Your body makes vitamin D when skin is exposed to sunlight, but production often drops with the shorter days of winter, especially in the northern hemisphere. This could increase the risk for vitamin D deficiency.
Tami Gangestad, MS, RD, CNSC, LN, LD, a registered dietitian at Sanford Health in Sioux Falls, South Dakota, explained that vitamin D plays an important role in promoting calcium and phosphorous absorption – both crucial for bone health.
Vitamin D is also involved in supporting the immune system, hormone regulation, cell growth, muscle function and cardiovascular health.
Risks of vitamin D deficiency
Nearly 37% of adults worldwide have vitamin D levels below the recommended amounts, according to research published in the journal Metabolites. Severe deficiency is reported in 7% of the global population.
In the U.S., studies have found that 14% to 18% of adults have low levels of vitamin D.
Without enough vitamin D, bones may become weak and brittle over time. In children, this condition is called rickets and remains a worldwide problem. Adults risk a softening of the bones called osteomalacia and osteoporosis. People with vitamin D deficiency also report bone pain.
Other signs and symptoms of vitamin D deficiency include muscle weakness, fatigue and a weakened immune system. Some people also report changes in their mood and ability to concentrate.
Some people are more at risk for too little intake or absorption of vitamin D:
- People with limited sun exposure
- Breastfed infants
- People with certain health conditions such as celiac disease, cystic fibrosis, kidney diseases and malabsorption syndromes
- Older adults
- People with obesity
- People with a history of gastric bypass surgery
Additionally, you could be missing out on this important vitamin if you have a milk allergy, lactose intolerance, or if you follow an ovo-vegetarian or vegan diet.
How to get more vitamin D
To compensate for the lack of vitamin D from sunlight, it is important to get plenty of vitamin D from foods.
“Food sources of vitamin D can be challenging to include regularly in our diet,” Gangestad said.
Food sources of vitamin D include:
- Fatty fish such as salmon, trout, and sardines
- Egg yolks
- Beef liver
There are also foods that are fortified with vitamin D, such as:
- Cow’s milk
- Soy milk
- Oat milk
- Almond milk
- Some brands of orange juice and yogurts
If you’re having trouble consistently meeting your complete vitamin D needs, your primary care provider may advise you to take a vitamin D supplement.
Dietitians recommend children and adults get the following vitamin D amounts each day:
- Up to 12 months of age — 400 IU
- Ages 1-18 years — 600 IU
- Between 18 and 70 — 600 IU
- Older than 70 years — 800 IU
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