The term goiter refers to an abnormal swelling of the thyroid gland, which sits in the lower part of the neck. In medical school, I was taught that iodine deficiency was responsible for the goiter epidemic that affected the United States at the turn of the 20th century.

We also were told that iodization of salt had cured the goiter epidemic of the early 1900s, and that it was one of the greatest public health achievements in history.

Professors claimed that iodine deficiency simply did not exist in our modern times.

When I look back at those days, I can see that while my professors may have understood the history of iodine, they knew next to nothing about what was going on in the present day.

The early 20th century was a very different time. Back then, a small amount of iodine — about 74 mcg — was enough to prevent and even treat goiter for the vast majority of the population.

But things changed as the 20th century progressed. In the 1950s, the United States government along with the American Dental Association persuaded Americans that adding fluoride to tap water would improve the health of people’s teeth. This step was taken even though the studies that were performed at the time appear to have been suboptimal and poorly designed.

Much of the Western world followed suit, adding fluoride to their water supplies as well. But since then, science has clearly shown that the risks of fluoridating water outweigh the benefits.

Furthermore, studies have concluded that there is no difference in cavity rates between countries with fluoridated water and those with non-fluoridated water.

Today, most of the Western world has ceased fluoridation of water. Those countries looked at the science and came to the scientific conclusion that water fluoridation does not prevent tooth decay, yet it does contribute to other health problems. That was the right decision.