Research against antioxidant supplementation
Over the past twelve years there has been an abundant amount of research supporting the benefits of a low-fat plant based diet, high in fruits & vegetables, for disease prevention and treatment. In addition, numerous studies have been published speaking against antioxidant supplementation.
Six large population studies have either found no added benefit of supplementation and, in some cases, an increased risk of disease in supplement takers compared to non-users.
Let's take a look at some of the research.
A study published in the New England Journal of Medicine
in 1994 followed roughly 29,000 Finnish male smokers. Groups took beta-carotene (33,000 IU), vitamin E (110 IU), both, or a placebo daily for 5 to 8 years. Lung cancer rates were 18% higher in the beta-carotene takers
. In a later study of the same men, the beta-carotene takers who had previous heart attacks were more likely to die of heart disease
Another study published in the same journal is 1996, the CARET study
, looking at 18,000 smokers, former smokers, and workers exposed to asbestos who took beta-carotene (50,000 IU) and vitamin A (25,000) or a placebo daily for 4 years. Their findings: supplement takers had a 28% higher risk of cancer
The findings of the Physicians' Health Study
involving 22,000 healthy men taking beta-carotene (83,000 IU) or a placebo on alternate days for 12 years was published in 1999 in the Journal of the American Medical Association
(JAMA). In this study no difference in the risk of cancer, heart disease, or diabetes was seen between those taking a placebo or beta-carotene
A study published in 2002 in the British medical journal Lancet
, the Heart Protection Study
followed 20,000 people at high risk of heart disease who took vitamin E (2,300 IU), vitamin C (250 mg), and beta-carotene (33,000 IU) or a placebo for 5 years. Once again, no difference in heart attack rates was observed
In the HOPE-TOO trial
, 7,000 people with either cardiovascular disease or diabetes who took vitamin E (400 IU) or a placebo daily for 7 years was published in 2005 in the JAMA
. Unexpectedly, the Vitamin E takers exhibited an increased (13%) risk of heart failure and no lower rate of cancer
In the Women's Health Study
involving 40,000 healthy female health professionals who took vitamin E (600 IU), aspirin (100 mg), both, or a placebo on alternate days for 10 years no difference in heart disease, stroke, or cancer rates was found
. This last study was published also in JAMA
in 2005.Combined, these studies do not support individual supplement use for the prevention of disease
. Several more studies being funded by the National Institutes on Health are on-going and including the:
Women's Antioxidant and Cardiovascular Study, 8,000 women with cardiovascular disease are taking vitamin E (600 IU every other day), vitamin C (500 mg every day), and/or beta-carotene (83,000 IU every other day), or a placebo. The completion date for this study is this year.
The Physicians' Health Study II will be completed next year, in 2007. The study involves 15,000 male physicians who are taking vitamin E (400 IU every other day), vitamin C (500 mg every day), and/or beta-carotene (83,000 IU every other day), or a placebo.
Finally, in the SELECT Study, 35,000 men with elevated PSA levels are taking vitamin E (400 IU), selenium (200 mcg), both, or a placebo daily. The SELECT study has a completion date of 2013.
The take home messages from the research:
- In truth it may not be antioxidants, but something else in fruits and vegetable, that protects health.
- While individual antioxidants haven't proved promising in research studies, a large amount of research and numerous studies have linked dietary patterns high in fruits and vegetables to be associated with lower risk of disease.
- Other phytonutrients or fiber may provide the protective benefits of fruits and vegetables.
- Or it could be that people who eat more fruit and vegetables eat fewer damaging foods.
Whatever the case, a diet high in fruits, vegetables, and fiber is much better assurance of health than you could ever obtain from a tablet or pill.As the name implies, however, supplements are meant to add to an already healthy diet, not compensate for an inadequate one