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Department of Foods and Nutrition
Purdue University
West Lafayette, IN 47907-2059
E-mail: weavercm{at}purdue.edu
Texas A&M University
College Station, TX
Children's Hospital Oakland Research Institute
Oakland, CA
and University of California at Davis
Davis, CA
and University of California at Berkeley
Berkeley, CA
David Geffen School of Medicine
University of California at Los Angeles
Los Angeles, CA
Children's Nutrition Research Center
Baylor College of Medicine
Houston, TX
St Luke's–Roosevelt Hospital Center
Columbia University
New York, NY
Department of Food Science
University of Massachusetts
Amherst, MA
Pennsylvania State University
University Park, PA
Dear Sir:
In a recent article in the Journal (1), a proposed guidance system for beverage consumption in the United States was put forward by a panel initiated by the senior author, Barry Popkin. As members of the 2005 Dietary Guidelines for Americans Advisory Committee, our purpose for writing this letter is to compare some similarities and differences between the Dietary Guidelines Committee and the Beverage Guidance Panel of Popkin et al (1).
The 2005 US Dietary Guidelines Advisory Committee was charged to conduct an evidence-based review of the literature on the relation of diet and physical activity and health. The recommendations of this Committee (2) were the basis of the Dietary Guidelines for Americans 2005, the federal law issued jointly by the US Department of Health and Human Services and the US Department of Agriculture (3). The Committee's foundational goal was to determine food and beverage patterns that would meet the nutrient recommendations of the Daily Recommended Intake (DRI) panels within energy needs. A major focus of the 2005 Dietary Guidelines Advisory Committee was to provide advice for a diet consistent with maintaining a healthy weight while meeting nutrient needs. Given the alarming obesity epidemic in the United States, the nutrition community is keenly aware of the urgency to develop and implement population-based solutions that curb this public health crisis. The article by Popkin et al (1) addresses an important issue about the contribution of beverages to total energy intake and outlines possible strategies for reducing energy intake from a wide array of beverages, especially those that contribute little nutritional value. However, we believe that the article by Popkin et al (1) did not appropriately frame their guidance system for beverage consumption based on the evidence presented in the Dietary Guidelines for Americans 2005.
In the report by Popkin et al (1), beverages were ranked on the basis of caloric and nutrient contents and related health benefits and risks, as well as on fulfilling daily water needs. Rankings were based more on what negative attributes a beverage contains, ie, added sugars, than its ability to fulfill nutrient needs. Similar to Popkin et al (1), the 2005 US Dietary Guidelines Advisory Committee was concerned with overconsumption of energy-dense, nutrient-poor products and illustrated the limited amount of discretionary calories available to various age and sex groups after nutrient needs were met, particularly among sedentary individuals. This approach covers all beverage choices including sweetened tea and coffee. The common practice of sweetening coffee and tea by many individuals is not well considered by Popkin et al (1).
Below, we outline the specific differences between the recommendations of the 2005 US Dietary Guidelines Advisory Committee (2) and those proposed by Popkin et al (1).
Water
The DRI panel on fluid and electrolytes found insufficient evidence of a relation between a specific amount of water intake and health (4). Although an adequate intake for total water intake was set on the basis of mean total water intake, the panel noted that requirements vary greatly. The 2005 US Dietary Guidelines Committee recommended, as did the DRI panel, that thirst be the guide. The conclusive statement began, "The combination of thirst and usual drinking behavior, especially the consumption of fluids with meals, is sufficient to maintain normal hydration." There is no evidence base for the 20–50 fl oz water/d recommended by Popkin et al (1).
Tea and coffee
The 2005 Dietary Guidelines (2) lists no recommendations for including tea and coffee in the diet. No conclusive statements were developed due to insufficient evidence of a relation to health and no recognized contribution of essential nutrients. In contrast, Popkin et al (1) suggest 28 fl oz/d of tea or coffee and list 36 fl oz/d as acceptable for persons on a 2200 kcal diet and an overall recommended range of 0–40 fl oz/d for those aged 6 y.
Milk and soy beverages
The 2005 US Dietary Guidelines Advisory Committee (2) concluded, "Consuming 3 servings (equivalent to 3 cups) of milk and milk products each day can reduce risk of low bone mass and contribute important amounts of many nutrients." Popkin et al (1) recommended a range for low-fat, skim milk and soy beverages of 0–16 fl/oz/d for those aged 6 y and, for a person with a 2200 kcal requirement, they suggested 16 fl oz/d and accepted 6 fl oz/d. Three cups of milk (or calcium-fortified soy beverage) per day provides a substantial amount of the recommendations of several nutrients, ie, 87% of calcium, 54% of protein, 28% of potassium, 25% of magnesium, and 32% of riboflavin, for a woman aged 31–50 y. Milk also contributes vitamin D. Popkin et al (1) recommend replacing vitamin D in milk with supplemental vitamin D. If consumption of milk and soy beverages were reduced to 6 oz/d, individuals would be required to consume fortified foods or beverages and supplements to achieve the requirements of many nutrients. This would be particularly difficult for potassium intake. Moreover, the evidence base for relating consumption of 3 servings milk/d to health does not exist for alternative sources supplying equivalent amounts of several selected nutrients.
Fruit juices
Considering the fruit and fruit juices typically consumed by Americans (2), the 2005 US Dietary Guidelines Advisory Committee recommended that no more than one-third of the total recommended fruit group intakes come from fruit juice with the rest coming from whole fruit to meet the requirements for vitamin C, folate, and potassium. In the context of food-based guidance, the US Department of Agriculture Food Guide recommends 4 servings per day from the Fruit Group for a person on a 2000-calorie diet. One-third of this is 1 serving juice/d. This is somewhat similar to the upper end of what Popkin et al (1) proposed (0–8 fl oz fruit juice/d).
An essential difference between the recommendations of the US Dietary Guidelines 2005 (2) and the Popkin et al report (1) is that the Dietary Guidelines Committee supported the DRI report (4) that indicated that under most circumstances one does not have to choose water or other specific fluids to remain hydrated. Rather, the process is automatic as long as water is available. However, it is clear that the US Dietary Guidelines 2005 report (2) recommends a food-based approach and that individuals should choose foods and beverages that contain certain nutrients. It is our opinion that a graphic suggesting that tea and coffee are superior nutritional choices to skim milk is inappropriate. Despite this, the Popkin et al (1) article has raised an important issue that merits further scientific discussion. Such a dialogue is essential for the evolution of future dietary recommendations. As scientists involved in efforts to promote the health and well-being of Americans, we have a responsibility to take a robust, evidence-based approach to decrease the obesity epidemic. Therefore, we encourage the 2010 Dietary Guidelines Committee to perform an evidence-based review of the health effects of tea and coffee and to continue to monitor hydration, particularly as it relates to thirst in different age groups. We also are mindful of the need for additional research to determine the role of calorically sweetened beverages on weight control. Intertwined in this discussion is the reality that noncaloric beverages are an important part of the social fabric in our society, and we believe that some guidance should be provided in the future that addresses this issue.
ACKNOWLEDGMENTS
All authors were members of the 2005 Dietary Guidelines Advisory Committee.
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