05/22/2012 06:00 pm ET Updated Jul 22, 2012

Nutrition Guidance: Facts About Opinions About Facts

An opinion about a fact is just an opinion. And that's a fact.

It's a fact of particular importance to the world of nutrition guidance, where opinions are routinely substituted for facts, and where the expression of opinion all too often takes on a religious zeal. But it's of general relevance to any form of guidance -- including that of the navigational kind.

When you really the know the best route from here to there, you don't need GPS. But GPS can surprise you.

I was driving a route between my home and my lab for years before I got GPS. GPS recommended another route I didn't know I didn't know -- along country roads that ran by a series of reservoirs -- and it was shorter, far more scenic, and had less traffic into the bargain!

I suppose some might never have tried that alternate route, assuming that if it was important, they would have known it already. That's dangerous thinking in any field.

Some people think artificial sweeteners are poisons -- and even that their use in the food supply is part of some great conspiracy in which the FDA is complicit.

Others think that sugar is the poison. For this group, products such as diet soda are clearly preferable to their full-calorie, sugar-laden counterparts. If anything, fruit juices -- which provide a concentrated dose of fructose -- may be our true nemesis, as fructose has been singled out for its uniquely pernicious effects.

The likes of T. Colin Campbell and Caldwell Esselstyn argue that meat is poison, although I have heard them emphasize quite different reasons why. Others argue passionately in defense of our omnivorous Paleolithic origins, and consider the vegans loonies on the fringe.

Some in the latter camp clamor for a return to our Paleolithic diet. But they tend to overlook the fact that our Stone Age ancestors ate mammoth, not Big Macs; expended an estimated 4,500 kcal/day in physical exertion; and consumed roughly 100g of fiber daily. Often, we don't even bother to inform our opinions with complete stories -- but rather shop for the select factoids we like best.

Some think saturated fat is bad for us; others do not. Some say dairy promotes cancer; others extol its many virtues. Some think we need more omega-3, others put all their eggs in the "eat less omega-6" basket. Speaking of eggs...

And the U.S. government considers a slice of pizza a serving of vegetable -- despite the fact that the pasta sauce earning that designation may well be a more concentrated source of added sugar than standard-issue ice cream topping (yes, I 've done the math).

To be sure, we don't have complete facts about nutrition. But we do have many -- and we certainly have enough to reach cogent conclusions about nutrition guidance. We are not clueless about the basic care and feeding of Homo sapiens!

But getting to good guidance is a tough standard to satisfy. Those involved in selling food are clearly biased and unqualified to provide it. The government is lobbied by those who sell and grow food, and all too often generates policies that reflect the will of the special interests with the deepest pockets -- as all Michael Pollan fans and all who lament the state of our Farm Bill know.

Independent experts committed to public health, and only public health, would seem to be the way to go -- but even here, there are challenges. No one person has comprehensive expertise; and every individual, and even every field, has biases. So what is required is a "team of rivals" group of experts -- with comparable credentials, but different biases. Like the jury in 12 Angry Men, such a group creates a gauntlet through which verdicts must pass -- with bias beaten up, and removed, along the way. Only the most defensible positions prevail. It may not be perfect, but it's the best anyone knows how to do -- and such teams have done things like land us on the moon.

To inform such a jury's decision-making, there must be full testimony on both sides of every issue. In the case of nutrition guidance, that means extensive review of a fairly vast literature on diets, foods, nutrients, and health effects.

This is exactly how the overall nutritional quality index (ONQI) algorithm used in the NuVal system was developed: an extensive review of relevant diet, nutrition, and epidemiology literature; decision-making by an elite, multidisciplinary team of experts not overly inclined to agree with one another; and then rigorous validation testing. It is because of this that NuVal is, to our knowledge, the only such system shown to correlate directly with health outcomes. We know about other systems that have been put to this test -- and failed it.

Some of the leading nutrition and public health experts in North America came together to help develop the ONQI. They had no financial stake in it. In fact, Griffin Hospital supported development of the algorithm with plans to turn it over to the FDA. When it was completed, we offered to do just that.

But the harsh reality is that a government effectively lobbied to call pizza a vegetable is not truly able to speak the blunt truth about nutritional quality. And so, a scientist at the FDA told me candidly he thought the bureaucracy of his agency would tie such a system up in red tape for years. He suggested that Griffin Hospital should seek a business partner to get the ONQI into the hands of consumers, and that is how NuVal was created.

