Acrylamide has been in the news this week, with the UK’s Food Standards Agency (FSA) warning that eating overcooked potatoes, crisps, or burnt toast could increase your risk of developing cancer. Does this mean you should be consigning your toaster to the trash and avoiding roast potatoes with your roast dinner? This graphic assesses the realities of the risks.
Acrylamide is a compound which is formed by reactions that occur when certain types of foods are cooked at high temperatures. Carbohydrate-rich foods cooked at a temperature over 120˚C can end up containing small amounts of acrylamide. Reactions during cooking see amino acids combine with sugars in the food to form a whole range of chemical products; these reactions are collectively known as the Maillard reaction. Some of the products of these reactions are essential for flavour, but others are slightly less benign.
One such compound is acrylamide. Acrylamide is formed when a particular amino acid, asparagine, reacts with sugars at high temperatures. The amount of acrylamide that is formed is dependent on both temperature and cooking time; a higher cooking temperature and a longer cooking time will both increase the formation of the compound.
What are the dangers of acrylamide? Well, it’s classified by the International Agency for Research on Cancer as “probably carcinogenic in humans” in their ranking of a range of different risks. It’s worth noting that this specifically means that there’s evidence of it causing cancer in animals, often at quite high doses, but limited evidence in humans. The higher category of “carcinogenic to humans” includes things like alcohol and cigarettes – for these, sufficient evidence has been established in humans of increased cancer risk.
Though acrylamide is found in a number of foods, the quantity in which it is found is also important to consider. In the foodstuffs that have been examined, toasted bread has been found to contain up to 200 micrograms per kilogram, which converts to around 0.2 micrograms per gram, or for an average slice of toast (assuming it weighs around 24 grams) about 4.8 micrograms. For reference, a microgram is 0.000001 grams. A bag of crisps contains about 12.4 micrograms of acrylamide for an average-sized bag. Per day, it’s estimated that the average person’s daily intake of acrylamide is around 30 micrograms.
This sounds quite small, but sometimes small quantities of a compound can still cause harm, so should we be concerned? Well, based on studies, scientists have set a safe limit of 2.6 micrograms per kilograms of body weight. For a weight of 75kg, this would mean that you’d have to ingest over 195 micrograms of acrylamide per day to be breaching this recommended maximum. While this limit isn’t impossible to hit considering the numbers we already looked at, its significantly higher than the amount of acrylamide contained in one slice of toast or one bag of crisps.
In addition to this, the FSA’s announcement has received muted criticism in some quarters. Cancer Research UK pointed out that while encouraging healthy eating habits is a useful reminder, for most of us there are much bigger cancer risk factors in our lives than acrylamide in our food. Alcohol and smoking are two factors which increase your risk of developing cancer significantly more, and if you’re a frequent drinker or smoker, these should be of much more concern. Additionally, there’s still little evidence for increased risk of cancer from acrylamide at the levels found in foods – in fact the majority of studies have found no significant association.
Still, if the news does still have you concerned, there’s nothing wrong with the FSA’s advice to avoid eating burned foodstuffs, and perhaps cook foods a little less brown as this will reduce the acrylamide content. They also recommend not storing certain vegetables such as potatoes and parsnips in the fridge, as this can increase their free sugar content, which can in turn increase the amount of acrylamide formed during cooking.
If you want to read in more detail about acrylamide and its other risks, be sure to check out this post over at The Chronicle Flask!
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References & Further Reading
- Acrylamide – Food Standards Agency
- Estimation of safe dietary intake levels of acrylamide – R G Tardiff and others
- Warning over ‘burnt toast chemical’ cancer risk – NHS
- Dietary acrylamide and human cancer – a systematic review of literature – M K Virk-Baker and others
- Total diet study of acrylamide – Food Standards Agency