From sparkling water to yogurt to pasta sauce, natural flavors appears on the labels of countless packaged foods and beverages.

In fact, natural flavors are the fourth-most common ingredient listed on these labels, with only salt, water and sugar appearing more often, according to the Environmental Working Group .

But what are natural flavors, and how natural are they really?

For starters, the Food and Drug Administration defines natural flavors as substances derived from plants (fruits, vegetables, spices, herbs, barks and roots) or animals (meat, poultry, seafood, eggs and dairy) whose primary function is taste rather than nutrition. The flavor may be extracted via heating, fermentation, distillation or other processes.

There are tiny chemicals that make up the flavors of these foods or natural substances, such as benzaldehyde, for instance, registered dietitian Allison Baker told OpenFit.com . Benzaldehyde is found in cheese, mushrooms and almonds, to name a few, and can be extracted from these foods and used to flavor other foods.

Artificial flavors, on the other hand, come from non-food, synthetic sources.

An example would be artificial vanilla flavor, whose main constituent compound is [synthetic] vanillin , as opposed to the natural vanilla that would be obtained from Madagascar, Indonesia or Mexico , Chapman University food science professor Lilian Were told HuffPost.

Are natural flavors more healthful than artificial flavors?

Not necessarily. For one, both natural flavors and artificial flavors are created in labs by flavor chemists known as flavorists. The natural and artificial versions of the same flavor can be nearly identical in their chemical composition ; the only difference is the source.

Natural flavors may still contain synthetic preservatives, emulsifiers, solvents and other incidental additives.