Is burnt toast really a cancer risk?

This page is for anyone who has heard that burnt toast causes cancer. It explains what acrylamide is, what the studies show, and what FDA suggests.

The burnt toast story is not made up, but it has been stretched a long way from what the evidence actually shows.

The chemical at the center of it is acrylamide. FDA explains that it forms from sugars and an amino acid called asparagine during certain types of high-temperature cooking, such as frying, roasting and baking. It is not an additive and nobody puts it in deliberately. It appears as a by-product of heat.

FDA says it is found mainly in foods made from plants, such as potato products, grain products and coffee.

Here is the sentence that the headlines are built on, in FDA's own words: acrylamide caused cancer in animals in studies where animals were exposed to acrylamide at very high doses.

FDA is specific that these were levels much higher than those seen in foods. It is also open about the question still being live. As new research on the effect of acrylamide exposure becomes available, FDA says its experts will consider it. That work feeds into a continued evaluation of the risk acrylamide may pose to human health.

FDA also notes that an international expert committee concluded in 2010 that acrylamide is a human health concern.

A chemical that causes cancer in animals at high doses is worth studying. That is not the same as a slice of toast being dangerous.

If you want to lower how much acrylamide forms in your kitchen, FDA's suggestions are specific and easy.

• Toast lighter. Toasting bread to a light brown color rather than a dark brown color lowers the amount of acrylamide.
• Store potatoes out of the fridge. FDA advises keeping them in a dark, cool place such as a closet or pantry.
• Soak potato slices. Soaking raw slices in water for 15 to 30 minutes before frying or roasting helps reduce acrylamide formation.
• Choose water-based cooking when you can. FDA notes that boiling potatoes, and microwaving whole potatoes with the skin on to make microwaved baked potatoes, does not produce acrylamide.

Notice what is not on that list. FDA does not tell people to give up bread, potatoes or coffee.

The advice about keeping potatoes out of the refrigerator surprises people, since the fridge feels like the safer option for most food.

FDA's reason for storing them somewhere dark and cool is to prevent sprouting. It is also worth remembering how acrylamide forms in the first place: sugars are one of the two ingredients, alongside asparagine.

Asked whether consumers should change their diets because of acrylamide, FDA's answer begins with a plain no. Its best advice is that people adopt a healthy eating plan consistent with dietary guidelines, emphasizing fruits, vegetables, whole grains and lean proteins while limiting unhealthy fats and sodium.

That is a useful reality check. The overall pattern of what you eat carries more weight than the shade of a single slice of bread.

If you have cancer, or you love someone who does, food advice arrives from every direction and much of it is confident and wrong.

Acrylamide is a real research question. It is being studied by a federal agency, which tells you it is taken seriously. It has not been established that the amounts in ordinary food harm people, and FDA says so directly.

Lighter toast costs nothing. Rearranging your life around it is not what the evidence asks for.

Start with the four tips above, since they are free and require no special products. Then, if diet is something you want to work on properly, ask for a referral to a dietitian rather than assembling a plan from articles.

A dietitian can look at what you actually eat, and at your treatment, and give advice that fits both.