We Are Our Brains Read Online Free PDF Page B

still occurs when a placenta malfunctions, depriving the fetus of nourishment and causing it to be undersized at birth. Malnutrition in the womb can also occur when a pregnant woman vomits excessively, tries to keep her weight down by dieting, or eats too little because of the Ramadan fast.
    Some 200 million people live in regions with an iodine shortage, which affects their children’s growth. Such places aren’t necessarily remote; they can be found all over the world. Thyroid hormones are necessary for normal brain development but can only function if sufficient iodine is incorporated into the hormone. This happens in the thyroid gland. In mountainous areas, the iodine found naturally in soil can be washed away by rainwater. The resulting shortage of iodine affects the functioning of a child’s thyroid hormones, leading to impaired brain and inner ear development. Such children develop huge thyroids that desperately try to store every scrap of iodine ingested. In the worst cases, thyroid hormone deficiency results in cretinism, a condition of severely stunted mental and physical growth. The endocrinologist Dries Querido made it his life’s work to find remote places with an iodine shortage. I remember him calling me late one evening to ask if I could get him a sixteen-millimeter film projector for a lecture he had to give the next day in Amsterdam. That was how I became one of the first people to see a film he had shot in the Mulia Valley in New Guinea, then still a Dutch colony—a remote spot that could be reached only by a Cessna airplane—and hear about his expedition’s findings. Around 10 percent of the children in that valley were mentally deficient and deaf and had seriousneurological disorders. Querido proved that this was caused by iodine deficiency, and he treated the locals with an injection of Lipiodol, an oil containing iodine. Formerly used as a contrast agent in X-ray photos of the lungs, it was found to be potentially damaging to lung tissue. However, it turned out to be extremely effective as a depot injection to treat iodine deficiency. Similarly, the simple remedy of adding iodine to kitchen salt led to the closure of every single institution for deaf-mutes in Switzerland. In the twenty-first century, I myself witnessed developmental disorders resulting from iodine deficiencies in the mountains of Anhui, China. A woman suffering from cretinism—and disfigured by a huge goiter—was sweeping away leaves at a temple. When one of the members of our team, a Chinese professor, asked the woman if she would like to see a doctor, she merely growled and waved her broom threateningly at us.
    Heavy metals can also disrupt fetal brain development. The lead added to gasoline to reduce engine knocking entered the atmosphere, causing more children to be born with mental disabilities. The dangers of mercury became apparent only in the 1950s, when cats in the fishing villages around the Bay of Minamata in Japan started acting strangely and dying and fish began to swim in bizarre patterns. The fishermen had been selling their best fish and keeping the worst specimens for the family pantry. As a result of the fish’s high organic mercury content—mercury that proved to come from a plastics factory—6 percent of the children in the surrounding villages had suffered serious brain damage before birth. The formation of their brain cells and the growth of brain tissue had been inhibited by the mercury, leading to mental disability. The adults in these villages also developed various forms of paralysis. A monument has now been erected in Minamata’s environmental park, dedicated to all the life-forms in the Shiranui Sea that fell victim to this disaster. The park itself was built on twenty-seven tons of mercury-polluted sludge from the Bay of Minamata as well as dozens of sealed containers full of poisoned fish. The Japanese government never gave the victims proper financial