Many vitamins are important for personal health, but come the wintertime, vitamin D may dominate the headlines. That's because hours of sunlight dwindle in the winter, which can lower levels of vitamin D in the body.
Vitamin D is sometimes referred to as the "sunshine vitamin" because of its ties to the sun. The Cleveland Clinic says sun exposure on the skin is one way for people to get vitamin D. However, people with darker skin or those in certain geographical locations that do not get enough sunlight may not get sufficient vitamin D. Supplementation with foods that contain vitamin D or through pills may be necessary.
Vitamin D helps maintain a balance of calcium in the body and facilitates the building and maintaining of strong bones. The Mayo Clinic says low vitamin D levels have been tied to cancer, cognitive decline, multiple sclerosis, rickets, and psoriasis. But how much vitamin D does a person need? The recommended daily amount of vitamin D is 400 international units for children up to age 12 months, 600 IU for those ages one to 70 years old, and 800 IU for people over 70 years of age. However, some doctors recommend people take higher amounts. The Endocrine Society, for example, suggests higher daily doses of 1,500 to 2,000 IU may be needed for some adults.
Although vitamin D deficiency may compromise health, it's important to note that going too far in the other direction also is unhealthy. Harvard Health advises against taking more than 4,000 IU per day, which is considered the safe upper limit. High doses of vitamin D can cause too much calcium to form in the blood, a condition called hypercalcemia. This raises the risk of fatal heart conditions. Increasing vitamin D intake also increases the risk for kidney stones, so the pros and cons must be weighed. Symptoms of too much vitamin D can include vomiting, nausea, stomach pain, fatigue, dizziness, confusion, increased thirst, and frequent urination.
Getting vitamin D naturally through sunlight and food sources is preferable to supplements. Fatty fish, mushrooms, liver, shrimp, and oysters are some foods that are excellent sources of vitamin D. UCLA Health says eight to 10 minutes of sun exposure at noon produces the recommended amount of vitamin D. However, in the winter when only 10 percent of the body is exposed, nearly two hours of sun exposure at noon is needed to produce a sufficient amount of vitamin D. Geographic regions may produce different rates of exposure needed to ensure sufficient vitamin D production.
Vitamin D is necessary for health, but many people are not getting enough. Increasing exposure to the sun, eating the right foods and supplementation when needed can improve vitamin D levels.