Epidemiologic evidence suggests that a high potassium intake inhibits the development of cancer, and a high sodium intake increases the incidence of gastrointestinal malignancy. Once malignant transformation occurs the sodium/potassium ratio in the cancer cell increases to more than three times that of a normal cell. The ionic redistribution seen in the cancer cell is similar to that seen in the potassium-depleted state. The relationship between potassium depletion and the size at which villous adenomas of the large bowel undergo malignant transformation was examined in 144 patients. Villous adenomas containing invasive carcinoma were 40% smaller in potassium-depleted patients than in normal patients indicating that in the potassium-depleted state earlier malignant transformation had occurred.
Cancer 53:1260-1264. 1984. ARLY IN THE CENTURY Ross hypothesized that cancer E was caused by a potassium deficiency.' Total body potassium per kilogram body weight is lower in cancer patients than in healthy persons.2 The theory of Cone3
postulates that sustained depolarization of the cell membrane due to an increase in the resting sodium/potassium ratio is involved in the regulation and control of cell division during both normal and cancerous growth of tissues. Lower cancer rates in Seneca County, New York, have been attributed in part to high concentrations of potassium cations in water supplies and in the whereas the high rates of malignancy in Evans County, Georgia, have been linked with the high sodium intake in this region.' Using energy dispersive x-ray microanalysis, Cameron and associates have demonstrated that cancer cells have an increased intracellular sodium concentration and an increased sodium-potassium ratio which is more than three times the ratio found in their normal nonmalignant counterpam6 Similar studies in human epithelial-derived malignancies indicate that potassium depletion also occurs, contributing to the increased intracellular sodium/potassium ratio.' A similar redistribution in intracellular cations is found in the po-