Whole (13 page)

In brief, the relationship between amount consumed and amount used for virtually all nutrients is not a linear relationship. Although many professionals know this, few fully appreciate the significance of this complexity. It means nutrient databases are not nearly as useful as one might think. It also means reductionist supplementation with large doses of discrete nutrients does not guarantee the utilization of those nutrients. (In fact, our digestive processes are so complex and dynamic that super-dosing with a single nutrient all but guarantees an imbalance of some other nutrients, as we’ll see in Wrench #3 later in this chapter.)

Not knowing how much of a given nutrient will be used by the body is only part of our uncertainty. The nutrient content of the foods we eat themselves varies far more than most of us realize. Look at the research just on one antioxidant vitamin, beta-carotene (and/or its related carotenoids). Beta-carotene content in different samples of the same food is known to vary three- to nineteen-fold, although it may be up to forty-fold or more, as was reported for peaches. That’s right—you could hold a peach in each hand, and the one in your right hand could easily contain forty times more beta-carotene than the one in your left, depending on things like season, soil, storage, processing, and even the original location of the fruit on the tree. And beta-carotene is far from the only example. The “relatively stable” calcium content of four kinds of
cooked mature beans (black, kidney, navy, pinto) ranges 2.7-fold—from 46 to 126 mg—per cup.

The variation in food nutrient content and the variation in nutrient absorption and utilization by the body compound each other. A simple exercise might help to make the point. Suppose the amount of beta-carotene in a carrot varies about four-fold, and the amount of this uncertain proportion that is then absorbed across the intestinal wall into the bloodstream varies another two-fold. This means that the amount of beta-carotene theoretically delivered to the bloodstream from any given carrot on any given day might range as much as eight-fold.

These are huge but uncertain variations, and whether these ranges are two- or forty-fold, the ultimate message is the same: With the consumption of any particular food at any particular moment, we cannot know with any precision how much of any nutrient is actually available to our bodies, or how much our bodies actually use.

But wait—there’s more uncertainty! You may be surprised to learn that the three nutrients mentioned above can modify one another’s activities. Calcium decreases iron bioavailability by as much as 400 percent, while carotenoids (like beta-carotene) increase iron absorption by as much as 300 percent. Theoretically, in comparing a high-calcium, low-carotenoid diet with a low-calcium, high-carotenoid diet, we might see an 800-1,200 percent difference in iron absorption. But even if this theoretical variation were only 100-200 percent, this is still huge; for some nutrients, tissue concentrations varying by more than 10-20 percent can mean serious bad news.

Interactions among individual nutrients in food are substantial and dynamic—and have major practical implications. An outstanding review by researchers Karen Kubena and David McMurray at Texas A&M University summarized the published effects of a large number of nutrients on the exceptionally complex immune system.
⁶
Nutrient pairs that were found to influence each other and in turn, to influence components of the immune system include vitamin E-selenium, vitamin E–vitamin C, vitamin E–vitamin A, and vitamin A–vitamin D. The mineral magnesium influences the effects of iron, manganese, vitamin E, potassium, calcium, phosphorus, and sodium, and through them the activities of hundreds of
enzymes that process them; copper interacts with iron, zinc, molybdenum, and selenium to affect the immune system; dietary protein exerts different effects on zinc; and vitamin A and dietary fat affect each other’s ability to influence the development of experimentally created cancer.

Even closely related chemicals within the same chemical class can greatly influence each other. For example, various fatty acids affect the immune system activities of other fatty acids. The effect of polyunsaturated fats (found in plant oils) on breast cancer, for example, is greatly modified by the amount of total and saturated fat in the diet.

The fact that magnesium has already been shown to be an essential part of the function of more than 300 enzymes speaks volumes about the possibilities for the almost unlimited nutrient interactions. The effects of these interactions on drug-metabolizing enzymes and on the immune system also apply to other complex systems, such as the hormonal, acid-base balance, and neurological systems.
⁷

The evidence cited here represents only an infinitesimally small fraction of the total number of interactions operating every moment in our bodies. Clearly, the common belief that we can investigate the effects of a single nutrient or drug, unmindful of the potential modifications by other chemical factors, is foolhardy. This evidence should also make us extremely hesitant to “mega-dose” on nutrients isolated from whole foods. Our bodies have evolved to eat whole foods, and can therefore deal with the combinations and interactions of nutrients contained in those foods. Give a body 10,000 mg of vitamin C, however, and all bets are off.

