Vitamins

The human body does not produce vitamin C due to the lack of an enzyme called L-gulonolactone oxidase. As vitamin C deficiencies are bad for our health, we can ensure its optimum level through a proper diet and supplementation. The appropriate level of vitamin C has a positive effect, among others, on the body's ability to cope with oxidative stress, collagen synthesis, which is the main building block of the skin, the proper functioning of the immune system and many other important functions.*

The minimum daily requirement for vitamin C is the largest of all the vitamins. It is about 1 mg/kg of body weight in an adult, and approximately 2 mg/kg of body weight in infants and children.

*WHO Library Cataloguing-in-Publication Data. Joint FAO/WHO Expert Consultation on Human Vitamin and Mineral Requirements (1998 : Bangkok, Thailand). Vitamin and mineral requirements in human nutrition : report of a joint FAO/WHO expert consultation, Bangkok, Thailand, 21–30 September 1998. 1.Vitamins — standards 2.Micronutrients — standards 3.Trace elements — standards 4.Deficiency diseases — diet therapy 5.Nutritional requirements I.Title. ISBN 92 4 154612 3 (LC/NLM Classification: QU 145).

Sources and absorption of vitamin D

In the area of proper human nutrition, both vitamin D₂ and D₃ play the crucial role. In the human body, these vitamins are formed under the influence of sunlight (vitamin D₃) or supplied with food (vitamins D₂ and D₃). 

The most common cause of vitamin D deficit is the lack of exposure to sunlight due to lifestyle (working indoors), as well as fear of exposure to the sun and the use of cosmetics with UV filters improperly.