Vitamin D is a important vitamins you get in some of the foods you eat and through exposure to the sun. When the skin is exposed to the sun, it can produce vitamin D. Vitamin D can also be used as a dietary supplement.
- Helps to produce bones and absorb calcium, which is also important for healthy bones.
- Reduces inflammation.
- May help to prevent muscle cramps and spasms.
- Supports a healthy immune system. It can reduce your risk of getting a viral infection like the flu and lower the severity of the infection if you get sick, says registered dietitian Sonya Angelone, a San Francisco-based area spokeswoman for the Academy of Nutrition and Dietetics .
- Some health experts believe that vitamin D may lower your risk for certain types of cancer, such as colorectal cancer. Research in this area is ongoing.
There are two types of vitamin D that are important to humans: D2 is from plant-based sources, and D3 is produced by the body when the skin is not protected by sunscreen and exposed to ultraviolet rays in the sun.
The recommended daily allowance for vitamin D for children and adults is 600 IU (15 mcg) until age 70. Starting at age 70, the RDA is 800 IU (20 mcg). In infants up to one year of age, the RDA is 400 IU. All of these RDAs assume that a person gets little sun exposure, but federal guidelines do not specify how much the sun means.
Vitamin D Deficiency is Common
Many Americans are believed to be deficient in vitamin D. A 2012 report from the Centers for Disease Control and Prevention states that 8.1% of Americans are deficient in vitamin D, although other studies and estimates mention a higher percentage. In the CDC study, the highest deficiency was found in Black people, with 31% proven to be deficient in vitamin D.
On average, adults in the United States are thought to get 160 to 400 IU per day of vitamin D, which increases to 300 to 900 IU daily when supplements are used, according to Diet Practitioners on Calcium and Vitamin D from the National Academies of Science, Engineering and Medicine.
There are several reasons why people may not get enough vitamin D:
- It is not often found in food sources.
- Although you can get vitamin D from the sun, many of us do not get much outdoors because of the work that confines us indoors. In addition, many people use sunscreen to protect their skin from harmful UV rays. Plus, if you live farther away from the equator, you probably have less exposure to sunlight, says Michelle Bauche, a clinical dietitian of the Weight Management and Metabolic Institute at the University of Missouri Health Care in Columbia.
- Some people have gene variations that make it difficult for their bodies to produce vitamin D, even if their skin is exposed to ultraviolet light.
There is also a wide swath of the population typically deficient in vitamin D. These subgroups include:
- Older Americans. It is harder to get vitamin D as you get older. This is one reason why higher amounts of vitamin D are recommended for adults 70 or older.
- Those who work internally because they have no sunlight, says Antonette Hardie, a registered dietitian at Ohio State University Wexner Medical Center in Columbus.
- Those with darker skin.
- Those with inflammatory bowel disease or cystic fibrosis because these diseases make it more difficult for the body to absorb vitamin D.
- People who are vegan or lactose intolerant and certain types of vegetarians may struggle to get enough vitamin D, Hardie says. That is because food sources that provide vitamin D are often from animals, such as dairy and fish.
- Those who are very fat. Body fat can break down vitamin D instead of spreading it to other parts of the body, says registered dietitian Ali Webster, director of nutrition research and communication at the International Food Information Council in Washington, DC Obesity considered body mass index of 30 kg / m2 or higher.
- Breastfeeding babies. That’s because breast milk is not a good source of vitamin D, and babies should not be exposed directly to the sun, Webster says. Breastfed infants should receive a 400 IU vitamin D supplement a day until they consume 1,000 milliliters of formula D-fortified formula or whole cow’s milk daily, according to the American Academy of Pediatrics .
Signs of Vitamin D Deficiency
There are many signs of vitamin D deficiency, including:
- More frequent infections and illnesses.
- Back pain hurts.
- Change of mood.
- Muscle pain or cramps.
- A softening of the bones that manifests as rickets in children and as osteomalacia in adults, Bauche says.
- Chronic vitamin D deficiency can put you at higher risk for fractures and osteoporosis, Webster says.
Of course, these same signs can be attributed to many other health problems, such as stress, dehydration or painful joints caused by weather changes, Hardie says. If you have these signs and suspect they are linked to vitamin D deficiency, talk to your healthcare provider about getting a blood test that can be tested for vitamin D deficiency.
A normal level from a vitamin D lab test is generally considered to be 20 to 40 ng / mL, but some health care providers prefer to see levels close to 30 to 50 ng / mL.
What to Do If You Are Deficient in Vitamin D
If a lab test indicates that you are not getting enough vitamin D, there are many things you can do.
First, turn to food. Some good food sources for vitamin D include:
- Fatty fish like salmon. A three-ounce serving of sockeye salmon provides 71% of the RDA for vitamin D.
- Dairy and non-dairy products, all of which are generally fortified with vitamin D. A cup of 2% cow’s milk provides 15% of the vitamin D needed by children and adults daily. For non-dairy milk, one cup will provide 13% to 18% of an adult’s RDA for vitamin D.
- Eggs An egg contains 6% of the RDA for vitamin D.
- Liver. Three ounces of liver provide 5% of the RDA for vitamin D.
- Mushrooms are a potential source of vitamin D, but the amount of vitamin D they have increases if they are exposed to UV light in the growing process. For example, one-half cup of portabella mushrooms contains only 1% of the vitamin D RDA, but when exposed to UV light, it rises to 120%, according to the Mushroom Council. Look at the packaging for a note indicating that the mushrooms are treated with UV light.
- Orange juice and cereal fortified with vitamin D. A regular serving size of cereal typically provides 10% of the daily amount needed for vitamin D.
Eating a healthy, overall healthy diet can help you get more vitamin D, Hardie says.
Next, aim to get just a few minutes of sunlight a day. After all, vitamin D is often called the sunshine vitamin. However, day-to-day exposure to sun protection requires minimal time – 10 to 15 minutes a day should be sufficient, with some of your skin (such as your arms or legs) exposed.
However, the American Academy of Dermatology advises people to take their vitamin D from food sources, not the sun.
The third option in place of or in addition to food and sun exposure is a dietary supplement. This is best done in collaboration with your healthcare provider, who will help you decide on the right dose for you. In general, 1,000 to 5,000 IUs are considered safe, Bauche said. These higher doses are used because many people do not receive all of the vitamin D their body gets, Angelone says. Some people receive vitamin D supplement up to 50,000 IU weekly. You can use either D2 o D3 supplements, though D3 supplements are more common.
Here are some tips to help you choose a good vitamin D supplement:
- Find out if a supplement will interact with any of the medications you are using. For example, cholesterol-lowering cholestramine may reduce your absorption of vitamin D.
- Look for a supplement with a USP stamp. This indicates that the product has been proven for purity, strength and quality of manufacturing by US Pharmacopoeia. This is a major step because dietary supplements are not regulated by the Food and Drug Administration, Webster warns.
- Buy directly from the manufacturer. Supplements offered by third-party distributors may not be stored in ideal conditions or may be counterfeit, Bauche cautioned.
- Ask your healthcare provider if you should use other supplements including vitamin D, Angelone’s advice. Some health experts want you to use vitamin K2 or magnesium along with vitamin D to help your body absorb vitamin D.