For years, we’ve been told to avoid salt as it increases blood pressure. There is more to the story than that. After all, there is what is known as “salt sensitive hypertensives”. So why do some people seem to be sensitive to salt, and others are not? Whenever this pattern arises, there is some more digging to be done. Perhaps the link is sugar.

But first, let’s discuss how salt can raise blood pressure. Salt is necessary for human life and it’s part of muscle contraction. Our bodies rely on a balance of water and salt. This balance is detected in our kidneys, which signals to our endocrine system where the balance stands. Too much salt, the pituitary secretes vasopressin to tell the kidneys to hold on to water. Not enough salt, the adrenal glands secrete aldosterone to tell the kidneys to hold on to salt.

Water chases salt, so where there is more salt, there is more water, and total blood volume increases. This means blood pressure will increase as well. Increased insulin levels raise aldosterone (Kubzansky & Adler, 2009). A diet that is chronically high in carbohydrates will lead to insulin resistance, and therefore more aldosterone when carbs are eaten. So this may explain why some are sensitive to salt, and some are not. Perhaps those that are salt sensitive, are insulin resistant. Quite simply: a diet high in carbs>insulin resistance>increased aldosterone>increased salt and water retention>elevated blood pressure.

Another way that sugars may increase blood pressure is through its effect on the blood vessels. Insulin has two important effects on the vasculature. Normally, insulin suppresses cytokines, adhesion molecules, and reactive oxygen species (the damaging stuff for vessels). It also stimulates nitric oxide release, a known vasodilator (widens the vessel). In an insulin resistant state, this hormone no longer exhibits its effects (Fonseca, 2007). So now you have a tube that is thickened from the inside, and narrowed because of the lack of nitric oxide; a double whammy.

That’s 3 ways that sugars can increase blood pressure. And that’s just what we know of. Time and time again, we learn that the farther we stray from how our ancestors ate, the worse our health becomes.

References:

Fonseca VA. The effects of insulin on the endothelium. Endocrinol Metab Clin North Am. 2007 Dec;36 Suppl 2:20-6. doi: 10.1016/s0889-8529(07)80009-0. PMID: 18407031.

Kubzansky LD, Adler GK. Aldosterone: a forgotten mediator of the relationship between psychological stress and heart disease. Neurosci Biobehav Rev. 2010;34(1):80-86. doi:10.1016/j.neubiorev.2009.07.005

High Blood Pressure? Drop the Sugar.