Vitamin D is unique because you can synthesize your needs for this vitamin from sunlight. When the ultraviolet rays of the sun hit your skin, the vitamin is then converted into its active form. Even though your body synthesizes vitamin D, it is still an essential nutrient that you need to get from food due to differences in sunlight throughout the year and limited sun exposure for some people (especially the elderly).

There are other ways to obtain a significant amount of vitamin D without sun, which is through food or supplements. Many people believe that sun exposure is the only valid form of vitamin D. However, in the cold winter months and the rainy days, an alternate source of vitamin D is needed.

Good food sources of vitamin D are:
• Salmon, canned, solids + bones or cooked: A serving size of 2 oz. will provide you with 343 IU of vitamin D.
• Mackerel, cooked: A serving size of 2 oz. will provide you with 197 IU of vitamin D.
• Sardines, canned + bones: 2 ounces of sardines will provide you with 150 IU of vitamin D.
• Fortified milk: One cup of 1% or nonfat milk will provide you with 98 IU vitamin D.
• Margarine, fortified: 1 tablespoon of fortified margarine will provide you with 60 IU of vitamin D.
• Fortified, ready to eat cereals: A 1 oz serving will give you 40 IU of vitamin D.

Fortified foods are a major source of vitamin D. Fortification is the enrichment of foods with micronutrients during food processing. Breakfast cereals, pastries, breads, crackers, cereal grain bars and other foods may be fortified with 10% to 15% of the daily value for vitamin D. It is important to read the nutrition facts panel of the food label to determine whether a food fortified with vitamin D is a good source or not.

Many people find it difficult to find vitamin D foods that they like or will actually eat. Because of this and in addition to climate control of sun exposure, supplements should be considered as well. The best form of vitamin D supplement should be in the D3 cholecalciferol form (1,25 DiOH D3), since this is the active form that is synthesized in the body. The recommended dietary allowance (RDA) of vitamin D is 600 international units (IU) per day for adults up to age 70. The RDA for adults older than 70 is consume 800 IU per day.

Absorbing vitamin D directly from the sun can take anywhere from 15 minutes for fair-skinned individuals to a couple of hours for dark-skinned individuals. That is why it is always good to buy foods fortified in vitamin D or take a daily supplement to make sure your body is getting enough on a day-to-day basis. When relying on sun, the amount of sunlight needed to produce an adequate supply of vitamin D depends on several factors:

• Time of Day: The sun’s rays are the most intense between 10 am and 2 pm.
• Season: The sun delivers more radiation during the summer months.
• Environment: 80% or more of the sun’s rays penetrate clouds. Window glass blocks UV radiation.
• Location: Sunlight is less intense in the northern and southern latitudes than near the equator.
• Skin Type: Light-skinned people absorb UV rays more quickly than dark-skinned people.
• Use of Sunscreen: Sunscreen protects the skin against sun damage, but it also blocks the UV light necessary for vitamin D synthesis. However, it is still extremely important to routinely use sunscreen whenever sun exposure is longer than 10-15 minutes to decrease your risk of skin cancer.

It is important to provide your body with adequate vitamin D to help with calcium absorption, and to keep the heart, kidney and immune system healthy and functioning properly. If you are using the sun as your source, remember to apply sunscreen after 10-15 minutes to make sure your skin does not get burned from over exposure, as well as reducing your risk of getting skin cancer.

Remember, when getting adequate vitamin D from the sun is not possible, you must get it from your meals or supplements. This is important because Vitamin D is essential to your health. Vitamin D is critical for bone maintenance; low sources of vitamin D may cause osteoporosis, bone pain, and fractures. It is also critical in maintaining calcium levels to ensure proper heart functioning, muscle contraction and bone maintenance. Make sure you incorporate good vitamin D sources in your meals, or take a supplement after receiving the okay from your doctor.

Author's Bio: 

Bonnie R. Giller is a registered and certified dietitian nutritionist and certified intuitive eating counselor who helps chronic dieters break free of the pain of dieting and get the healthy body they love. She has multiple degrees in clinical nutrition, a certification as a certified diabetes educator and she works with people who are struggling with dieting or health conditions like diabetes take back control so they can get a healthy body and live their lives symptom free.

Bonnie utilizes the principles of intuitive eating in her work with her clients, which is eating based on internal signals of hunger and satiety versus situations or emotions. The result is they lose weight, keep it off without dieting and live a healthy life of guilt-free eating.

Bonnie is the author of 2 cookbooks and is now working on her third cookbook. She is also the author of an e-book called “5 Steps to a Body You Love Without Dieting” which you can download free at

For more information on Bonnie’s programs, books, lectures and presentations, visit