Verifying Natural Ingredients in Dietary Supplements and Food

In January, the U.S. Pharmacopeial Convention (USP; Rockville, MD) proposed adding a new method to the appendix of its Food Chemicals Codex (FCC), a method specifically designed to evaluate naturally derived food ingredients. The method, which uses carbon isotope signatures, would allow users to determine whether ingredients are made from plant or animal sources versus other sources like petroleum wax or mineral oil.

USP states that this method would allow stakeholders to label the bio-based percentage of a product. It could also prevent counterfeit ingredient sources, such as the addition of synthetic compounds to natural ingredients. Industry members are encouraged to provide feedback to the proposed standards by March 31 at www.usp.org/fcc/fccForum.html.

Nutritional Outlook discussed the new standard with USP’s James Griffiths, PhD, vice president of food, dietary supplement, and excipient standards; and Markus Lipp, PhD, director of food standards.

Q: Why is this method needed?
Demand is increasing from manufacturers and consumers to reduce the environmental impact of their products (their environmental footprint) and utilize ingredients derived from bio-based (natural plant or animal) sources that are considered to be renewable. This new method for determining the bio-based content of food ingredients is among the latest proposed additions to the Food Chemicals Codex (FCC) compendium.

This method fills a niche. The FCC previously did not offer any resources to its users to allow for the verification of a claim that a certain material is bio-based. Such a claim has been important to some stakeholders and users of the FCC.

USP strives to offer a compendium that offers science-based specifications for the authenticity, quality, and identity of food ingredients; suitable methods for the verification of those claims; and reference materials to demonstrate that these methods are performing appropriately. This new method supports USP’s mission to increase food safety by offering tools that allow all stakeholders in the food-supply chain to independently verify such product attributes.
 

How can this method help the food, beverage, and dietary supplements industries in terms of preventing counterfeiting?
The method had initially been suggested only for analysis of the amount of bio-based 1,3-propanediol; however, it is suitable for all carbon-based materials. This method is applicable to all industries that would like to verify a claim that an ingredient is derived from current bio-based materials rather than crude oil.

Besides this application, this technique can also be used in counterfeit detection, especially in cases in which an expensive natural extract exists, along with a synthetically produced compound offered at a lower price, both of which may have similar features. For example, the new FCC method would be able to detect the addition of synthetically produced vanillin to natural vanilla extract-something that other anticounterfeiting methods are not specific enough to do.

USP intends to expand the FCC appendix on authentication methods in the future to include additional procedures for detecting counterfeit food ingredients and is encouraging industry to submit useful methods for consideration.
 

Aside from this newly proposed method, what options do companies currently have for verifying natural ingredients?
If an ingredient is sourced through a supply chain that embraces the concept of traceability, then companies in that supply chain can rely on a paper trail to establish the authenticity of that ingredient.

Can you describe in detail how the method works?
The proposed method uses the isotope analysis of a sample compared to that of a modern reference standard. In short, isotope analysis is the identification of the distribution of certain isotopes within chemical compounds. Isotope ratios are measured using mass spectrometry, which separates the different isotopes of an element on the basis of their mass-to-charge ratios. The proposed method relies on the isotopes of carbon.

There are three naturally occurring isotopes of carbon. The different isotopes of carbon do not differ appreciably in their chemical properties. Carbon-12 (C-12,12C) is the more abundant of the two stable carbon isotopes, accounting for 98.89% of the natural carbon. It contains 6 protons, 6 neutrons, and 6 electrons. Carbon-13 (C-13,13C) is the other natural, stable isotope and makes up about 1.1% of all natural carbon on earth. Carbon-14, (C-14,14C, or radiocarbon) is a radioactive isotope of carbon with a nucleus containing 6 protons and 8 neutrons. Its presence in organic materials is the basis of the radiocarbon dating method used to date archaeological, geological, and hydrogeological samples.

Carbon-14 occurs in trace amounts, making up as much as one part per trillion (0.0000000001%) of the carbon in the atmosphere. The half-life of carbon-14 is 5730±40 years. It decays into nitrogen-14 (14N) through beta decay. In other words, plant material that is 5730 years old would only contain half of the amount of radiocarbon when compared to modern plants. Living plant and animal feedstocks will have radiocarbon in them in an amount defined as 100%. Petrochemicals will not have any radiocarbon (i.e., 0%) because it has long since decayed away.

The quantities of the different isotopes can be measured via combustion to convert all carbon quantitatively to carbon dioxide. Accelerator mass spectrometry is used to relate the signatures between the two isotopes (12C:14C; 13C:14C), which are then compared to a standard. The result is expressed as a ratio.

A bio-based content value of 100% indicates that all carbon originated from modern plants or animals. A value of 0% indicates all carbon originated from petrochemicals. A value between 0% and 100% indicates the relative amount of carbon derived from recent plants and animals versus petrochemicals.

Are there any limitations as to which types of ingredients or applications the method can be used for?
The method works only for carbon-based materials. The method is most applicable at the level of individual ingredients in a final product. One would not be able to distinguish between different carbon-based ingredients [in a finished product], and the result would only reflect the sum of all ingredients.
 

Can this method be used for natural ingredients in both food and supplements?
Yes, it is suitable for carbon-based ingredients used in food and dietary supplements.