Behind the label: Diet Coke

Far from being the healthy drink implied by its sports sponsorships, Diet Coke is a worrying cocktail of neurotoxic and potentially carcinogenic chemicals

Diet Coke was first introduced in the US in July 1982 and today it is the fourth most commonly consumed carbonated beverage in the world.

Apart from being the beverage of choice for sugar-phobic individuals the world over, Coca-Cola is one of the longest standing ‘corporate partners’ (since 1974) of the Fédération Internationale de Football Association (FIFA). In 1998 the company signed an unprecedented eight-year agreement to sponsor FIFA events – not just the prestigious World Cup, but also the Women’s World Cup, the Confederation Cup, various youth championships and the upcoming World Cup Trophy Trip, a roadshow that will take the FIFA World Cup Trophy on tour to cities throughout the world.

Last year Coca-Cola extended its FIFA sponsorship commitment until 2022, a move that prompted the preposterous statement by company Chairman and CEO, E. Neville Isdell, that Coke’s recommitment to the
world’s most popular sport ‘affords us a new opportunity to bring people closer together through football’.

It also helps them shift a lot of cans and bottles. A recent study by marketing information company ACNeilsen revealed that the Coca-Cola brand is the global leader among beverages, generating well over $15 billion in sales globally each year. Coke and Diet Coke each generate more than a billion dollars in sales yearly.

Five countries – the US, the UK, Germany, Canada and Brazil – guzzle more of this supposedly healthy, sugar-free alternative to regular Coke than anywhere else in the world.

Aggressive marketing like the FIFA sponsorship and clever jingles like ‘Always Coca-Cola’ keep Coke in our consciousness, but before you ‘grab a Coke and a smile’ at this year’s main event, consider just what you are putting into your body. Although Diet Coke has a strong association with sport and health, it is actually a worrying mixture of neurotoxic and potentially carcinogenic high intensity sweeteners (aspartame and acesulfame K), tooth and bone destroying acids (phosphoric acid) and DNA damaging colourings (sulphite ammonia caramel), as well as psychoaddictive caffeine and other undisclosed ‘fl avourings’.

It also contains sodium benzoate, which can be broken down into the listed carcinogen benzene in the presence of strong acids, such as the citric acid found in this product.

Soda manufacturers have been aware of this synergistic possibility since the 1990s, but without pressure from regulatory authorities to change their formula to prevent the formation of benzene, have continued to mix benzoates and acids.

Ironically, the high fructose syrups used in regular drinks seem to slow this reaction down, and the formation of benzene appears to be most problematic in diet drinks.

Ingredients Purpose Adverse Effects
Aspartame Sweetener Breaks down easily in heat and during storage to its neurotoxic components phenylalanine, aspartic
acid and methyl alcohol. According to the FDA aspartame is associated with headaches, dizziness,
loss of balance, mood swings, nausea, memory loss, muscle weakness, blurred vision, fatigue,
weakness, skin rashes, joint and musculoskeletal pain. (For a full report on aspartame toxicity see the
Ecologist September 2005). The most recent evidence shows that aspartame ingested at levels that
are currently found in daily soft drink consumption raises the risk of otherwise rare brain tumours
known as lymphomas.
Acesulfame K Sweetener Causes cancer in animals. Acetoacetamide, a breakdown product, has been shown to affect the
thyroid gland in rats, rabbits, and dogs. Although it is commonly blended with aspartame to cover its bitter taste, there are no studies to show if the combination is safe or whether it produces other toxic by-products.
Phosphoric acid Acidifier Can contribute to erosion of tooth enamel; leaches calcium from bones. Children with high intake of phosphoric acid suffer from brittle bones and a higher risk of fractures that follow them throughout life. Children consuming at least six glasses (1.5 litres) of phosphoric acid-containing soft drinks daily have more than five times the risk of developing low blood levels of calcium, compared to children who don’t drink sodas.
Citric acid Preservative,
On its own relatively harmless, though it can be harsh on tooth enamel. When mixed with potassium
or sodium benzoate (see below) during storage, and especially at raised temperatures, it can aid the
formation of carcinogenic benzene.
Caffeine Flavouring A stimulant, psychoactive compound that can provoke mood changes, lethargy and headache.
Caffeine is addictive and ingestion of high levels can cause miscarriage as well as contribute to peptic ulcers and heart ailments. At the levels added to soft drinks caffeine adds virtually no flavour but does, if consumed regularly, trigger caffeine addiction. Children consuming caffeine have higher incidences of illness, headaches, sleep problems and iron depletion. A 330ml bottle of cola contains
about half the caffeine of a cup of coffee.
Sodium Benzoate (E211) Preservatives People who suffer from asthma, rhinitis or urticaria may find their symptoms get worse following the consumption of benzoates. In acidic solutions (such as sodas), benzoates can break down into benzene, a known carcinogen. Surveys have shown that levels in soft drinks can be up to 40 times
higher than recognised ‘safe’ doses.
Sulphite ammonia
caramel (E150d)
Colouring Made by heating sugar, ammonia and sulphite-containing compounds, the sugar can sometimes come from GM maize. Ammonia is toxic by all routes of exposure, and caramels made by an
ammonia process may damage genes, slow down growth, cause enlargement of the intestines and kidneys and may destroy vitamin B. This colouring has never been fully evaluated for its potential carcinogenicity or reproductive toxicity.


This article first appeared in the Ecologist June 2006

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