In the latest Science News, I read a blurb that partially supports the theory I posited in my rant about the height study a month ago. In particular, my assertion that “if one is undernourished as a kid, the body gets most of the nutritive value and the brain is starved.” The article, entitled “Ketones to the Rescue” in the Dec. 13, 2003 issue (vol. 164, no. 24), is unfortunately only available to subscribers online. But I’ll quote the couple paragraphs I care about:
In times of plenty, both the mind and the body thrive. But deprived of basic sustenance, the mind perishes before the body does. That’s not New Age philosophy; it’s basic metabolic chemistry. While most of the body manages food shortages with relative ease, the tissues of the brain are vulnerable during periods of scarcity. So when blood sugar dips, the brain must fall back on special biochemistry to meet its energy needs. …Most of the time, the body makes its fundamental fuel, glucose, from ingested carbohydrates. With each meal, the bloodstream gets replenished with glucose to replace the blood sugar that hungry cells have consumed to satisfy their metabolic needs. The body can’t store glucose well, yet cells must be fed continually. So the body puts away extra energy in the form of fat, which it can break down into energy-supplying fatty acids when needed. A starving animal or a person with normal fat stores can thus sustain most of the body’s cells for weeks or months without eating.
But brain cells, even hungry ones, can’t avail themselves of these emergency stores. A physiological barrier that blocks toxins in the bloodstream so they can’t enter the delicate brain also keeps out fat and fatty acids. As a consequence, when glucose in the blood runs low, brain cells can run into trouble.
People are uniquely vulnerable to such glucose starvation because of their disproportionate braininess. Although the brain makes up about 2 percent of a normal adult’s weight, it commands roughly 20 percent of the body’s resting metabolic budget.
So this supports my theory that if there is a lack of nutrition, the brain will suffer disproportionately. And if childhood nutrition correlates to height, which was the other part of my theory, the results of the height study are explained. My unsolicited email to that effect was never answered by the scientist responsible for the study, not that I expected it to be. But I’m satisfied with my explanation.