01 July 2004

Potential Harbinger of Hypertension

Aldosterone is a hormone produced by the adrenal glands. It helps regulate levels of sodium and potassium in the body, which in turn helps control blood pressure by regulating fluid distribution and electrolyte balance in the body. Today, doctors request a serum aldosterone test to detect excess secretion of aldosterone by the adrenal glands, which is a manifestation of a condition called aldosteronism or hyperaldosteronism.

There are 2 kinds of hypertension. There's what we call essential or primary hypertension, which accounts for more than 90% of all cases of high blood pressure. The real cause(s) of essential hypertension hasn't been determined as of this time, and despite years and years of research, scientists can not come up with a unifying theory to account for its development. The other type of hypertension is called secondary hypertension," because it is usually "secondary to--" some primary cause. It accounts for the remaining 5-10% cases of hypertension and is usually due to identifiable primary causes like chronic kidney disease, renal artery stenosis, pheochromocytoma, pre-eclampsia of pregnancy, stress, aortic coarctation, sleep apnea, hyper- or hypothyroidism, and primary hyperaldosteronism.

In another significant article (click here) in today's issue of the NEJM, a group of researchers focused on the role of aldosterone in essential hypertension, beginning with a hypothesis that "a gradient of increasing risk of hypertension may exist within the "normal" range of serum aldosterone and that this risk may vary according to dietary sodium intake." They also "evaluated the relation of the serum aldosterone level measured at a routine examination to the risk of an increase in blood pressure and the risk of the development of hypertension in a large, community-based sample."

You know what they found? The table below says it all.

This is a very interesting finding as far as I'm concerned. The researchers were able to demonstrate that increased aldosterone levels within the physiologic range of the community-based sample population predisposed persons to the development of hypertension.

And referring to my previous posts wherein I discussed that early humans were used to diets that were rich in potassium and low in sodium (fruit and vegetable diets), the researchers who wrote this study also doubt "whether human beings have biologic feedback mechanisms to lower aldosterone levels in the face of high-salt intakes" brought about by the diets we consume today, be it a Western or a Filipino type of diet. The authors (and I agree with them on this) theorize that "it is conceivable that an adaptive response essential to survival in a low-sodium environment could turn maladaptive in contemporary society."

Our ancestors (early humans) moved around a lot in rugged terrain (there were no cars then) and thus, I would assume, had plenty of physical activity and exercise. Their diet consisted mainly of fruits and vegetables that were low in sodium and high in potassium. Progress and industrialization, however, has reversed most of that way of life. The question is, has our bodies evolved and adapted to such progress? If so, why are there so many cases of hypertension, stroke, heart conditions and diabetes? These questions make me wonder if we can pick up some lessons from early humans on how we can modify our lives and become healthier individuals. I am not saying industrialization is bad. I'm saying if our bodies cannot adapt, then we should at least modify our lifestyle --- mainly diet and exercise.

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