TED演講:什么是我與生俱有的（3/4）

Why would undernutrition in the womb result in disease later? One explanation is that fetuses are making the best of a bad situation. When food is scarce, they divert nutrients towards the really critical organ, the brain, and away from other organs like the heart and liver. This keeps the fetus alive in the short-term, but the bill comes due later on in life when those other organs, deprived early on, become more susceptible to disease. But that may not be all that's going on. It seems that fetuses are taking cues from the intrauterine environment and tailoring their physiology accordingly. They're preparing themselves for the kind of world they will encounter on the other side of the womb. The fetus adjusts its metabolism and other physiological processes in anticipation of the environment that awaits it. And the basis of the fetus' prediction is what its mother eats. The meals a pregnant woman consumes constitute a kind of story, a fairy tale of abundance or a grim chronicle of deprivation. This story imparts information that the fetus uses to organize its body and its systems -- an adaptation to prevailing circumstances that facilitates its future survival. Faced with severely limited resources, a smaller-sized child with reduced energy requirements will, in fact, have a better chance of living to adulthood.