You may need to increase your vitamin D intake during the winter months, and taking supplements or eating certain foods can help.
“The risk of deficiency can increase because there’s no sunlight,” Marie van der Merwe, PhD, coordinator of the doctoral program in Applied Physiology and Nutrition at the University of Memphis, told Health. “This becomes more pronounced during the winter.”
How much vitamin D do you need?
Vitamin D helps the body absorb calcium and, by doing so, helps prevent osteoporosis, which weakens the bones.
Additionally, vitamin D is needed for nerves to send messages between the brain and body, and it helps the immune system defend against viruses and bacteria. This nutrient also helps muscles move; a deficiency can cause muscle weakness and pain.
The recommended daily amount depends on age:
Infants under 12 months: 10 micrograms (mcg), or 400 international units (IU)
People from 1 to 70 years old: 15 mcg, or 600 IU
People 71 years and older: 20 mcg, or 800 IU
How to get more vitamin D through diet
It’s possible — but difficult — to get enough vitamin D from food alone.
“The problem with vitamin D is that it’s very difficult to get it from the diet, because there aren’t many foods that contain vitamin D,” van der Merwe said.
Fatty fish — such as trout, tuna, salmon, and mackerel — as well as fish liver oils are among the best sources of vitamin D, while egg yolks, cheese, beef liver, and mushrooms contain smaller amounts.
Also, many breakfast cereals are fortified with vitamin D, as are some types of milk, yogurt, and orange juice.
When to try a vitamin D supplement
A survey by the Centers for Disease Control and Prevention (CDC) found that about 19% of adults take a vitamin D supplement.
Although vitamin D deficiency is common, it’s not necessarily necessary to take a supplement unless a doctor has recommended it, Pieter Cohen, MD, associate professor of medicine at Harvard Medical School, told Health.
“It’s not something people should feel obligated to take,” he said. “We don’t recommend that healthy people [who have no evidence of vitamin D deficiency] take vitamin D during the winter, even in northern latitudes.”
If you already take a supplement, Cohen does not recommend increasing the dosage during the winter months, nor does he recommend starting a supplement just to take it during the winter.
However, he explained that it’s okay to add a vitamin D supplement to your daily routine, if you want to and if you stick to the recommended dosage.
“As long as you stick to the recommended daily amount, it’s completely safe — but that’s the key,” Cohen said.
It is possible to get too much vitamin D; vitamin D toxicity can cause drowsiness, confusion, abdominal pain, vomiting, and weakness. If symptoms worsen, the condition can include confusion, agitation, and even coma.
