In order to satisfy the increasing demand for healthy products and vitamin supplements, shop vitamin supplement outlets specialize in selling vitamin supplements to consumers. Originally the only place to find shop vitamin supplements was through a medical practitioner providing a prescription that had to be filled at the local drug store. As the research into the benefits of vitamin supplements became more in depth the drug administration allowed for the production of shop vitamin supplements that could be bought over the counter without the need for a prescription. This led to shop vitamin supplements being widely available in grocery stores and even gas stations, especially for the most commonly required shop vitamin supplements such as vitamin C. The production of shop vitamin supplements has increased to such a level that there are now specific shop vitamin supplements available to cater for different age groups, including children and the over 50s. The increase in demand for shop vitamin supplements does not seem to be decreasing but the variety and choice available to consumers is constantly being improved.

The laws governing the sale of drugs have led to many companies diversifying their businesses to concentrate on selling shop vitamin supplements. This has been one of the main reasons for the appearance of a number of internet based businesses selling a wide variety of shop vitamin supplements. The sales tactics for these websites are becoming increasingly more dubious with the promise that some of their shop vitamin supplements can cure almost any illness or condition. The regulation of these internet shop vitamin supplements is constantly being found to be lacking and the federal drug administration is powerless to prevent some of these sites from making false claims. It is therefore down to the consumer to research the claims of these store vitamin supplement manufacturers and to make their own judgment as to the validity of the sales pitches. The most important factor to consider is the possible overdose effects that some of these shop vitamin supplements can have. There are a number of vitamins that can actually be toxic if consumed in too high a quantity and a person should always obtain professional medical advice before consuming any form of store vitamin supplement whether it claims to be from natural sources or not. This applies to shop vitamin supplements that are purchased from a specialist vitamin supplement retail outlet, grocery store or internet company.

The D vitamin is the only vitamin that is not obtained from foods that are consumed. Instead, the D vitamin is actually obtained by sunlight on the skin. There has been a lot of media coverage about the dangers of getting too much sun but it is essential that the skin is exposed to sunlight to obtain the recommended daily allowance of the D vitamin. In reality, the amount of time that a person has to spend in the sun to receive a sufficient dose of the D vitamin is extremely small and just a few minutes a day will be sufficient and not have any adverse effects from the amount of ultra-violet light received.

The most important function of the D vitamin is to help control how much calcium is absorbed from food. The majority of the calcium is used to build strong teeth and bones but it is also needed to send messages along the nerves and to help muscles, such as the heart muscles, to contract. It is the D vitamin that ensures that there is always sufficient calcium in the blood to perform these tasks. Other functions that require the D vitamin relate to the immune system and it is believed that it is also a contributing factor in reducing the risk of contracting cancer and, in particular, colon cancer.

The variant of the D vitamin that is formed under the skin is known as vitamin D3, or cholecalciferol. This D vitamin is created when the ultraviolet in the sunlight reacts with a type of cholesterol that is found under the skin naturally. The D3 is converted into a more active form of the d vitamin in the liver and is then diverted to where it is needed the most. Some of the D vitamin remains in the liver and kidneys to help reabsorb the calcium from the blood. The rest of the D vitamin is dispersed to the bones to help them retain their calcium and the intestines to aid absorption of calcium from food.

Even though the majority of the D vitamin is formed through the exposure of the skin to sunlight there are some foods that do contain some of the vitamin naturally. This form of the D vitamin is known as vitamin D2, or ergocalciferol. This is used in the same way as the other D vitamins and is the type used to create the majority of D vitamin supplements.