Greg Dixon

Greg Dixon is deputy editor of Canvas.

Is sugar toxic?

It used to be that sugar was the sweetest, most useful thing in our larder, a crystalline ambrosia that could make almost any food taste better and last longer. But things have gone sour. Sugar is now the centre of a rancorous war with allegations it’s toxic, addictive and a key contributor to the global obesity epidemic. Greg Dixon examines the bitter battle over whether too much sugar is slowly killing us

Candy can be a killer. Photo / Thinkstock
Candy can be a killer. Photo / Thinkstock

A tale of two stores

At the supermarket, temptation is always on special. Depending on the week, it's just $5 for four candy bars, or as little as $6 for 4.5 litres of soft drink, $3.89 for six cupcakes or $3.99 for 3 litres of Just Juice. Temptation nearly always comes sugar-coated.

And there's no escaping it. At the supermarket temptation chases you to the door. As you stand in line waiting to pay your five bucks for your four bars, all you can see is sugar, sugar and more sugar: bags of sweets, more bars of chocolate, lollipops, gum and more - for there are myriad ways in which sugar is packaged for our impulse purchase.

Across town, bookshops are flogging sugar too. On the shelves in the health and food sections you'll find an ever-expanding number of authors damning sugar to hell in the likes of How To Beat Sugar Addiction; Sugar Blues; Salt, Sugar, Fat; Sugar Nation: The Hidden Truth Behind America's Deadliest Habit and the Simple Way to Beat It; The Complete Sugar Detox Program and Fat Chance: The Bitter Truth About Sugar ...

If you were searching for a sign of what sugar now is, you could find no simpler illustration than this tale of two stores. Sugar, once the sweetest thing in our larder, the almost guilt-free ambrosia that makes food taste better and last longer, so cheap and so ubiquitous, has become the new front, the most bitter battle in the ever-widening food wars.

The case for the prosecution is long on allegations about sugar: that it is "addictive" and "toxic", that it contributes significantly to type 2 diabetes, Alzheimer's disease, dental decay, cardiovascular disease, hyperactivity, something called "metabolic syndrome" and - most damning of all - the global obesity epidemic.

Look at the evidence, says the prosecution. There is more sugar in our food than ever before - not just confectionary, one anti-sugar researcher claims 80 per cent of all of America's processed food contains sugar - and there are more obese people in the world than ever before, in fact the number has doubled in less than three decades. According to the World Health Organisation (WHO), there were, in 2008, 1.5 billion overweight adults and around 400 million who were obese. WHO expects these numbers to rise to 2.3 billion and 700 million by 2015. There are now, can you believe it, 30 per cent more obese people in the world than those who are undernourished.

Sugar is bad for us, then?

Well no it isn't, say its champions. The case for sugar's defence claims that it can be "enjoyed" as part of a "nutritious, balanced and enjoyable" diet, that it has no negative influences on any disease - "other than a partial contribution" - that it's not addictive and that, in fact, the Western world's intake of sugar has actually declined in the decade to 2008.

If you're feeling a mite confused, you should be. Both sides claim the science proves they are right. Both sides say the other is being selective about the evidence for their case.

Both sides are utterly convinced they are right. Does it matter? It does when we look in the mirror.

Me, bad?

We are fat, and getting fatter. New Zealanders are the fourth most obese and overweight population in the world, according to the OECD. University of Auckland researchers estimate 35 per cent of all New Zealanders aged over 15 - that's more than one in three of us - are overweight. Worse, a quarter of us are officially obese - that is, our body mass index (BMI), which is calculated by dividing weight by height, exceeds 30 kg/m2 - while Maori and Pacific New Zealanders have obesity rates of 44.4 per cent and 62.1 per cent respectively. One in five of our children is overweight, according to 2006/7 figures.

The price of our ever-expanding waistlines is getting fatter too. Back in 1991 the annual cost of obesity to the country in healthcare was $135 million. Late last year University of Auckland researchers announced it was now $624 million - 4.4 per cent of all our health spending. (You can add another $98 million-$225 million a year, depending on methodology, for lost productivity due to obesity).

The cost to the individual is even higher of course: being obese means you're more likely to die sooner, though it isn't obesity that kills you. What gets us is a group of chronic metabolic diseases - including type 2 diabetes, high blood pressure, heart disease and blood fat disorders - which together are called "metabolic syndrome".

"On the death certificate the medical examiner doesn't write down obesity," writes American anti-sugar campaigner Dr Robert Lustig in Fat Chance: The Bitter Truth About Sugar, "instead it's 'heart attack', 'heart failure', 'stroke', 'diabetes', cancer', 'dementia', or 'cirrhosis of the liver'. These are the diseases that 'travel' with obesity ... obesity is not the cause of chronic metabolic disease. It's a marker ... and it's metabolic disease that will kill you."

