High incidence and mortality from cancer determine the health and social burden of oncological diseases. Scientific and public attention is directed both to adequate diagnosis and treatment of the disease, as well as to the identification of certain risk factors and the preparation of preventive measures against the unlocking and development of malignant tumors.
The carcinogenic role of a number of chemicals has been scientifically proven. On the other hand, deficiencies of certain trace elements, vitamins and active substances are associated with an increased predisposition to malignant transformation of certain cells.
Even under these hypotheses and associations, there is a specific medical logic, there is no chemical that can lead to the development of cancer, and there is no food additive to be a panacea in the prophylaxis of certain oncological diseases.
There are many risk factors that in their complexity lead to genetic changes in cells and their malignant transformation. Many of the factors are preventable, although their elimination or correction does not eliminate the risk of developing cancer.
Among the major damaging factors of the cell are the free radicals that are formed in the body. Premixing antioxidants naturally by fruit and vegetables reduces the level of radicals and has a prophylactic role in cellular damage and the generation of mutations in the structure of DNA.
Only results of clinical trials in established international centers can be considered credible in determining the prophylactic benefit or medical harm of taking certain antioxidants as supplements. Among the most studied supplements are synthetic or natural retinoids, carotenoids, selenium, vitamin E and vitamin C, as well as various combinations of these.
It is easy to find a deficiency of these active substances in patients with oncological diseases. The question is whether this deficit is related to the development of the disease and would benefit from supplementing with anti-oxidants for prophylactic or curative purposes. Mandatory entry of these substances into food is not questionable. Additional supplements are studied in the form of supplements (tablets, capsules, drops, etc.).
The results of the conducted studies in the majority show that the prophylactic or curative effect of antioxidant intake does not have few exceptions for certain localizations and groups of patients.
In some areas of China (Linxian, Huikian) there is a high incidence and mortality rate from malignancies of the esophagus and stomach. Clinical trial results show that supplementing healthy people with a combination of beta-carotene (15 mg daily), selenium (50 micrograms per day) and vitamin E (30 mg per day) reduce the esophageal cancer mortality by 4% but from stomach cancer by 21%. In other combinations and dosages, no effect was reported.
Taking retinoids (13cRA) in patients with xeroderma pigmentosum reduces the risk of developing skin cancer by 63%. In renal transplant patients, daily intake of acitretin (30 mg) reduces the incidence of skin cancer in this population. However, in other patient groups, retinoid supplementation has no documented effect.
Antioxidants have no proven prophylactic or curative role in lung cancer. Moreover, the results of two studies (ATVC and CARET) show that beta-carotene in combination with vitamin E or retinol respectively increased the incidence of lung carcinoma among active smokers by 18% and 28%, respectively. Adding smokers with antioxidants not only does not have a prophylactic role but also increases the risk of lung cancer.
Taking antioxidants in the form of supplements can not be considered universally useful or harmful. Science still determines when, in what doses and in which patients certain active substances and combinations would have an effect. On the other hand, everything necessary for the human organism is obtained in adequate and beneficial quantities through complete nutrition.
