Why the supplementation of vitamin A is important and dangerous at the same time, and can it be optimized?
Vitamin A (retinol) contained in our body can originate from two sources:
- carotenoids (mainly alfa and beta carotene) contained in our food (mainly in vegetables) are transformed into retinol by the organism.
- Food of animal origin already contain vitamin A (retinol)
Both deficiency and surplus of vitamin A are harmful. Its surplus causes a relative deficiency of vitamin d3 on the receptor level, and so it is harmful (due to which D3 reduces its toxicity). On the other hand, the body transforms carotenoids into retinol only in the required quantity, so no overdosing is possible in this case (although a research test found the supplementation of both vitamin A and beta-carotene harmful; taking them increased the risk of lung cancer for smokers. But in that research synthetic beta carotene was used, and carotenoids are never present in food only in form of beta carotene, there is always at least alfa carotene present, too, so it is not lifelike, and the same problem exists, as in case of another test, where the supplementation of vitamin E was found harmful... it turned out that vitamin E was only present there as alfa-tocopherol, although gamma-tocopherol, for example, is much more efficient in many ways, and tocopherols are always present together in food, so taking vitamin E as only alfa tocopherol is harmful, even if it comes from natural sources, as it distorts the natural tocopherol ratios of the tissue. We take something that is good, but by doing so we reduce something that is even better - so the net impact is negative.)