The Frontal Cortex

Why is Nutritional Science So Bad?

Posted by Jonah Lehrer on January 27, 2007
(7)
More »

It almost seems as if the faddish claims of nutritional science have an inverse relationship with reality. If a nutrient is supposed to be good for us, chances are that later research will contradict the claim. Here’s Michael Pollan in the Times Magazine:

Last winter came the news that a low-fat diet, long believed to protect against breast cancer, may do no such thing — this from the monumental, federally financed Women’s Health Initiative, which has also found no link between a low-fat diet and rates of coronary disease. The year before we learned that dietary fiber might not, as we had been confidently told, help prevent colon cancer. Just last fall two prestigious studies on omega-3 fats published at the same time presented us with strikingly different conclusions. While the Institute of Medicine stated that “it is uncertain how much these omega-3s contribute to improving health” (and they might do the opposite if you get them from mercury-contaminated fish), a Harvard study declared that simply by eating a couple of servings of fish each week (or by downing enough fish oil), you could cut your risk of dying from a heart attack by more than a third — a stunningly hopeful piece of news. It’s no wonder that omega-3 fatty acids are poised to become the oat bran of 2007, as food scientists micro-encapsulate fish oil and algae oil and blast them into such formerly all-terrestrial foods as bread and tortillas, milk and yogurt and cheese, all of which will soon, you can be sure, sprout fishy new health claims.

Pollan’s article is a persuasive takedown of “nutrionism,” which he defines as an ideology built around “the widely shared but unexamined assumption is that the key to understanding food is indeed the nutrient.” The problem with this approach is that it involves breaking whole foods apart, until the carrot is nothing but an assemblage of different nutrients, vitamins, and minerals. Unfortunately, nutrionism is too often depends upon shoddy science, and ends up causing Americans to indulge in one food fad after another.

So why does nutrionism endure? Pollan blames the scientific process:

Because a nutrient bias is built into the way science is done: scientists need individual variables they can isolate. Yet even the simplest food is a hopelessly complex thing to study, a virtual wilderness of chemical compounds, many of which exist in complex and dynamic relation to one another, and all of which together are in the process of changing from one state to another. So if you’re a nutritional scientist, you do the only thing you can do, given the tools at your disposal: break the thing down into its component parts and study those one by one, even if that means ignoring complex interactions and contexts, as well as the fact that the whole may be more than, or just different from, the sum of its parts. This is what we mean by reductionist science.

Scientific reductionism is an undeniably powerful tool, but it can mislead us too, especially when applied to something as complex as, on the one side, a food, and on the other, a human eater. It encourages us to take a mechanistic view of that transaction: put in this nutrient; get out that physiological result.

Needless to say, Pollan takes issue with this reductionist approach and shows, in study after study, that nutrient-based nutrition is bad science. It relies on medical oversimplifications and faulty longitudinal studies. It has helped to create a food industry that is making us fatter, sicker and less satisfied with dinner. So what’s the alternative? Pollan argues for the de-medicalization of food. He begins the essay with the secret of healthy eating:

Eat food. Not too much. Mostly plants.

PS. For those interested in the shoddiness of most nutrionism, you might also want to check out this book.

(7)
More »

Comments

  1. #1 Greg
    January 27, 2007

    Americans do not indulge in a food fad simply because some nutitionist has torn a vegetable into its component atoms and published a tally. They would be highly unlikely to hear about it. They would certainly fail to understand it.

    The fad occurs when some corporation perceives an opportunity to profit and spends millions of advertising dollars persuading people to abandon their senses.

  2. #2 Agnostic
    January 27, 2007

    The guy is nuts. First, common statistical tests can tell you about the complex interactions between individual variables. So the claim that the real world is potentially more complicated than a purely additive scenario, while true, is boring and presents no trouble in assessing the interaction effects aside from the main effects. If he’s saying we need more research, and more careful research, well, no shit.

    Second, you’d think the guy hadn’t studied even the most basic history of nutrition science. If I followed his advice and ate “mostly plants,” let’s assume I really dug corn — natural, not-fooled-around-with corn. Pretty soon, I’d develop dermatitis, red skin lesions, and become dazed and confused. I would have Pellagra, due to a niacin deficiency. If you think this couldn’t balloon into a public health problem — guess again. This is exactly what happened when Spanish commoners began relying solely on maize after it was introduced from the Americas.

    In fact, the main storyline throughout our post-agricultural history is how malnourished we became after leaving our hunter-gatherer lifestyle. H-Gs eat a wide variety of foods and have a pretty balanced nutritional intake. Most agriculturalists, especially those below the level of super-rich, depended on a few staples. And again, if they lacked key nutrients, you got an epidemic of Pellagra or Scurvy; and if the crop failed, you got the Irish potato famine.

