5 Best Vitamin D Supplements

Vitamin D is both a nutrient that is delivered by food intake and a hormone produced by the kidneys. Vitamin D is known as a fat-soluble vitamin; unlike vitamins B and C, vitamin D is absorbed into the body and stored in fatty tissues and the liver. The body uses the stored vitamin D for future use. Because it is a fat-soluble vitamin, it is possible to take too much of vitamin D, which could lead to toxicity and adverse reactions.

Vitamin D2

Vitamin D2, also known as ergocalciferol, is a fungus/yeast derived product; it is synthetically made by exposing ergot mold to ultraviolet light. Vitamin D2 is used to treat hypoparathyroidism (diminished functioning of the parathyroid gland), rickets (softening of bones due to vitamin D deficiency in children), osteomalacia (softening of bones in adults), and hypophosphatemia (low phosphate levels).

Vitamin D3

Vitamin D3, also known as cholecalciferol, is synthetically made by irradiating wool sources of cholesterol to create vitamin D3. This method of manufacture is similar to the way it is produced intrinsically in human skin when exposed to ultraviolet light. Vitamin D3 treats the same conditions as vitamin D2, but it also encourages the kidneys to return phosphate to the bloodstream where it is used as a nutrient and a chemical to regulate blood pH. Vitamin D3 helps to treat other disorders as well.

Vitamin D promotes calcium absorption from the gut and maintains adequate amounts of calcium in the blood, which enables mineralization of bone to keep bones strong and healthy. There is also an inverse relationship between calcium and phosphorus, so in a way, calcium helps to maintain proper phosphorus levels in the blood. It also helps to prevent cramps and spasms called hypocalcemic tetany. Adequate vitamin D is also linked to a lower risk of certain diseases, including conditions like depression and weight gain.

Vitamin D deficiency can occur as a result of these things:
•    Inadequate dietary intake
•    Impaired absorption and utilization
•    Increased requirements
•    Increased elimination
•    Kidney impairment
•    Limited exposure to sunlight

Efforts to protect skin from sun damage and modern living spent largely indoors can lead to serious vitamin D deficiencies. Too little vitamin D in children causes rickets; too little vitamin D in adults causes osteoporosis. Vitamin D deficiency softens bones and leads to an increased risk of fractures and falling. Soft, weak bones also cause bone and back pain; bones that don't function properly increase the work of the muscles, causing muscle pain.

A Vitamin D deficiency causes more than soft, brittle, weak bones. Vitamin D has a relationship between calcium and phosphorus absorption and utilization. Vitamin D also has a role in the modulation of cell growth and immune function. Calcium and phosphorus, either too low or too high, can also lead to cardiac disturbances which for certain populations can become emergency situations.

The side effects of vitamin D can mimic the side effects of other conditions; it is imperative to inform your healthcare provider if you experience any of the following:
•    Kidney stones
•    Confusion or disorientation
•    Muscle weakness
•    Bone pain
•    Weight loss or poor appetite
•    Extreme thirst
•    Frequent urination
•    Nausea, vomiting, or constipation
•    Fatigue

While this is not a complete list of possible side effects of vitamin D supplements, the listed conditions are serious enough to warrant a visit to your healthcare provider.

Vitamin D is a fat-soluble vitamin, which means that it is not excreted in the urine on a daily basis. Side effects from vitamin D supplements are usually related to excessive levels of vitamin D, leading to vitamin D toxicity. Symptoms of toxicity can be quite specific when excess calcium is absorbed into the blood vessels and tissues, causing heart, blood vessel and kidney damage. Excessive use of both calcium and vitamin D by post-menopausal women has been associated with a 17% increase in the risk of kidney stones over seven years.

Interestingly, excessive sun exposure does not result in toxicity because sustained heat on the skin degrades the precursors of D3. Toxicity is more likely to occur with high intakes of dietary supplements containing vitamin D. Vitamin D supplements can interact with medication to create serious side effects. Examples of medications that can interact with vitamin D are steroids, certain weight loss drugs, anti-epileptics, and certain cholesterol-lowering medications.

Vitamin D supplements that are sold over-the-counter do not require a doctor's prescription; dosages that exceed the usual and customary limits require a prescription. Selecting the best vitamin D supplement, however, requires the consideration of a holistic approach to vitamin D consumption. The reason for taking a supplement is the belief that one is deficient in vitamin D. Complete management of one's dietary intake of vitamin D should include asking your healthcare provider to draw your blood levels of calcium, phosphorus, and vitamin D; if you don't know what your blood levels of these substances are, then how will you know if you're getting too much or too little?