One of the important implications of these origins is that while NuVal, LLC -- a for-profit business -- is authorized to license use of the NuVal system, it does not own the algorithm and has no control over it. The algorithm is, now and forever, owned by a not-for-profit community hospital that is the global headquarters of an organization devoted solely to patient empowerment in all aspects of health care. The algorithm is overseen by a team of scientists retained as advisors to Griffin Hospital, with no financial stake in NuVal. The system is of, by, and for public health -- and is walled off from any other motive in perpetuity.

These are facts. The paper trail in support of them is readily available.

But facts don't preclude opinions about facts. The peril lies in conflating the two!

Recently, a food blogger "graded" several nutrition profiling systems, including NuVal. NuVal was given a poor grade because scores were at odds with the blogger's preconceived notions. But that would be like me trashing my GPS because it recommended a route other than the one I had chosen in advance.

The blogger in question was, apparently, appalled that NuVal gave a score of 1 to "pomegranate juice," and a higher score to some salty snack food. At first, that sounds like a justifiable reaction.

Except... This pomegranate juice was NOT pomegranate juice (which, by the way, scores a 38; pomegranates themselves score a 91) -- but rather some kind of fruit cocktail made WITH pomegranate juice. The first ingredients were water and sugar -- followed by a dilute mix of juices. In other words, this is a glorified soft drink, with just enough pomegranate juice to allow for that to figure in the product's name. It reminds me of Strawberry Kiwi Kool-Aid Jammers -- which has very nice pictures of strawberries and kiwis on the package, and contains... neither strawberry nor kiwi!

Putting "pomegranate" in the name of sugar-water was enough to fool the blogger in question.

But it didn't fool NuVal. Far from being a basis to give NuVal a low score, this actually shows just how a good food guidance system should work. It should tell you what you didn't already know. It should point out the objective truth you might overlook. Which, by the way, includes the fact that most so-called "salty" snacks are less concentrated sources of sodium than most commercial breakfast cereals.

The same pertains to recent, and apparently ongoing, noise that an organization called the NCL is making about NuVal scores for canned fruit. This group seems to think that stripped-down peach bits in a can of syrup are the same as a peach direct from the tree. The NuVal scores, based on objective nutrition facts, accurately reveal the considerable distance between the two.

This same group goes on to say that diet soda should score a 0 (not easily achieved on a scale of 1 to 100), while invoking an IOM panel report that concluded that food should be judged solely on the basis of calories, sugar, sodium, saturated fat and trans fat. Using such a metric, diet soda is, in fact, "perfect" -- while mixed nuts, guacamole, and fruit juices would fare a whole lot worse. My opinion is that NuVal sorts this all out quite handily, giving regular soda a 1; diet soda a 15; fruit juices scores in the 30s; walnuts, almonds, and avocados scores in the 80s.

My GPS was right about the best route between my hospital and lab. NuVal is right about sugar water disguised as fruit juice, salty snacks that aren't very salty, and fruit bits swimming in syrup.

There is an intrinsic problem with measuring the quality of a system by how well it conforms to what you already believe. Such a system gets bonus points for agreeing with you -- even when you are wrong. If you're lost, and only follow the directions you already have -- you are going to stay lost.

We do not have perfect knowledge of nutrition, and what we know evolves like all science. Even now, ONQI 2.0 -- an update of the algorithm, based on the most recent science -- is in the works. Our intent is for it to correlate even more strongly with health outcomes that matter, and we will put that to the test.

But perfect is the enemy of good, and we certainly do have good knowledge of nutrition. Plenty good enough to get us out of the dark wood we've been lost in for the decades over which epidemic obesity and diabetes have developed.

Good nutrition guidance is based on the best available science, interpreted by the best scientists, for purposes of public health and without ulterior motives or outside influence. That's hard to achieve -- but it has been done.

Assessments about nutritional quality are apparently often based on what a food is called, rather than what is actually in it, and are just opinions -- and apt to be wrong. What's true about the covers of books is at least as true about the covers of foods.

If we sanction the evaluation of nutrition guidance by how well it conforms to what we already believe, then when we're wrong -- we are destined to stay wrong. When we're lost in a labyrinth of deceptively-labeled products, we are destined to stay lost.

GPS for nutrition can help get us out of this mess -- but only if we subordinate opinion to the facts at our disposal, work hard to keep up with new facts that come in, and acknowledge there may be things about the route from here to there we didn't already know.


Dr. David L. Katz;

For more by David Katz, M.D., click here.

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