The use of salt replacers in the diet, as a means of reducing sodium intake, may improve blood pressure and artery health, says a new study from China.
Results of the randomised, controlled trial indicate that people who replaced 100 sodium chloride with a salt substitute, containing 65 per cent sodium chloride, 25 per cent potassium chloride, and 10 per cent magnesium sulfate, experienced improvements in systolic blood pressure.
“Over the 12-month study period the salt substitute significantly reduced not only peripheral and central systolic blood pressure but also reduced arterial stiffness,” wrote lead author Jihong Hu in the journal Hypertension Research.
The study, by researchers from the Chinese Academy of Medical Sciences and Peking Union Medical College, and Ningxia Medical College, is sure to be welcomed by the burgeoning salt replacer market.
Numerous scientists are convinced that high salt intake is responsible for increasing blood pressure (hypertension), a major risk factor for cardiovascular disease (CVD).
Salt is of course a vital nutrient and is necessary for the body to function, but campaigners for salt reduction, like the Consensus Action on Salt and Health (CASH) consider the average daily salt consumption in the western world, between 10 and 12g, far too high.
The pressure has been mounting on food manufacturers to reduce the salt content of their foods and the UK's food standards agency (FSA) recommendation of six grams of salt per day for the general population is understood to be more a realistic target than the ideal healthy limit recommended by WHO/FAO.
Hu and his co-workers recruited 600 high-risk people with an average age of 57.4, and an average blood pressure of 150.1/91.4 mm Hg in rural China to take part in The China Salt Substitute Study. Participants were randomly assigned to consume the salt substitute or regular salt for one year.
After 12 months of intervention, the researchers noted significant improvements in both peripheral and central systolic blood pressure of 7.4 and 6.9 mm Hg, respectively.
The central pulse pressure was also found to be reduced by 4.5 mm Hg, added the researchers. On the other hand, no improvements in diastolic blood pressure were observed.
Markers of the health of the arteries also improved, in the aortic pressure augmentation (AUG) or 1.5 mmHg, and pulse wave reflection time of 2.59 milliseconds. These indicated that the stiffness of the arteries improved.
Earlier this year, scientists from Harvard Medical School reported in the Archives of Internal Medicine that higher sodium and lower potassium intakes may increase the risk of heart disease by 24 per cent.
The trials of hypertension prevention (TOHP) I and II – looked at the effects of sodium reduction and other interventions on the risk of cardiovascular disease (CVD). Researchers, led by Nancy Cook from Harvard Medical School, found that increasing levels of sodium in the urine increased the risk of CVD.
“The totality of evidence suggests that lowering dietary sodium intake, while increasing potassium consumption, at the population level might reduce the incidence of CVD,” wrote Cook.
Source: Hypertension Research
Published online ahead of print, 27 February 2009, doi:10.1038/hr.2009.7
“Effects of salt substitute on pulse wave analysis among individuals at high cardiovascular risk in rural China: a randomized controlled trial”
Authors: J. Hu, X. Jiang, N. Li, X. Yu, V. Perkovic, B. Chen, L. Zhao, B. Neal, Y. Wu