Crunchy, but crisps can give you cancer, doctors warn


Your favourite chips and crisps just got poisoned again – this time not with heart-stopping salt or oils, but with a cancer causing chemical with children and adolescents facing the biggest threat.

It has been known for some time now that the chemical, acrylamide, a byproduct associated with frying; baking, roasting or toasting foods at high temperatures is bad but now governments are stepping in with guidelines on the best way to reduce exposure.

More than 13 food products, which include crisps, chips, breakfast cereals, toasted bread, cookies, crackers and even coffee have been found to contain raised levels of the chemical.

While nobody is advocating the banning of these foods, experts are telling consumers to go for foods cooked to light golden colour instead of the more preferred golden brown hue.

In general, the crispier and browner your food is, the higher the acrylamide level will be hence the unhealthier it is.

Last week the US Food and Drug Agency issued guidelines to food processing companies and even home cooks on measures to take to lower the incidence of the chemical in the foods they handle.

For example, the guidelines tell cooks to keep raw potatoes out of the refrigerator, soak potatoes in water before frying them and avoid burnt toast. Locally more emphasizes is being given to the potato because it is a major food component only second to maize.

According to Dr Jackson Kabira, head of the National Potato Research Centre, an arm of the Kenya Agricultural Research Institute based at Tigoni in Limuru, potatoes are grown by over 800,000 farmers on 160,000 ha and are valued at Sh26 billion annually.

While much of the potatoes are mashed, boiled or baked full and pose little threat of the chemical acrylamide, Dr Kabira says processed products such as crisps and chips are now a major part of consumed foods mainly in urban areas.

In Nairobi alone more than 40 brands of crisps are sold in supermarkets, shops and kiosks. Hundreds others are not even branded. Mr Wachira Kaguongo, CEO National Potato Council of Kenya, says crisps processing has become the major form of value addition for potatoes today.

A survey done in Nairobi in July by Dr Jackline Akinyi Ogolla of the College of Agriculture and Veterinary Services of the University of Nairobi found potato crisps sold in Nairobi to contain worrisome levels of acrylamide contamination.

The researcher has purchased 35 brands of crisps from retail outlets in Nairobi and 15 unbranded samples from the street vendors and analysed them in the laboratory for the offensive chemical.

The researcher concluded that the amount of acrylamide contamination in potato crisps being sold in Nairobi exposes consumers to health risks associated with the chemical.

“Important steps are therefore required to mitigate the high exposure by reducing level of acrylamide contamination and decreasing consumption,” she says in her paper posted at the University’s repository.

She also recommends that appropriate varieties and processing parameters be chosen to ensure less acrylamide in potato crisps.

This advice is being taken seriously with a draft proposal on how to reduce acrylamide in potato products being circulated among food experts and government officials in Kenya and other Africa Union members.

The draft Code of Practice has been developed by the Nairobi based Africa Organisation for Standardisation (ARSO) and has been circulated to member countries for comments before it is adopted in practice.

While the guidelines, developed last year, target commercial processors they also give good advice to home cooks and consumers as well.

Just like it is being advised in the US, the local draft recommends that  potato chips, crisps and roast potatoes be cooked to a golden-yellow rather than golden-brown colour, whilst still ensuring that the food is fully cooked.

It is also advising against slicing the potato into very thin slices because these are known to carry more of the chemical compared to thicker pieces. “Removal of fine pieces of potato before or after frying has been shown to reduce levels of acrylamide in fried or roasted potatoes,” says the draft.

Processors and cooks are advised against using very high temperatures while processing chips, crisps or roast potatoes.  “In order to achieve significant reductions in the acrylamide content in these foods set the initial oil temperature to no more than 170 degrees centigrade,” says the draft.

In her study Dr Ogolla found acrylamide levels to significantly go up with increased frying temperature and slice thickness.

Farmers and researchers can also help by developing and supplying potato varieties that have low levels of sugars. “Tubers with high levels of sugar tend to produce darker fried products with potentially higher levels of acrylamide,” says the Arso draft.

One area that is a completely no go is the use of immature tubers which should be avoided by selecting, sorting or grading of potatoes before processing or frying.

“We are advising food processors on the most appropriate potato varieties to use for chips or crisps that will be healthier for consumers as well as for their businesses,” says Dr Kabira.

In her study Dr Ogolla compared the effect of potato variety with levels of acrylamide in the fried product. Among the four varieties they tested; Tigoni, Kenya Mpya, Dutch Robjin and Sheherekea, the much favoured for crisps Dutch Robjin recorded the lowest levels of the chemical.

Further research shows children and teenagers to be at the greatest risk of ingesting the chemicals because they are the main consumers of chips and crisps. A study conducted on the patterns of potato crisps consumption in Nairobi showed children and adolescents to be the major consumers.

Carried out by the National Potato Research Centre and University of Nairobi, the researchers sampled 80 outlets in Nairobi with results showing women to be consuming twice as much when compared to men.

“The results showed that 33 per cent of consumers are males while 67 per cent were females with the most popular flavour being onion-salted,” says the study led by Dr George Ooko Abong of the University of Nairobi and published in the journal Applied Biosciences.

Of the 215 consumers who participated in the study, 74 per cent said they consumed potato crisps at least once a week on average. The team which also included Dr Kabira said only a quarter of the respondents bought crisps for their own consumption with 72 per cent buying them for the family.

A good portion of the crisps meant for the family, 53 per cent was shown to be consumed by children only.

This information, the team explains, tells why a large per cent of consumers, 56 per cent, bought more potato crisps during the holidays when schools are closed, 17 per cent during the going back to school periods compared to 8.7 per cent during in school periods.

“It is apparent that most of the potato crisps are consumed by children, another reason why quality should be assured to prevent any hazards that could be related to these foodstuffs such as may be caused by high salt and fat intake,” says the study.

The increasing prevalence of obesity in children, the food experts say, has been partially attributed to increased consumption of snacks high with fat, sugar and salt content and now with the cancer causing acrylamide.