Further evidence of salt’s harm

A recent study by Liggins Institute Research Fellow Dr Clint Gray adds weight to recommendations to limit the amount of salt we consume.

Excess sodium intake, in the form of dietary salt, has been linked to high blood pressure, cardiovascular disease and premature death amongst adults in the Western World. Yet it appears many fail to heed public health warnings.

A study published today in the science journal PLOS ONE describes the long term effects of excess dietary salt intake by pregnant rats. The animals were maintained on a high salt diet throughout pregnancy and lactation, and the mothers and offspring monitored through to adulthood. Results were compared with a control group which consumed a standard diet throughout the study.

The investigators showed that, as adults, male offspring whose mothers consumed high salt diets during pregnancy and lactation had higher resting blood pressure, compared with the control group, despite having normal salt intake after weaning. Further analyses suggested that high salt intake during pregnancy affected fetal brain and gut development, effectively “programming” to offspring for high blood pressure in later life.

Dr Gray says the study supports public health warnings across the general population to avoid adding excess salt to food and limit intake of processed food high in salt.

“In view of our findings in rats, there may be added risks associated with high salt intake during pregnancy. However, these would need to be corroborated by appropriate clinical studies before any human dietary recommendations could be made,” he said.

The study was carried out with colleagues at Nottingham University (UK) before Dr Gray moved to New Zealand. He is conducting further studies at the Liggins Institute investigating the effects of early life exposure to salt on rat offspring’s growth, metabolism and long term cardiovascular health.

Gray C, Al-Dujaili EA, Sparrow AJ, Gardiner SM, Craigon J, et al. (2013) Excess Maternal Salt Intake Produces Sex-Specific Hypertension in Offspring: Putative Roles for Kidney and Gastrointestinal Sodium Handling. PLoS ONE 8(8): e72682. doi:10.1371/journal.pone.0072682. View on line.

New Zealand Ministry of Health guidelines Eating for Healthy Pregnant Women/Ngā Kai Totika mā te Wahine Hapū recommend choosing and preparing foods that are low in fat, sugar and salt. They give examples and advise mothers not to add extra salt to meals. See: https://www.healthed.govt.nz/resource/eating-healthy-pregnant-womenng%C4%81-kai-totika-m%C4%81-te-wahine-hap%C5%AB