    Earlier in the 20th C in the US, they found out that fortifying table salt with iodine increased IQ by several points — pretty cheap solution, with permanent effects, unlike educational interventions. The developing world is beginning to understand the importance of this nutrient for IQ and has begun fortifying their salt with iodine also. There was an NYT article on this topic 12/16/06 (“In Raising the World’s I.Q., the Secret’s in the Salt”).

    All of Pollan’s obfuscation could be accurately predicted just conditioning on reading the phrase “reductionist science.”

  3. #3 Lauren Muney
    January 27, 2007

    What works for health and fitness is to understand the human body’s needs and eat towards that end. As a wellness and fitness coach, I’ve been long railing against the “no carb” movement (as an example) because of its dangers to health: this was due to my understanding (and investigations) of the human body’s need for carbohydrate sources. To that end, I am consistantly discussing with clients (and others) about understanding the body’s needs — then correlating those needs with available foods.

    That being said, there are two non-profit eduactional organizations which have done this, begun by two separate doctors in the 1930′s who correlated ‘healthy [body]‘ against the current food fads. They studied cultures around the world to understand what made them healthy — or unhealthy. Their day’s food fads were the sudden influx of oevr-processed and convenience foods; they discovered that when people varied from their land’s healthy whole-food diets (relying on fast foods, packaged stripped foods, etc), the generations lost health. Information about this can be found on http://www.westonaprice.org/tour/index.html

    I’m not trying to do a commercial on these people – I’m not a member of their organzation. My (and your point) point is that nutrionism makes gods out of one nutrient or another, yet forgets about the impact of all nutrients on the whole — as well as forgets about the impact of whole foods as the ‘original’ manner of getting nutrients. Commercialism becomes the god: create the pedestal under a nutrient, and then create the commercial product to sell it. Real information is boiled down to marketable info-bites (see any women’s magazine to understand this) which sell a product to go with the fad. Atkins, Inc made a TON of money selling its books, then its food…

    …but few people stopped to realize that the reason that “no carb/low carb” became so popular was from one thing: Americans were becoming increasingly sedentary and the extra energy (carbs =glycogen, stored energy) were being stored by the body. Water was being stored by the body to prepare the energy (glycogen): there’s a 3:1 ration of water:glycogen. Atkins’ idea was simple: stop the carbs to stop the storing of carbs and also drop the water. His idea forgot one principle: the body is SUPPOSED to be active, and thus supposed to intake carbs for energy — and retain enough water to active glycogen at the correct time.

    Atkins solved the symptom and not the problem. But ‘solving the problem’ didn’t generate HIM money. The real solution is to eat a variety of whole foods of proteins, fats, carbohydrates, (reduce processed foods which only simluate whole foods), drink water, and be active.

    But this easy advice doesn’t sell. It’s too easy…or too hard.

    There’s nothing wrong with omega-3 fatty acids. Broken down to its easy components, those ‘healthy fatty acids’ can be easily found in whole yogurts, fish, plants, olive oils, seeds, and nuts. People sell pills because they can — it’s so much harder to get people to eat a healthy well-rounded diet. Taco Bell always seem to ring twice, and the fish oil pills can solve the “pesky problem” of needing the whole-food nutrition that people are rarely getting.

    What DOES sell is the diet advice and salesmanship of ‘products’ — and, when all else fails (and they hope it does), diet pills.

    Is nutrionism shoddy science? I don’t agree entirely: what I do agree that if one studies something only ‘in part’ (takes the carrot away from the grand scheme of whole whole day’s meal of macronutrients balanced for an individual’s needs), one will see only the results ‘in part’. Scientic studies are filled with ‘scientific studies’ which only study one aspect of an idea: they may not study nutrients in combination with a myriad of activity factors, or macronutrient combinations, or seasonal changes, or bio-individuality, etc.

    Nutrionism may be only the science of looking at the trees instead of the whole forest.

    MHO, and I could be wrong.

  4. #4 mike
    January 28, 2007

    Atkins solved the symptom and not the problem. But ‘solving the problem’ didn’t generate HIM money. The real solution is to eat a variety of whole foods of proteins, fats, carbohydrates, (reduce processed foods which only simluate whole foods), drink water, and be active.

    Well, being active is good advice regardless of diet, and certainly there is no harm in eating more no-calorie green leafy vegetables, either. Your other advice seems to be to do what nutritional scientists have been recommending all along with few positive results: eat variety. That is exactly what Atkins had been opposed to; that is how we go into this mess in the first place.

