Health: Should I Avoid Eating Burnt Food?

When we are young, we often unknowingly learn habits about food or cooking from adults. Examples include never licking food on a knife, or sprinkling salt to expel bad energy.

Many of these idiosyncratic behaviors would be nothing more than superstition. However, there would have been no scientific basis at the time, but there is one action that has stood out with foresight from several decades ago.

In 2002, a team of researchers at Stockholm University published a study suggesting that scraping off burnt areas from toast may be a smart move. When we heat certain foods, such as potatoes, bread, biscuits, cereals, and coffee, over 120 degrees, the sugar in these foods reacts with the amino acid asparagine to create a substance called ‘acrylamide’.

This is called the ‘Maillard reaction’, and food turns brown and acquires a distinctive taste through this reaction. However, studies have shown that ingesting acrylamide can cause cancer in animals. However, eating much more than the amount a person eats causes cancer.

The European Food Safety Authority believes that acrylamide may also increase the risk of cancer in humans, especially in young children. However, academics have yet to come to a definitive conclusion about the effects of acrylamide on humans.

Fatima Saleh, a professor of medicine at the Arab University of Beirut, Lebanon, said: “It has been almost 30 years since (acrylamide) was classified as a potential carcinogen in humans, but the supporting studies on whether it is definitely carcinogenic in humans are still mixed. there is,” he said.

“Continuing further studies in humans will give us enough data to distinguish acrylamide as a definitive human carcinogen.”

Scientists believe that acrylamide may have adverse effects on the human nervous system. The exact mechanism involved has not yet been fully elucidated.

However, hypotheses such as ‘attacking structural proteins in nerve cells’ or ‘may inhibit the anti-inflammatory system that protects nerve cells from damage’ are being tested.

The toxic effects of acrylamide have been shown to be cumulative. This means that long-term consumption of small amounts of acrylamide can have long-term effects on the body.

Federica Raguchi introduced acrylamide research on animals. According to him, it was concluded that long-term exposure of animals to acrylamide through food can increase the risk of neurodegenerative diseases such as dementia and affect the development of neurodevelopmental disorders in young animals. Federica Raguchi is a researcher in the field of cardiovascular and nutritional epidemiology at the Institute of Environmental Medicine, Karolinska University, Sweden.

“Because acrylamide is small in molecular weight and highly soluble in water, it penetrates all tissues, including the placenta,” said Raguchi. Raguchi found a link between high intake of acrylamide by pregnant women and reduced newborn weight, head circumference and height.

The mechanism by which acrylamide increases the risk of cancer in humans remains unknown. Leo Schauten, a professor of epidemiology (a branch of medicine that studies methods for preventing or controlling infectious diseases) at Maastricht University in the Netherlands, put forward a hypothesis about this.

After Swedish researchers discovered the presence of acrylamide in human food in 2002, the Dutch Food Authority, together with Schauten and a Dutch diet and cancer cohort, investigated the possible effects of acrylamide in food on humans. influence was investigated. At the time, Schauten and his colleagues used questionnaires to determine how much acrylamide people consumed.

The study found that a popular Dutch food called ‘ontbijtkoek’ was responsible for a significant difference in acrylamide intake among older adults in the Netherlands. This food was very high in acrylamide because baking soda was used in the production process.

The researchers also looked at the association between acrylamide intake (since smoking contains it) and all cancers in non-smokers. They found that women who were exposed to high levels of acrylamide had a higher risk of endometrial and ovarian cancer. Additional studies also found a weak association between acrylamide consumption and kidney cancer.

However, no other studies have been published to support these findings. The closest thing is a 2012 US study. The American study concluded that nonsmokers who consumed high amounts of acrylamide had an increased risk of ovarian and endometrial cancer after menopause.

However, it is difficult to fully trust this study. This is because other factors in the lifestyle of people who consume large amounts of acrylamide may have influenced cancer rates.

