Why Vitamin D Is a Big Deal

If you’re looking for a reason to enjoy some time in the sun, call it “getting your vitamin D.” Five to 10 minutes a day, two to three times a week, can help your body create the vitamin D it needs. Technically speaking, vitamin D is a pro-hormone. (Vitamins are nutrients that you primarily receive through diet.) Here’s why vitamin D is so important:

1. Enables strong bones – Vitamin D helps regulate and make use of calcium and phosphorus, two ingredients of strong bones. And strong bones are your best defense against osteoporosis.
2. Supports muscle movements – Nerves need vitamin D to carry messages from the brain to parts of the body.
3. Defends against colds and flu – Studies show that adequate levels of vitamin D can help reduce the risks of colds and flu.
4. May lower risk for chronic diseases – Vitamin D deficiency has been connected to the incidence of diseases such as type 2 diabetes, cardiovascular disease and cancer. While the direct evidence is not conclusive due to many variables, vitamin D plays a role across numerous body functions.

Are you at risk for vitamin D deficiency?

Symptoms of vitamin D deficiency may not be obvious, and it can be difficult to get sufficient vitamin D from only natural sources. Six factors that may decrease availability of vitamin D include:

1. Age – Your skin has reduced ability to synthesize vitamin D as you get older. And elderly people may be more likely to spend time indoors.
2. Indoor lifestyle – Office workers, homebound individuals or people who consistently wear long sleeve shirts and pants reduce the opportunity for natural vitamin D.
3. Dark skin – Darker skin tends to produce less vitamin D from the sun.
4. Obesity – Greater amounts of fat absorb vitamin D, inhibiting its use via blood.
5. Gastric bypass surgery – Because part of the small intestine that absorbs vitamin D is bypassed, the vitamin may not be available for use.
6. Lack of fat absorption – Vitamin D is fat-soluble and needs the body’s ability to process fat properly. Diseases such as inflammatory bowel disease, Celiac disease, some liver diseases or cystic fibrosis can decrease fat absorption and may inhibit the use of vitamin D.

Food sources of vitamin D

Sunlight is the most common natural source for vitamin D. Fish oils and fatty fish such as cod liver oil, herring, salmon and sardines are also natural sources. Milk is also often fortified with vitamin D.

Next Steps

Having less than 30 nmol/L is too low for overall health for most people. It is rare that someone would have too much. Groups that are most likely to have lower levels of vitamin D are:

• Older adults – skin doesn’t produce as efficiently and kidneys less able to convert to active form
• People with dark skin – less ability to convert vitamin D from the sun
• People with Crohn’s disease or celiac disease – disease inhibits absorption
• Obese people – body fat may prevent absorption
• Breastfed infants – human milk is not a good source of vitamin D

Talk with your doctor before self-prescribing a vitamin D supplement. Vitamin D supplements may interact with several types of medications. Ask your doctor if he or she recommends a blood test to determine your vitamin D level as part of routine bloodwork.