Do pet vitamins really work?

Vitamin supplements can also increase the risk of cancer in smokers


Vitamins are actually said to be healthy and can protect against cancer. This also seems to apply to non-smokers. Smokers, on the other hand, should not take any dietary supplements or vitamin preparations containing beta-carotene-beta-carotene
Beta-carotene is also called provitamin A because the body can produce vitamin A from beta-carotene, which is mainly needed for the visual process, tissue growth and the defense against pathogens. Fruits and vegetables are the most important natural sources of beta-carotene as it is found in many plants as a plant pigment to protect against the harmful effects of sunlight.
as these do not appear to reduce your cancer risk, but can actually double it.

Vitamins have a good reputation for protecting against cancer. In fact, non-smokers can significantly reduce their risk of tobacco-related cancer (for example from passive smoking) with high-dose beta-carotene vitamin preparations. But if you smoke and at the same time take large amounts of beta-carotene in the form of preparations or dietary supplements, you run the risk of even increasing your risk of cancer. This is the result of a study by Dr. Marie-Christine Boutron-Ruault from the INSERM Institute in Villejuif, France, recently published in the Journal of the National Cancer Institute.

Almost 60,000 women took part in the study. The amounts of beta-carotene to be taken in vitamin supplements were classified as “low”, “medium” and “high”. 700 of the study participants fell ill with tobacco-related cancer within the observation period of around seven years. As expected, non-smokers were able to reduce their cancer risk by 28% by taking moderate amounts of vitamin supplements and by 56% by taking high doses. In contrast, the opposite effect was observed in women smokers: they increased their risk of developing tobacco-related cancer by 43% if they consumed medium amounts of beta-carotene and even doubled it if they took high-dose vitamin substitutes.

Vitamin supplements are not recommended for smokers
This completely opposite effect of beta-carotene on the cancer risk in smokers and non-smokers was very surprising, Boutron-Ruault comments on the result of her study. In any case, she would advise active smokers and ex-smokers against taking beta-carotene vitamin supplements. As far as the diet with beta-carotene-rich foods such as spinach, carrots or fennel is concerned, however, she cannot make any statement, since these foods contain other vitamins that counteract the negative interaction of beta-carotene and nicotine-nicotine
There are several reasons that the addiction-inducing substance in cigarettes is nicotine:
* Nicotine penetrates the central nervous system (CNS) and is psychoactive.
* The physiological effects of smoking and injected nicotine are identical.
* Nicotine works as a "positive amplifier". Humans (and also animals) add nicotine to themselves in experiments.
* It is easier to get rid of the addictive substance (tobacco abstinence) if nicotine is administered (substituted, i.e. replaced) with medication.
* Smokers tend to adapt their smoking behavior to the different nicotine contents of tobacco products
or other tobacco ingredients could also pick up again. In order to be able to confirm the results so far on a larger scale, Boutron-Ruault and her colleagues intend to carry out a more comprehensive follow-up study on men and women, in which a more finely tuned range of variations in vitamin and tobacco quantities should also be taken into account.

Source: Journal of the National Cancer Institute 97: 1338-1344 (2005)