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Study suggests genetic mechanisms for blood pressure and salt intake

By Nathan Gray , 20-Oct-2010
Last updated on 20-Oct-2010 at 13:14 GMT

Blood pressure responses to high and low salt intakes may share similar genetic control mechanisms, according to a new study published in the Journal of Human Hypertension.

The research suggests there is a strong genetic correlation between blood pressure responses to high and low sodium intakes that could help to identify the genes that regulate blood pressure.

“Our study found that blood pressure responses to cold pressor test might share the same genetic mechanisms of blood pressure responses to dietary sodium intake.

“In addition, blood pressure responses to low- and high-sodium intake might share the same genetic mechanism,” said lead author Dr. Hao Mei, assistant professor in the Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans.

“[These] findings indicate that the same gene(s) may influence blood pressure responses to dietary low- and high-sodium intervention. These results can be used to localize and identify genes for blood pressure regulation,” Mei told FoodNavigator.com.

Sodium intake

Low dietary intakes of sodium, in conjunction with high potassium intakes have been shown by several studies to be an effective approach in the prevention and treatment of hypertension.

However, blood pressure responses to dietary sodium and potassium intakes are known to vary among individuals. Such variation in sodium and potassium sensitivity may be partially determined by individual genetic predisposition, noted the authors.

Previous research has suggested a genetic control mechanism for blood pressure responses to the cold pressor test, a test used to predict hypertension, performed by immersing the hand into ice water, and measuring changes in blood pressure and heart rate.

A recent study also reported responses to the cold pressor test were significantly related to blood pressure responses to dietary sodium and potassium interventions. (Chen et al – Archives of Internal Medicine ). However, whether these associations are because of genetic determinants or environmental factors is unclear, as genetic correlations between blood pressure responses to the cold pressor test and dietary sodium and potassium intake have not been studied.

The new study investigated genetic associations between blood pressure responses to dietary sodium and potassium intervention and to cold pressor test in a large family-based dietary feeding study.

Genetic correlations

The researchers reported that both blood pressure (BP) responses to a high-sodium intervention and to potassium-supplementation interventions have genetic correlations with BP responses to cold pressor tests.

Dr. Mei and colleagues found BP responses to high dietary sodium had strong genetic correlations with both BP responses to low sodium and to potassium supplementation interventions.

The authors emphasised that genetic correlations between BP responses to the cold pressor test, and to high-sodium intervention and potassium supplementation were especially strong.

Strong association?

The authors concluded there is a significant genetic correlation between blood pressure responses to high sodium and low sodium interventions, as well as responses to high dietary sodium, and to potassium supplementation interventions.

“Our study suggests that there are common genetic determinants that influence blood pressure responses to dietary sodium and potassium interventions and to the cold pressor test,” they wrote.

“The same genetic factors might be responsible for blood pressure lowering during low-sodium intake and blood increase during high-sodium intake,” said Dr. Mei.

Direct measurements

However, commenting independently on behalf of Consensus Action on Salt and Health (CASH), Prof. Graham MacGregor told FoodNavigator.com that the research was “a long way from relating genetic mutations to salt intake”, as it does not directly measure any genes or mutations that relate to salt intake.

The researchers stated that further studies are needed “to identify genetic variants which contribute to blood pressure responses to dietary sodium and potassium interventions.”

Source: Journal of Human Hypertension

Published online ahead of print, doi: 10.1038/jhh.2010.88

“Genetic correlation of blood pressure responses to dietary sodium and potassium intervention and cold pressor test in chinese population”

Authors: H. Mei, T.K. Rice, D. Gu, J.E. Hixson, C.E. Jaquish, Q. Zhao, J.C. Chen, J. Cao, J. Li, T.N. Kelly, D.C. Rao, J. He

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