Measuring and Labeling Carbohydrates

“Later this fall, we are going to take another step forward by helping to demystify carbohydrates,” stated Lester M. Crawford, Acting Commissioner, Food and Drug Administration. Crawford included this statement in his presentation at a National Press Club luncheon in August, where he outlined the agency’s priorities and important anticipated major actions to be taken in the next six months.

“I would also like to touch on two of our priorities to empower consumers through better health information. You are all aware by now of our efforts to battle obesity,” he commented. “Consumers are confused when they see the terms ‘low carb’ and ‘net carb.’”

Food researchers and processors are also confused. What are the legal requirements for labeling carbohydrates in food products? Consumers have reacted very quickly with positive acceptance of the wide variety of carbohydrate-controlled foods that food manufacturers developed surprisingly quickly in response to the popularity of the Atkins Diet and South Beach Diet. Only time will tell whether these and other low-carbohydrate diets will become another “fad” in consumer diet trends, but while it lasts, the food industry is “making hay while the sun shines.” In all my years of food product development, I never thought I would see low-carb bread on the store shelf; the bread took only a year to develop and it tastes good, too! And even more unbelievable, researchers at the University of Florida have now developed a low-carb potato, with 30% fewer carbohydrates than the standard Russet baking potato.

Actually, FDA’s current position is clearly stated in defining the amount of carbohydrates that must be declared on the nutrition label as measured by the appropriate approved Association of Official Analytical Chemists (AOAC) methods. “Total carbohydrates” is what must be specified, and this is commonly measured by simple analysis of the end food product for percentages of moisture, protein, fat, and ash. These four percentages are then subtracted from 100%, and the balance is total carbohydrates.

When consumers started to select foods labeled with lower percentages of carbohydrates to achieve a low-carb diet, researchers began to realize that dietary fiber was being included in this total. The controversy began when researchers recognized the value of retaining dietary fiber for its physiological benefits, while still seeking to lower the total carbohydrate numbers. Numerous processors began to also analyze their products for “total dietary fiber,” which they then subtracted from total carbohydrates to determine “net carbs.”

Industry Reactions
Although many scientists have been urging FDA to recognize the value of dietary fiber and reducing carbohydrate content, a starch supplier summarized it very well: National Starch and Chemical Co., Bridgewater, N.J., recently submitted a petition asking FDA to modify carbohydrate content labeling on foods. The company’s goal is to create more standardization regarding carbohydrate information, thereby allowing consumers to make better-educated food choices.

National Starch proposed that carbohydrates can be divided into two categories: those which are digested in the small intestine and those which are not. Sugars and most starches fall into the first category. They are rapidly digested to glucose and absorbed, and subsequently used for short-term energy needs or stored. These are available, digestible, and glycemic carbohydrates. Fiber, by definition, passes through the small intestine and provides no short-term energy; it is composed of nondigestible, nonglycemic carbohydrates. They have a variety of physiological effects. Therefore, separating dietary fiber from total carbohydrates would begin the process of differentiating these ingredients on the Nutrition Facts panel.

To emphasize the high interest in lower net-carb values, a food industry workshop titled “How Low Can You Go? Practical Solutions for Formulating Low-Carb Foods” was held in Chicago in May 2004. The workshop was hosted by the American Association of Cereal Chemists (AACC) together with Pizzey’s Milling, Angusville, Manitoba, Canada, and General Mills/Medallion Laboratories, Minneapolis, Minn. Linda Pizzey, President of Pizzey’s Milling, suggested that “the low-carb revolution offers the industry the opportunity to create new margin-enhanced products with unassailable nutritional value. That is a ‘win-win’ proposition.”

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A new study published in the August 2004 issue of Cancer Epidemiology Biomarkers & Prevention reported that there may be a link between high consumption of carbohydrates and breast cancer. Women who received 62% or more of their calories from carbohydrates doubled their risk of breast cancer compared to those who consumed 52% or less in their diet. In February 2004, the Grocery Manufacturers of America petitioned FDA to establish new regulations for carbohydrate nutrient content claims in single-serving foods, meal-type products, and main dishes. GMA recommended specific labeling such as “carbohydrate-free,” “low-carbohydrate,” “good source of carbohydrate,” and “excellent source of carbohydrate.”

A new study reported in the Annals of Internal Medicine found that dieters on low-carbohydrate plans don’t lose any more weight over the long term than traditional dieters. Half of the 132 obese adults studied for a year by the Veterans Affairs Medical Center in Philadelphia, Pa., ate less than 30 g of carbohydrates/day. The others were told to cut 500 kcal/day and limit fat to 30% of calories. Results showed no significant difference in total weight loss.

John McDougall, an advisory board member of Physicians Committee for Responsible Medicine, stated in a letter to the editor in Mayo Clinic Proceedings that the reason low-carb dieters often lose weight and sometimes show improvements in their cholesterol and blood pressure levels is because they are in essence sickened by the diet. McDougall claims that low-carb diets can throw people into a metabolic state called ketosis, which also occurs during severe illness. People on low-carb diets who become ill enough to experience loss of appetite, he said, are taking in less fat and cholesterol since they are consuming less food overall. “A better approach,” he stated, “is to encourage people to eat foods that promote both ideal body weight and health—those from a high complex carbohydrate, low-fat diet.”

Measuring Carbohydrates
According to Kathy Barry, Chemistry Lab Director, and Mark Villoria, Supervisor, Food Chemistry, both with ABC Research Corp., Gainesville, Fla., the usual analytical methods used to measure carbohydrates are pretty simple and basic. When a customer requests a complete nutrition label analysis, all items required by the Nutrition Labeling and Education Act (NLEA), are analyzed. Two items included in this analysis are total carbohydrate and dietary fiber, which can be partially used to calculate net carbs.

To calculate net carbs, as defined by Atkins Nutritionals, Inc., Ronkonkoma, N.Y., the sum of the dietary fiber, glycerine, sugar alcohols, and polydextrose is subtracted from the total carbohydrates. These ingredients, if digested, affect blood sugar only negligibly.

The only other mandatory carbohydrate item required on a Nutrition Facts panel by NLEA is a test for sugars. Individual sugars (sucrose, glucose, maltose, lactose, and fructose) are extracted from their food matrix and analyzed by high-performance liquid chromatography (HPLC) using modified AOAC-approved method for sugar 977.20. Refractive index detection results in the separation and quantitation of five individual sugars. Detection limits are 0.1% for each sugar. Another reason for analyzing individual sugar contents is so that formulators can know, for labeling purposes, where the sugar is coming from in their end products.

by DEAN DUXBURY
Contributing Editor
Consultant, Oak Brook, Ill.
[email protected]