NUTRITION

Dietary Calcium

Calcium Sources

Estimating Calcium Intake

Calcium Supplements

Reading Food Labels for Calcium Content

Vitamin D

Reading Foods Labels for Vitamin D

Caffeine

Magnesium

Protein

Phosphorus

Sodium

Soy

Vitamin A

Vitamin K

Other Dietary Factors

RISK FACTOR REDUCTION

Exercise

Safety/Fall Prevention

Tobacco

Alcohol

Vitamin D

What is vitamin D?

Vitamin D is a fat soluble vitamin that your body needs to absorb calcium. It also plays an important role in maintaining muscle strength. Vitamin D deficiency is associated with reduced calcium absorption, bone loss, reduced muscle strength, and increased risk of fractures.

What are the sources of vitamin D?

Sunlight is the major source of vitamin D for many populations but sun exposure is a risk factor for skin cancer. It is important to know that even without sun exposure, you can get vitamin D from some foods and supplements.

Vitamin D Sources

Why is vitamin D called the "sunshine vitamin" ?

Vitamin D is often referred to as the "sunshine vitamin". That is because the human body has the potential to make vitamin D from casual sun exposure of short duration. However, sun exposure can put an individual at risk for skin cancer, cataracts, and premature aging. According to the American Academy of Dermatology, vitamin D from food and dietary supplements offer the same benefits as vitamin D from the sun- without the danger of UV exposure- as vitamin D obtained from the sun. For more information, click on the American Academy of Dermatology Vitamin D Fact Sheet:
http://www.aad.org/media/background/factsheets/fact_vitamind.htm

For quick tips for sun protection, take the American Cancer Society's Sun Safety Quiz:

What foods and supplements contain vitamin D?

There are only a few naturally occurring food sources of vitamin D, such as fatty fish. Some foods are fortified with vitamin D. It is important to know that the type of vitamin D added to fortified foods varies. Vitamin D3 (cholecalciferol) is preferred since it is 4 to 9 times more bioactive than vitamin D2 (ergocalciferol).  Vitamin D3 is found in animal products or made from the ultraviolet irradiation of lanolin. Vitamin D2 is more common in vegetarian food sources and manufactured through the ultraviolet irradiation of yeast. Foods fortified with vitamin D3 include cow's milk, some yogurts, vitamin D fortified orange juice, some breakfast cereals and some breakfast bars. Vitamin D3 can also be obtained from multivitamins (most contain 400 IU), in combination with some calcium supplements, or alone as a separate vitamin D3 supplement. It is important to read nutrition fact labels of supplements to determine the source of vitamin D since vitamin D3 is preferable. Since the vegetarian source of vitamin D is vitamin D2, individuals who follow vegan diets  (strict vegetarian diets that exclude all animal products and by-products) should to speak to their healthcare provider to find out more about their vitamin D needs.

What are the sources of vitamin D?

There is currently limited information about the vitamin D content of foods.  The average vitamin D content of some foods has been measured.  Vitamin D content is stated in international units (IU).
The amount of vitamin D that is found in food varies depending on the feed given to animal sources of vitamin D, the brand purchased, as well as the amount of vitamin D added to fortified foods. For example, milk is fortified with 100 IU of vitamin D3 per 8-ounce cup. Most dairy products including yogurts and cheeses have not traditionally been made with fortified milk. However, recently a few dairy products and other foods have been manufactured with vitamin D3 added. It is important to read food labels for vitamin  
D content.

It's sensible to avoid sources of vitamin D that are high in retinol.

Vitamin D and vitamin A are both fat-soluble vitamins that may be present in some of the same foods or supplements. Cod liver oil, for example, contains high amounts of both vitamin D and a type of vitamin A called retinol. 

A large study found that postmenopausal women who consumed very high intakes of retinol (from food sources such as cod liver oil and liver, from certain multivitamins or from vitamin A supplements) appeared to have an increased risk of hip fractures. However, there was no association between high intakes of another type of vitamin A, called beta-carotene and the risk of hip fracture. Beta-carotene is found in a wide variety of yellow and orange-colored fruits and vegetables, as well as green leafy vegetables. 

A large population study also found an association between high intakes of retinol from supplements and hip fracture but reported no association between retinol from cod liver oil or other food sources and fracture risk.  Although further investigation is needed to study the relationship between retinol from various sources and fracture risk, it is sensible to avoid foods and supplemental sources of vitamin D that are high in retinol. This includes the avoidance of cod liver oil and vitamin D supplements that have vitamin A added.

How much vitamin D do I need?

According to The National Osteoporosis Foundation, experts recommend that adults under age 50 consume a daily intake of 400 to 800 international units (IU) of vitamin D. People age 50 and older need between 800 and 1000 IU. Some people will need even more.Your doctor or medical professional may recommend more Vitamin D than recommended for the general population, if you are at high risk for vitamin D deficiency or if you have been diagnosed with low serum vitamin D levels.

What populations are at higher risk for vitamin D deficiency?

The following populations are at higher risk for vitamin D deficiency than the general population:

  • Older individuals  who consume diets low in vitamin D and do not take supplements containing vitamin D
  • Individuals who take total sun precautions, consume diets low in vitamin D and do not take a supplement containing vitamin D
  • Homebound individuals who get little sun exposure, consume diets low in vitamin D and do not take a supplement containing vitamin D
  • Individuals with malabsorption syndromes who are not able to absorb dietary vitamin D (examples include: some people with Crohn's disease or celiac disease)
  • Individuals with liver or kidney diseases who may be less able to process vitamin D
  • Individuals taking certain medications that interfere with vitamin D metabolism (Some of these medications include steroids taken for more than 3 months, certain medications used to control seizures such as dilantin or phenobarbitol and cholestryamine used to lower the cholesterol level)

What should I do if I am at high risk for vitamin D deficiency?

If you happen to be at high risk for vitamin D deficiency, it does not mean that you actually have vitamin D deficiency. Only your doctor or medical professional can make that determination. If you think that you may be at risk for vitamin D deficiency, it is important to speak to their doctor or medical professional. If your doctor or medical professional feels that it is necessary, he or she may recommend a blood test to check your vitamin D level.

There is evidence that the intake of 800 IU/day of vitamin D (or more) along with adequate calcium may reduce the risk for falls (by increasing muscle strength) and reduce the risk for fracture in postmenopausal women and seniors. We know that as adults age, the need for vitamin D increases, however older adults are often not not meeting the recommended intake for vitamin D. In order for seniors to get enough vitamin D, a supplement if often required. It is a good idea for all adults to speak to their medical professional about their individual recommendations for vitamin D. 

Can too much vitamin D be harmful?

Since vitamin D can be stored in your body, it has been presumed that too much may be harmful. However, toxicity is rarely seen. It is important to follow the advice of your doctor or medical professional and not to exceed 2000 IU/day of vitamin D from diet and/or supplements without a prescription.






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