Brain Rules for Baby (7 page)

So, it’s a bit boring. And familiar. Eating a balanced meal, with a heavy emphasis on fruits and vegetables, is probably still
the
best
advice for pregnant women. For the non-vegetarians in the crowd, a source of iron in the form of red meat is appropriate. Iron is necessary for proper brain development and normal functioning even in adults, vegetarian or not.

 

There is a lot of mythological thinking out there about what you should and should not eat—not just during pregnancy but your whole life long. I had an honors student at the University of Washington, the thoughtful type of kid who has to sit on his hands not to answer a question. One day he came up to me after class, breathless. He was taking an entrance exam for medical school and had just found out about a“miracle” drug.“It’s a neurotonic!” he exclaimed.“It improves your memory. It’ll make you think better. Should I take it?” He thrust in front of my face an advertisement for ginkgo root.

Derived from the ginkgo tree,
ginkgo biloba
has been advertised for decades as a brain booster, improving memory in both young and old, even treating Alzheimer’s. These claims are testable. A number of researchers began to study gingko as they would any promising pharmaceutical. Sorry, I told the student.
Ginkgo biloba
does not improve cognition of any kind in healthy adults—not memory, not visual-spatial construction, not language or psychomotor speed or executive function. “What about old people? my student asked. Nope. It doesn’t prevent or slow down Alzheimer’s or dementia. It can’t even affect normal age-related cognitive decline. Other botanicals, like St. John’s wort (purported to treat depression) show similar impotence. My student left, crestfallen. “The best thing you could do is get a good night’s sleep!” I hollered after him.

Why is it that these nutrition myths can fool even bright kids like my student? First, nutrition research is really, really hard to do, and it is shockingly underfunded. The types of long-term, rigorous, randomized trials needed to establish the effects of food often go undone. Second, most foods we consume are very complex at the molecular
level (wines can have more than 300 ingredients). It is often tough to discern what part of a food product is actually giving the benefit—or doing the harm.

The way our bodies handle food is even more complex. We don’t all metabolize food exactly the same way. Some people can suck calories out of a piece of paper; some people wouldn’t gain weight if they inhaled milkshakes. Some people use peanut butter as their primary source of protein; others will die of an allergic reaction if they smell it on an airplane. To the eternal frustration of just about every researcher in the field, no single diet is going to work the same way for all people, and that’s because of this extraordinary individuality. This is especially true if you’re pregnant.

 

So you can see why, so far, only two supplements have enough data behind them to support an influence on brain development in utero. One is the folic acid taken around conception. The other: omega-3 fatty acids. Omega-3s are critical components of the membranes that make up a neuron; without it, they don’t function very well. Humans have a hard time making omega-3s, so we have to out-source the materials to get them into our nerves. Eating fish, especially oily ones, is a good way to do it. If you don’t get enough omega-3, studies show, you are at much greater risk for dyslexia, attention-deficit disorders, depression, bipolar disorder, even schizophrenia. Most of us get enough of the fatty acids in our regular diet, so it’s generally not a problem. But the data underscore a central fact: The brain needs omega-3 fatty acids for its neurons to function properly. Apparently, the Three Stooges knew this decades ago! (Larry: “You know, fish is great brain food.” Moe: “You know, you should fish for a whale.”)

So, if a moderate amount of omega-3 keeps you from being mentally disabled, does a whale-sized helping of it increase brain power, especially for the baby? Here the evidence is decidedly mixed, but a few studies indicate the question warrants further research. One
Harvard study looked at 135 infants and the eating habits of their mothers during pregnancy. The researchers determined that mothers who ate more fish starting in the second trimester had smarter babies than those who didn’t. By smarter, I mean babies who performed better on cognitive tests that measure memory, recognition, and attention at six months post-birth. The effects weren’t large, but they existed. As a result, researchers recommend that pregnant women eat at least 12 ounces of fish per week.

What about the mercury in fish, which can hurt cognition? It appears that the benefits outweigh the harm. Researchers recommend that pregnant women eat those 12 ounces from sources possessing less concentrated mercury (salmon, cod, haddock, sardines, and canned light tuna) as opposed to longer-lived predatory fish (sword-fish, mackerel, and albacore tuna).

I certainly know that eating properly is tough, whether you are trying to control how much you eat, what you eat, or both. There’s Goldilocks again: You need enough, but not too much, of the right types of food. And the third factor usually doesn’t help.

It was not a good idea to be in Quebec and pregnant around January 4, 1998. For more than 80 hours, freezing rain and drizzle fell relentlessly all over eastern Canada—immediately followed by a steep drop in surface temperature. This meteorological one-two punch turned eastern Canada into ice hell. Under the weight of the freeze, more than a thousand towering metal power-line structures toppled like dominoes. Tunnels collapsed. Thirty people died. A state of emergency was soon declared; the army was called up. Even so, thousands of residents were without power for weeks. And in freezing temperatures. If you were pregnant and could not get to a hospital for your regular checkups—God forbid if you went into labor—you were stressed out of your mind. And so, it turned out, was your infant. The effects of that storm could be seen on their brains
years
later.