The hand-wringing about all this has been going on for years - but so has the argument around why it is we've been getting so much fatter.

The established "cause" of obesity is simple enough, according to the Ministry of Health.

"Overweight and obesity are the result of a positive energy balance - that is a long term excess of energy intake (food and beverage consumption) over energy expenditure (basal metabolic rate [what we burn at rest] and physical activity) ... Most experts believe [the rapid rise in obesity numbers] is due to living in an increasingly 'obesogenic' environment - one that promotes over-consumption of food and drinks and limits opportunities for physical activity."

Under this model the world is full of sloth and greed: of people who eat too much and whose only workout is the walk to the fridge. In other words, if you're overweight or obese it is your fault. You choose to be fat.

Toxic: the science of sugar according to Robert Lustig

By his own admission, Lustig, child obesity expert, researcher and author, was the first. "In terms of the sugar toxic thing," he says by phone from his office at the University of California, San Francisco, "I am the first one to call it. But I always qualify it, I always say that it is a chronic not acute [illness], you don't keel over from it, it ... depends on dose, how much you're absorbing and how much hits your liver and how fast."

While far from a lone voice on our problem with sugar, Lustig, a professor of pediatrics in the division of endocrinology, has certainly become one of the most visible anti-sugar campaigners since an hour and half-long video of his lecture Sugar: The Bitter Truth was uploaded to YouTube in 2009. It has since been viewed nearly 3.8 million times and Lustig has since appeared on America's 60 Minutes, on the Colbert Report (Colbert dubbed him "Dr Buzz Kill") and on Alec Baldwin's New York radio show, Here's The Thing, to name just three of his most high-profile media appearances. He also lectures widely around the world. He published Fat Chance in New Zealand in February.

"The bottom line is that I now have four full-time jobs, I used to have two," he tells me. "I used to be a full-time clinician and a full-time researcher. Now I'm a full-time clinician, a full-time researcher, a full-time policy person and a full-time media person."

We will come to sugar shortly. But on the matter of obesity, Lustig argues in the first part of Fat Chance that it is not a function of personal responsibility, of our sloth and greed. "The obesity pandemic is due to our altered biochemistry, which is a result of our altered environment."

Does obesity equal the metabolic diseases like diabetes and heart disease that are killing us? The answer is no.

"Twenty per cent of obese people are completely metabolically normal," says Lustig.

"They will have a completely normal life and die at a completely normal age. They will not cost the taxpayer anything: they are just fat. Conversely, 40 per cent of the normal weight population have the same metabolic dysfunction that the [majority of the] obese do. They have metabolic syndrome and they manifest the same diseases: type 2 diabetes, hypertension, heart disease, cancer, dementia. These are all diseases that occur in normal weight people too. And they have the same metabolic dysfunction, they have insulin resistance also. They are just normal weight. What this demonstrates is that obesity is not the cause of metabolic syndrome. What it is demonstrates is that obesity is a marker for metabolic syndrome. Yes, there are more obese people with metabolic syndrome than normal weight, 80 [compared] to 40 per cent. But normal weight people get this too because normal weight people are exposed to the same toxin that cause metabolic syndrome."

That toxin is sugar, Lustig says.

Just why sugar is a poison - the Voldemort of the story, he says - is complicated. Sugar is a carbohydrate. Much of the sugar we eat (table sugar for example, or in fruit) is called sucrose, consisting of half glucose and half fructose. Fructose is much sweeter than glucose and is metabolised by the liver (while glucose is metabolised by all our cells).

Excess consumption of fructose, Lustig says, does two things. First, because the liver can't handle the heavy load and the rate it's arriving at, it's forced to convert fructose into liver fat (and other visceral or organ fats), which, secondly and ultimately, leads the pancreas to produce much more insulin than our body needs, which in turn encourages more fat storage.

"Insulin is the hormone that drives energy storage and we've known about that forever.
But we didn't know that insulin was the hormone that blocked leptin-signalling in the brain. Leptin is the starvation hormone. When your brain can't see leptin, your brain sees starvation [so we eat more].

"So we had learned enough about leptin to make it very clear what the problem was and we knew enough about what insulin did to make it clear that this was the problem. Then the question was, okay, insulin is the bad guy, what's driving the insulin? Because everybody around the world now is releasing two to three times the amount of insulin than they used to. The question was: what's driving that? That's when it became obvious that sugar was the answer."

But hold on, whole fruit and some vegetables contain sucrose, and therefore fructose.

