Thursday, January 24, 2008

Health labels and symbols

The Canadian Broadcasting Corporation this week offered a fascinating feature on food rating systems. Yoni Freedhoff from the Weighty Matters blog takes the interviewer on a tour through the grocery store and comes down hard on Canada's Health Check symbol. The CBC compares the Health Check symbol unfavorably to the "Guiding Star" system introduced last year by the Hannaford supermarket chain. And David Katz defends the Overall Nutrition Quality Index (ONQI) system he and his colleagues have proposed.

Katz also discussed his ONQI system on Marion Nestle's blog, What to Eat. Nestle is not a big fan of such systems. I found this part of Katz's response badly insufficient:

As for the concern raised about the system being proprietary: the ONQI was developed with no commercial interest in view. It was supported by the non-profit Griffin Hospital, in Derby, CT- and when finished, offered first to the US FDA. The FDA, while very supportive of the work and the sophistication of the ONQI, encouraged commercialization as the only way to get the ONQI into consumer hands any time soon.

So now, yes, there are business interests involved. And there is intellectual property. But the fundamental workings of the ONQI algorithm were shared with scientists at a conference held in Washington, DC on 11/30/07 devoted to the purpose of transparency. Dr. Nestle was invited, but unable to attend. The ONQI will soon be published in the peer-reviewed literature as well. Not every last detail of the algorithm will be shared, but more than enough for those even with somewhat less expertise than Dr. Nestle to judge the reliability and robustness of the system. Of the 100 or so scientists who attended the November conference, not a one complained that they had insufficient detail to judge the algorithm.

I won't trust any food rating system whose full scoring details can't be widely shared with everybody and scrutinized. A conference presentation or partial write-up does not suffice.

2 comments:

Mark said...

Enough of the details were released to reveal that it's ridiculously complicated. I doubt many people would be interested in seeing the whole thing unless they are Ph.D. candidates!

I think where they go wrong is in the belief that it's better because it includes "more nutrients" than previous nutrient density rankings. This is like the "our amp goes to 11" line in Spinal Tap. Since it's a single dimensional ranking number, the more you put in it, the more diluted the consideration of other factors is.

And they attempt to weigh the importance of minor nutrients by how much effect they have on health. It would seem if a nutrient were a minor nutrient and it doesn't have much of an effect on health compared to others, you should just omit it.

I think if you include just a few nutrients that are mostly vegetable sourced, they act as proxies for the minor nutrients, and that is enough. If you're influenced to eat more veggies by a ranking system, you'll do O.K.

At any rate, malnutrition is hardly the problem in the U.S. Just putting calories on foods and using a simple rule like Michael Pollan's is probably enough.

t-mac said...

Interesting. On a distantly-related yet coincidental note, Nestle Corp. is one food company that has tried to study the Muslim world's halal standards for food in order to make products geared towards that exacting market segment.
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