The influence of shark liver oils on normal and transformed mammalian cells in culture.

n3 polyunsaturated fatty acids have been reported to have anti-carcinogenic effects on mammalian carcinomas. n3 fatty acids occur in high concentrations in marine oils, especially shark liver oils. Several reports have indicated an extremely low incidence of cancer in sharks, although other reports indicate carcinogenesis in some shark species. It has been hypothesised that n3 fatty acids and other components of shark liver oil may exert anti-carcinogenic effects. The aim of this study was to assess whether shark liver oil, from four Indian Ocean shark species, exerted anti-proliferative effects on transformed and normal mammalian cells in culture, and to assess whether the ratio of n3 to n6 polyunsaturates influenced the results. Neither the shark liver oils themselves, nor the ratio of n3 to n6, showed any consistently significant effects with either transformed or normal cells.