At this stage of the game, almost everything I’m studying comes with “OH! That’s so cool!” moments.  For as weird and complex as things that we engineer are, they pale in comparison to just how marvelous our bodies are.  Through eons of evolution, our bodies have developed finely-tuned, complex systems to keep us going.  In general, our bodies are fairly robust and can tolerate a wide variety of environmental pressures because our bodies have adaptive mechanisms to bring the body into homeostasis, or physiological balance.  Without our conscious thought, our body will enact certain measures to protect us, such as breaking down bone matrix to release stored calcium, or shunting blood from the extremities during extreme cold to protect vital organs.  However, sometimes our bodies need some help.

Humans, in our marvelous capacity, migrated into all sorts of areas that we were not adapted to naturally.  Evolution selects for traits that best ensures reproductive survival in particular environmental conditions.  But evolution is slow in humans because we reproduce fairly slowly, so we often take a long time to develop protection against environmental changes.  To help mitigate harm, modern society has adopted many practices to ensure populations are protected from certain diseases and conditions.  Over time, we grow accustomed to the new norm and collectively forget what life was like before the intervention was introduced.  This is why I find public health so fascinating – there are so many systems built into western societies that we take for granted that were enacted to address specific diseases.

Goiters

At the moment, I’m studying for my endocrinology chapter test, so I’m learning about the complex systems of glands and hormones our bodies use.  When I say it’s complex, I mean it’s COMPLEX!  Outside of the nervous system, the endocrine system is what is responsible for keeping our body functioning.  It finely tunes our internal conditions to preserve homeostasis.  It does its best, but sometimes it needs some support.

Vitamin and mineral deficiencies can have dramatic impacts on our bodies.  One in particular is iodine deficiency.  In certain geographic areas, iodine is scarce in the food supply.  This problem doesn’t exist where diets are rich in seafood or foods grown in proximity to saltwater.  However, in the interior regions of North America, iodine is less common in the ground, so the nutrients are not absorbed into the local vegetation.  Humans need iodine in their diet for, among other things, healthy thyroid functioning.  The cells of the thyroid uses iodine in part of protein synthesis, so when iodine levels are low, protein synthesis is stalled and extra material accumulates in the tissues.  This leads to an enlarged thyroid, also known as a goiters.  This effect is so common among people with iodine-deficiency that large geographic populations exhibit similar physical characteristics.  In the United States, the phenomena was so common that the “goiter belt” was used to describe areas of the country where people commonly had the affliction.  In addition to physiological problems that arise from atypical thyroid functioning, iodine-deficiency also can result in impaired cognition.

As a public health measure, it was proposed that iodine be added to table salt, as was done in other countries like Switzerland.  Within a short amount of time, incidents of goiters declined and IQ scores were improved in goiter belts.  The practice is now common in developed nations, but according to estimates iodine-deficiency still afflicts some 2-billion people worldwide.

The funny irony with public health initiatives is that we often forget why the measures were enacted in the first place when we are no longer exposed to the diseases the prophylaxis was implemented to address.  This collective-forgetting of the harm our populations were once exposed to then leads to foolish rejections of those very policies that help keep us healthy, whether it’s rejection of vaccines or decrying fluoride in drinking water.  Legitimate questions of long-term exposure effects aside, knee-jerk reactions to chemicals and scientific illiteracy is reversing decades of public health initiatives that keep us healthy.  The hidden world of public health — when it works, you don’t even know it’s keeping you alive.

So, that’s why my table salt is iodized!  Cool!

Stay Awesome!

Ryan