Reducing salt intake may help reduce the severity of asthma attack, ensure a lower blood pressure and combat obesity linked to consumption of high-energy beverages, scientists have said.

A joint Anglo-American review of the science by Timothy Mickleborough from Indiana University and Andrew Fogarty from the University of Nottingham after analysing both epidemiological and clinical evidence, concluded that collectively, increased salt intake may increase the severity of asthma for people with the disease.

Much as salt is a vital nutrient and is necessary for the body to function, epidemiological evidence has supported, in general, that lower salt consumption was associated with improved airway responses.

On the other hand, four studies with a total population of almost 4,000 subjects did not support this hypothesis, a discrepancy that was difficult to explain, said Mickleborough and Fogarty on NutraIngredient on line.

“Possible explanations for the inconsistency of the data are that dietary factors may have a different effect in children and young adults, as the age of the individual is an important factor in determining the sensitivity to sodium”, both said. ‘Alternatively, dietary sodium may not have an effect on asthma in the general population”.

However, for people with asthma, the science appears to be against salt, they said, quoting several clinical trials that focused on salt intake for people with the condition that is on the rise and with long term effect.

“Collectively, the studies to date investigating the potential relationship between dietary sodium and the severity of asthma or airway hyper-responsiveness have provided support for the hypothesis that increased dietary intake of sodium may increase the severity of disease in those with asthma,” they said in the International Journal of Clinical Practice.

Because a low sodium diet has other beneficial health effects, they said, it can be considered as a therapeutic option for adults with asthma, although it should be considered as an adjunctive intervention to supplement optimal management of asthma using drugs and not as an alternative, they said.

For several reasons, eating lots of fresh foods have being found to help in reducing symptoms in some people with asthma and many processed foods contain high levels of salt, Dr Soji Ige , a chest doctor at the University College Hospital, (UCH), Ibadan said. Such, he said includes carrot

Even if the relationship between higher sodium intake and increased prevalence and severity of asthma is casual, the potential benefits for obesity and blood pressure control needs to be tapped into.

Scientists from Finland claimed that comprehensive salt reduction would be a potentially powerful means to combat obesity. The research, published in the journal Progress in Cardiovascular Diseases, they said” an increased intake of salt has apparently played an important role in the increase in the consumption of soft drinks and hence, also in the increase in energy intake”.

The authors, Dr. Heikki Karppanen of the University of Helsinki and Dr. Eero Mervaala of the University of Kuopio, wrote that “higher consumption of sweetened beverages was associated with both a greater magnitude of weight gain and an increased risk for development of type–2 diabetes.”

Looking at their home country, Karppanen and Mervaala reported that an average of 30 to 35 per cent reduction in salt intake during 30 years in Finland was associated with a 75 to 80 per cent decrease in both stroke and coronary heart disease deaths in the population under 65 years.

The study reports that increasing intakes of sodium (salt) obligatorily produce a progressive increase in thirst, and between 1977 and 2001, the energy intake from soft drinks also increased by 135 per cent, adding about 278 kilocalories to the average person’s daily energy intake.

Numerous scientists are convinced that high salt intake is responsible for increasing blood pressure (hypertension). A new meta-analysis of clinical trials on the effect of salt reduction in children reports that a modest reduction in intake does have a significant effect on blood pressure.

The research, published in the American Heart Association’s journal of Hypertension looks set to increase pressure on the food industry to reduce salt content in a wide range of foods, particularly those aimed at children.

The meta-analysis combined results of 10 trials with a total of 966 children and adolescents aged between eight and 16, and three trials studying a total of 551 infants. Analysis of 10 trials of children and adolescents revealed that a reduction in salt intake of 42 per cent provided significant decreases in blood pressure of 1.17mmHg (systolic) and 1.29 mmHg (diastolic). Analysis of the infant trials revealed that a reduction in salt intake of 54 per cent was associated with significant drop in systolic blood pressure of about 2.5mmHg.

“This is the first meta analysis of salt reduction in children that demonstrates that a modest reduction in salt intake causes immediate falls in blood pressure and, if continued, may well lessen the subsequent rise in blood pressure with age.

An accompanying editorial by Jeffrey Cutler and Edward Roccella, they said this is evidence that suggest that a primary prevention strategy based on dietary salt reduction which when initiated in childhood is capable of reducing exposure to an important cardiovascular risk factor.

A global campaign against salt was launched last year April with the aim of preventing over 2.5 million deaths a year. It is estimated that reducing salt intake by 6g a day could lead to a 24 per cent reduction in deaths from strokes and an 18 per cent reduction in deaths from coronary heart disease, these preventing approximately 2.6 million stroke and heart attack deaths each year worldwide.