Natural Flavors: What the FDA Definition Actually Means

“Natural flavors” is the fourth most common ingredient on food labels in the United States, after salt, sugar, and water.

It’s also among the least informative.

What the FDA Says It Means

Under 21 CFR 101.22, a natural flavor is defined as the essential oil, oleoresin, essence, extract, protein hydrolysate, distillate, or any product of roasting, heating, or enzymolysis of one of the following: fruits, vegetables, edible yeast, herbs, bark, buds, root leaves, meat, seafood, poultry, eggs, dairy products, or fermentation products thereof — whose significant function is flavoring rather than nutritional.

Two things matter in that definition.

First: the source must be natural (plant or animal). The extraction and processing can be extensive. The source gives the ingredient its legal status. Hundreds of chemical processing steps can happen between the natural source and the finished flavor compound, as long as the starting material was from an approved natural origin.

Second: the purpose is flavor, not nutrition. This distinguishes natural flavors from ingredients that also flavor food but are present for nutritional or structural purposes (like spices, which are listed separately).

What’s Actually in “Natural Strawberry Flavor”

Take a strawberry-flavored yogurt. The “natural strawberry flavor” in the ingredient list does not have to come from strawberries.

Strawberry’s characteristic aroma comes primarily from a compound called furaneol (2,5-dimethyl-4-hydroxy-3(2H)-furanone) plus dozens of supporting esters and aldehydes. These compounds can be isolated from strawberries — but can also be produced by fermentation using microorganisms acting on other natural substrates, or extracted from entirely different plants that happen to produce similar flavor chemicals.

A “natural strawberry flavor” might contain compounds sourced from:

• Actual strawberries (rare in industrially produced flavors due to cost)
• Fermentation of wood pulp or corn sugars by selected microorganisms
• Other fruits and plant materials that produce the target aroma compounds

The flavor manufacturer knows exactly what’s in it. The food company using it usually knows too. The consumer does not, and legally doesn’t need to.

The Trade Secret Protection

Exact flavor formulations are trade secrets. The flavor industry is specialized enough that many companies (International Flavors & Fragrances, Givaudan, Firmenich, Symrise) consider their specific formulas proprietary. Requiring disclosure would, they argue, eliminate any advantage from R&D investment in better flavors.

The FDA agreed. Natural flavors can be listed as a single item even if the actual flavor is a complex mixture of 30 or more compounds.

The safety side of this trade secret: each individual compound in a natural flavor must be GRAS or an approved food additive. The Flavor and Extract Manufacturers Association (FEMA) maintains a GRAS program for flavor compounds that has been recognized by the FDA. So the safety review happens at the ingredient level, even if the formulation isn’t disclosed.

The Animal Source Problem

“Natural flavors” in a product marketed as vegetarian, vegan, or plant-based can legally contain animal-derived ingredients — unless they trigger a major allergen disclosure.

Casein (milk protein), chicken broth, anchovy extract, and other animal-derived compounds can appear as components of natural flavors. If they don’t constitute one of the eight major allergens, they don’t need to be named.

This creates a genuine problem for people with strict dietary restrictions. A soup labeled vegetarian might contain natural flavors derived from chicken. A protein bar without a dairy disclosure might have casein-derived compounds in its natural flavors.

The FDA’s allergen labeling rules require the major allergens to be named even within natural flavors. But the naming only applies to the specific listed allergens, not all animal-derived materials.

Natural vs. Artificial: The Actual Difference

This is the part that most food labeling doesn’t explain well.

“Natural” flavor means the flavor compound was derived from a natural source. “Artificial” flavor means the same or a functionally similar compound was synthesized from a non-natural starting material (often petroleum-derived guaiacol or other chemical precursors).

The key word: same. Vanillin (the primary flavor compound in vanilla) produced by fermenting ferulic acid from rice bran using bacteria is “natural vanillin.” Vanillin produced by chemical synthesis from guaiacol is “artificial vanillin.” Both molecules are chemically identical. Both activate the same flavor receptors. No toxicological difference exists between them at equivalent doses.

This doesn’t mean “artificial” is always identical to “natural” — some artificial flavors use slightly different molecular analogs that natural sources don’t produce in quantity. But the categories “natural” and “artificial” don’t map onto “safer” and “less safe” in any reliable way.

What You Can and Can’t Learn from a Label

You can learn:

• Whether the product has a flavor for taste purposes (as opposed to nutrition)
• Whether it comes from a natural source (natural flavors) or synthetic source (artificial flavors)
• Whether any of the major allergens appear in the flavor (must be disclosed)

You can’t learn:

• Which natural sources are used
• What specific compounds are present
• Whether animal-derived materials are included (unless they’re a major allergen)
• Whether the flavoring was extracted simply or processed extensively

This is a legitimate transparency issue. The safety record of natural flavors as a category is solid — each component must be GRAS, and the system has operated for decades without meaningful evidence of harm. But “safe” and “transparent” are different standards, and natural flavors only meet one of them fully.