[Dual action of vitamin C versus degradation and supplementation].

The article discusses vitamin C from the point of view of its supplementation with food and in the form of oral supplements. The dual action of vitamin C is connected with the presence of oxygen, which may reduce the amount of the vitamin in food products, influence thermal resistance, cause degradation and show an antioxidation effect. Vitamin C stimulates the immune cells and collagen synthesis. It may protect the LDL fraction against oxidation, and therefore it is interesting for cosmetology, rheumatology, immunology and dietetics. The latest research with respect to vitamin C proved that it has the ability to dissolve neurotoxic senile plaques. Equally effective in the treatment of Alzheimer's disease is the oxidised form of vitamin C, i.e. dehydroascorbic acid. Vitamin C may be used in a combined vitamin E supplementation to avoid the pro-oxidative effect and reduce the risk of diabetes mellitus type 2 complications. In the review there is a description of the types of vitamin C degradation depending on a specific factor such as pH, temperature, oxygen, enzyme and the impact of diet on the quantity of the supplied vitamin. The literature data confirmed the positive influence of vitamin C as an addition to food. The last part of the article presents the methods of vitamin C protection used in food processing technology and of determining its content in food products. Additionally, the article describes the problems related to vitamin C oxidation processes during food processing and storage. The presented research results indicate that an adequate diet contains a sufficient amount of vitamin C for healthy people. In the case of chronic patients it is better to use supplementation.