If you're more likely to understand how to program a VCR than to figure out the nutritional content of the foods you eat, you're not alone. In my private practice, I continually have to explain nutrition labels to clients.
According to U.S. research published this month, difficulty in translating the nutrition facts box on packaged foods can result in shortchanging your body out of vitamins and minerals, especially calcium.
If you're at risk of osteoporosis, then you've probably been told to consume 1,500 milligrams of calcium a day. Yet, figuring out how much calcium is in a serving of yogurt or cheese is challenging because the mineral is listed only by a percentage of "daily value." It appears that most people - and their doctors - can't convert that into milligrams of calcium.
Researchers from the University of Wisconsin-Milwaukee found that only two out of 37 respondents correctly translated the calcium information from a carton of yogurt to milligrams. When 20 physicians were shown the same label, only six gave the right answer.
In another study, 41 women who were pregnant or breastfeeding were told to consume 1,200 to 1,500 milligrams of calcium a day. Half the women were given a fact sheet on calcium that included the formula for converting percentage of daily value to milligrams.
The women who were given the fact sheet consumed significantly more calcium each day compared with those who received no instructions for reading labels (1,430 milligrams compared with 988 milligrams).
A percentage of daily value is confusing because most of us don't know what the "daily value" is for each nutrient. The measurement is based on the average recommended intake for a 2000-calorie diet. For calcium, percentage of daily value is based on 1,100 milligrams. That means that a 175-gram carton of yogurt delivering 25-per-cent daily value contains 275 milligrams of calcium (0.25 multiplied by 1,100).
But you don't have to take a calculator grocery shopping. You can get a quick estimate by simply adding a 0 to the percentage on the label. Although this formula slightly underestimates calcium content, it's easy to calculate.
The recent research isn't the first to report consumer confusion over food labels. A 2006 study of educated adults found that 75 per cent had trouble understanding nutrition labels and many lacked the math skills needed to decipher them.
According to the Canadian Council of Food and Nutrition, 75 per cent of Canadians use food labels at least sometimes and one in four always consults the label when deciding what to eat.
In an effort to make food labels easier to understand, Health Canada introduced mandatory nutrition labelling for most prepackaged foods in December 2005. (Small food companies have until the end of this year to post nutrition labels on their products.) Compared with old labels, the revised nutrition facts box is larger and easier to find, and provides more information.
Yet for many people, nutrition labels are still difficult to interpret.
To help you decipher nutrition labels - and apply the numbers to your diet - follow these tips:
Check serving size
The only way to know how much fat, sugar, sodium or fibre you're consuming is to compare the serving size listed on the label with the amount you actually eat. Don't assume that one package of food - a bottle of fruit juice, a frozen dinner, or even a bagel - is one serving. Figure out how much you eat and then do the math.
Use percentage
of daily values
These percentages are listed for fat, saturated and trans fat, sodium, carbohydrate, fibre, vitamins A and C, calcium and iron. Instead of trying to remember the amount each figure is based on, follow the "5 and 25 rule."
