Are you getting enough vitamin D? According to data from the National Health and Nutrition Examination Surveys, two thirds of the U.S. population was deficient in vitamin D from 2001 to 2006. And this is a vitamin you don’t want to be deficient in: Vitamin D not only helps keep your bones strong, it also plays a role in the life cycle of cells, enhances your immune system and neuromuscular function, and reduces inflammation. This article explores how much vitamin D you should be getting, and where you can get it from.
Getting the Right Amount
The recommended daily allowance for vitamin D, established by the Food and Nutrition Board, is 600 IU for individuals 1 to 70 years of age, and 800 IU for individuals 70 years of age and older. In contrast, the Vitamin D Council recommends adults take 5,000 IU a day, saying smaller amounts aren’t enough to meet your body’s needs.
Sunshine versus Vitamin D Supplements
Because food tends to be low in vitamin D (unless it is fortified with vitamin D, such as breakfast cereal and dairy), the most common sources for vitamin D are the sun and supplements. The sun can be dangerous if you are overexposed to its rays, but in limited quantities, it can be an option for you to get your daily dose of vitamin D. It is the most natural way for you to get vitamin D (the way your ancestors did), and you also cannot generate too much vitamin D from sun exposure: Your body produces vitamin D from sunlight and can regulate the amount produced. It’s impossible to overdose.
Vitamin D supplements, while they don’t promote skin cancer like the sun does, can increase the possibility of accumulating too much vitamin D in your tissues. Complications from taking too much vitamin D can include:
- Damage to soft tissue, bones, and kidneys
- High blood pressure
- Muscle weakness
If you decide to supplement with vitamin D, be sure to discuss with your doctor first, and stick with cholecalciferol (vitamin D3) rather than ergocalciferol (vitamin D2). Research published in the American Journal of Clinical Nutrition in 2006 showed that vitamin D2 is less potent than vitamin D3. The authors of the study advised that vitamin D2 “should not be regarded as a nutrient suitable for supplementation or fortification.” Be aware that, despite this evidence, vitamin D2 is the most commonly prescribed form of vitamin D.
How to Get Vitamin D from the Sun (Without Burning)
When ultraviolet B (UVB) rays from the sun hit your skin, components in your skin go through a conversion process to become vitamin D3. To get enough vitamin D from the sun, researchers suggest you should be in the sun for 5 to 30 minutes between 10 a.m. and 3 p.m. at least twice a week without sunscreen, making sure to expose your face, arms, legs, or back to the sun. According to the Vitamin D Council, you will get plenty of vitamin D if you stay in the sun for half the time it takes your skin to turn pink and begin to burn.
A variety of factors can reduce the amount of vitamin D your skin produces from being outside, including the following.
- Cloud coverage, which can reduce UVB energy by 50 percent.
- Significant pollution, which can reduce UVB energy by 60 percent.
- Sunscreens with an SPF of 8 or more, which block UVB rays; however, with consideration to how it is usually applied to the skin (e.g., incomplete coverage or insufficient amounts), the skin is most likely able to create some Vitamin D while wearing sunscreen.
- Darker skin, which may take up to six times longer to gain adequate sun exposure to produce the necessary amounts of vitamin D (so, up to two hours, rather than the recommended 5 to 30 minutes).
- Living far from the equator: If you live far from the equator, there are less UVB rays during the winter months, which can make it difficult for your skin to produce vitamin D.
- Windows: UVB rays do not penetrate through glass, so you cannot get vitamin D through a window of your car, office, or home.
Don’t forget that radiation from the sun causes cancer; be careful to watch how much time you spend in the sun without protection.
Protecting Your Skin While Getting Vitamin D from the Sun
Ever heard of an internal sunscreen? Researchers, in fact, have shown certain foods and supplements can help protect your skin from the damaging effects of the sun, including:
- Rosemary and citrus fruits: Daily consumption of citrus and rosemary bioflavonoids provided significant skin protection from the sun in a study published by the Journal of Photochemistry and Photobiology B: Biology.
- Astaxanthin: A clinical study run by Cyanotech showed that consuming high concentrations of astaxanthin, the active component of a microalgae, in supplement form significantly decreased the skin’s tendency to burn from UV light.
Taking supplements such as these does not guarantee you will not get a sunburn. Supplements can also cause side effects or interactions with other medications; be sure to check with your doctor before starting any new supplements.
For some, especially those who live far from the equator, maintaining a healthy level of vitamin D all year may involve a combination of sunlight and vitamin D supplements. In general, it’s a good idea to test your vitamin D level annually, at home or with your doctor, to make sure it’s at a healthy level in your body.