Latest Research: Another good reason to skip the salt shaker

We all know that eating too much salt isn’t good for our blood pressure and heart health but a new study has found that a high salt intake might also contribute to weight gain.

Previous studies have found a relationship between salt intake and obesity, but the reasons for this have been unclear.  In this study, Chinese researchers recruited thirty-eight male and female subjects of normal weight from a rural community in Northern China and looked at the impact of salt intake on blood levels of ghrelin. Ghrelin is known as the “hunger hormone”, and is released when our stomach is empty, stimulating our appetite.

The subjects followed a normal salt diet for 3-days, followed by a low salt diet (3g) for 7 days and then a high salt diet (18g) for another 7 days.   The researchers measured their ghrelin levels during each stage of the study.  They found that the high salt diet significantly increased ghrelin levels, while there was a small decrease on the lower salt diet.

While more research is needed to confirm these findings, the researchers suggest that the impact of salt on ghrelin levels may explain the link between salt intake and obesity.

Zhang, Y., Li, F., Liu, F., Chu, C., Wang, Y., Wang, D., Guo, T., Wang, J., Guan, G., Ren, K. and Mu, J. (2016). Elevation of Fasting Ghrelin in Healthy Human Subjects Consuming a High-Salt Diet: A Novel Mechanism of Obesity?. Nutrients, 8(6), p.323.

Research Review: Sleep important for a healthy heart

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Poor or inadequate sleep can increase the risk of cardiovascular disease and cardiometabolic disease, according to a new scientific statement from the American Heart Association.

Published ahead of print in the journal Circulation, the authors report that sleep apnoea and insomnia can increase disease risk.  In particular, sleeping less than 7 hours per night can put people at risk of coronary heart disease, stroke, high blood pressure, abnormal blood fats, arrhythmias, heart failure, type 2 diabetes and obesity. Sleeping longer than 9 hours has also been linked with obesity, diabetes and high blood pressure.

These studies only show associations, and not cause and effect, and further research is needed to determine whether improving sleep can reduce disease risk. However the statement recommends  increasing awareness about the importance of sleep and say that healthy sleep behaviours should be promoted along with other lifestyle factors associated with cardiovascular disease including diet, exercise and smoking cessation.

Source: St-Onge MP, Grandner MA, Brown D, et al. Sleep duration and quality: Impact on lifestyle behaviors and cardiometabolic health. Circulation 2016; DOI:10.1161/CIR.0000000000000444.

Does exercise cancel out the negative effects of sitting all day?

If your job requires you to sit at a desk all day you’ll be pleased with the findings of new research which shows the negative health effects of prolonged sitting can be offset with a daily 1 hour walk.

Researchers combined the findings of 16 studies, involving more than 1 million people from the US, Europe and Australia.  There is now a significant amount of research showing an association between sedentary time and mortality, and the researchers wanted to work out how much exercise would be needed to eliminate this association.

The participants were divided into four groups based on physical activity levels (ranging from less than 5 minutes a day to 60-75 minutes per day), sitting time and television viewing time.

Not surprisingly, those who sat the most and did the least exercise had the highest risk of death.  In fact sitting for at least 8 hours per day and not exercising resulted in a 60% higher risk of death compared to those who sat for less than 4 hours per day and were most active.

But in those who were most active, there was no association between sitting time and death suggesting that you may be able to negate the effects of sitting by incorporating an hour of daily exercise.

However those who sat less (under 4 hours) but had the lowest activity levels had a 27% increased risk of death, highlighting the importance of regular exercise, independent of sitting time.

The researchers also looked separately at television watching. In those who watched 5 or more hours per day, no amount of exercise reduced the increase risk of death associated with television watching, while in those who watched 3 hours or more, only the highest levels of activity reduced the risk.

 Ekelund et al. Does physical activity attenuate, or even eliminate, the detrimental association of sitting time with mortality? A harmonised meta-analysis of data from more than 1 million men and women. Lancet. 2016 Jul 27. [Epub ahead of print]

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