The UK Food Standards Agency (FSA), the rough equivalent of the FDA in the US, has started a campaign warning of the cancer risk associated with cooked potatoes and other starchy foods.
Put simply, the problem is acrylamide. Acrylamide is a chemical substance formed through a Maillard reaction between amino acids and sugars. It typically results when foods with high starch content such as potatoes, root vegetables, or bread are cooked at high temperatures (over 120°C) in a process of frying, roasting, or baking. It's not something added into foods, but something that emerges as a result of a chemical reaction, from cooking.
High levels of acrylamide are found in starchy foods, like potatoes and bread, when cooked at high temperatures, but the chemical can also be found in breakfast cereals, biscuit, and coffee. Basically, if you cook potatoes at lower temperatures, the acrylamide level is not so high. As a rule of thumb, you should aim for a golden yellow colour or lighter when cooking starchy foods like potatoes, root vegetables and bread. Brown potatoes, for instance, have more acrylamide -- and that's bad.
The problem with acrylamide is that our bodies synthesize it into another compound, glycidamide, which can bind to our DNA and cause mutations, leading to cancers. Animal tests clearly show this happening and although this hasn't been clearly translated to humans, there is a good cause for concern.
“Although evidence from animal studies has shown that acrylamide in food could be linked to cancer, this link isn’t clear and consistent in humans,” says Emma Shields, at charity Cancer Research UK.
While there are other, much more significant factors connected to cancer (such as smoking and a sedentary lifestyle), the concerns that acrylamide can be harmful to us seem valid.
What this means
Studies have shown that high levels of acrylamide can cause neurological damage and cancer. Across the pond, the US Environmental Protection Agency has said acrylamide is “likely to be carcinogenic to humans” and the International Agency for Research on Cancer (IARC), part of the World Health Organisation, says it is a “probable human carcinogen”. Researchers say that the off meal shouldn't worry anyone -- it's more a lifestyle thing that can be dangerous. Basically, if you eat potatoes or toast every day, you might want to start considering other meal options.
Steve Wearne, director of policy at the FSA, says manufacturers are already taking steps following their campaign, and consumers should too.
“We are not saying people should worry about the occasional meal... this is about managing risk over a lifetime. Anything you can do to reduce your exposure will reduce your lifetime risk. People might, for example, think 'I like my roast potatoes crispy', but they will just decide to have them less often.”
What you can do
The first thing you can do is "go for gold" -- don't cook potatoes at high temperatures and keep them from browning. When it comes to buying food, you can ask for that at a restaurant, or for prepackaged chips you can... just not eat chips, preferably. If you must eat chips, make sure it's not too often -- there's no clear indication here, but a few times a month should be fine. No one is expecting a radical diet shift.
The next thing contains storage. Storing raw potatoes in the fridge may lead to the formation of more free sugars in the potatoes (a process sometimes referred to as ‘cold sweetening’) and this, in turn, leads to the formation of more acrylamide.
Lastly, eating a varied diet helps. Don't overly rely on potatoes (or any vegetable or cereal for that matter) and try to diversity your meals whenever possible. This will definitely help reduce your risk of cancer, and not only from acrylamide.