    Nutritional scientists have not only been wrong, but have been dangerously wrong and stubbornly resistant to any alternative theories in spite of an almost total lack of scientific evidence to support their own recommendations. The more studies that are conducted, the more prevailing nutritional wisdom is cast to the wind, and the more Atkins looks like he had it pretty much right all along. More protein and less carbs seems to be the way to go with today’s more sedentary population.

    Even saturated fats are not looking as bad as they once did. I find it an irony that it is usually high carbohydrate products that tend to be laden with trans-fats, and now it turns out that trans-fats are also looking lot worse than they used to.

    Thank you for not looking before you leaped nutritional scientists!

  5. #5 Rugosa
    January 29, 2007

    I don’t think it’s fair to call Pollan nuts. His basic premise is sound. The focus on individual nutrients is less than helpful to individuals making mealtime decisions in the real world. Agnostic is mischaracterizing Pollan’s article, since nowhere does Pollan advocate eating a diet consisting mainly of one food item, and in fact advocates the opposite.

    Pollan makes clear the distinction between scientists studying nutrition and the food industry that turns every finding into a new fad. Food fads are almost always popularized by shoddy journalism (“scientists found x is healthful; therefore you should eat 5 pounds of it every day”) and, as Lauren Muney points out, lots of advertising that convinces people they can eat crap as long as it has been enriched with x.

    I took a nutrition course 30 years ago to fulfill part of my non-science-major science requirement. The basic advice then: eat a variety of foods, including non-meat sources of protein and plenty of fruits and vegetables; don’t eat too much fat; watch your calorie intake in relation to your activity level. The more things change, n’est pas?

  6. #6 Seanbenet
    January 29, 2007

    I agree with Greg and Agnostic that the real problem here is not nutritional science, but the misinterpretation thereof. Pollan does indeed distinguish among scientists, journalists, and the food industry, but he damns them all, and the subtitle of his article, printed clearly in bold on the front cover of the magazine, is “How scientists have ruined the way we eat.”

    This claim is ridiculous for multiple reasons. First, let’s review a list of single compounds and the diseases that their discovery and study has helped to reduce or eliminate: in addition to Agnostic’s niacin/pellagra let’s add vitamin A/blindness, vitamin C/scurvy, vitamin D/rickets, vitamin K/bleeding, iron/anemia, folate/neural tube defects, and calcium/osteoporosis. Is this enough of a positive contribution from science?

    Second, Pollan is happy to spout his own scientific facts when he wishes to wax arrogant on, for example, the subtle distinctions between omega-3 and omega-6 fatty acids. Did he do this work in his own lab?

    Third, nutritional science is not all biochemistry. It involves, among many others, epidemiologists, primary care physicians, endocrinologists, cardiologists, nutritionists, and basic scientists. And not all conclusions and recommendations of these researchers have to do with single nutrients. Check out http://www.5aday.gov. The US goverment (by which I mean the CDC, HHS, and NCI), contrary to Pollan’s claims, was at least 4 years ahead of him.

    All Pollan does is repackage advice that others came up with, bash scientists, and let his own profession off the hook.

  7. #7 roger
    January 30, 2007

    Agnostic, when you write, “All of Pollan’s obfuscation could be accurately predicted just conditioning on reading the phrase “reductionist science,” you make your point by… obviously not reading Pollan’s article, which concentrates on just the point you made about the omnivore’s diet (that was, in fact, the whole point of Pollan’s book, and long sections of the article were devoted to the danger of food habits that have become dangerously narrow. As for this point:

    “First, common statistical tests can tell you about the complex interactions between individual variables. So the claim that the real world is potentially more complicated than a purely additive scenario, while true, is boring and presents no trouble in assessing the interaction effects aside from the main effects. If he’s saying we need more research, and more careful research, well, no shit – that’s nice, but he singles out various studies that de-emphasize those interactions – studies that have been conducted by reputable scientists. It is platitudinous to say that there are complex interactions between the different chemicals in food – but it is a platitude that is ignored. If you really wanted to dispute what Pollan’s article says about this, take up the case that he presents – of beta carotene, to dispute what he says.

    It should be said that the counter-example you are using – Iodine – doesn’t really work as an all purpose knock down argument. Pollan says, very clearly, “Scientific reductionism is an undeniably powerful tool, but it can mislead us too, especially when applied to something as complex as, on the one side, a food, and on the other, a human eater.” He is not making an argument that absolutely all additions to “food” are bad, but that the majority of those additions do not take into account the place of foods in diet, the way foods are grown, and the fact that often, the addition could be found more cheaply and more nutritiously in another food. Your example is, of course, of an inorganic entity, salt. I would not mount an argument that another person is saying meretricious and trivial things, and then use, as a counter-example, something that doesn’t fall within the domain of the things he is arguing about. That seems like a very cheap debater’s trick.