If you shun the sun, suffer from milk allergies, or adhere to a strict vegan diet, you may be at risk for vitamin D deficiency. Known as the sunshine vitamin, vitamin D
is produced by the body in response to skin being exposed to sunlight.
It is also occurs naturally in a few foods -- including some fish, fish
liver oils, and egg yolks -- and in fortified dairy and grain products.
Vitamin D is essential for strong bones, because it helps the body use calcium from the diet. Traditionally, vitamin D deficiency has been associated with rickets,
a disease in which the bone tissue doesn't properly mineralize, leading
to soft bones and skeletal deformities. But increasingly, research is
revealing the importance of vitamin D in protecting against a host of
health problems.
Symptoms and Health Risks of Vitamin D Deficiency
Symptoms of bone pain
and muscle weakness can mean you have a vitamin D deficiency. However,
for many people, the symptoms are subtle. Yet, even without symptoms,
too little vitamin D can pose health risks. Low blood levels of the
vitamin have been associated with the following:
- Increased risk of death from cardiovascular disease
- Cognitive impairment in older adults
- Severe asthma in children
- Cancer
Research suggests that vitamin D could play a role
in the prevention and treatment of a number of different conditions,
including type1 and type 2 diabetes, hypertension, glucose intolerance, and multiple sclerosis.
Causes of Vitamin D Deficiency
Vitamin D deficiency can occur for a number of reasons:
You don't consume the recommended levels of the vitamin over time.
This is likely if you follow a strict vegan diet, because most of the
natural sources are animal-based, including fish and fish oils, egg
yolks, cheese, fortified milk, and beef liver.
Your exposure to sunlight is limited. Because the body makes vitamin D when your skin
is exposed to sunlight, you may be at risk of deficiency if you are
homebound, live in northern latitudes, wear long robes or head coverings
for religious reasons, or have an occupation that prevents sun
exposure.
You have dark skin. The pigment melanin reduces the skin's
ability to make vitamin D in response to sunlight exposure. Some studies
show that older adults with darker skin are at high risk of vitamin D
deficiency.
Your kidneys cannot convert vitamin D to its active form.
As people age, their kidneys are less able to convert vitamin D to its
active form, thus increasing their risk of vitamin D deficiency.
Your digestive tract cannot adequately absorb vitamin D. Certain medical problems, including Crohn's disease, cystic fibrosis, and celiac disease, can affect your intestine's ability to absorb vitamin D from the food you eat.
You are obese. Vitamin D is extracted from the blood by fat cells, altering its release into the circulation. People with a body mass index of 30 or greater often have low blood levels of vitamin D.
Tests for Vitamin D Deficiency
The most accurate way to measure how much vitamin D
is in your body is the 25-hydroxy vitamin D blood test. A level of 20
nanograms/milliliter to 50 ng/mL is considered adequate for healthy
people. A level less than 12 ng/mL indicates vitamin D deficiency.
Treatment for Vitamin D Deficiency
Treatment for vitamin D deficiency involves getting more vitamin D -- through diet and supplements.
Although there is no consensus on vitamin D levels required for optimal
health -- and it likely differs depending on age and health conditions
-- a concentration of less than 20 nanograms per milliliter is generally
considered inadequate, requiring treatment.
Guidelines from the Institute of Medicine increased
the recommended dietary allowance (RDA) of vitamin D to 600
international units (IU) for everyone ages 1-70, and raised it to 800 IU
for adults older than age 70 to optimize bone health. The safe upper
limit was also raised to 4,000 IUs.
If you don't spend much time in the sun or always are careful to cover your skin (sunscreen
inhibits vitamin D production), you should speak to your doctor about
taking a vitamin D supplement, particularly if you have risk factors for
vitamin D deficiency.
Source: webmd.com
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