Sunday, 28 June 2009

Vitamin D.








New York State
Department of Health

Vitamin D and Healthy Bones
Vitamin D is essential for the absorption and use of calcium in our bodies.
It promotes the growth and maintenance of strong bones.
How can I get enough vitamin D.

Vitamin D has been referred to as "the sunshine vitamin." Your body can make vitamin D from casual sun exposure of short duration (as little as 5 to 15 minutes of sunshine per day, two to three times per week on the face and hands).

Vitamin D is a fat-soluble vitamin that is stored in your body fat. In general, adults and children living in New York State can get enough casual sun exposure from March to October to store a significant amount of vitamin D.

It will later be released for the body's use during the winter months. However, the use of sunscreen and/or sun-protective clothing, cloudy northern climate, and window glass block your body's ability to make vitamin D from sun exposure.

It is important to know that your body is not able to overdose on vitamin D from the sun, but your skin can suffer damaging effects from too much sun. Therefore, to prevent sunburn and reduce the risk of skin cancer, it is important to limit sun exposure to brief periods (5 to 15 minutes) and then apply sunscreeen (SPF of 15 or higher).

How much vitamin D do I need?
It is difficult to know how much vitamin D your body makes from sunlight. Scientists have established Adequate Intakes (AI) for vitamin D to help you know the amount of vitamin D needed from dietary and/or supplemental sources regardless of your sunlight exposure and body stores.

The AI may overestimate your true biological need if you are able to obtain vitamin D from the sun. However, the AI is a safe level for individuals even if adequate vitamin D is already obtained from the sun.
Adequate Intakes of Vitamin D
Age (years) Vitamin D (IU/day)*
Birth to age 50 200
51-70 400
71 and older 600
*IU = international units/day.

Dietary Reference Intakes, National Academy of Sciences, 1997
For individuals with certain conditions, a physician may recommend slightly more vitamin D than indicated in the table above. For example, some scientists have reported that homebound individuals or people over age 65 achieve optimal bone health benefits when consuming approximately 800 IU of vitamin D daily. Since vitamin D can be stored in your body, too much can be harmful. It is important to follow your medical professional's advice and not to exceed 2000 IU of vitamin D from diet and/or supplements without a prescription.

What foods and supplements contain vitamin D?
There are only a few naturally occurring food sources of vitamin D, most of which are high in fat. These include fatty fish and eggs. Some foods are fortified with vitamin D. These include cow's milk, some soymilk and rice milk, some breakfast cereals and some breakfast bars. Vitamin D can also be obtained from multivitamins (most contain 400 IU), in combination with some calcium supplements, or alone as a separate vitamin D supplement.

Special considerations about vitamin D.
Healthy children and adults can usually get enough vitamin D from sunlight, food and/or multivitamins. Adults, who carefully protect their skin with sunscreen and/or wear protective clothing, do not consume milk or other vitamin D rich foods and do not take a multivitamin should speak to their healthcare provider about how to get enough vitamin D. Homebound individuals with little sun exposure should discuss their risk of vitamin D deficiency with their healthcare provider and try to get enough vitamin D from diet and/or supplements. Senior adults over age 70 have the greatest need for vitamin D and are less able to make vitamin D from sunlight.

Seniors need to be sure to consume enough vitamin D. It is difficult for many seniors to get enough vitamin D from foods and therefore a supplement may be needed. There is some evidence that adequate calcium and vitamin D intake in seniors may even reduce the risk for fracture.

Sources of vitamin D.
The table lists the average vitamin D content for sources of vitamin D that have been measured. Vitamin D content is stated in international units (IU). The list is limited because there is currently little information available about the vitamin D content of other foods.

There are natural sources of vitamin D that also tend to be high in fat. In addition, there are fortified foods (food with vitamin D added) and supplements that contain vitamin D. 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 D per 8-ounce cup. On the other hand, most dairy products including yogurts and cheeses are not made with fortified milk so they are not good sources of vitamin D. Recently, a few dairy products and other foods have been manufactured with vitamin D added. It is important to read food labels.

