FoodFacts.com has been keeping our community up to date about controversies surrounding sodium levels. While it appears that we consume far too much salt on a daily basis, there have been conflicting studies about just how much is too much, how we need to control sodium levels in our diets and the effects of consuming too much of it. But today we found information that really got under our skin … literally.
According to new studies out of Vanderbilt University, a different and important organ system is significant to our bodies’ blood pressure control abilities. It appears that our skin stores sodium. Traditionally the model for blood pressure regulation has been relegated to the kidney, circulatory system and the brain. But that model still left questions about the reasons for elevated blood pressure in 90 percent of hypertension patients.
In these studies, researchers sought to find other ways the body stores sodium and they discovered that the skin, the immune system cells and lymph capillaries do, in fact, help to regulate sodium balance and blood pressure.
Mice who were fed a high-salt diet had large amounts of salt accumulate in their skin. The immune system cells seemed to sense the sodium and activated a protein called TONEBP. This protein increased a growth factor in the immune cells which in turn builds lymph vessel capacity and helps to clear the sodium.
The study shows that elimination of the TONEBP gene in immune cells prevented the normal response to a high-salt diet and increased blood pressure. Likewise, blocking signaling through the lymph vessel receptor inhibited the changes in lymph vessel density and resulted in salt-sensitive hypertension.
The findings support the idea that the immune and lymphatic systems in the skin work together to regulate electrolyte composition and blood pressure. Defects in this regulatory system may be associated with salt-sensitive hypertension.
To study the clinical relevance of sodium storage in humans, the investigators implemented special magnetic resonance imaging (MRI) technologies to detect sodium. They reported earlier this year that sodium is stored in muscle and skin in human beings, and that sodium storage increases with age and is associated with hypertension.
In future studies they intend to explore the meaning of that sodium storage. Will it, for example, elevate the risk for cardiovascular disease? They are planning to follow 2000 individuals for five years to measure tissue sodium two times per year to determine if elevated tissue sodium levels are linked to heart attacks, stroke or other arterial diseases.
There’s salt everywhere in our food supply. FoodFacts.com knows that our sodium consumption really isn’t coming from the salt shakers on our tables. This new information about how sodium is stored in the skin gives us a better idea of what our bodies are doing with all that salt and how it can possibly be affecting our health. We’ll be watching for the new studies exploring the relationship of cardiac disease and the salt-skin phenomenon. It’s just one more reason we should all be as aware as we possibly can be of our sodium consumption. We should all make our best effort to rid our diets of salt-laden processed foods. Let’s keep the salt on our tables where it belongs.