Antioxidants In Medical Research
It is now believed that human aging and most chronic diseases are the results of oxidative stress which is caused by an abundance of free radical molecules in the body. Since antioxidants neutralize free radicals, medical researchers have been investigating their potential in preventing and treating diseases like cancers and Alzheimer’s disease which are believed to be related to the effects of oxidative stress.
Vitamin E and Selenium
There is no evidence that vitamin E, alone, has any effect on preventing or curing cancers, but when paired with selenium it was found to reduce the risk of gastric cancers by more than 11% in a Chinese study. There is additional evidence that selenium may be solely responsible for this protective action. Additional studies found that people with low levels of selenium were more prone to gastric and colorectal cancers than those with high selenium levels.
Beta-Carotene in Cancer Research
Clinical trials with increased dosages of beta carotene as a possible cancer preventative yielded disappointing results. There was no difference in the incidence of cancer between people receiving the antioxidants and the control group. While laboratory research of antioxidants has shown them effective in combating the development of cancer cells, studies with people have produced contradictory or inconclusive results.
Neurodegenerative Disease Research
Neurodegenerative diseases like Alzheimer’s, Parkinson’s, and ALS are thought to be the result of oxidative stress. Preliminary laboratory studies showed that specific antioxidants, particularly copper, could combat oxidative stress in these conditions. A secondary factor in these diseases is a build-up of protein which the body is unable to remove. Unfortunately, human trials indicated that copper supplements interfered with the removal of the proteins and did not slow the progression of the diseases.
The Role of Antioxidants in Mental Health
Although no clinical studies have been published at this time, some medical professionals are advocating the use of antioxidants in the treatment of disorders like schizophrenia and severe depression. These disorders are believed to be caused by chemical imbalances in the brain and those who advocate antioxidant therapy believe that these nutrients may have a balancing action on brain chemicals. Antioxidants may also counteract some side effects of drugs, like Tardives kinesis, that are used in the treatment of the disorders
Inconclusive Results of Clinical Trials
When populations that consumed a diet high in antioxidants were studied, they were found to have lower incidences of chronic diseases and longer life spans than populations that did not consume diets high in antioxidants. While researchers focused on diet, other factors, like lifestyle and environment, may also play an important role. The human body is a complex organism that depends on the production and interaction of many chemicals and this may account for the discrepancies between laboratory research and human trials.
There is clear evidence that the regular intake of antioxidants can aid in preventing age-related cell degeneration. Although most clinical trials have failed to support their role in the prevention of chronic diseases, it may be that these nutrients need to be present over long periods of time in order to be effective and most of the trials were conducted over periods of 5 years or less.