About Vitamin D

Introduction
One of the fat-soluble vitamins, vitamin D constitutes two major forms which are vitamin D2 or ergocalciferol and vitamin D3 or cholecalciferol. Vitamin D2 is synthesised by plants whilst vitamin D3 is synthesised by the body. Vitamin D is naturally present in a number of food sources and dietary supplements, and is also manufactured with the aid of sun exposure. It is produced within the body when ultraviolet-B or UVB rays from sunlight reaches the skin. The liver and the kidney eventually help to convert vitamin D to an active hormone form.
Functions of Vitamin D
Vitamin D plays several key roles in the maintenance of organ systems. For example:
* Vitamin D helps regulate calcium concentrations in the blood. Since it works more like a hormone, its active form, calcitriol acts with the parathyroid hormone or PTH. If the calcium level is low, this would trigger the secretion of PTH, which would stimulate the conversion of vitamin D to calcitriol. Calcitriol would then act to increase calcium absorption in the intestines, calcium resorption in the kidneys and stimulate calcium release from the bones.
* Vitamin D helps maintain blood phosphorus levels. Low levels of vitamin D can result to an overactive parathyroid gland. Also with inadequate phosphorus in the body, bones cannot undergo normal mineralisation.
* It is also said that vitamin D benefits the immune system since the T-cells or immune cells have receptors for vitamin D. It acts by boosting phagocytosis, the bodily functions to combat tumours, modulate neuromuscular and immune functions and reduce inflammation.
* Vitamin D is also responsible for maintaining normal cell growth and function. It may be an important element to the prevention and treatment of cancer. It has also been suggested that vitamin D plays a role in regulating the growth and function of brain cells.
* Research studies suggest that vitamin D, because of its anti-inflammatory effect, plays a role in providing protection against osteoporosis, hypertension, cancer, type 1 diabetes, psoriasis and numerous autoimmune diseases.
Deficiency Conditions
There may be certain underlying causes of vitamin D deficiency. It can result from:
* Inadequate vitamin D intake together with inadequate sun exposure
* Certain disorders that compromise vitamin D absorption
* Conditions that can impair the conversion of vitamin D metabolites such as kidney or liver diseases or hereditary disorders.
Insufficient vitamin D intake can have serious effects on the bones, which can make them thin, brittle or deformed. Vitamin D deficiency often results in conditions like:
* Rickets which is common in children and is characterised by delayed growth and deformity of long bones.
* Osteomalacia, which occurs in adults and results in thinning of the bones. Signs of proximal weakness and bone fragility are familiar characteristics.
* Osteoporosis which is a condition wherein the bone mineral density is reduced and bone fragility is increased.
Lack of vitamin D may also be linked to increased susceptibility of several chronic diseases like high blood pressure, cancer, tuberculosis, periodontal disease, multiple sclerosis, chronic pain, schisophrenia, depression, affective disorders, peripheral arterial disease and a number of autoimmune diseases such as type-1 diabetes.
Deficiency Symptoms in Adults and Infants
Signs of vitamin D deficiency includes muscle aches, myopathy or muscle weakness and bone pain. These symptoms can occur at any age. Pregnant mothers who have vitamin D deficiency can also cause fetal deficiency.
In younger infants, rickets can produce a condition called craniotabes or softening of the skull. In older babies, rickets can impede or delay sitting and crawling and the closure of the fontanels; bossing of the infants' skull and presence of costochondral thickening or what is referred to as 'rachitic rosary'. Children with rickets aged 1-4 years old experience epiphyseal cartilage enlargements on the long bones and delayed walking. Older children and adolescents can experience pain upon walking and in worst cases it can result in 'bowlegs' or 'knock-knees'.
Tetany that is caused by hypocalcemia may go along with vitamin D deficiency in infants and adults. This condition can lead to symptoms such as loss of feeling in the lip or tongue areas and the fingers, facial spasms, and at worst, seizures.
Recommended Daily Dose of Vitamin D
Doses or intake of vitamin D is determined according to age groups. These amounts are vital to maintain normal growth and bone health and also normal calcium metabolism in the body. The adequate intakes or AIs for vitamin D indicated are based on the supposition that the vitamin D is not synthesized by sunlight exposure.
From birth to age 13, the recommended AI for children is 5 mcg or 200 IU; for both males and females aged 14-50 years old, 5 mcg or 200 IU is needed; for both males and females aged 51-70 years of age, 10 mcg or 400 IU is required; both males and females reaching the age of 71 and up require 15 mcg or 600 IU of vitamin D. Pregnant and lactating mothers need 5 mcg or 200 IU of the vitamin.
Vitamin D Food Sources
Only a few food sources contain vitamin D. Best sources of vitamin D are fish meat and fish liver oils. There are also small amounts of vitamin D, in the form of vitamin D3, found in dairy products like cheese and egg as well as beef and liver. Some types of mushrooms also contain varying amounts of vitamin D2.
Common sources of vitamin D include the following:
* Cod liver oil
* Fish like salmon, mackerel, tuna, sardines
* Milk including non-fat, reduced fat, whole or vitamin D fortified
* Margarine
* Cereals
* Egg
* Beef liver
* Swiss cheese
* Fortified orange juice
* Fortified rice or soy beverage
The Need for Increased Amounts
Since obtaining sufficient amounts of vitamin D in the diet can be quite difficult, many people now consume vitamin D fortified foods in order to maintain a healthy dose of the vitamin. There are some groups however who need increased amounts of vitamin D:
* Breastfed infants because vitamin D cannot be supplied by breast milk alone
* Older people due to the fact that synthesis of vitamin D decreases with age and the ability of the kidney to convert vitamin D diminishes
* People with limited sun exposure especially those living in northern latitudes, those wearing robes or head covers or those with occupations that prevent them from having sun exposure
* People with dark skin as more skin pigments like melanin reduces the ability of the skin to produce vitamin D.
* People with fat malabsorption conditions such as Crohn's disease, cystic fibrosis, liver and celiac disease or patients who have undergone surgical removal of any part of the stomach or intestine.
* People who are obese. An increased amount of subcutaneous fat can snatch more of the vitamin D and somehow alter its release in the circulation.
Interaction of Vitamin D with Prescribed Drugs
Vitamin D supplements have the tendency to react with certain types of prescription medications. These include the following:
* Steroids or corticosteroid medications like prednisone which can cause decreased calcium absorption and also damage the vitamin D metabolism process.
* Weight-loss medications such as orlistat and cholesterol-lowering drugs like cholestyramine also decrease the absorption of vitamin D and other fat-soluble vitamins
* Phenobarbital and phenytoin increases vitamin D metabolism and decreases calcium absorption.

