Today’s industrial food system is still relying on assumptions made decades ago, while modern nutrition science can disprove 3 of them using milk as its prime example.
Is a natural approach to living really best for human and environmental health? Award-winning journalist Nathanael Johnson argues that both organic and high-tech lifestyles pose a threat when taken to extremes in All Natural (Rodale, 2013). Returning to his family’s hippie roots he begins to fact-check, and scrutinize, the all-natural ideology he was raised with. In the following excerpt from “Fixing Dinner” we get a close look at 3 common assumptions made by the industrial food system and how something as simple as milk may prove them wrong.
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These three assumptions—that molecules matter while the food itself is irrelevant, that everyone is the same, and that institutions rather than individuals should be trusted to control nutrition—are to a large extent responsible for the epidemics in heart disease, obesity, type 2 diabetes, and osteoporosis, Bruce German, a food chemist at University of California, Davis, said. More than a third of U.S. citizens are clinically obese. Demographers estimate that one of every three children who were born in the year 2000 will develop type 2 diabetes during their lives. Today's children are expected to be the first generation in 200 years to die younger than their parents. And the epidemic reaches far beyond the United States. Countries rapidly modernizing are suffering the heaviest brunt of diet-related illnesses. Walk into clinics in China and you will find doctors overwhelmed by diabetes and heart disease. The results of our experiment in eating scientifically haven't been good.
ASSUMPTION 1: Molecules Matter, Food Is Irrelevant
It's relatively easy for scientists to measure the type and number of molecules of any nutrient (using mass spectrometry for instance) but infuriatingly hard to see how they fit together to form actual food. This is a common problem for science—categorizing and counting the parts of a system is simple (or at least feasible) but understanding the relationships between the parts is difficult. So for a long time many scientists simply assumed that the structure of food was irrelevant. When the early nutritionists thought about food structure at all, it was to plot its destruction. The molecular nutritionists, remember, had won their fame in identifying the nutrients needed to prevent deficiencies, so they favored simple foods that digestive tracts could easily absorb. For years, therefore, scientists encouraged processing the complexity out of foods. The results were products like Wonderbread—vehicles for vitamins and minerals that barely required chewing.
"They're rocket fuel," German said. "The nutrients have just been atomized—they go into the bloodstream like they've been injected."
Milk suggests that perhaps we should be striving for the exact opposite: calories bound up in complex structures that break down bit by bit. Milk doesn't start out in complex chunks; in order to pass through a narrow aperture—the nipple—it has to be fluid. But once through, enzymes in the baby's stomach trigger a transformation of milk proteins and, like a ship unfolding in a bottle, they open and link together, forming large curds. Put another way, evolutionary trial and error has fixed it so that babies drink milk, but digest cheese*. Next, of course, the baby must break down this cheese to extract the nutrients. Evolution would not tolerate the expense of knitting together this complex structure then breaking it down again if it had no benefit. But according to the dominant dietary theory, which holds that food is simply independent molecules, there is no benefit: Chunky milk and fluid milk are nutritionally identical.
It's unequivocally apparent to German that the structure of foods matters. A simple restacking of identical nutrients was so important, so advantageous in the sink-or-swim test of natural selection, that it made it worth solving the devilish engineering problem of getting cheese through a nipple. The implications are enormous: It means that a nutrient that's good for you in one food may be bad for you in another. And that makes the nutritional information boxes required on all food packaging almost completely irrelevant: The same type of fat may have different consequences if it arrives in a slice of coconut, a steak, or a scoop of gelato.
ASSUMPTION 2: Everyone Is The Same
There's a page from Sports Illustrated magazine that German sometimes uses in lectures with photographs of Olympic athletes in their underwear: Some bulge like comic book characters; some are planed down to willowy smoothness; some are birdlike, gracile; some hulk as if they'd been wrapped for shipping. It's ridiculous to suggest that each of these people would be better off eating the same diet. And yet for years the nutritionists have advised just that.
Mother's milk, on the other hand, is personalized for each infant. It contains antibodies specialized to protect against local germs. Its balance of fats and sugars shifts depending on the baby's size, hunger, and energy expenditure. When a baby is more active and burning more calories, its movements—butting and jiggling the breast—cause the fat content of the milk to increase. And—at least among rhesus macaques, which produce milk similar to human milk—the breast produces a different mix of nutrients depending on whether the baby is male or female (the boys get fattier milk, while the girls get a greater volume of thinner milk—the upshot is that males feed less frequently and explore more, while females feed more often and perhaps learn more from their mothers). Milk changes continuously, providing age-appropriate levels of nutrients for different stages of development.
The major components of milk, however, remain the same, even as their amounts shift relative to one another. The way that fats are assembled, in particular, are consistent. "The most well-conserved gene set across all mammals is the set that creates fats in milk," German told me. "It's one of the great treasures in the genome." The bulk of the fats in breast milk are saturated, which are suspect under the nutritional orthodoxy because they are associated with cholesterol. If breast milk were sold in grocery stores, it would be considered a dangerously high-cholesterol food. Yet researchers found that cholesterol levels in breast milk couldn't be budged by putting mothers on diets. Scientists also noticed that the more cholesterol neonates drank in their milk, the less they produced in their livers, which led to the hypothesis that mothers were programming their babies—tuning their bodies to produce no more and no less cholesterol than they uniquely needed. This discovery contributed to science showing that people can have high cholesterol for different reasons: Some are eating too much of it, some are producing too much, and some aren't efficiently eliminating it from the bloodstream**. The study of milk, in other words, has suggested that the meaning of "high cholesterol" depends utterly on context.
