Types of supplements
There are various types of supplements. Different preparations suit different people and it is a good idea to experiment with different types to find the best combination.
Water solubilized fat soluble vitamins
The oil soluble vitamins A, D, E and K are available in dry or water soluble form for people who cannot, or do not want to consume oil, for example acne sufferers or people with fat malabsorption disorders such as celiac disease.
Natural vs synthetic
In most cases, natural vitamins have not been shown to be more beneficial than synthetic vitamins. However, vitamin E seems to be the exception and the natural form of vitamin E, d-alpha tocopherol is more potent than the synthetic form, dl-alpha tocopherol. Sometimes vitamin supplements contain other compounds which may enhance the effectiveness of the vitamin, although this is a much debated issue. For example, natural vitamin C contains compounds known as bioflavonoids which, although they may or may not enhance absorption, possibly have anticancer properties of their own. Yeast grown on chromium and selenium- rich media form organic compounds which may be better absorbed by the body than inorganic salts.
Some minerals in supplements are combined with other compounds to make organic forms. This process is known as chelation and may make the minerals more digestible as it is similar to the form in which they occur in nature. For example, ferrous fumarate is a chelated form of iron. Chelated mineral supplements may be absorbed better than nonchelated minerals. Some people, particularly those who are older, often have low stomach acid; and minerals are often chelated with acidic compounds, for example calcium citrate. In some cases, chelated minerals may be less irritating to the stomach than nonchelated minerals.
Timed release supplements
Timed release or sustained release vitamins are designed to dissolve and be absorbed slowly. The theory behind this is that the vitamins have maximum effectiveness when blood levels are stable, and losses through excretion are minimal. However, some experts believe that timed release supplements are not necessarily better. It is possible that by the time some of these tablets have dissolved, they have passed the particular part of the intestine where they would be absorbed. High blood levels of some vitamins may also be useful in treating some conditions.