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Vitamin D - What You DON'T Know

The benefits of Vitamin D are not much talked about in the press. That could be why most folks are unaware of the major benefits of Vitamin D. But please don't think that Vitamin D is not for you.

Vitamin D is another one of those fat soluble vitamins. Fat soluble means that Vitamin D (along with Vitamin A and E) are stored by your body.

Vitamin D is the only vitamin that your body can manufacture. Your body needs exposure to sunlight (without sunscreen) for this to occur.

Your body can also get benefits of Vitamin D from food sources or from supplements. Food sources of Vitamin D include cod liver oil, fatty fish like sardines, tuna or salmon, milk that is Vitamin D fortified and eggs.

However, most folks do not get the required amount of Vitamin D from their diet or exposure to sunlight.

Can't I Get the Benefits of Vitamin D from My Diet Alone

An article in the READER'S DIGEST titled "The Healing Vitamin" states that "Even with a healthy diet, you may be D-ficient (get it? D-ficient?)." The article argues that Vitamin D is not found in many foods and the foods that it is found in, people don't eat enough of.

In addition, folks are using sunscreen to keep the sun from damaging their skin. And even sunscreen with an 8 SPF cuts the UV rays necessary to make your Vitamin D to almost nothing.

An article in the JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION titled "Vitamins for Chronic Disease Prevention in Adults" points out the benefits of Vitamin D. It states that "low levels of vitamin D contribute to osteopenia (comes before osteoporosis) and fractures."

This same article goes on to state that "most people do not consume an optimal amount of all vitamins by diet alone" and "pending strong evidence of effectiveness from randomized trials, it appears prudent for all adults to take vitamin supplements."

Benefits of Vitamin D in Preventing Osteoporosis

Another article appearing in the JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION titled "Osteoporosis, Prevention, Diagnosis and Therapy" tells us that "adequate calcium and vitamin D intake is crucial to develop optimal peak bone mass and to preserve bone mass throughout life."

