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Reduction of benzo[a]pyrene-induced forestomach neoplasms in mice given nitrite and dietary soy sauce
H Benjamin1, J Storkson, P G Tallas
1Department of Food Microbiology and Toxicology, University of Wisconsin, Madison 53706.
Abstract:
This study was conducted to determine the effects of nitrite (0.05% in drinking-water) and soy sauce (20% in a refined diet) on the initiation and promotion of benzo[a]pyrene-induced forestomach neoplasia in ICR mice. In two experiments nitrite and soy sauce together significantly reduced the number of neoplasms per animal. Soy sauce (without nitrite) produced a smaller apparent (non-significant) reduction whereas nitrite (without soy sauce) had no effect. Evidence suggested that soy sauce might contain factors that reduce calorie absorption or utilization, but this observation was independent of the inclusion of nitrite in the drinking-water and therefore could not by itself explain the significant reduction in neoplasms in mice given soy sauce plus nitrite. Protection appeared to primarily involve the tumour promotion stage.
Insights
Nitrite and soy sauce significantly reduced forestomach tumors in mice. This protective effect, primarily during tumor promotion, suggests a synergistic interaction between soy sauce and nitrite in cancer prevention.
Area of Science:
- Oncology
- Toxicology
- Nutrition
Background:
- Benzo[a]pyrene is a potent carcinogen that induces forestomach neoplasms in rodents.
- Dietary factors can modulate chemical carcinogenesis, influencing both initiation and promotion stages.
- Nitrite and soy sauce are common dietary components with potential roles in cancer development or prevention.
Purpose of the Study:
- To investigate the combined and individual effects of nitrite and soy sauce on benzo[a]pyrene-induced forestomach neoplasia in ICR mice.
- To determine whether these dietary agents influence tumor initiation or promotion.
- To explore potential mechanisms underlying any observed protective effects.
Main Methods:
- ICR mice were administered benzo[a]pyrene to induce forestomach tumors.
- Experimental groups received varying dietary interventions: nitrite in drinking water, soy sauce in the diet, or a combination.
- Tumor incidence, multiplicity, and histological characteristics were assessed.
Main Results:
- The combination of nitrite and soy sauce significantly reduced the number of forestomach neoplasms per mouse.
- Soy sauce alone showed a non-significant trend towards tumor reduction.
- Nitrite alone had no significant effect on neoplasm development.
- Evidence suggested soy sauce may reduce calorie absorption, but this was independent of the nitrite effect.
- The protective effect of the combination appeared to target the tumor promotion stage.
Conclusions:
- Combined administration of nitrite and soy sauce exhibits a synergistic chemopreventive effect against benzo[a]pyrene-induced forestomach tumors in mice.
- Soy sauce, potentially through mechanisms affecting nutrient utilization, and nitrite together significantly inhibit tumor promotion.
- Further research is warranted to elucidate the precise molecular mechanisms of this interaction and its relevance to human health.