Approximately 200 studies that examined the relationship between fruit and vegetable intake and cancers of the lung, colon, breast, cervix, esophagus, oral cavity, stomach, bladder, pancreas, and ovary are reviewed. A statistically significant protective effect of fruit and vegetable consumption was found in 128 of 156 dietary studies in which results were expressed in terms of relative risk. For most cancer sites, persons with low fruit and vegetable intake (at least the lower one-fourth of the population) experience about twice the risk of cancer compared with those with high intake, even after control for potentially confounding factors. For lung cancer, significant protection was found in 24 of 25 studies after control for smoking in most instances. Fruits, in particular, were significantly protective in cancers of the esophagus, oral cavity, and larynx, for which 28 of 29 studies were significant. Strong evidence of a protective effect of fruit and vegetable consumption was seen in cancers of the pancreas and stomach (26 of 30 studies), as well as in colorectal and bladder cancers (23 of 38 studies). For cancers of the cervix, ovary, and endometrium, a significant protective effect was shown in 11 of 13 studies, and for breast cancer a protective effect was found to be strong and consistent in a meta analysis. It would appear that major public health benefits could be achieved by substantially increasing consumption of these foods.

Fruit, vegetables, and cancer prevention: A review of the epidemiological evidence

Vitamin C and cancer prevention: the epidemiologic evidence.

The orthomolecular treatment of cancer. II. Clinical trial of high-dose ascorbic acid supplements in advanced human cancer

Malonaldeh yde was applied once to the shaved backs of mice. After daily treatment with 0.1% croton oil, 52% of the mice had tumors at 30 weeks. In the same experiment, other mice were treated once with fi-propiolactone, glycidaldehyde, or 7,12-dimethylbenz[a]anthracene DMBA), and then daily with croton oil. These animals had 44, 40, and 95% tumors, respectively, at 30 weeks. Twelve mg malonaldehyde applied daily proved toxic, sometimes fatally so. Five animals also had carcinomas of their internal organs. After daily treatment with 0.36 mg malonaldehyde, no animals died of carcinoma. The predicted reactivity of malonaldehyde was confirmed; after 1 hour, only 1.9% of the applied malcaaldehyde was detectable. All skin treated with DMBA, benzo[a]pyrene, and 3-methylcholanthrene had increased

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Antioxidants and Cancer. IV. Initiating Activity of Malonaldehyde as a Carcinogen

The heme enzyme indoleamine 2,3-dioxygenase (IDO) oxidizes the pyrrole moiety of L-tryptophan (Trp) and other indoleamines and represents the initial and rate-limiting enzyme of the kynurenine (Kyn) pathway. IDO is a unique enzyme in that it can utilize superoxide anion radical (O2*- ) as both a substrate and a co-factor. The latter role is due to the ability of O2*- to reduce inactive ferric-IDO to the active ferrous form. Nitrogen monoxide (*NO) and H2O2 inhibit the dioxygenase and various inter-relationships between the nitric oxide synthase- and IDO-initiated amino acid degradative pathways exist. Induction of IDO and metabolism of Trp along the Kyn pathway is implicated in a variety of physiological and pathophysiological processes, including anti-microbial and anti-tumor defense, neuropathology, immunoregulation and antioxidant activity. Antioxidant activity may arise from O2*- scavenging by IDO and formation of the potent radical scavengers and Kyn pathway metabolites, 3-hydroxyanthranilic acid and 3-hydroxykynurenine. Under certain conditions, these aminophenols and other Kyn pathway metabolites may exhibit pro-oxidant activities. This article reviews findings indicating that redox reactions are involved in the regulation of IDO and Trp metabolism along the Kyn pathway and also participate in the biological activities exhibited by Kyn pathway metabolites.

https://www.tandfonline.com/doi/pdf/10.1179/135100099101534927

G.N. Shultz

Papers

Sarcoma of the Spermatic Cord and Tunics: Review of the Literature, Case Report and Discussion of the Role of Retroperitoneal Lymph Node Dissection

The role of ascorbic acid in the prevention of bladder tumor formation.