Doesn't that make them equally bad? Well no, says Lustig, because sugar in whole foods comes with a healthy serving of fibre, which slows down digestion and, therefore, the rate that we metabolise the fructose, the toxic Voldemort. Processed food on the other hand, when high in sugar, often has little or no fibre.

Lustig says there is scientific evidence for this sort of feedback loop, in which sugar, an addictive substance, makes you hungry and makes you fat at the same time - because it alters our biochemistry. The mainstream health message is that if you reduce your calorie intake and up your exercise - if you burn more calories than you eat - you can avoid weight-gain, obesity and the metabolic diseases that travel with it, but Lustig says the bio-chemistry means this mantra is a fallacy.

His ultimate message is that - because of fructose - sugar's calories are not like other calories. "A calorie is not a calorie," he writes in Fat Chance. "Rather, perhaps the [health industry] dogma should be restated thus: a calorie burned is a calorie burned, but calorie eaten is not a calorie eaten. And therein lies the key to understanding the obesity pandemic. The quality of what we eat determines the quantity. It also determines our desire to burn it. And personal responsibility? Just another urban myth to be busted by real science."

Science fact and science friction

The trouble is that the "real science" around sugar is far from settled, according to others.
The sugar industry in America has, rather predictably, been vociferous in its objection to Lustig's conclusions. In New Zealand, the Sugar Research Advisory Service (SRAS) - funded by Australian and New Zealand sugar producers - was set up in 2002 to "provide the scientific facts on sugar and health from Australian and New Zealand experts", which include nutritionists, dieticians and university researchers. If, as I did, you contact the SRAS, however, the reply comes not from a university but from a public relations company, Network Communications, a firm which also represents Chelsea Sugar.

Network's Donnell Alexander, a nutritionist herself, says the views of SRAS "aren't necessarily those of the industry", though the SRAS' views appear to be the same as those of its international equivalent, the World Sugar Research Organisation (WSOA) - a couple of the half-dozen reports Alexander sent through to me before we spoke were from the WSOA, which is also funded by the sugar industry.

The most boisterous of the WSOA papers - in response to a commentary by Lustig and colleagues published in Nature last year - accuses Lustig of "shock tactics", "resurrecting an old hypothesis" and says Lustig's claim that sugar is "harmful at current levels of intake is without foundation".

It also alleges that Lustig makes the "entirely unreasonable" assertion that "sugar consumption is a central cause of obesity", though Lustig maintains extremely forcefully to me that he has never said such a thing. In any case, this is the only time obesity is mentioned in this five-page WSOA document.

Ask Alexander what the driver of obesity is and she says it isn't caused by any one thing that can be fixed to make it go away. "I think that is the main concern that I have with the likes of Lustig's theory. It's a very silver bullet approach: we should just cut out sugar and everything will be fine. I don't believe that would be the case. I think the problem that we have as a society, and it seems to be increasing around the world, is that we don't actually understand what moderation, balance and variety are. And they're really boring messages to people, saying you should consume something in moderation, you should have a balanced diet. It's the dietician's mantra and it's incredibly boring [because of repetition]."

So what of the scientists not advising organisations like the SRAS or WSOA? Lustig says "none of my colleagues have come up with any arguments or scientific data that disproves anything that I have said. For the most part, my colleagues have been in lockstep agreement with what I have said." And certainly nutrition scientists and researchers would seem happy to appear on the same bill as Lustig, as they will at a symposium called "Sugar Drink Free Pacific by 2030?" in Auckland next February.

However, another speaker at this conference on sugar and sugar-sweetened beverages, Dr Lisa Te Morenga from the University of Otago's department of human nutrition, says in her view Lustig is presenting a "plausible theory but not a convincing argument".

"Robert Lustig would say ... that sugar is deadly and toxic," she says over a sugar-free coffee. "He's said that it's worse than alcohol, that it is terribly addictive. I think he overstates the body of evidence that is out there ... I think he really believes in what he is saying and in making the statements he does he's got people thinking about reducing the amount of sugar that we eat - because we do eat too much."

Te Morenga, who also does work for the National Centre for Diabetes and Obesity Research, recently published a study in the British Medical Journal, showing that cutting back on sugar did help the study's subjects lose a small amount of weight. However, she tells me she is not convinced that too much sugar is what is causing the increasing prevalence of the metabolic syndrome.

"Consuming too much alcohol, too many refined carbohydrates [generally the white stuff], too much fat, too much tasty and moreish processed and fast foods, too much red meat, and not enough dietary fibre, fruits and vegetables are also equally plausible factors, and things people can change to improve their health risks."

Getting our just desserts

How much sugar do we eat? Well, according to SRAS spokeswoman Alexander, "sucrose" provides about 9 per cent of New Zealanders' dietary energy, which is about what WHO recommends.

