Jozef Victor Joossens and Hugo Kesteloot on Salt, Stroke, and Stomach Cancer
An astonishing and interesting finding in 1964 was that of a highly significant link at the population level between cerebrovascular attacks (CVA) and stomach cancer (SC) mortality.1. This was found during testing an hypothesis on the role of smoking in stroke, when a correlation was made between CVA and lung cancer mortality, age-adjusted, in which SC was introduced as a control cancer. Unexpectedly, the correlation between CVA and SC was markedly greater than that between CVA and lung cancer. Since then, the correlation between SC and CVA has been followed unabated and made the subject of several publications. For example, in 1978 a correlation of r = 0.70 was found between SC and CVA deaths for 12 western countries. 5,6.
Separate studies of salt and arterial pressure were begun in 1971 in the area around Leuven, Belgium by measuring 24-hour urinary Na excretion.2. Highly significant positive relations were found especially among men, and this was confirmed by several international studies. 3,4. Over the years the work in Belgium contributed to evidence of a causal relation. Recently, multicenter population studies, such as Intersalt and Intermap, and intervention studies such as DASH, have also confirmed the diet-blood pressure relation. They also pointed to a relationship between salt intake and the slope of the blood pressure rise with age at the population level in many countries. These and other studies also confirm that high blood pressure is the major cause of stroke.
In 1965 the hypothesis was formulated that salt could also be the major cause of CVA mortality rates (J.V.J.). Not unexpectedly, that hypothesis was received with a large dose of “salt” (scepticism), but soon supporting data emerged. For example, in the second half of the 20th century, countries with a high salt intake and high stroke rates, such as Japan, Korea, Finland, Iceland, China, Columbia and Portugal, also had high rates of stomach cancer deaths. In most other aspects their diet was very different. Countries with low salt intake such as the U.S. (compared to the average world level) had relatively low stomach cancer and CVA death rates. 6.
Another unexpected finding in these ecologic relationships was the decrease in SC mortality rates worldwide during the last 40 years. 5. The decreased salt intake worldwide due to refrigeration made salting for food conservation obsolete and is a presumed explanation for the fall in stomach cancer deaths. The strong relation between dietary salt intake and SC offers additional evidence of the potential value of reducing salt intake in populations.
The salt-stomach cancer-cerebrovascular disease relation found in observational studies, if causal, means that both cause and prevention of one of the deadliest cancers and crippling of vascular illnesses might be demonstrated by a lowered salt intake–at almost no cost. Such a demonstration would not offer final “proof.” But the high probability and universal applicability of the concept provides great incentive to continued work in this field, particularly since a randomised trial is near infeasible. (Jozef Victor Joossens and Hugo Kesteloot)
- Joossens, J.V. 1980. Stroke, stomach cancer and salt. The epidemiology of arterial blood pressure. Eds. Kesteloot, H., Joossens, J.V. The Hague, Boston, London: Martinus Nijhoff.
- Kesteloot H., Park, B.C., Lee, C.S., Brems-Heyns, E., Joossens, J.V. 1980. A comparative study of blood pressure and sodium intake in Belgium and Korea. The epidemiology of arterial blood pressure. Eds. Kesteloot, H., Joossens, J.V. Martinus Nijhoff, The Hague, Boston, London; p. 453-70.
- Sasaki, S., Zhang, X.H., Kesteloot, H. 1995. Dietary sodium, potassium, saturated fat, alcohol, and stroke mortality. Stroke 26: 783-9.
- Xie, J., Liu, L., Kesteloot, H. 2001 Blood pressure and urinary cations in a low-fat intake Chinese population sample. Acta Cardiol 56: 163-8.
- Joossens, J.V., Kesteloot, H. 1998 Nutrition in relation to stomach cancer and stroke mortality. Current Perspectives on Nutrition and Health. Ed. Carroll, K.K., Montreal & Kingston, London, Buffalo: McGill-Queen’s University Press.
- Joossens, J.V., Hill, M.J., Elliott, P., Stamler, R., Stamler, J., Lesaffre, E., Dyer, A., Nichols, R., Kesteloot, H. 1996. Dietary salt, nitrate and stomach cancer mortality in 24 countries. Int J Epidemiol 25:494-504.