The Alphabet Soup of Nutrition Terminology: Part 2
Staying abreast of emerging nutrition research studies can be a real challenge for busy wellness professionals. Half the battle is making sense of the terms used to describe new scientific findings. One day “genetics” is making headlines, while the next day everyone is talking about the “glycemic index.”
Things get even trickier when your clients pose questions about these newfangled buzz words and you don’t have a clue as to what they mean. That’s why we devised this primer to explain 10 key terms related to breaking food and nutrition research news. We explored the first five in the April issue of Inner IDEA Body-Mind-Spirit Review and take a look at the remaining topics below.
This is a term that is used incorrectly and often these days. According to the USDA, the term organic refers solely to a farming practice that eschews the use of antibiotics, conventional pesticides, growth hormones and irradiation in animal or plant products. Contrary to popular opinion and manufacturers’ claims, the term is not synonymous with “nutritionally better for you” or “having improved nutritional status.”
When shopping, consumers should look for the USDA’s “organic” symbol, which indicates that the food was raised using organic farming procedures and that the product is at least 95% organic (some foods are 100% organic, whereas others contain only one organic ingredient) (USDA 2002). However, it is not currently a federal requirement to use this symbol; manufacturers display it on a voluntary basis. Anything less than 95% organic will not carry the USDA’s symbol. Urge your clients always to read the food packaging and labels for clarification.
It should be noted that the terms organic and natural are often used interchangeably and incorrectly. In fact, the term natural simply indicates that the product was made without artificial ingredients or colorings and possibly with minimal processing. As with the term organic, the word natural on a food label does not guarantee that it is healthy.
Bioavailability refers to the body’s ability to absorb and use the nutrients derived from food. For example, certain nutrients, such as sodium and potassium, are readily available for use by the body, whereas others, such as iron and chromium, are less available.
What’s more, studies have shown that some nutrients enhance absorption of other nutrients, while others actually detract from adequate absorption. For example, vitamin C augments iron absorption, and vitamin D boosts calcium absorption. On the other hand, oxalic acid, found in spinach and chard, and phytic acid, found in whole grains, both work to decrease calcium absorption (Mahan & Escott-Stump 2000).
Hydrogenation refers to the process of adding hydrogen molecules to unsaturated fatty acids in certain foods, such as snack cakes, cookies, baked goods and, especially, stick margarine and vegetable shortening. The process of forcing hydrogen into the fat creates a chemical formation that results in the formation of trans fats, which have been shown to have negative health effects. Once hydrogenated, the fat solidifies, allowing the product to withstand longer time on store shelves and in our cupboards at home.
As of January 2006, all food labels are required to display trans fat levels. Although there is still no recommended daily intake for trans fats, the Institute of Medicine (IOM) has gone on record as stating that no level of trans fats is safe (IOM 2002). Many nutrition experts tell their clients to avoid or minimize consumption of products that contain partially hydrogenated fat, in order to cut trans fat intake. One note of caution when scouring labels for trans fats: The FDA permits manufacturers to “round down” for any product that contains less than 0.5 g of trans fat per serving (IFIC 2005). That means a label may say “0 grams of trans fat,” yet you may be consuming 0.4 g with each serving!
9. Glycemic Index
According to the International Food Information Council (IFIC), the term glycemic index (GI) is a measure of how the carbohydrates in a particular food influence blood sugar levels (IFIC 2003). Researchers determined the GI of a host of individual foods by measuring subjects’ blood sugar response after eating a given amount of a carbohydrate food and then comparing that value to their blood sugar response after eating a control food (usually white bread or glucose). For example, researchers measured the blood sugar response after subjects ate 50 g of potatoes and compared this to their response after eating a 50-g serving of white bread. The average change in blood sugar levels over a set period of time relative to the change in levels after consumption of the control food determined the food’s glycemic index.
While this may sound like a straightforward procedure, it is not without its limitations. In fact, the concept is complex and not particularly user-friendly, given all the different foods one might ingest in a given day. Additionally, the GI of a particular food can be altered by its ripeness, how it is prepared or cooked, and its overall nutrient composition (IFIC 2003).
10. Glycemic Load
Glycemic load (GL) is a relative of GI and may ultimately prove to be the better method for determining glycemic response. The GL takes into account not only the GI of a particular food but also the serving size of that food. (A food’s GL is calculated by multiplying the food’s GI by serving size and then dividing by 100.) In other words, the GL is more practical than the GI because it addresses both the quality and quantity of the carbohydrate in question.
International Food Information Council (IFIC). 2003. Glycemic index: The ups and downs of indexing blood sugar. www.ific.org/foodinsight/2003/mj/glycemicfi303.cfm; retrieved Dec. 1, 2005.
IFIC. 2005. Translating the facts about trans fat. www.ific.org/foodinsight/2005/ma/transfatfi205.cfm; retrieved Dec. 1, 2005.
Institute of Medicine (IOM). 2002. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, DC: National Academies Press.
Mahan, L.K., & Escott-Stump, S. 2000. Krause’s Food, Nutrition, & Diet Therapy (10th ed.). Philadelphia: W.B. Saunders Company.
U.S. Department of Agriculture (USDA). 2002. Organic food standards and labels: The facts. www.ams.usda.gov/nop/Consumers/brochure.html; retrieved December 1, 2005.
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