The U.S. Food and Drug Administration (FDA) has a designation for substances that are intentionally added to food called GRAS: Generally Recognized As Safe. A number of essential oils, absolutes, and hydrosols have made the GRAS list. But this is where most people stop digging for information and assume that this designation means an essential oil is safe in any application that will be going into their mouth – in a glass of a water, a cup of soup, or on top of a scoop of ice cream. Unfortunately for their internal organs, they couldn’t be more wrong.
GRAS and Food Substances
In order for a food substance to meet GRAS status with the FDA the following four criteria must be met:
- The substance must be recognized as safe by qualified experts.
- The experts need to have the appropriate training and experience to evaluate the substance’s safety.
- Safety is determined via scientific procedures or through a rigorously referenced common use in food prior to 1958.
- GRAS is determined by the conditions of intended use in the food.
The specific data and information that demonstrate safety depend on the characteristics of the substance, the estimated dietary intake, and the population that will consume the substance.
– U.S. Department of Health and Human Services, Food and Drug Administration, Center for Food Safety and Applied Nutrition (CFSAN), December 2004
Determining Dietary Intake with Essential Oils
The conditions of intended use clause is where associations like the Flavor and Extract Manufacturers Association (FEMA), and experts like Fenaroli’s Handbook of Flavor Ingredients come in to provide estimates of safe consumption.
In order for an essential oil to reach GRAS status experts look at:
- toxicology – at what strength does the essential oil become poisonous to a human adult?
- organic chemistry – what is the chemical nature of the essential oil?
- biochemistry – how will the chemistry of the essential oil interact with the chemistry of the human?
- metabolism – what is the path the essential oil will travel through the human body? How quickly is it absorbed and excreted?
- pathology – when the essential oil concentration is strong enough to be poisonous how will it affect the human body? What disease or illness will it cause? Which organs will be most affected by the poisoning?
Example of GRAS Essential Oil Intake
Since GRAS essential oils are intended to flavor a food or beverage let’s look at the concentration that qualified experts have determined for a popular essential oil, Lemon:
Lemon (Citrus x limon) has a FEMA GRAS determination (Flavor and Extract Manufacturers’ Association D-Limonene Monograph, 1-4, 1991) based on the chemical constituent d-limonene, a terpene, of 100 part per million (ppm) (or 0.01%) usage in non-alcoholic beverages. Limonene ranges from 56-76% (Tisserand-Young 2014) in a batch of cold-pressed Lemon rinds, so let’s say you’ve got 75% limonene in your bottle at home your dose per liter would be 74.8655 milligrams. If you don’t have a chemist’s scale at home you can use the general rule of thumb that an average drop of essential oil weighs between 20-30 milligrams. So to dilute your one drop of Lemon essential oil to achieve the GRAS safety level of 100 ppm you’d need 0.3 liters of lemonade: 74.8655 mg/L x 0.3 = 22.26 milligrams or roughly 1 drop Lemon EO.
But as we know from Why essential oils are not water flavoring agents, and Friends don’t let friends drink essential oils, essential oils are fat soluble, not water soluble. So you’d need to add some kind of dispersant to your lemonade to safely distribute that drop in your 0.3 liters so you’re not coating your sensitive internal skin from mouth to rectum or urethra with the equivalent of driveway degreaser.
In commercial settings an essential oil like Lemon would be re-distilled, or folded, to remove some of the constituents and give a higher concentration of other constituents. The end product would deliver a GRAS substance that is sold to the food and beverage industries that wouldn’t require quite the same level of dilution as an essential oil that is intended for aromatherapy (the therapeutic use of essential oils and hydrosols) use. There’s a number of concerns about using strong chemical substances, whether obtained from botanicals or produced in a laboratory, in food and beverages. It’s an interesting discussion and I’d encourage you to bend the ear of your favorite chemist. For some inspirational discussion points here’s some articles and monographs you may wish to read:
- GRAS Flavoring Substances, FEMA (PDF) – includes some good points on flaws around estimating intake and exposure.
- Safety Evaluation of Certain Food Additives, World Health Commission (PDF) – includes info on a variety of botanical constituents, including limonene that we talked about in Lemon above.
- Food additives on the rise as FDA scrutiny wanes, Washington Post – issues around self-regulation are discussed.
Editor’s note: An unfortunate error affected my original calculations in the D-Limonene GRAS referenced in this post. I have corrected this error and sincerely apologize for any inconvenience this may have caused and thank those who helped me find it.