Even in this discussion of the variability of nutrient absorption, you may have noticed, I’ve still toed a fairly reductionist line. I’ve examined variability in terms of single nutrients and how much their quantities vary in food and at their site of action in the body. As we’ve seen, consuming two nutrients simultaneously typically affects the utilization of both. This variation becomes orders of magnitude more complex and uncertain when combinations of a large number of nutrients are simultaneously consumed (also known as “eating food”). Now we’re talking not just about three or
so different nutrients affecting each other and the various systems of the body; we’re talking about all the active elements of a whole food. We simply cannot know how many kinds of chemicals are consumed in a single morsel of food or at a single meal or during the course of a day. Hundreds of thousands? Millions? The complexity increases virtually without limit.

If we had to rely on our brains to figure out what to eat, in what quantities, and in which combinations, or risk malnutrition or disease, the human race would have died out long ago. Luckily, our task is considerably simpler. When we eat the right foods, in amounts that satisfy but don’t stuff us silly, our bodies naturally metabolize the nutrients in those foods to give us exactly what we need at any given moment.

Our bodies control concentrations of nutrients and their metabolites very carefully, so that the amounts available to particular sites of action in the body often rest within very narrow ranges. For some nutrients, concentrations must stay within these limits for us to avoid serious health problems and even death. In short, the body is able to reduce the highly variable concentrations of nutrients in food into much more stable concentrations in our tissues by sorting out what’s necessary and what’s excessive.

One way to gain perspective on this discussion is to consider the “reference” ranges of a few nutrients in our blood plasma, as illustrated in
Figure 5-3
. You may have seen these ranges on your clinical lab report at
the doctor’s office. Based on analyses of the blood of presumably healthy people, these ranges are generally considered “normal.” But notice how narrow these ranges vary—only 1.1-2.3-fold, compared with the five- to ten-fold (or more) nutrient variation in food.

FIGURE 5-3.
Reference ranges for blood tests
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In short, your body is constantly monitoring and adjusting the concentrations of nutrients in the food you consume in order to turn massive variability into the narrower ranges it requires to be healthy.

This sounds like a lot of work for the body to be doing, I know. But that’s what it’s built for. That’s what it does best. And it does it without requiring any amount of conscious intervention in the process.

Think about the simple act of catching a ball that someone has tossed to you. Do you have any idea how complicated that process is? First, your eyes have to notice the object and identify it as a ball and not, say, a swarm of hornets or a balloon filled with petroleum jelly. Then your eyes, working in binocular fashion, begin sending a dizzying array of data to your brain to help determine the size and velocity of the ball. Even if you failed high school geometry, your brain calculates its parabolic path. Even if you flunked physics, your brain calculates the mass, acceleration, and force of the ball. And while your brain is processing all this information, it’s also communicating with the nerves that control your arm and hand, the stabilizing muscles of your back, neck, and legs, and the parasympathetic nervous system that may need to calm you down following the initial sight of an incoming projectile.

Your body is amazing at juggling all these myriad inputs and orchestrating a perfectly timed response: your arm reaches and your hand closes around the ball. But imagine if someone insisted that the right way to learn how to do this was to do all the math and physics. To measure and calculate the velocity, parabolic arc, wind speed, and everything else. School curricula around “catching” would proliferate; educators would argue about which methods work best. About 1 percent of students would excel at this methodology, while the vast majority of us would walk around getting pelted by balls that we couldn’t catch if our lives depended on it. Whenever we came across cultures where everybody could catch, we
scientists would study their physiology and the materials used in making their balls and their public policy around the topic of catching, hoping to unravel the mystery and find the “cure” for ball dropping.

Focusing on individual nutrients, their identities, their contents in food, their tissue concentrations, and their biological mechanisms, is like using math and physics to catch balls. It’s not the way nature evolved, and it makes proper nutrition far more difficult than it needs to be. Our bodies use countless mechanisms, strategically placed throughout our digestion, absorption, and transport and metabolic pathways, to effortlessly ensure tissue concentrations consistent with good health—no database consultation required. But as long as we let reductionism guide our research and our understanding of nutrition, good health will remain unattainable.

Don’t be afraid to take a big step. You can’t cross a chasm in two small jumps.

—
DAVID LLOYD GEORGE

S
o far we’ve looked at how the scientific and governmental understanding of nutrition is firmly rooted in the reductionist paradigm, and how that affects the way the public views nutrition. We’ve also seen how, when you look at it carefully, nutrition is a wholistic phenomenon that can never be fully comprehended within a reductionist framework. It’s too complex, with too many variables.

In this chapter I’d like to look a little closer at the differences between reductionist and wholistic scientific research, to show the various ways that the reductionist worldview inevitably fails us when it tries to comprehend and manipulate the amazingly complex system that is the human body.

As we saw in
chapter five
, reductionism treats science like a math equation. It searches for cause and effect, and the more focused that search, the better. The holy grail of research is the ability to state with confidence that A causes B. Once you know this, if you want to reduce or eliminate B (liver cancer, for example), you simply look for ways to reduce or eliminate A (say, aflatoxin) or to block the process by which A causes B.