"The thing that bothers me most about the industrial, authoritarian model of nutrition," German said, "is that it is in diametric opposition with human evolution."
Homo sapiens has evolved a remarkable elasticity when it comes to diet: We have both shearing teeth and grinding molars, and our digestive system is that of a generalist. If you look deeper, beyond the tissue and bone, it becomes clear that the human genome contains multitudes: Most people in the world—aside from those with ancestors from the Eurasian cow belt, and a few cattle-rich spots in Africa—lack the genetic mutation required to digest dairy after infancy. Similarly, descendants of grain-growing cultures have genetics to manufacture more salivary amylase—an enzyme that breaks down starches—than hunter-gatherers. Furthermore, people routinely overcome these genetic predispositions, recruiting gut bacteria to help them digest lactose, for instance.
"We are at the platinum level of freedom," German continued, "and yet nutritional dogma says we are all supposed to eat the same way?"
Humans have been molded to eat diets as diverse as humanity itself. To cater to the wondrous diversity of humankind, German thinks that nutrition science must follow the example of milk, and tailor recommendations for each individual. Which brings us to the third assumption.
ASSUMPTION 3: Institutions, Not Individuals, Should Be In Charge of Diet
It would be impossible for institutions to fabricate and furnish tailor-made diets for every individual on a national, or industrial, scale. To accomplish this, people would have to devise guidelines for themselves, which seemed like a recipe for disaster to early nutritionists. The example of milk, however, shows that people are capable of learning and adapting to personalized dietary guidelines by the time they are six months old.
Breast milk, as it shapes itself to the needs of the baby, is also shaping the infant to its surroundings. Long before babies are capable of speech, mothers communicate with them through flavors and scents to provide a personalized education in nutrition. This education starts in the womb, where babies begin to imprint on volatile compounds they inhale with amniotic fluid, and continues through the breast as they drink milk. Scents are transmitted from foods into milk (a phenomenon that the dairy industry studied extensively since cows that eat wild onions or garlic can dramatically alter the flavor of dairy products). Researchers sniffing breast milk have successfully detected the smell of garlic, alcohol, vanilla, and carrots after mothers had ingested the same. And babies are more likely to welcome foods the moms have regularly eaten during pregnancy and breastfeeding. It seems that a mother tunes her children's tastes, using the knowledge she has accumulated over her lifetime about what foods best satisfy the needs of her genotype, along with the cultural knowledge built up over several lifetimes about what combinations of foods best meet the needs of someone living in the local climate, among the local of plants and animals, and within the local economic system.
"You see this not just in humans, but in all mammals," said Julie Mennella, a scientist at the Monell Chemical Senses Center who is responsible for many of the discoveries on the development of flavor preferences. "Information about what plants to avoid, what plants to eat occasionally, and when plants are at their peak nutritional content is not innate knowledge, it's learned. And it's learned through the amniotic fluid and milk. These are the biological mechanisms on which culture acts when it comes to food."
Cultures place great importance on food traditions and these established food preferences tend to outlast language when people immigrate to new countries. "When a cuisine disappears, that's when a culture is truly dead," Mennella said. And not only is the cuisine of every culture different, each mother offers her own twist, eating only what works for her and imbuing the infancy of her children with powerful flavor memories—be they of Parisian madeleines or brown rice. "When we think of the emotional potency of these flavor-based memories, those that take us to our past, those that trigger the reward centers in our brains, they all originate early in life," she said.
The early nutritionists eschewed this complexity. They understood that everyone needed slightly different amounts of nutrients, but figured it wouldn't hurt to provide double and triple doses in some cases. So they made food companies the stewards of our health by asking them to fortify the food supply. When it came to curing deficiencies, this strategy was wonderfully successful. Salt companies added a few drops of iodine to their crystals, and within a decade, goiters disappeared from America. Bakers cut rates of neural tube defects at least 25 percent by mixing folic acid in flour. Adjusting the nutrients at the national level led to the near eradication of pellagra, beriberi, and rickets. The great triumph of the uniform, top-down approach to nutrition was in providing an abundance of cheap nutrients. Rather than trusting individuals with the tools to solve our dietary problems, nutritionists simply drowned those problems in a flood of calories. By now, however, it has become clear that in attacking the nutrient-deficiency problem we created a super-sufficiency problem.
The education an infant receives through breast milk, of course, is only as good as the knowledge of the mother. And today, after years of misinformation have convinced people to mistrust the dietary evidence they observe in their own bodies, the lessons babies are learning from breast milk are not the result of years of optimizing and experimentation by the mother, but instead the dictates of the industry.
*If we are to give credit where credit is due, the honor for the invention of cheese belongs to babies. We still employ the enzyme, rennet, from the stomach of a baby goat, or sheep, to perform this magic trick. It's likely the first man-made cheese was a happy accident that occurred when someone used a bag made from a calf's stomach to carry milk.
**It's possible to zero in on these issues by looking at different molecules in the blood: One (phytosterol) can show you are taking too much cholesterol in, another (mevalonate) can reveal if your liver is the problem, and a third (7-α-hydroxy-4-cholesten-3-one) can indicate that you aren't eliminating enough cholesterol by converting it to bile. Each condition demands a different treatment. But these tests aren't routinely performed before doctors make a prescription to control cholesterol.
Reprinted from All Natural by Nathanael Johnson. Copyright (c) 2013 by Nathanael Johnson. By permission of Rodale Books. Available wherever books are sold. Purchase this book from our store: All Natural.