The major benefits of Vitamin D is in enabling your body to use calcium and phosphorous. Without Vitamin D, your body cannot process the calcium in your diet and starts taking it from your bones.

In adults, this results in the bone disease called osteoporosis. In children, a severe Vitamin D deficiency causes what's called rickets.

Rickets is a softening of bones in children and is rare in the industrialized nations though.

An article in the NATIONAL LIBRARY OF MEDICINE titled "What Was Wrong With Tiny Tim" amusingly argues that Tiny Tim of the Charles Dickens’s "A Christmas Carol" fame is thought to have suffered from Rickets.

That's Not Very Funny

Although Rickets is rare in the industrialized world, osteoporosis is not. In the U.S. it is estimated that 10 million folks have osteoporosis. 18 million more have low bone mass making it highly likely that they too will eventually have this crippling disease.

Osteoporosis is a major health concern and major source of suffering for us older folks. It is estimated that one in two women and one out of every eight men over 50 years of age will have a fracture related to osteoporosis.

300,000 fractures of the hip, 700,000 fractures of the vertebrae, 250,000 fractures of the wrist and over 300,000 other fractures happen every year related to this disease.

Again, the major benefits of Vitamin D is that it enables your small intestine to absorb calcium from the foods you eat. Calcium is required by your muscles and nerves as well as for bone formation.

When your muscles and nerves are not getting enough calcium because of low Vitamin D levels, your body robs it from your bones.

Your bones then become porous and brittle. This does not happen overnight but over the course of your lifetime. That is why prevention of osteoporosis should begin at childhood. And making sure you get the benefits of Vitamin D along with an adequate supply of calcium is one way to do so.

Benefits of Vitamin D in Slowing Progression of Osteoarthritis

Another Osteo you say? Sorry! This time it's osteoarthritis (OA). This disease is a gradual deterioration of the cartilage in the joints. It is the most common form of arthritis.

Another of the benefits of Vitamin D is that it has been shown to lessen the severity of the pain and disability of this disease. The Arthritis Foundation has also reported on the link between low levels of Vitamin D and the increased progression of osteoarthritis of the knees.

Also, in an article in the JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION titled "Steps Toward Understanding, Alleviating Osteoarthritis Will Help Aging Population," we are advised that "preliminary results appear particularly strong for vitamin D."

Are There Other Benefits of Vitamin D? What About Vitamin D and Cancer?

More research is needed but preliminary studies have shown benefits of Vitamin D in areas such as high blood pressure, cancer of the colon as well as breast cancer and diabetes.

Can I Get My Benefits of Vitamin D Without Taking Too Much?

Dr Reinhold Vieth, Dept. of Pathology and Laboratory Medicine at Mount Sinai Hospital in Toronto argues that the Recommended Dietary Allowance (birth to 50 years - 200 IU, 50+ years - 400 IU) may keep you from getting osteomalacia. But he feels more is needed to keep you from getting osteoporosis and secondary hyperparathyroidism.

In an article published in THE AMERICAN JOURNAL OF CLINICAL NUTRITION, titled "Vitamin D supplementation, 25-hydroxyvitamin D concentrations, and safety," he argues that our ancestors were "naked apes in tropical Africa (his words)." And as such they enjoyed full body exposure to the sun on a daily basis. This, he stated, could give them the equivalent of 10,000 IU every day (and possibly a severe sunburn - my words).

A Tolerable Upper Intake Level (UL) has been set by The Food and Nutrition Board of the Institute of Medicine. This is the level of Vitamin D that they suggest you do not exceed. The UL for infants 0 to 12 months old is 1000 IU. The UL for both children as well as adults is 2000 IU.

Studies done since 1997 suggest that the current UL is conservative and that Vitamin D is safe below levels up to as high as 10,000 IU.

Since multivitamins supply Vitamin D in doses of 400 to 800 IU as do the single supplements, you should feel more than safe getting your benefits of Vitamin D.

You can learn much more about the benefits of vitamin d by visiting http://www.health-supplements-advisor.com/benefits-of-vitamin-d.html Article Source: http://EzineArticles.com/?expert=R._Edward_Jones