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By JOHN NAISH
Sweet, cheap and natural — fructose sounds like the ideal ‘healthy’ sweetener.
The high content of fructose in processed fruit juice may be the trigger for rectal cancer
However, the sugar, which is found naturally in fruit but is now added to many processed foods, may hide a range of deadly secrets.
Scientists are discovering that fructose appears to be linked to serious modern epidemics such as cancers, heart disease, hypertension, kidney damage and even dementia.
The latest fears were raised last week by research that found people who consume lots of fructose by drinking fruit juice have an increased risk of rectal cancer.
The research, published in the Journal of the American Dietetic Association, suggests that the high content of fructose in processed fruit juice may be the trigger.
The problem, the researchers say, is that many substances found in fruit which help protect against bowel cancer — such as fibre, vitamin C and other antioxidants — are lost during processing.
There have been other concerns about the fructose content of fruit juice. Earlier this year, scientists at Bangor University warned that even freshly-squeezed juice contains up to five teaspoons of fructose per glass, which may lead to weight gain or even diabetes.
The British Dietetic Association says that because of this we should drink only one 150ml glass of juice a day.
It warns: ‘Although fruit juice is natural, it has had all the fibre squeezed out of it and so the fructose is easily absorbed into the bloodstream.’
If only keeping one’s consumption of fructose down to safe daily levels were that straightforward.
Nowadays, fructose is cropping up not just in fruit juice, where it occurs naturally, but in all sorts of foods and drinks — from biscuits to ice cream.
Most consumers wouldn’t know: it can be listed in the ingredients under a variety of names. The most common name for industrially produced versions is high-fructose corn syrup. It is a processed form of fructose derived basically from corn.
In the UK, it is replacing beet and cane sugar, because it’s cheap and keeps foods moist, boosting shelf life. It adds texture to food such as cereal bars and biscuits, making them chewy, and thickens ice cream and yoghurt drinks.
High-fructose-corn syrup is used in frozen products, too, as it reduces crystallisation. Another benefit is that it turns baked products an appetising brown, so you can often find it in cakes, pastries and bread rolls, crackers and cereals.
It’s easy to see why manufacturers of food and drink love corn syrup — and are using so much of it. A low-fat, fruit-flavoured yoghurt, for instance, can harbour ten teaspoons of the fructose-based sweetener in one pot. A can of soft drink can contain as much as 13 teaspoons.
Scientists are now growing increasingly worried about fructose syrup’s health effects, because although it contains around the same number of calories as cane sugar, the body does not metabolise fructose syrup in the same way.
It places a far greater load on the liver, which, in turn, prompts a range of problems, including raised levels of fat in the bloodstream.
In August, a U.S. study published in the Journal of Clinical Endocrinology & Metabolism found that adults who consumed high fructose corn syrup in fizzy drinks for two weeks as 25 per cent of their daily calorie requirement had increased blood levels of cholesterol and fats called triglycerides, which are linked to an increased risk of heart disease.
Fructose may also cause liver damage, the U.S. study found. As Dr Kimber Stanhope, who led the study, explains: ‘Fructose overloads the liver. It then gets turned into liver fat, which then increases blood triglycerides, cholesterol and the risk of cardiovascular disease.’
High levels of fructose intake has been linked with the formation of beta-amyloid plaques in the brain, which are often seen in people with Alzheimer’s
She adds that fructose may also increase the risk of diabetes in this way.
‘The extra liver fat may cause the increased insulin resistance we see in people consuming fructose.’ Insulin resistance is linked to a higher risk of diabetes.
Fructose may also make you more prone to obesity. For example, laboratory research by Princeton University this year concluded that ‘long-term consumption of high-fructose corn syrup resulted in abnormal increases in body fat, especially in the abdomen’.
Such abdominal fat may raise your risk of heart disease and stroke.
Professor Bart Hoebel, who led the study, says: ‘Some people have claimed that high-fructose corn syrup is no different to other sweeteners when it comes to weight gain and obesity, but our results make it clear that this just isn’t true.’
High blood pressure is another danger, say researchers at Imperial College, London. The study, published in the journal Hypertension earlier this year, showed that people’s blood pressure rose significantly for every extra sweetened drink they consumed per day.
Dr Ian Brown, one of the researchers, says fructose may reduce nitric oxide levels in the bloodstream. This chemical is vital for keeping blood vessels healthily dilated.
Professor Richard Johnson, who led the University of Colorado study, was moved by the seriousness of this result to declare: ‘Excessive fructose intake should be considered an environmental toxin with major health implications.’
Perhaps even more worrying, research by Cambridge University suggests fructose may be helping to fuel rising levels of dementia.
Laboratory studies have linked high intakes of fructose with the formation of beta-amyloid plaques in the brains of animals. These plaques are frequently seen in people with Alzheimer’s.
In the U.S., concerns over risks of high fructose corn syrup have led to it being branded ‘the devil’s candy’ — even Michelle Obama has declared she doesn’t want her daughters eating it.
In response, its makers, the Corn Refiners Association, are trying to rebrand high fructose corn syrup as ‘corn sugar’.
This attempt to camouflage the product has prompted a high-level legal case in the U.S. courts –launched by makers of traditional cane-sugar sucrose who don’t want to be sullied by high-fructose corn syrup’s worsening reputation.
However, British health authorities seem unworried and unwilling to accept responsibility.
The Food Standards Agency says: ‘The syrup is not classed as an additive. It’s just thick sugar. It’s not even classed as a novel food, so it is an issue about nutrition rather than food safety.’
The agency says any food-safety concerns should be the Department of Health’s responsibility. But the latter says the former should be regulating it.
So how can British consumers keep an eye on their intake of high corn fructose syrup?
The problem is that it’s listed under confusingly different names on food labels — it can be known as glucose-fructose syrup, isoglucose and maize syrup.
The food-makers’ Food and Drink Federation does not believe there are problems with labelling, as it ‘fits with current EU legislation’. It adds: ‘High-fructose corn syrup is not widely used in the UK’.
But a quick check at my local supermarket shows ‘glucose fructose syrup’ and fructose are ingredients in many products including: Muller Light Vanilla Yoghurt, Yoplait Petits Filous, Mr Kipling Almond Slices, Bakewell Slices and Victoria Slices, Lucozade Energy drink, Carte D’or ice cream and McVitie’s Hob Nobs, Ginger Nuts and Jaffa Cakes.
As Helen Bond, of the British Dietetic Association, says: ‘There are a lot of frightening trials out there about the potential effects of high fructose corn syrup. What we need, though, is more scientific work.’
In the meantime, it is surely wise to err on the side of caution.