How do we know that? A group of researchers decided to study the effects of this natural disaster on babies in the womb—then follow the children as they grew older and entered the Canadian education system. The result is scary. By the time these “ice storm” children were 5, their behaviors differed markedly from children whose mothers hadn’t experienced the storm. Their verbal IQs and language development appeared stunted, even when the parents education, occupation, and income were taken into account. Was the mother’s stress the culprit? The answer turned out to be yes.

Maternal stress can profoundly influence prenatal development. We didn’t used to think so. For a while, we weren’t even sure if mom’s stress hormones could reach her baby. But they do, and that has long-lasting behavioral consequences, especially if the woman is stressed, severely or chronically or both, in those magic, hypersensitive last months of pregnancy. What kind of consequences?

If you are severely stressed during pregnancy:

A review of more than 100 studies in various economically developed countries confirm that these powerful, negative effects on prenatal brain development are cross-cultural. David Laplante, lead author of the ice-storm study, said in a somewhat understated fashion: “We
suspect that exposure to high levels of stress may have altered fetal neurodevelopment, thereby influencing the expression of the children’s neurobehavioral abilities in early childhood.”

Is this stressing you out? Luckily, not all stresses are created equal. Moderate stress in small amounts, the type most women feel in a typical pregnancy, actually appears to be good for infants. (Stress tends to get people moving, and we think that enriches the baby’s environment.) The womb is a surprisingly hearty structure, and both it and its tiny passenger are well-equipped to ride out the typical stressors of pregnancy. It is just not prepared for a sustained assault. So, how can you tell the brain-damaging stress from the typical, benign, even mildly positive stress?

 

Researchers have isolated three toxic types. Their common characteristic: that you feel out of control over the bad stuff coming at you. As stress moves from moderate to severe, and from acute to chronic, this loss of control turns catastrophic and begins to affect baby. Here are the bad types of stress:

Lots of research has gone into trying to understand
how
maternal stress affects brain development. And we have begun to answer this question at the most intimate level possible: the level of cell and molecule. For this progress we mostly can thank the klutzy researcher Hans Selye. He is the founder of the modern concept of stress. As a young scientist, Selye would grind up “endocrine extracts”, which presumably contained active stress hormones, and inject them into rats to see what the rats would do. He was not good at it.

His lab technique, to put it charitably, was horrible. He often dropped the poor lab animals he was attempting to inject. He had to chase them around with a broom, trying to get them back into their cages. Not surprisingly, the rats became anxious in his presence. Selye observed that he could create this physiological response just by showing up. His main job was to inject some animals with endocrine extract and others, in the control group, with saline. But he was perplexed to discover that both were getting ulcers, losing sleep, and becoming more susceptible to infectious diseases.

After many observations, he concluded that anxiety was producing the effect, a concept surprisingly new at the time. If the rats couldn’t remove the source of anxiety or cope with it once it arrived, he found, it could lead to disease and other consequences. To describe the phenomenon, Selye eventually coined the term “stress.”

Selye’s insight led to that rarest of all findings: the link between visible behaviors and invisible molecular processes. Selye’s work gave the research community permission to investigate how stressful
perceptions could influence biological tissues, including brain development. We know a lot about how stress hormones affect growing neural tissues, including a baby’s, thanks to this pioneering insight. Though most of the research was done on rats, many of the same key processes have been found in humans, too.

The important stress hormone is cortisol. It’s the star player in a team of nasty molecules called glucocorticoids. These hormones control many of our most familiar stress responses, from making our hearts race like NASCAR autos to a sudden urge to pee and poop. Glucocorticoids are so powerful, the brain has developed a natural “braking” system to turn them off as soon as the stress has passed. A pea-sized piece of neural real estate in the middle of the brain, called the hypothalamus, controls the release and braking of these hormones.

 

A woman’s stress hormones affect her baby by slipping through the placenta and entering the baby’s brain, like cruise missiles programmed to hit two targets. This is the basis of the Brain Rule: Stressed mom, stressed baby.

The first target is the baby’s limbic system, an area profoundly involved in emotional regulation and memory. This region develops more slowly in the presence of excess hormone, one of the reasons we think baby cognition is damaged if mom is severely or chronically stressed.

The second target is that braking system I mentioned, the one that’s supposed to rein in glucocorticoid levels after the stress has passed. Excess hormone from mom can mean baby has a difficult time turning off her own stress hormone system. Her brain becomes marinated in glucocorticoids whose concentrations are no longer easily controllable. The baby can carry this damaged stress-response system into adulthood. The child may have a difficult time putting on the brakes whenever she gets stressed out; elevated levels of glucocorticoids thus become a regular part of her life. If she eventually gets
pregnant, she bathes
her
developing infant with the excess toxic stuff. The fetus develops a partially confused hypothalamus, pumping out more glucocorticoids, and the next-generation brain shrinks further. The vicious cycle continues. Excessive stress is contagious: You can get it from your kids, and you can give it to them, too.