Salty Foods Right Before Bed Might Disrupt Sleep

Lisa Rapaport

October 08, 2021

If eating certain things ― like pizza or French fries ― makes it impossible to sleep at night, it might be because the hefty dose of salt in these foods is disrupting your sleep rhythms.

For decades, scientists have advised people to limit consumption of salty foods because of an increased risk for high blood pressure, heart attacks, and strokes. Some research has linked hypertension to an increased risk for insomnia and other sleep problems.

A new study in mice suggests that salty foods might directly affect sleep, rather than indirectly contribute to sleep problems by raising blood pressure.

The findings, presented virtually at the Seventeenth International Conference on Endothelin, are from a study of how a high-salt diet affected physical activity as well as activity in a region of the brain known as the suprachiasmatic nucleus, which manages circadian rhythms, or the biological clock.

Normally, this region is more active during the day and is less so at night. This pattern is aligned with healthy sleep-wake cycles that make it easier for us to get up in the morning well rested after a good night’s sleep.

In this new study, mice had similar physical activity levels whether their diets were high in salt or not. But mice on a high-salt diet had more neuronal excitability in the suprachiasmatic nucleus at night than mice on a regular diet. Neuronal excitability at night could disrupt the biological clock and make sleep more difficult, the authors concluded.

Results from animal studies often don’t hold up in human trials, which are a long way off in this case. And the results have not yet been reviewed by independent experts.

Still, the findings offer another reason for people to consider how much salt they eat. Americans eat an average about 3400 mg of sodium daily, according to the US Food and Drug Administration. That’s far more than the maximum recommended daily sodium intake of 2300 mg, or about 1 teaspoon of table salt. Most of this salt comes from packaged and prepared foods.