woman smiling on a sunny beach

When you're catching the last rays of summer sunshine, it's a great time to think about vitamin D. Sometimes called the "sunshine vitamin" because it's produced in your skin in response to sunlight, vitamin D is a fat-soluble steroid vitamin in a family of compounds that includes vitamins D1, D2, and D3. It can affect as many as 2,000 genes in the body.

Uses and Benefits
Vitamin D has several important uses, the most important of which are helping to regulate absorption of calcium and phosphorous, and to facilitate normal immune system function. Getting a sufficient amount of the vitamin is important for normal growth and development of bones and teeth and improved resistance against certain diseases.

In addition to these primary benefits, research suggests that vitamin D may also play a role in:

  • Reducing risk of multiple sclerosis
  • Helping to improve brain function later in life
  • Maintaining healthy body weight
  • Reducing women's risk of developing rheumatoid arthritis

If your body doesn't get enough vitamin D, you're at risk of developing bone abnormalities such as soft bones (osteomalacia) or fragile bones (osteoporosis).

How do you get it?
Besides getting vitamin D through sunlight, you can also get it through certain foods and supplements. It's recommended that you obtain vitamin D from all three of these sources in order to ensure adequate levels of the vitamin in your blood.

Sunlight

Your body produces vitamin D naturally through direct exposure to sunlight. A little can go a long way: just 10 minutes a day of mid-day sun exposure can be plenty for your need, especially if you're fair-skinned.

However, many lifestyle and environmental factors can affect your ability to get sufficient amounts of the vitamin through the sun alone. These factors include:

  • Pollution
  • Use of sunscreen
  • Spending more time indoors
  • Working longer hours in offices
  • Living in big cities where buildings block sunlight

These factors contribute to vitamin D deficiency in an increasing number of people. Because of this, it's important to get some of your vitamin D from sources besides sunlight.

Food

Although few foods contain vitamin D naturally, some foods are fortified with it. Foods that contain vitamin D include:

  • Salmon
  • Sardines
  • Egg yolk
  • Shrimp
  • Milk (fortified)
  • Cereal (fortified)
  • Curd (fortified)
  • Orange juice (fortified)

Supplementation

If it's difficult for you to get enough vitamin D each day through sun exposure and food alone, supplements can help. In particular, older people and those with dark skin are encouraged to supplement their intake, according to the Institute of Food and Agricultural Sciences (IFAS).

How much do you need?
There has been some controversy over the amount of vitamin D needed for healthy functioning. Recent research indicates that we need more vitamin D than we used to think was needed. The Institute of Food and Agricultural Sciences (IFAS) reports that new intake recommendations are as follows (based on international units--IUs per day):

  • Children and Teens: 600 IU
  • Adults up to age 70: 600 IU
  • Adults over age 70: 800 IU
  • Pregnant or breastfeeding women: 600 IU

However, other sources suggest that considerably higher daily amounts--as high as 2000 IU per day--are needed. Although the amount may be in question, the importance of vitamin D is not. Talk to your doctor for guidance on how to ensure you get the right amount for your needs.