Pick up any packaged, processed food, and there's a decent chance that one of its listed ingredients will be "natural flavor." The ingredient sounds good, particularly in contrast to another common and mysterious ingredient, "artificial flavor." But what exactly does natural flavor mean? When a reader posed the question, I contacted nutritionists and flavorists — yes, that's a profession — to find out.

"Basically, if something is a natural flavor, it's derived from some natural source," explains Charles Platkin, director of the New York City Food Policy Center at Hunter College.

The U.S. Food and Drug Administration defines "natural flavor" as oils, resins or other extracts derived from natural sources like plants, meat or seafood. Processes like heating or fermentation are used to extract the flavor. The function of these products is flavoring, not to add any nutritional content.

"We do a lot of this in cooking," says Chef Bruce Mattel, senior associate dean of culinary arts at The Culinary Institute of America. "Let's say I poach shrimp in water. Then I take that big pot and reduce it all the way down to a teaspoon of shrimp essence." That essence could then be added to a different dish. The food industry does this on a massive scale — scientists find the chemical responsible for a specific flavor in nature, extract it, and then add it to candy, beverages and throngs of other processed products.

When consumers see "natural flavor" on a beverage label, they shouldn't assume that someone is zesting oranges into their bottle, says Mattel. Even though natural flavor must come from natural sources, it need not all come from the plant or meat whose flavor is being mimicked. For example, orange flavor might contain not only orange extract, but also extracts from bark and grass.

So if companies are trying to approximate flavors like orange, why not just use oranges? The answer comes down to availability, cost and flexibility, according to flavor chemist Gary Reineccius, of the University of Minnesota. "At one time, there were 10 times more grape-flavored products than grapes grown," Reineccius says. "If you're going to use all your grapes on grape soda, you don't have any for wine. It would be exceedingly expensive. Then what do you do with the byproduct you create after you've sucked all the juice out of the grape?"

Flavor chemists might also want a particular kind of grape taste, he explains, and mixing the grape flavor in the lab allows them the flexibility to create exactly the flavor they want, rather than relying on farmers' produce.

All three experts say that ultimately, natural and artificial flavors are not that different. While chemists make natural flavors by extracting chemicals from natural ingredients, artificial flavors are made by creating the same chemicals synthetically.

Platkin says the reason companies bother to use natural flavors rather than artificial flavors is simple: marketing.

"Many of these products have health halos, and that's what concerns me typically," says Platkin. Consumers may believe products with natural flavors are healthier, though they're nutritionally no different from those with artificial flavors.

Nor are ingredients extracted from nature necessarily safer than something artificially made. Reineccius points out that many deadly toxins are produced in nature. What's more, in some cases, natural flavors may have more detrimental environmental consequences than artificial flavors. Mattel explains that because natural flavors must come from resources in nature, they may involve more forest clear-cutting and carbon emissions from transport than flavors created from scratch in the lab.

Platkin suggests consumers lobby their congressional representatives to get more transparent labeling on packaging that describe exactly what the natural or artificial flavors are, so consumers are not hoodwinked into buying one product over another because of "natural flavors."

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