A publication of Senior Services of Snohomish County
11627 Airport Rd., Suite B, Everett WA 98204-8714
425.290.1277  web-sites: srfocusnews.org  sssc.org
Meal Times …
Studies indicate vitamin D
plays vital role in one’s health
By Lilly Kuo, MS, RDN
The Pacific Northwest is known for its dreary winter and lack of sunlight, which is an important
factor for your body to make vitamin D. Vitamin D – known as the “sunshine vitamin” – requires sun
exposure to activate it.
Unfortunately, we do not get enough sunshine during the winter and the chance of vitamin D
insufficiency becomes much greater.
Why is vitamin D so important? Many studies have indicated that vitamin D deficiency raises risks
for cancer, increases susceptibility to cardiovascular disease and affects cognitive health in older adults.
Researchers also suggest vitamin D could play a role in prevention of many conditions including Type 1
and 2 Diabetes, glucose intolerance, and multiple sclerosis.
It is known that vitamin D increases calcium absorption in the gut to maintain healthy bone.
Vitamin D also helps to improve muscle function, along with maintaining healthy bone, and helps to
prevent fall and fractures.
Sources and types of vitamin D
Vitamin D can be obtained from dietary source, or can be made by our body from cholesterol. There
are few foods that naturally have vitamin D, so the biggest dietary sources of vitamin D are fortified
foods (see table, page 2). Our body makes vitamin D when exposed to sunlight. Approximately 15
minutes under the sunlight between 10 a.m. and 3 p.m. provides a sufficient amount of vitamin D.
There are many forms of vitamin D. The two important ones are vitamin D3 (Cholecalciferol) and
vitamin D2 (Ergocalciferol).
Your body makes vitamin D3 when exposed to sunlight; supplements are usually made from the
fat of lambs’ wool. Vitamin D2 is found in some plants and fungus.
Vitamin D3 supplement is most often recommended for those with severely low vitamin D status.
Vitamin D deficiency can occur for many reasons
Diet habits: People who do not consume vitamin D-source foods over time, such as strict vegans,
are at higher risk of vitamin D deficiency. Most vitamin D-source foods, either through fortification or
naturally occurring, are animal-based (see table, page 2). It is also important to remember that vitamin D is a fat-soluble vitamin and requires fat to aide its absorption. When a diet is extremely low in
fat, the body’s ability to absorb vitamin D may be diminished.
Skin color: People with darker skin pigmentation are also prone to vitamin D deficiency. The
dark skin pigments reduce the skin’s ability to make vitamin D in responding to sunlight exposure.
CONTINUED ON PAGE 2
The Senior Focus is published as a community services by Senior Services of Snohomish County. It is our goal to provide news
and information that meets the diverse interests and needs of the senior community. To receive the paper in the mail, call
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Vitamin D Study, continued
Age: As we age, our body’s ability to synthesize vitamin D reduces. Additionally, older adults are
more likely to stay indoors which limits their exposure to sunlight. Older adults who are homebound or
live in institutionalized facilities such as a skilled nursing facility, are at much greater risk for vitamin
D deficiency.
Liver/kidney dysfunction: The liver and kidney are the two organs that turn inactive vitamin D
into the active form with sunlight exposure. For people with liver or kidney disease, the ability to
activate vitamin D can be impaired. Patients with chronic liver disease and kidney disease usually
need a vitamin D supplement to maintain optimal levels.
Be sure to talk with your health care provider if you are concerned about your vitamin D level.
Vitamin D deficiency and toxicity
To prevent vitamin D deficiency, be sure to get at least 15 minutes of sunlight on a sunny day. You
can also get vitamin D from diet. Some animal products naturally have vitamin D; fortified foods include
dairy products, orange juice and soy milk. The recommendation from the Institute of Medicine for adults
up to age 50 is 600 IUs; for those 71 and older, the recommendation is 800 IUs.
Before taking a vitamin D supplement, it is best to ask your primary healthcare provider to test your
vitamin D status. The 25-hydroxy vitamin D test is the most accurate way to measure how much vitamin
D is in your body. The normal range should be between 30.0 to 74.0 nanograms per milliliter (ng/mL).
Most vitamin D toxicity takes place when a high dose of a vitamin D supplement is used. Too much
vitamin D circulating in the blood can result in side effects including nausea, vomiting, headache, weakness and hypercalcemia. Most reports suggest a toxicity level for vitamin D of 10,000 to 40,000 IU/day
and serum vitamin D levels of 200-240 ng/mL.
The Institute of Medicine also concluded that when taking more than 4,000 IUs of vitamin D per day,
the risk for adverse health effect begins to increase. It is also important to understand that more is not
necessarily better. High doses of vitamin D (about 10,000 IUs a day) are known to increase levels of calcium in the blood and can cause kidney and tissue damage.
1 tablespoon
3.5 oz
IUs per
Serving*
1,360
360
1 cup (8oz)
142
Food Sources of Vitamin D
Serving Size
Sardines, canned
3 oz
Cod liver oil
Salmon, cooked
Tuna fish, canned in oil
Orange juice, vitamin D fortified
(amount varies by brand)
Milk, vitamin D fortified
Yogurt, vitamin D fortified
Soy milk, vitamin D fortified
Egg (vitamin D is found in the yolk)
Cheese, swiss
Fresh shitake mushroom, sliced
Ready-to-eat cereal, fortified
3 oz
1 cup (8oz)
3/4 cup (6oz)
1 cup (8oz)
1 large
1 slice
1/2 cup
1 cup
231
200
98
80
100
20
12
40
40
Lilly Kuo is a dietitian with Senior Services Nutrition Program. For information about Senior
Nutrition, call 425-347-1229 or 800-824-2183. Additional nutrition-related articles can be found
at www.sssc.org (click on the Nutrition Update tab).