Vitamin D

The hottest topic in medicine now is vitamin D.

A recent study showing that people taking normal vitamin D supplements were 7% less likely to die than those who didn't take the daily supplements. Another major study found that when women with low vitamin D levels get breast cancer, they have a much higher chance of dying from their cancer than women with normal vitamin D levels. That was surprising news. But just as surprising is the fact that many men, women, and children have insufficient blood levels of this important vitamin. Many of us don't get the vitamin D we need.

The findings of the recent studies led the Doctors to double the recommended amount of vitamin D a child should take -- and have led many doctors to advise their adult patients to up their vitamin D intake

Why do I need vitamin D?

Your body must have vitamin D to absorb calcium and promote bone growth. Too little vitamin D results in soft bones in children (rickets) and fragile, misshapen bones in adults (osteomalacia). You also need vitamin D for other important body functions.

Vitamin D deficiency has now been linked to breast cancer, colon cancer, prostate cancer, heart disease, depression, weight gain, and many other maladies. These studies show that people with higher levels of vitamin D have a lower risk of disease, although they do not definitively prove that lack of vitamin D causes disease -- or that vitamin D supplements would lower risk.

The Vitamin D Council -- a scientist-led group promoting vitamin D deficiency awareness -- suggests vitamin D treatment might be found helpful in treating or preventing autism, autoimmune disease, cancer, chronic pain, depression, diabetes, heart disease, high bloodpressure, flu, neuromuscular diseases, and osteoporosis. However, there have been no definitive clinical trials.

The best known benefit of vitamin D is its role in helping calcium build strong bones. But that's far from the whole story. Vitamin D helps regulate the immune system and the neuromuscular system. Vitamin D also plays major roles in the life cycle of human cells.

Vitamin D is so important that your body makes it by itself -- but only after skin exposure to sufficient sunlight.

Dark skin absorbs less sunlight, so people with dark skin do not get as much vitamin D from sun exposure as do light-skinned people. This is a particular problem for African-Americans in the northern U.S.

How can I get enough vitamin D?

Thirty minutes of sun exposure to the face, legs, or back -- without sunscreen -- at least twice a week should give you plenty of vitamin D. It's probably a better idea to get vitamin D from foods or from supplements.

Will a vitamin D test tell me if I need more vitamin D?

Yes. As part of your regular blood test, your doctor should order a test for 25-hydroxyvitamin D (25-OHD).

Everyone agrees that anyone with a 25-OHD level of less than 15 ng/mL or 37.5 nmol/L (depending on the units reported by a lab) needs more vitamin D. A 2002 study found that 42% of African-American women of childbearing age had vitamin D levels below 15 ng/mL. The Vitamin D Council considers the ideal 25-OHD level to be between 40 ng/mL and 70 ng/mL.

Which foods contain vitamin D?

Surprisingly few foods contain vitamin D -- unless it's added to the food. That's because your body is built to get vitamin D through your skin (from sunlight) rather than through your mouth (by food). But once your body has enough, it doesn't matter whether you got it through your skin or through your stomach.

There are three vitamin D super foods:

· Salmon (especially wild-caught)

· Mackerel (especially wild-caught; eat up to 12 ounces a week of a variety of fish and shellfish that are low in mercury)

· Mushrooms exposed to ultraviolet light to increase vitamin D

Other food sources of vitamin D include:

· Cod liver oil (warning: cod liver oil is rich in vitamin A; too much may be bad )

· Tuna canned in water

· Milk or yogurt or curd -- regardless of whether it's whole, nonfat, or reduced fat -- fortified with vitamin D

· calf liver

· Egg yolks

· Cheese

Unlike in India, all milk in the U.S. is fortified with vitamin D. So are many brands of orange juice, yogurt, margarine, and ready-to-eat breakfast cereals.

How much vitamin D do I need?

The current recommended daily dose of vitamin D is 200 IU for people up to age 50, 400 IU for people aged 51 to 70, and 600 IU for people over age 70.

That's not enough, Boston University vitamin D expert , recommends a dose of 1,000 IU a day of vitamin D for both infants and adults -- unless they're getting plenty of safe sun exposure.

The Vitamin D Council recommends that healthy adults take 2,000 IU of vitamin D daily -- more if they get little or no sun exposure. There's evidence that people with a lot of body fat need more vitamin D than lean people.

Can I get too much vitamin D?

Too much of any good thing is a bad thing. Too much vitamin D can cause an abnormally high blood calcium level, which could result in nausea, constipation, confusion, abnormal heart rhythm, and even kidney stones.

It's nearly impossible to get too much vitamin D from sunlight or from foods (unless you take way too much cod liver oil). Nearly all vitamin D overdoses come from supplements.

The Institute of Medicine's Food and Nutrition Board's 1997 recommendations suggest that 2,000 IU per day of vitamin D is safe for adults and that 1,000 IU per day is safe for infants up to 12 months of age.

However, the relatively small doses of vitamin D in daily vitamin pills are not enough to correct serious vitamin D deficiency. A 2009 study suggested that the best regimen for treating vitamin D insufficiency is 50,000 IU of vitamin D3 taken three times a week for six weeks. This time-limited regimen did not result in vitamin D toxicity.

How much vitamin D is too much? That's controversial. According to the National Institutes of Health, the maximum upper limit for vitamin D is 25 micrograms (1,000 IU) for children up to age 12 months and 50 micrograms (2,000 IU) for everyone else.

But some recent studies suggest that healthy adults can tolerate more than 10,000 IU of vitamin D per day. The Vitamin D Council, notes that the skin makes 10,000 IU of vitamin D after 30 minutes of full-body sun exposure. He suggests that 10,000 IU of vitamin D is not toxic.

What kind of vitamin D is best?

The recommended form of vitamin D is vitamin D3 or cholecalciferol. This is the natural form of vitamin D that your body makes from sunlight. Supplements are made from the fat of lambs' wool. However, a clinical study reported in 2008 suggested that vitamin D2 works as well as vitamin D3. Many supplements contain vitamin D as vitamin D2 or calciferol. It's derived from irradiated fungus. Because this is not the form of vitamin D naturally made by your body,

Because of its potency, different forms of vitamin D are used in prescription medications. If you have a prescription for one of these medications, do not switch to another form of vitamin D.

Does vitamin D interact with other medications?

Yes. Steroid medications such as prednisone can interfere with vitamin D metabolism. If you take steroid drugs regularly, discuss vitamin D with your doctor.

It is believed that the weight loss drugs may cut absorption of vitamin D. So does some of the cholesterol-lowering drugs too. People taking these drugs should discuss vitamin intake with their doctors.

The seizure drugs affect vitamin D metabolism and affect calcium absorption. So do anti-tuberculosis drugs.

On the other hand, cholesterol-lowering statin drugs and thiazide diuretics increase vitamin D levels.

Vitamin D Deficiency

If you shun the sun, suffer from milk allergies, or adhere to a strict vegetarian 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 sunlight. It is also occurs naturally in a few foods -- including 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 vegetarian diet, because most of the natural sources are animal-based, including fish and fish oils, egg yolks, cheese, and 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.

Courtesy: Webmd