When the federal government’s 2010 Dietary Guidelines finally came out at the end of January 2011, there was more praise for their dos than their don’ts. Some consumer groups and nutrition experts commended the emphasis on combating obesity, controlling calorie intake, and eating fresh fruit and vegetables. But Walter Willett, chair of the Harvard School of Public Health’s nutrition department, says the guidelines would be more effective if the message to Americans were more specific—eat less red meat, cheese, ice cream, white rice and white bread—and less abstract, specifically urging people to stay away from added sugar and solid fat
One problem that has occurred in the past is that the guidelines, which are written by government officials, have deviated significantly from the recommendations of the scientific advisory committees charged with collecting and analyzing the evidence upon which the guidelines are supposed to be based. The disconnect reflects the influence of powerful agricultural and food industry interests.
Here are a couple of key areas where the final version parted company with the recommendations of the scientific committee.
Sugar-sweetened beverages: Avoid vs. reduce
The guidelines are pretty tough on added sugars, a group that includes honey, molasses, and maple syrup, as well as high-fructose corn syrup and chemical concoctions like anhydrous dextrose. As the guidelines point out, the body doesn’t distinguish in a big way between sugars that are found naturally in food and those that are added, but many of the foods that contain added sugars are nutritionally vacuous, supplying calories and little else. Sugar-sweetened beverages — soda, energy drinks, and sports drinks — are the main sources of added sugars in the American diet.
The scientific advisory committee wanted the guidelines to say that people should avoid sugar-sweetened beverages — a simple, clear don’t-go-there message. Instead, there’s a much milder admonition to reduce intake, either by drinking fewer of them or having smaller servings (which is certainly good news for soda companies marketing 7.5-ounce “mini” servings).
Sodium: 2,300 mg vs. 1,500 mg
Sodium is on the dietary watch list because it tends to increase blood pressure, and high blood pressure is a risk factor for stroke, heart disease, and kidney disease. Only a fraction (between 5% and 10%) of the sodium in the American diet comes from salt we add at the table or in cooking at home. The lion’s share is in processed and ready-to-eat food like pizza and, somewhat surprisingly, breads made with yeast.
The 2005 Dietary Guidelines set a daily goal of no more than 2,300 milligrams (mg) of sodium, which is the amount in a teaspoon of table salt. The scientific advisory panel recommended lowering the goal to 1,500 mg a day, although gradually, to give salt-crazed American palates time to adjust. But the writers of the 2010 guidelines stuck with 2,300 mg for the general population, noting that only 15% of Americans currently manage to keep their intake that low.
The guidelines do set the bar at 1,500 mg for groups of people who, on average, are known to be more sensitive to the blood pressure–raising effects of salt, which include African Americans, people who already have high blood pressure, and those ages 51 and older. That’s half of the population, so the difference between the scientists’ advice and the guidelines isn’t huge.
Till then, there are some steps we can take as individuals: read labels and buy low-sodium alternatives, eat more fresh fruit and vegetables, dine in rather than out. There’s also some evidence that the harmful effects of sodium can be offset by leafy green vegetables, bananas, and other foods that contain a great deal of potassium.
April 2011 update
Healthy Eating: A guide to the new nutrition
Eat real food. That’s the essence of today’s nutrition message. Our knowledge of nutrition has come full circle, back to eating food that is as close as possible to the way nature made it. Based on a solid foundation of current nutrition science, Harvard’s Special Health Report Healthy Eating: A guide to the new nutrition describes how to eat for optimum health.
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