• Current opinion on low salt intakes contradicted by new research on the risk of developing cardiovascular disease.

A research paper has suggested that adopting a low-salt diet might actually being doing harm by raising the risk of heart disease although careful attention has to be paid to whether they already have high blood pressure to begin with. We have taken for granted now that too much salt in the diet raises blood pressure (hypertension) which in turn leads to precisely the same problems of developing cardiovascular disease as reported in this recent research.

In Europe, high blood pressure or hypertension has an increased prevalence of 60% compared to the incidence generally in North America (USA and Canada). It is linked directly to about 25% of all heart attacks in Europe and the condition often progresses to various forms of cardiovascular disease where it causes 42% of all deaths on the continent every year.

The study looked at 133,118 people with an average age of 55 from 49 countries, almost half of which had high blood pressure whilst the remaining half did not. The research team from the Population Health Research Institute based at McMaster University and Hamilton Health Sciences investigated the links between sodium ingestion and death, various types of heart disease including stroke and whether there was a difference between those with high or normal blood pressure. The study was funded by a variety of bodies including the PHRI, the Heart and Stroke Foundation of Canada and the Canadian Institutes of Health Research.

The evidence suggested that a low sodium intake compared to one of moderate consumption was linked to an increased risk of cardiovascular disease and death irrespective of how high their blood pressure was. They also found that a high sodium intake was associated with an increased risk of cardiovascular related issues including death in the subjects with high blood pressure.

The lead author, Andrew Mente who is the Associate Professor of Clinical Epidemiology and Biostatistics at McMaster University stated:-

“Our findings are important because they show that lowering sodium is best targeted at those with hypertension who also consume high sodium diets”

“While our data highlights the importance of reducing high salt intake in people with hypertension, it does not support reducing salt intake to low levels.”

“This study adds to our understanding of the relationship between salt intake and health, and questions the appropriateness of current guidelines that recommend low sodium intake in the entire population,” added the study’s co-author Dr. Martin O’Donnell, a clinical professor at McMaster University, in the statement. “An approach that recommends salt in moderation, particularly focused on those with hypertension, appears more in-line with current evidence.”

The UK group Consensus Action on Salt and Health (CASH) which is encouraging food manufacturers to reduce salt use, argues that the reasons for such low salt intake are due to illness in the subjects or patients. They point to well established evidence that high levels of salt intake cause high blood pressure and to reduce this means reducing these levels of intake.

Reference

Yusuf, S., Teo, K., Mente, A., et al., (2016) Associations of urinary sodium excretion with cardiovascular events in individuals with and without hypertension: a pooled analysis of data from four studies. The Lancet DOI: 10.1016/S0140-6736(16)30467-6

Postscript – The challenge we have found at FoodWrite Ltd and Insights2Innovate Ltd in our product development activities, is achieving the same salty like impact when the customer wants to develop a low-salt or no added salt range. Check out our article on the nutritional issues and challenges faced in this activity.