However, the 2008/09 New Zealand Adult Nutrition Survey, the most recent look at what we eat, says our median daily intake of all sugars was 120g for males and 96g for women - less than in 1997, the year of the previous survey. Fruit contributed 18 per cent of this. But the bad stuff - non-alcoholic beverages and sugar and sweets - accounted for nearly a third. Of this total sugar intake, the sucrose content amounted to 55g for males and 42g for females (again less than 1997). As a comparison, there is 38g of sucrose in a single 335ml can of coke and 44g in the same sized can of Fanta.

The Ministry of Health recommends sugar should provide no more than 15 per cent of total energy (WHO recommends 10 per cent). This means that for an average 80kg Kiwi man, about 104g of sugar daily is recommended by the ministry - not much more than two cans of Fanta - and for the average 65kg woman, about 68g.

Comparing these numbers suggest our actual intake of total sugars is a bit higher than what the Ministry of Health recommends - but our actual intake could actually be higher than the Nutrition Survey reports. The University of Otago's Te Morenga doesn't really put much stock in our intake figures because people play down how much "bad" food they eat. "Intake data is not reliable in my opinion and we really only have good data going back to 1989. Sugary foods are one of the food items most likely to be under-reported [because] when asked, people either forget about the sugary foods and drinks they have eaten, or don't want to admit that they have scoffed something perceived as a 'bad' food.

"The latest nutrition survey, 2008/09, would suggest sucrose intakes have reduced slightly since 1997 - despite the prevalence of obesity rising substantially."

Another major problem for working out whether we're eating too much sugar is that there are, as Lustig points out, over 50 different names for it. Te Morenga says sugar can be "disguised in processed foods" - and you may be surprised by the foods that have higher sugar levels too. Consumer NZ recently found 35 kids' breakfast cereals contained too much sugar and that some brands of tomato sauce were 20 per cent sugar, while some barbecue sauces were 33 per cent sugar. Another trap for the unwary is "low fat" foods, which often contain lots of sugar to make them more appealing. Just have a look at the dietary information for "regular" yoghurts and fruit juices.

So, sugar can be where you don't expect it. This ubiquity of sugar is what Lustig means by the "altered environment" which has "altered" our biochemistry. What should we do?

In Fat Chance, Lustig floats a number of ideas around taxation, legislation and education to control sugar in the same way many societies control the use of alcohol and tobacco. This, predictably, has been roundly pooh-poohed by the WSOA.

While taxing all sugary products in general has been raised here, the focus in New Zealand, as evinced by next year's "Sugar Drink Free Pacific by 2030?" symposium, seems to be soft drinks, which, according to the 2008/9 Focus On Nutrition study, is where 15-to-18 year olds in particular get a significant amount (just over 30 per cent for males, 27 per cent for females on average) of the sucrose they consume daily. Taxing sugar-sweetened beverages will certainly be discussed at the symposium.

Elsewhere, as the war of sugar has grown, local and international health authorities and governments have restated their guidelines about reducing sugar consumption. Our Ministry of Health recommendations are pretty vague about how to reduce sugar intake.

It says when preparing food, or choosing pre-prepared foods, drinks and snacks, you should make sure they have little added sugar and you should "limit your intake of high-sugar foods". There are no definitions of what "little" or "limit" mean in this context - other than "have cakes, biscuits, chocolate bars and health bars occasionally" - or what you might do if, as Lustig maintains, sugar, besides having a unique action on the body, is addictive.


Sugar: A glossary

Sucrose: found in fruit and some vegetables. It is also derived from sugar cane and sugar beet to make table sugar. It is found in processed foods with added sugar. Sucrose is made up of glucose and fructose.

Fructose: the sweet part of sucrose, fructose is never found alone in nature although it may be by itself in some processed foods. It is found naturally in fruit and honey. It is metabolised in the liver.

Glucose: found naturally in fruit and plant juices with fructose. When found alone (in rice or potatoes, for example) it is called starch. The body coverts carbohydrates into glucose which is then transported around the body in the bloodstream.

Lactose: found in milk and dairy products.

Galactose: found in milk sugar (lactose).

Total sugar: our diets typically include sucrose, fructose and glucose from whole or processed foods, as well as maltose from starch in brewing and lactose and galactose found in milk and milk products.

Added sugar: sugar added during cooking or manufacturing. A product containing processed fruit could contain both naturally occurring sugar from the fruit and added sugar.

- NZ Herald

© Copyright 2014, APN New Zealand Limited

Assembled by: (static) on red akl_n4 at 31 Jul 2014 15:55:18 Processing Time: 568ms