Environmental Nutrition: On the hunt for high quality carbs
Good carbs, bad carbs. By now we’ve all heard those terms and we know, basically, it’s a prod to choose good quality carbs — those less refined. But finding high value carbohydrates can get tricky, especially with varying advice, changes in the Nutrition Facts panel, and the never-ending internet lists of magic foods. The American Heart Association recommends one gram of fiber for every 10 grams of total carbohydrate per serving (10:1 carb:fiber ratio). Whether or not this ratio had been tested to filter for meaningful, nutrient dense foods was unknown until last year.
Americans get about 51% of their calories from carbohydrates (close to the Dietary Guidelines recommendation of 50%). Unfortunately, 42% of that is from low quality carbs, starchy vegetables, added sugars, juices, and other carbs; and 9% is from high-quality carbs from whole grains, fruits, legumes and less eaten, non-starchy vegetables.
Higher-value carbohydrate-containing foods have more fiber, whole grains, less added sugar and a lower glycemic index. In addition, high quality carbs often contain loads of other vitamins, minerals and phytonutrients.
A meta-analysis of 185 prospective studies and 58 clinical trials, high fiber consumers had a 15% to 30% reduction in cardiovascular and coronary heart disease, stroke, Type 2 diabetes and colon cancer compared to those who ate less fiber. They also had lower body weights, systolic blood pressure, total cholesterol and breast cancer risk. The health benefits were similar for foods rich in whole grains, but not necessarily foods with a lower glycemic index or load. Eating patterns that are lower in added sugar are associated with reduced risk of heart disease, obesity and diabetes. More recently, an observational study in Brazil found that people who ate more foods with a lower 10:1 ratio had fewer cardiovascular risk factors and lower insulin resistance.
Research published in 2013 indicated foods with a carbohydrate ratio greater than 10:1 should be avoided, less than 10:1 was a good choice, and less than 5:1 was a great choice, but there weren’t many good and great choice options available on the market. Can the 10:1 ratio be trusted, or should it be more restrictive to account for added sugar?
A group of nutrition scientists studied the 10:1 ratio with a variety of fiber and sugar-free ratios in carbohydrate-rich foods commonly consumed in the U.S. and then analyzed the nutritional value of those foods. The 10:1 ratio was the “standard” used for comparison. The first ratio, 10:1:1 (carbohydrates:fiber:free sugar ratio), was based on 50% of calories coming from carbohydrates and a maximum of 5% of energy coming from “free sugar” (or added sugar). A less restrictive sugar ratio of less than two grams of added sugar was tested in a similar, second ratio of 10:1:2 (carbohydrates:fiber:free sugar ratio) that assumed 10% of calories from added sugar. And finally, a third ratio 10:1|1:2 (carb:fiber plus fiber:free sugar ratio), tried to allow for more added sugar if the food contained more whole grain. It was based on 30 grams of fiber a day and less than 10% of energy needs coming from added sugar.
The 10:1 and 10:1|1:2 identified the most commonly consumed and the greatest number of products with lower calories, fat, free sugar, and sodium, and higher protein, fiber, potassium, magnesium, iron, vitamin B6, vitamin E, zinc, and iron. The 10:1:1 and 10:1:2 had the least benefits for protein, fiber, potassium, and magnesium, and lower levels of folic acid, thiamine, riboflavin, and niacin. For now, the 10:1 ratio looks to be a solid choice.
(Environmental Nutrition is the award-winning independent newsletter written by nutrition experts dedicated to providing readers up-to-date, accurate information about health and nutrition in clear, concise English. For more information, visit www.environmentalnutrition.com.)
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