What are the health benefits of vitamin D?

Humans produce vitamin D when they are exposed to the sun. People can also increase their vitamin D intake by eating certain foods and taking supplements.

Vitamin D helps maintain bone and tooth health. It is also believed to protect against diabetes and other diseases.

Not a vitamin, vitamin D is actually a prohormone, or precursor to a hormone.

The body cannot produce vitamins, so they must be consumed as part of a balanced diet. The body, however, can produce vitamin D.

This article discusses the benefits of vitamin D, what happens when a person does not consume enough, and how to increase vitamin D intake.

Benefits

Vitamin D plays several roles in the body. These include:

• strengthening bones and teeth
  
• as well as supporting the immune, nervous, and brain systems
• and controlling diabetes
• diabetes
• which affects cancer-related genes
  

1. Healthy bones

Calcium and phosphorus levels in the blood are maintained by vitamin D. Healthy bones require calcium and phosphorus.

The intestines absorb calcium and reclaim calcium otherwise excreted by the kidneys.

Deficient in vitamin D, children may develop rickets, which causes softening of the bones, resulting in bowlegs.

An adult with osteomalacia, or softening of the bones, is also suffering from vitamin D deficiency. In adults, osteomalacia, or softening of the bones, is another symptom of vitamin D deficiency. An adult with osteomalacia, or softening of the bones, is another symptom of vitamin D deficiency. An adult with osteomalacia, or softening of the bones, is another symptom of vitamin D deficiency. Osteomalacia, or softening of the bones, is another hallmark of vitamin D deficiency in adults. Osteomalacia leads to weakened muscles and weak bones.

A vitamin D deficiency can also lead to osteoporosis, which affects over 53 million Americans.

2. Reduced risk of flu

According to a 2018 review of existing research by Trusted Source, vitamin D appears to be protective against the influenza virus.

Additionally, the authors examined other studies in which vitamin D had no effect on flu or flu risk.

Therefore, further studies are needed to confirm the protective effects of vitamin D against influenza.

3. Healthy infants

can suffer from high blood pressure due to vitamin D deficiency. Low vitamin D levels may contribute to stiff arteries in children, according to a 2018 study.

As per the American Academy of Allergy Asthma and Immunology (AAAAI), evidence suggests a link between low vitamin D exposure and an increased risk of allergic sensitization.

As an example, children who live closer to the equator are less likely to be admitted to the hospital for allergies and are less likely to require epinephrine autoinjectors. Additionally, they are less likely to have a peanut allergy.

An Australian study of egg intake is also highlighted by the AAAAI. A common early source of vitamin D is eggs. Children who started eating eggs after 6 months were more likely to develop food allergies than children who started between 4 and 6 months of age.

Vitamin D may also enhance the anti-inflammatory effects of glucocorticoids. With this benefit, it can be used as a supportive therapy for people with steroid-resistant asthma.

4. Healthy pregnancy

According to a study by Trusted Source in 2019, pregnant women who are deficient in vitamin D may be at greater risk for preeclampsia and preterm birth.

Pregnant women who have low vitamin D levels are also more likely to develop gestational diabetes and bacterial vaginosis.

It is also important to note that in a 2013 studyTrusted Source, researchers associated high vitamin D levels during pregnancy with an increased risk of food allergy in the child during the first 2 years of life.

Deficiency

Although the body can create vitamin D, a deficiency can occur for many reasons.

Causes

• Skin type: Darker skin, for instance, and sunscreen reduce the body's ability to absorb ultraviolet radiation B (UVB) rays from the sun. Vitamin D is produced by the skin when it absorbs sunlight.
• SPF 30 sunscreens can reduce the body's ability to synthesize vitamin D by 95% or more. Wearing clothing can also impair vitamin D production.
  
• People living in northern latitudes or areas with high pollution, working night shifts, or who are homebound should often consume vitamin D through food sources.
  
• If an infant exclusively breastfeeds or has dark skin or minimal exposure to the sun, a vitamin D supplement is recommended. The American Academy of Pediatrics recommends that all breastfed infants receive 400 international units (IU) per day of oral vitamin D.
  
• Supplements of vitamin D are available, but it is best to obtain vitamins and minerals from natural sources whenever possible.
  

Symptoms

Symptoms of vitamin D deficiency may include:

• regular sickness or infection
  
• fatigue
• bone and back pain
• low mood
• impaired wound healing
• hair loss
• muscle pain

If Vitamin D deficiency lasts for an extended period, it may lead to complications, including:

• cardiovascular disease
  
• and autoimmune disorders
• include neurological disorders
• and infection
• during pregnancy
• including breast, prostate, and colon cancers.

Vitamin D sources

The best way to get enough vitamin D is to get enough sunlight. There are many foods that contain vitamin D, including:

• Salmon, mackerel, and tuna are fatty fish
  
• rich in yolks
• yolks
• beef liver
• mushrooms
• fortified milk
• fortified cereals and juices

Here, learn how to get more vitamin D from the sun.

Dosage

Vitamin D intake can be measured in micrograms (mcg) or international units (IU). One microgram of vitamin D equals 40 IU.

Recommended daily intakes of vitamin D are as follows:

• Infants 0–12 months: 400 IU (10 mcg).
  
• Children 1–18 years: 600 IU (15 mcg).
• Adults up to 70 years: 600 IU (15 mcg).
• Adults over 70 years: 800 IU (20 mcg).
• Pregnant or lactating women: 600 IU (15 mcg).

Most people can produce sufficient vitamin D by exposing themselves to the sun for five to ten minutes on bare skin, two to three times per week. During the winter, however, vitamin D stores may run low as it breaks down quite quickly.

Risks

Healthcare professionals recommend 4,000 IU of vitamin D per day for adults. Vitamin D toxicity is unlikely, however, at intakes below 10,000 IU per day, according to the National Institutes of Health (NIH).

Vitamin D can lead to overcalcification of bones and hardening of blood vessels, kidney, lung, and heart tissues when consumed in excess.

Excessive vitamin D can lead to headaches and nausea. It can also cause:

• loss of appetite
  
• dry mouth
• a metallic taste
• vomiting
• constipation
• diarrhea

Overdoses of vitamin D are usually caused by taking too many supplements. A natural source of vitamin D is best.

Supplements should be chosen carefully since the FDA does not monitor the safety or purity of supplements.

Online vitamin D supplements are readily available.

The most important factor for disease prevention and good health is a healthy diet and eating pattern. The key to good health is to eat a diverse diet filled with various nutrients rather than relying on one nutrient only.

Q:

Is sunlight exposure worth the skin cancer risk to make sure people get enough vitamin D?

A:

It does seem like 10–15 minutes of sun exposure a few times a week is harmless, but that exposure can have consequences over your lifetime.

As little as 60 seconds of UVA exposure to the sun can increase your risk for melanoma. You are likely to get enough vitamin D through food, and increasing your intake of vitamin D through sun exposure is not worth the added risk.

If you are not getting enough, then seek out supplements. Experts also recommend that if you will be going outside, you apply sunscreen every 2 hours with a good, broad spectrum sunscreen of SPF 15 or higher. A useful resource for this type of information is skincancer.org.

Debra Sullivan, PhD, MSN, RN, CNE, COI