Monday, August 24, 2009

Antioxidants As Nutrients

By Rita Goldman

The 3 most studied cases of antioxidants are Vitamin A, including the carotenoids, and vitamin C and E. Although there have been many experimental proposals, there has been no firm conclusions drawn, though they have been planted by implication.

The vitamin A family are a group of insoluble vitamins that has retinoids and they regulate cell division; therefore there is a big possibility that they may have an effect on the growth of tumors. Carotenoids consume single oxygen and therefore act as powerful antioxidants to minimize damage. It has been argued that there function may be regulated by the immune system, and the healthier the immune system is the more that they will work, however there is no solid proof to support this.

Some studies have made that indicated that retinol or Vitamin A helps in protecting against the lung cancer. Recent data has shown a consistent inverse relationship between various carotenoids and which are the precursors of vitamin A, and also high levels of beta carotene.

However Finland has carried out clinical trials and in the initial trial they gave 30,000 male smokers beta carotene and vitamin A or a placebo which is a tablet which contains nothing medicinal, but which the patient being studied believes will have a positive benefit on their health.

This study was repeated twice since 1994 and there have been no reduction in the levels of lung and smoking related cancers. However it is extremely difficult to accurately interpret data from studies that involve smokers because the act of smoking itself is a confounding variable and increases the risk of cancer. Other studies have found that an increased level of any single antioxidant is not desirable and two studies have linked an increase risk of colon cancer with high levels of beta carotene in humans.

The Nurses Health study in America found a 20% rise in breast cancer rates between the highest and lowest levels of Vitamin A and carotenoids. These figures were improved greatly when the women with lower instances of Vitamin A were given supplements. However there were no differences when the same supplements were tried against prostate and stomach cancers.

What is important is that all of these studies linking vitamins and cancer prevention were looking at vitamins as part of the whole diet, it clearly shows that when the results were tried to be replicated with single foods that in fact there was an adverse affect. This once again links to the fact that a varied diet with plenty of fruit and vegetables offers better protection than enormous consumptions of one super food.

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