Moreover, other studies have found no association, or only a weak one. In the end, it’s unclear whether the association Schauten and his team found was inaccurate, or whether other studies have been unable to accurately measure acrylamide intake.

“The increased risk of cancers of the female genital organs, such as endometrial and ovarian cancer, is related to certain hormones,” said Schauten. said.

“Acrylamide may have effects on estrogen or progesterone, which have been linked to cancer in women, but this relationship has not been proven,” Schauten said.

Laboratory studies involving mice have also found associations between acrylamide intake and cancers in the mammary, thyroid, testicular and cervical regions. This also suggests a hormonal connection, but this does not lead to the conclusion that it presents a similar risk in humans as it is.

In 2010, the Food and Agriculture Organization (FAO) and World Health Organization Food Additives Expert Committee suggested that longer-term studies are needed to understand the link between acrylamide and cancer. However, it expressed support for efforts to reduce acrylamide levels in food.

However, one of the biggest challenges is accurately measuring the amount of acrylamide we consume.

“Although it has been established that acrylamide is genotoxic and can cause cancer in animals, the link between acrylamide and cancer in humans is still unclear,” said Raguchi. “Most epidemiological studies measure acrylamide intake through questionnaires, which can lead to erroneous results.”

Schauten believes there is a way to accurately measure acrylamide in people’s diets. However, there are many scholars who disagree with this. Another way to measure acrylamide intake is to measure biomarkers in urine and blood. But Schauten said he didn’t find anything specific about this method either.

Raguchi said more research was needed to measure acrylamide, especially as a biomarker in blood. This is because blood shows acrylamide intake over a longer period of time than urine.

A US study from 2022 measured acrylamide using biomarkers. Using data spanning 10 years, the study showed an association between acrylamide consumption and death from cancer, but did not conclude which cancer it was.

There is another reason why there is not much conclusive evidence that acrylamide intake can increase cancer risk. This is because we can take protective measures to limit the increased risk of excessive consumption.

Raguchi reviewed the 2022 US study summaries, but found no association between acrylamide consumption and the risk of developing cancers outside the women’s gynecological class. It is possible that humans have a recovery mechanism that prevents both potentially carcinogenic and neurotoxic effects, or that the study itself did not accurately measure the amount of acrylamide in food, he said.

“Also, we don’t just eat acrylamide,” he says. “Acrylamide is often found in foods that also contain ingredients such as antioxidants that can help counteract its toxic mechanisms.”

Although there are no studies of definitive dangers from consuming acrylamide in humans, the food industry is working to reduce acrylamide in food.

Nigel Halford said: “The EU sets maximum limits for acrylamide in food, and if this is made, it could have a major impact on the food supply chain.” Halford is working on reducing the potential for acrylamide formation in products made from wheat by farmers.

Acrylamide is not found in plants. On the other hand, asparagine, a substance that converts to acrylamide when heated, is found in plants.

“Acrylamide has a very big impact on the food industry because it affects a variety of grain-derived foods,” he said.

Halford said wheat grains can build up more asparagine than you need, especially if you don’t get all the nutrients you need, such as sulfur. Halford is trying to genetically control this process using the gene-editing technology ‘CRISPR’.

Consumers often ask producers to reduce the acrylamide content in their products as much as possible, especially in baby foods.

According to Schauten, these changes have been quite successful. He said it was an encouraging achievement that acrylamide was reduced to about 20% of the previous level due to a change in the production method of the Dutch breakfast cake, Ontbaitcook.

There are also ways to reduce acrylamide when cooking at home, Saleh said. For example, when potatoes cut to make potato chips are soaked in hot water for 10 minutes, the formation of acrylamide is reduced by about 90%.

Raguchi said that in recent years there has been a resurgence of interest in the health effects of acrylamide in academia. He said it will take time, but within a few years the link between acrylamide consumption and cancer risk will become clearer. In the meantime, the eating habit of cutting off the burned part of the toast may not be so bad.