|
Lakeshore Family Care - Medical News
Do you know if your levels of Vitamin D are adequate?
Recently in the news, there has been more and more information regarding Vitamin D. The more this remarkable vitamin is studied, the more we realize that it plays a vital role in maintaining our health.
What is vitamin D?
Vitamin D, although classified as a vitamin is not really a vitamin at all. A vitamin is a substance that is required by the body in small amounts but which the body cannot make and is, therefore, required to be supplied in the daily diet. Vitamin D is manufactured in the skin when it is exposed to sunlight. Vitamin D actually functions as a hormone in the body. Every cell in your body has receptors for Vitamin D.
Why is vitamin D needed?
Research is showing that Vitamin D plays a greater role in the body than just calcium, phosphorus, and bone metabolism. The more this remarkable “vitamin” is studied, the more it seems that adequate levels are vital for optimal health.
Both prospective and retrospective epidemiologic studies indicate that levels of 25-hydroxyvitamin D below 20 ng per milliliter are associated with a 30 to 50% increased risk of incident colon, prostate, and breast cancer, along with higher mortality from these cancers (NEJM July 19,2007).
Low levels of Vitamin D are associated with congestive heart failure and increased blood levels of inflammatory factors (NEJM July 19,2007).
Lower levels of Vitamin D were found in people with obesity, hypertension, or diabetes mellitus (Arch Internal Medicine 2007). Levels of Vitamin D were inversely associated with age-related Macular Degeneration (Arch. Ophthalmology. 2007).
In a small case-control study, deficient and extremely low levels of vitamin D were found in significantly more ambulatory women with Alzheimer’s disease than in control women of the same age without Alzheimer’s or fractures (Bone 1998)
A meta-analysis of double blind, randomized, trials showed that vitamin D reduced the risk of falling by 22% (JAMA 2004).
Measures of lung function were significantly higher among people who had high levels of vitamin D as compared to those who had low levels(Chest 2005).
What are the sources of Vitamin D?
The majority of the body’s vitamin D comes from sun exposure. The sun’s UV rays trigger vitamin D synthesis in skin. Season, geographic latitude, time of day, cloud cover, smog, and sunscreen affect UV ray exposure and vitamin D synthesis. Most of us in Michigan (especially November through April) do not get an adequate amount of sun exposure to make enough Vitamin D. A sunscreen with an SPF of 8 or higher will block the synthesis of Vitamin D. Sunscreen is important. But if you can get 10-15 minutes worth of sun prior to the application of sunscreen, you will get much closer to adequate blood levels of Vitamin D. You can also get Vitamin D through your diet by eating variety of foods (see the table below). There are also supplements for vitamin D that you can find at health food stores, pharmacies, and your local Supermarket.
Selected food sources of vitamin D
Food |
International Units (IU) per serving |
Percent DV* |
| Cod liver oil, 1 Tablespoon |
1,360 |
340 |
| Salmon, cooked, 3½ ounces |
360 |
90 |
| Mackerel, cooked, 3½ ounces |
345 |
90 |
| Tuna fish, canned in oil, 3 ounces |
200 |
50 |
| Sardines, canned in oil, drained, 1¾ ounces |
250 |
70 |
| Milk, nonfat, reduced fat, and whole, vitamin D fortified, 1 cup |
98 |
25 |
| Margarine, fortified, 1 Tablespoon |
60 |
15 |
| Pudding, prepared from mix and made with vitamin D fortified milk, ½ cup |
50 |
10 |
| Ready-to-eat cereals fortified with 10% of the DV for vitamin D, ¾ cup to 1 cup servings (servings vary according to the brand) |
40 |
10 |
| Egg, 1 whole (vitamin D is found in egg yolk) |
20 |
6 |
| Liver, beef, cooked, 3½ ounces |
15 |
4 |
| Cheese, Swiss, 1 ounce |
12 |
4 |
There are also supplements for vitamin D that you can find at health food stores, pharmacies, and your local Supermarket.
What is the daily-recommended amount (RDA) of Vitamin D?
Currently the RDA of Vitamin D is 400 IU. However for older adults, the RDA is 600 IU. I believe as more and more research is done, the RDA will be set higher.
Can you get too much vitamin D and what happens if you do?
Vitamin D toxicity can cause nausea, vomiting, poor appetite, constipation, weakness, and weight loss. It can also raise blood levels of calcium, causing mental status changes such as confusion. Vitamin D helps with the absorption of calcium and high blood levels of calcium also can cause heart rhythm abnormalities. Calcinosis, the deposition of calcium and phosphate in the body's soft tissues such as the kidney, can also be caused by too much vitamin D.
It is very hard to get vitamin D toxicity from sun exposure. It is also would be extremely rare to get too much from natural sources. You could get it from taking supplements, so if you are using very high doses of vitamin D, you should have your levels monitored.
Can I find out my level of vitamin D?
You can have your vitamin D level checked with a simple blood test. There are a few different types of vitamin D that can be checked this way: 0,25 hydroxy vitamin D and 1,25 hydroxy vitamin D. The 0,25 hydroxy vitamin D is the one that gives you the better indication of your nutritional status of vitamin D. You should also fast for about 4 hours prior to your test.
Do you know what your level of vitamin D is? Come in and have it checked!
|
