You might not ever think about it, but that tan you get when you spend too much time out in the sun is actually the body's adaptation for preventing vitamin D deficiency. Fair-skinned people are able to absorb more sunlight through their melanocytes—the skin cells responsible for tan skin. This decreases their risk of vitamin D deficiency, even when they don't spend much time outside.
Nature, though, may not be able to keep up with our increasingly sedentary indoor lives. More than 75% of Americans are deficient in vitamin D—a massive increase from 1994's figure of just 45%. If you have unexplained health problems that are getting worse, a deficiency in vitamin D could be partially to blame.
What Does Vitamin D Do?
You probably already know that calcium is vital for healthy bones and teeth, but vitamin D plays a key role in the way your body processes calcium. Without adequate vitamin D intake, you won't be able to use most of the calcium you take in. Vitamin D may also play a role in fighting and preventing cancer. Its role in cardiovascular health, immunity, and mental health are well-documented, and evidence increasingly suggests that this vitamin may prevent diabetes, multiple sclerosis, and allergies.
Very low vitamin D levels can lead to a life-threatening condition called rickets. Symptoms include broken or bending bones, muscle weakness, fatigue, bone pain, skeletal deformities, and low blood calcium levels.
What Are the Symptoms of a Vitamin D Deficiency?
The most significant indicator of a vitamin D deficiency is an issue with the health of your bones or teeth. Broken bones, osteoporosis, and broken teeth may all point to inadequate vitamin D intake. Some other symptoms of a deficiency may include:
- Being overweight
- Having dark skin, since dark skin decreases your ability to absorb vitamin D
- Aching bones
- Gastrointestinal problems
- Difficulty getting pregnant
- Menstrual cycle disruptions
- A sweaty head
- You follow a strict vegan diet, consuming no animal products.
Your doctor can test you for a vitamin D deficiency with a simple blood test. If your levels are low or marginal, you may want to take steps to get more vitamin D, but talk to your doctor about which options are safest for you.
How to Get More Vitamin D
The easiest way to get more vitamin D is to spend 10 to 15 minutes in the sun each day. Walking to work, going to outdoor festivals, or even eating outside can all help you achieve this goal. If you're concerned about skin cancer or have a deficiency in spite of spending lots of time outside, consider taking a supplement containing at least 2,000 IU of vitamin D. Foods fortified with vitamin D, milk, animal organs such as liver, and fish oil are all high in vitamin D.