Nature-Identical Butterscotch Flavour

About

What it is and where it shows up.

Nature-identical butterscotch flavour is a synthetically manufactured blend of chemically defined flavouring substances—primarily diacetyl (2,3-butanedione), acetoin, ethyl maltol, and related diketones—that are chemically identical to compounds naturally present in butterscotch and dairy products. It is used to impart a characteristic buttery, caramel-toffee taste and aroma to confectionery, bakery goods, beverages, dairy desserts, and snack foods.

Safety summary

The regulatory and scientific consensus.

When consumed orally at typical food-use levels, the individual components (e.g., diacetyl, acetoin) are considered GRAS or FEMA GRAS and pose no significant risk to the general adult population. However, occupational inhalation of diacetyl vapour—a key butterscotch/butter flavour component—has been causally linked to bronchiolitis obliterans ('popcorn lung'), a severe and irreversible obstructive lung disease; this risk is specific to industrial workers, not consumers. High dietary intake of ethyl maltol (a co-component) has been associated in animal studies with headaches, nausea, and hepato-renal effects at excessive doses, though ADIs at approved food-use levels are considered safe.

Regulatory landscape

What food-safety regulators have decided.

Jurisdiction	Status	Note
FSANZ (Food Standards Australia New Zealand) (Australia)	Approved	Permitted under Food Standards Australia New Zealand (FSANZ) Standard 1.3.1 – Food Additives. Nature-identical flavourings are permitted at GMP levels. Individual component substances must be approved or meet JECFA safety evaluations.source
EFSA (European Food Safety Authority) (European Union)	Approved	Governed by Regulation (EC) No 1334/2008. The EU adopted a positive Union list of approved flavouring substances effective 1 October 2012; only listed substances may be used in or on foods. Nature-identical flavourings as a category are assessed on individual component substances. The regulation also restricts 15 naturally occurring substances of toxicological concern (e.g., estragol, coumarin) that may not be added as such. Diacetyl and acetoin are included in the Union list under their individual FL numbers.source
FSSAI (Food Safety and Standards Authority of India) (India)	Approved	FSSAI permits nature-identical flavouring substances in food under the Food Safety and Standards (Food Products Standards and Food Additives) Regulations 2011 and associated flavouring compendium. Individual components must conform to FSSAI/JECFA specifications. No specific maximum use level is set for butterscotch flavour as a blend; GMP (good manufacturing practice) applies.source
FDA (Food and Drug Administration) (United States)

Who should approach with care

Whose guidance would steer them away.

Other — Workers involved in manufacturing or handling concentrated butterscotch/butter flavour compounds containing diacetyl face serious inhalation risk of bronchiolitis obliterans ('popcorn lung') and should comply with NIOSH/OSHA occupational exposure limits; this does not apply to consumers eating finished foods.

Liver Disease — Ethyl maltol, a co-component of butterscotch flavour formulations, has been shown in animal studies to target the liver at elevated doses, so individuals with pre-existing liver disease should exercise caution with frequent high-intake exposure.

Kidney Disease — Ethyl maltol and its iron complexes have been shown to affect kidney function in animal toxicity studies at high doses, warranting caution in individuals with pre-existing renal impairment.

Children — Nature-identical flavourings may be present in confectionery, snacks, and beverages heavily consumed by children; while individual components are approved, cumulative dietary exposure to diacetyl and related diketones from multiple flavoured products should be minimised as a precautionary measure.

Research citations

The sources behind this verdict.

1PubMed. Evaluation of the butter flavoring chemical diacetyl and a fluorochemical paper additive for mutagenicity and toxicity using the mammalian cell gene mutation assay in L5178Y mouse lymphoma cells. pubmed.ncbi.nlm.nih.gov
2PubMed. Flavoring Chemicals in E-Cigarettes: Diacetyl, 2,3-Pentanedione, and Acetoin in a Sample of 51 Products, Including Fruit-, Candy-, and Cocktail-Flavored E-Cigarettes. pmc.ncbi.nlm.nih.gov
3PubMed. Emission of diacetyl (2,3-butanedione) from natural butter, microwave popcorn butter flavor powder, paste, and liquid products. pubmed.ncbi.nlm.nih.gov
4PubMed. Toxicity Studies of Ethyl Maltol and Iron Complexes in Mice. pmc.ncbi.nlm.nih.gov
5EFSA / European Commission. EU Rules on Flavourings – Regulation (EC) No 1334/2008 and Union List of Flavouring Substances, 2012. food.ec.europa.eu
6NTP / NIOSH. Artificial Butter Flavoring Components (Diacetyl, Acetoin, 2,3-Pentanedione) – NTP Research Summary, 2007.

Independently researched6 citations