancer. Food and supplements can fill the gap.
How do you get vitamin D in the winter?
Mainly from food and supplements. Far from the equator, winter sun is too weak for your skin to make enough: Harvard says Boston gets 4 months like this. Oily fish, UV-exposed mushrooms and fortified milk or cereal help, and the NHS advises everyone in the UK to consider a 10 mcg (400 IU) daily supplement in autumn and winter.
Does vitamin D give you energy?
It can help if your levels are low, since Cleveland Clinic lists fatigue among possible signs of vitamin D deficiency in adults, along with bone pain and muscle weakness. Tiredness has many other causes, though. A blood test is the only way to know whether low vitamin D is part of the problem.
How much vitamin D is too much?
For adults, the upper limit is 4,000 IU (100 mcg) a day from food, drinks and supplements combined, according to NIH and the NHS. Too much almost always comes from supplements. Very high levels can cause nausea, vomiting, muscle weakness, confusion, thirst and kidney stones. Your doctor may advise more for a short time to treat a deficiency.
Is vitamin D3 the same as vitamin D?
Vitamin D3 is one of two forms of vitamin D. The other is D2. D3 is the form your skin makes from sunlight and is found in animal foods, while D2 comes from plants, Harvard says. NIH says both raise blood levels, but D3 might raise them higher and keep them up longer.
This article is general information, not medical advice. Ask your doctor or pharmacist before taking vitamin D supplements, especially if you take regular medicines or have kidney disease, and never stop or change a medicine on your own.
Sources
- NIH Office of Dietary Supplements. Vitamin D: Fact Sheet for Health Professionals
- NIH Office of Dietary Supplements. Vitamin D: Fact Sheet for Consumers
- USDA FoodData Central, SR Legacy data
- NHS. Vitamin D
- NHS. Sunscreen and sun safety
- Harvard T.H. Chan School of Public Health. The Nutrition Source: Vitamin D
- Cleveland Clinic. Vitamin D Deficiency
- MedlinePlus. Vitamin D Test