Higher Antioxidant Intakes Reduce Risk of Lung Cancer in Male Smokers

Research in the 1990's seemed to indicate that beta-carotene supplements may increase lung cancer risk in smokers. However, a new analysis of dietary records from one of these studies led researchers to a different conclusion. Male smokers with the highest overall antioxidant intake, including beta-carotene, actually had a reduced risk of lung cancer.

In observational studies, a high intake of individual antioxidants was related to increased lung cancer risk in male smokers. However, data from many experiments suggest that there are interactions among antioxidant nutrients; therefore, consideration of multiple antioxidants simultaneously may be important in terms of assessing risk.

Yale University researchers evaluated dietary records of participants in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (ATBC). A group of over 27,000 Finnish male smokers aged 50-69 had food records analyzed along with intakes of carotenoids, flavonoids, vitamin E, selenium, and vitamin C. After evaluating the overall intake of antioxidants in this group, the conclusion differs somewhat from the original study.

According to this new analysis, the men with higher overall intakes of antioxidants had lower relative risks of lung cancer, regardless of their assigned study group (beta-carotene or placebo). While researchers of the ATBC study concluded that high-dose beta-carotene supplementation may increase lung cancer risk in male smokers, these findings support the hypothesis that a combination of dietary antioxidants reduces lung cancer risk in men who smoke.

Am J Epidemiol 2004 Jul 1;160(1):68-76

High antioxidant levels are associated with a reduced risk of periodontitis

Periodontitis is an inflammatory disease that affects the supporting tissues of the teeth and is associated with an increased risk of stroke, type-2 diabetes, and heart disease. A new study reveals that increased serum antioxidant concentrations are associated with a reduced risk of periodontitis, even in people who have never smoked.

Periodontitis is an inflammatory condition of the tissue surrounding the teeth which has been linked with an increased risk of stroke, type-2 diabetes, and heart disease. A new report published in the Journal of Nutrition revealed that higher serum antioxidant levels are associated with a reduction in the risk of periodontitis.

The current research examined data from 11,480 participants in the Third National Health and Nutrition Examination Survey (NHANES III), for whom periodontal measurements and serum levels of several antioxidants had been recorded. These antioxidants included alpha-carotene, beta-carotene, selenium, lutein, beta-cryptoxanthin, vitamins A, C and E, and total antioxidant levels.

Mild periodentitis was found in 14% of the subjects and 5% had severe disease. Higher vitamin C and total antioxidant levels were associated with a lower incidence of periodontitis, especially with severe disease. Individuals whose vitamin C levels were in the top 20% of participants had a 39% lower risk of periodontitis than participants with the lowest intakes. For subjects who had never smoked, those with the highest intake of vitamin C experienced only half the risk of periodontitis compared to those with the lowest vitamin C levels.

Vitamin C has a role in collagen synthesis and maintenance of connective tissue, which may explain its benefit in protecting against periodontitis. In addition, it is known as a potent antioxidant that may also help reduce inflammation.

Journal of Nutrition Vol. 137, 657-664, March 2007.

Antioxidants block prostate cancer

In experimental mice that naturally develop prostate cancer, supplementing with antioxidants vitamin E, lycopene and selenium effectively blocks the development or progression of prostate cancer.

According to a study published in the journal Cancer Research, dietary antioxidants (vitamin E, selenium, and lycopene) inhibited prostate cancer development in a group of mice that naturally develop prostate cancer. The prostate cancer disease process in these mice is similar to the human process in many respects, providing a good research model for the natural history of human prostate cancer.

Treatment of animals with the antioxidants resulted in a 4-fold reduction in the incidence of prostate cancer compared with the untreated animals. Prostate cancer developed in 73.68% (14 of 19) and 100% (19 of 19) of the animals from the standard and high fat diet, respectively.

In contrast, tumors developed in only 10.53% (2 of 19) and 15.79% (3 of 19) of the animals in the standard and high fat diets supplemented with antioxidants.

These observations support results from a growing body of research indicating a significant protective benefit of antioxidants on the development of prostate cancer.

Cancer Res. 2004 Aug 15;64(16):5891-6.