Natural Sources IU Vitamin D/Serving
Herring 1383 per 3 ounces
Herring, pickled 578 per 3 ounces
Salmon, pink, canned 530 per 3 ounces
Halibut 510 per 3 ounces
Cod liver oil* 450 per teaspoon
Catfish 425 per 3 ounces
Mackerel, Atlantic 306 per 3 ounces
Oyster 272 per 3 ounces
Shitake mushrooms, dried 249 per 4
Sardines, pacific, canned in tomato sauce 213 per 1/2 cup or 182 per sardine
Sardines, atlantic, canned in oil 203 per 1/2 cup or 33 per sardine
Tuna, light meat, canned in oil 200 per 3 ounces
Shrimp 129 per 3 ounces
Egg, cooked 26 per whole egg 25 per yolk
Fortified Sources IU Vitamin D/Serving
Tofu, fortified 120 per 1/5 block
Cow's milk, all types 100 per 8 ounces
Milk, canned evaporated 102 per 4 ounces
Rice milk, fortified 100 per 8 ounces
Soy milk, fortified 100 per 8 ounces
Orange juice, fortified 100 per 8 ounces
Pudding, made with fortified milk 50 per 1/2 cup
Cereal, fortified 40 per serving
Yogurt, fortified (Danimals) 40 per 1/2 cup
Supplemental Sources IU Vitamin D/Dose
Most multivitamins** Usually 400 IU
Calcium with Vitamin D Amount varies
Vitamin D only Amount varies
* High in retinol
** May be high in retinol
USDA National Nutrient Data Base: http://www.nal.usda.gov

It's sensible to avoid sources of vitamin D that are high in retinol.
Vitamin D and vitamin A are both fat-soluble and may be present in 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.

Recent studies have found that postmenopausal women who consumed very high intakes of retinol (from sources such as cod liver oil, liver, certain multivitamins or vitamin A supplements) appeared to have an increased risk for 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 darkly colored orange and green fruits and vegetables. Although further investigation is needed to study the relationship between retinol and fracture risk, it is sensible to avoid consuming too much retinol.

You can get your adequate intake (AI) of vitamin D by selecting foods and supplements that are lower in retinol. It is important to note that retinol may also be listed on the label of fortified foods or supplements as vitamin A acetate or vitamin A palmitate. Multivitamins may be a major source of retinol so it is important to check the label and choose those with more beta-carotene and less retinol.

Even though fortified foods may contain vitamin A from retinol sources, the small amounts that they contain are generally not a concern. It is important and easy to get enough vitamin A from by eating generous servings of darkly-colored orange and green fruits and vegetables each day.

How do you read a food label for vitamin D content?
1. It is important to know that on food labels, 100% Daily Value (%DV) for vitamin D is 400 IU per day.
2. Read the % DV for vitamin D per serving. For example, 1 serving (8 ounces) milk contains 25% vitamin D.
3. Calculate vitamin D content (IU per serving) For example, 25% vitamin D = 25% of 400 IU = 100 IU per serving.
Nutrition Facts
100% JUICE Fortified with Calcium & Vitamin D
Serving Size 8 fl oz (240mL)
Servings per Container 12 There are about 12 - 8 ounce servings in this container.
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Amount Per Serving
Calories 110 Calories from Fat 0
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% Daily Value Percent Daily Values are based on the recommendations for an adult male consuming a 2,000 calorie diet.
Total Fat 0g 0%
Sodium 0mg 0%
Potassium 450mg 13%
Total Carbohydrates 26g 9%
Sugars 22g
Protein 2g
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Vitamin C 130% Calcium 35%
Thiamin 10% Riboflavin 4%
Niacin 4% Vitamin B6 6%
Folate 15% Magnesium 6%
Vitamin D 25% One 8 oz serving of this juice contains 25% Daily Value for Vitamin D = 100 IU

(c) Helen Hayes Hospital/NYS Department of Health - 11/03

2 comments:

Barbara said...

Informative site on eating healthy. I have myelofibrosis and I often wonder what I should be eating more of. Considering it involves the bones, I'm thinking maybe more calcium. But I hate milk.

Herrad said...

Hi Barbara,

Cheese and tofu, brocoli and spinach are some of the other ways you can get calcium.

Thanks for your visit.
Have a good start to the week.
Love,
Herrad