Dr. Dariush Mozaffarian and Dr. David Ludwig of Harvard Medical School claim that a new approach to dietary guidelines is needed – not abandoning nutritional science, but using it to inform food-based guidelines.
The commentary is timely, as the draft 2010 Dietary Guidelines for Americans are currently being revised, and the final guidelines are due to be published later this year.
“The prevailing nutrient-focused approach…contributes to confusion, distracts from more effective strategies, and promotes marketing and consumption of processed products that nominally meet selected nutrient cut points but undermine overall dietary quality,” the authors wrote. “The relatively recent focus on nutrients parallels an increasing discrepancy between theory and practice: the greater the focus on nutrients, the less healthful foods have become.”
They argue that there is a place for understanding the way different nutrients work on their own and in combination, and that such scientific research should continue. However, they criticize in particular the way in which the food and beverage industry has conformed to nutrient-based guidelines, whether through fortifying highly refined products in order to characterize them as nutritious, or through using ingredients like fat replacers, for instance, which do not add nutritional value to products, but make them appear healthier.
“Based primarily on consideration of a few nutrients, a national obesity prevention program categorizes whole-milk yogurt and cheese with donuts and french fries as foods to eat occasionally; sautéed vegetables and tuna canned in vegetable oil with processed cheese spread and pretzels as foods to eat sometimes; and fresh fruits and vegetables with trimmed beef and fat-free mayonnaise as foods to eat almost anytime,” they wrote.
Nevertheless, they added that certain populations or regions with nutrient deficiencies or food shortages could benefit from the application of food-based guidelines that are in turn based on nutrient requirements.
“Healthier food-based dietary patterns have existed for generations among some populations,” the authors concluded. “Modern nutritional science now provides substantial evidence for how foods and food-based patterns affect health, guiding the design of more effective approaches for the prevention of chronic disease.”
The Dietary Guidelines are revised every five years in order to reflect changes in nutrition knowledge over time, including a review of contemporary US intakes of various foods and nutrients, examining those areas in which consumption may be inadequate, or where it may be excessive.
Source: Journal of the American Medical Association
Vol. 304, No. 6, pp.681-682
“Dietary Guidelines in the 21st Century – a Time for Food”
Authors: Dariush Mozaffarian, David Ludwig