Dangerous and scientifically unsound
Nutrition, Metabolism and Cardiovascular Disease (NMCD), the official journal of the Italian Society of Human Nutrition, today publishes an important Statement * by ESAN, the European Salt Action Network, the Working Group supported by the World Health Organization, that includes delegates of 39 European countries committed to salt reduction policies at the population level.
“High blood pressure remains the leading cause of death and disability in the world due to its cardiovascular complications. A high habitual salt intake is associated with an increase in blood pressure whereas its reduction leads to a decrease in blood pressure, as shown by numerous controlled intervention studies " says prof. Pasquale Strazzullo, Professor of Internal Medicine at Federico II University of Naples Medical School and President of the Italian Society of Human Nutrition.
Nevertheless, a series of recent publications, mostly attributable to a single research group, generated a scientific controversy and disseminated doubts through popular communication media about the usefulness and safety of correction of salt abuse. These studies suggest in essence the existence of a J-shaped relationship between level of salt intake and risk of cardiovascular events, so that reducing consumption to the level recommended by the WHO (i.e. less than 5 grams per day) would be dangerous whereas the optimal level of consumption would be the current one in most European countries or even higher. This position is strongly in contrast with the objective set since 2013 by the WHO-United Nations Commission for the contrast to chronic degenerative diseases (or non-communicable diseases, NCD) of a 30% global reduction in salt intake compared to current values by 2025, with the aim of progressively reaching a consumption of no more than 5 grams per day.
As reported in the Statement published on NMCD, the ESAN, after careful examination of the methodology used in the studies that generated the recent controversy, concluded that such studies are affected by numerous and substantial methodological errors: these errors had indeed been already pointed out repeatedly to the authors through the international medical literature but this rebuttal has been from them systematically ignored even in the most recent publications.
“The most important mistakes” – states Francesco P. Cappuccio, Professor of Cardiovascular Epidemiology and Director of the WHO Collaborative Center for Nutrition at the University of Warwick and President of the British and Irish Hypertension Society - "are i) the use of inadequate methods to estimate the habitual consumption of salt, ii) an assessment of the relationship between salt consumption and cardiovascular events based therefore on unreliable consumption estimates, iii) the inclusion in these studies of patients affected by severe metabolic and cardiovascular diseases and often on treatment with dietary and pharmacological prescriptions that hinder the correct interpretation of the results. To this must be added the implausibility of the hypothesis that a moderate reduction in salt consumption, as recommended by WHO, may represent a health hazard given the lack of any scientific evidence that can convincingly explain how and why the reduction in blood pressure values resulting from lower salt consumption may be associated with an increase in cardiovascular risk or the risk of death ". "On the contrary" – states Dr. Michael Beer (Swiss Federal Food and Safety Veterinary Office), ESAN coordinator - "as demonstrated by the results of well-conducted observational studies and a few intervention trials, the scientific evidence in favor of a substantial benefit of reducing salt consumption to the levels indicated by WHO (less than 5 grams overall per day, which include the share taken with food plus the discretionary one) remains definitely strong in the opinion of the most authoritative experts in the field ". ESAN considered it necessary to reaffirm the above, considering the dispute raised in this regard scientifically unsound and dangerous in relation to the possibility that it spreads in the public opinion or even within the medical profession itself, a relaxed and tolerant attitude towards the abuse of salt, still the main cause of the increase in blood pressure with age, in turn the leading global cause of disabling and preventable diseases, such as heart attack, stroke and heart and kidney failure.
* Ref .: Cappuccio FP, Beer M, Strazzullo P on behalf of the European Salt Action Network. Population dietary salt reduction and the risk of cardiovascular disease. A scientific statement from the European Salt Action Network. Nutr Metab Cardiovasc Dis 2018; DOI: https://doi.org/10.1016/j.numecd.2018.11.010
Nevertheless, a series of recent publications, mostly attributable to a single research group, generated a scientific controversy and disseminated doubts through popular communication media about the usefulness and safety of correction of salt abuse. These studies suggest in essence the existence of a J-shaped relationship between level of salt intake and risk of cardiovascular events, so that reducing consumption to the level recommended by the WHO (i.e. less than 5 grams per day) would be dangerous whereas the optimal level of consumption would be the current one in most European countries or even higher. This position is strongly in contrast with the objective set since 2013 by the WHO-United Nations Commission for the contrast to chronic degenerative diseases (or non-communicable diseases, NCD) of a 30% global reduction in salt intake compared to current values by 2025, with the aim of progressively reaching a consumption of no more than 5 grams per day.
As reported in the Statement published on NMCD, the ESAN, after careful examination of the methodology used in the studies that generated the recent controversy, concluded that such studies are affected by numerous and substantial methodological errors: these errors had indeed been already pointed out repeatedly to the authors through the international medical literature but this rebuttal has been from them systematically ignored even in the most recent publications.
“The most important mistakes” – states Francesco P. Cappuccio, Professor of Cardiovascular Epidemiology and Director of the WHO Collaborative Center for Nutrition at the University of Warwick and President of the British and Irish Hypertension Society - "are i) the use of inadequate methods to estimate the habitual consumption of salt, ii) an assessment of the relationship between salt consumption and cardiovascular events based therefore on unreliable consumption estimates, iii) the inclusion in these studies of patients affected by severe metabolic and cardiovascular diseases and often on treatment with dietary and pharmacological prescriptions that hinder the correct interpretation of the results. To this must be added the implausibility of the hypothesis that a moderate reduction in salt consumption, as recommended by WHO, may represent a health hazard given the lack of any scientific evidence that can convincingly explain how and why the reduction in blood pressure values resulting from lower salt consumption may be associated with an increase in cardiovascular risk or the risk of death ". "On the contrary" – states Dr. Michael Beer (Swiss Federal Food and Safety Veterinary Office), ESAN coordinator - "as demonstrated by the results of well-conducted observational studies and a few intervention trials, the scientific evidence in favor of a substantial benefit of reducing salt consumption to the levels indicated by WHO (less than 5 grams overall per day, which include the share taken with food plus the discretionary one) remains definitely strong in the opinion of the most authoritative experts in the field ". ESAN considered it necessary to reaffirm the above, considering the dispute raised in this regard scientifically unsound and dangerous in relation to the possibility that it spreads in the public opinion or even within the medical profession itself, a relaxed and tolerant attitude towards the abuse of salt, still the main cause of the increase in blood pressure with age, in turn the leading global cause of disabling and preventable diseases, such as heart attack, stroke and heart and kidney failure.
* Ref .: Cappuccio FP, Beer M, Strazzullo P on behalf of the European Salt Action Network. Population dietary salt reduction and the risk of cardiovascular disease. A scientific statement from the European Salt Action Network. Nutr Metab Cardiovasc Dis 2018; DOI: https://doi.org/10.1016/j.numecd.2018.11.010