SummaryLow-dose exposures to common environmental chemicals that are deemed safe individually may be combining to instigate carcinogenesis, thereby contributing to the incidence of cancer. This risk may be overlooked by current regulatory practices and needs to be vigorously investigated.

The effect of ascorbic acid on cancer has been a subject of great controversy. This is a follow-up review of the 1979 article by Cameron, Pauling, and Leibovitz published in Cancer Research. In this updated version, the authors address general aspects of ascorbic acid and cancer that have been presented before, while reviewing, analyzing, and updating new existing literature on the subject. In addition, they present and discuss their own mechanistic hypothesis on the effect of ascorbic acid on the cancer cell. The objective of this review is to provide an updated scientific basis for the use of ascorbic acid, especially intravenously as adjuvant treatment in pharmacological nutritional oncology.

Female athymic nude mice were implanted subcutaneously with human breast carcinoma MDA-MB231. Seven to ten days later, the mice were divided into groups and fed a purified diet containing the following types of fat (% of diet): (i) 20% corn oil (CO); (ii) 15% CO:5% fish (menhaden) oil (FO); (iii) 10% CO:10% FO; (iv) 5% CO:15% FO; (v) 1% CO:19% FO; and (vi) 1% CO:19% FO plus antioxidants (alpha-tocopherol acetate, 2000 IU/kg diet and tertiary butyl-hydroquinone, 2% of total fat). The linoleic acid levels (% of diet) of the groups were 12.0, 9.1, 6.2, 3.3, 0.9 and 0.9%, respectively. After 6-8 wk, the carcinomas were assessed for tumor volume (cm3) and assayed for thiobarbituric acid reactive substances (TBARS). Human breast carcinoma growth was suppressed in mice consuming FO diets without antioxidants as compared to mice fed CO; the greater the amount of dietary FO fed, the greater the carcinoma growth suppression (P < 0.05). The addition of antioxidants to the FO diet significantly (P < 0.05) reversed the FO-induced carcinoma growth suppression. Concentrations of TBARS in the human breast carcinomas were increased in all the FO (without antioxidants) fed mice, compared to mice fed CO; the level of increase in TBARS was directly related to the increase in the level of FO fed (P < 0.05). The addition of antioxidants to the FO diet significantly (P < 0.05) reduced the concentration of TBARS in the breast carcinomas.(ABSTRACT TRUNCATED AT 250 WORDS)

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