Fructose - A Debate

Health & Body
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Yes, the PMC paper is very good, I have posted the abstract here.

“The consumption of fructose has increased tremendously over the last five decades, which is to a large extent due to the development of high-fructose corn syrup (HFCS), a commercial sugar additive that contains high amounts of free fructose. HFCS is often added to processed food and beverages partly because it is a powerful sweetener but even more so because the production is cheap. Although fructose in combination with fiber, vitamins, and minerals, as present in fruits, is a healthy source of energy, isolated fructose, in processed food products has been associated with several health disorders such as insulin resistance and hypertension. Apart from its metabolic consequences, a growing body of literature suggests that free fructose can also affect neuronal systems. High-fructose intake may on the one hand affect central appetite regulation by altering specific components of the endocannabinoid system. On the other hand, it appears to impact on cognitive function by affecting phosphorylation levels of insulin receptor, synapsin 1, and synaptophysin. The present report reviews the recent evidence showing a negative effect of free fructose consumption on central appetite control, as well as cognitive function.”

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Interesting discussion, thanks for all the comments so far.

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Interesting point in that article:
2. Added Sugar is High in Fructose, Which Can Overload Your Liver
…

Keep in mind that all of this does NOT apply to fruit. It is almost impossible to overeat fructose by eating fruit.

And the point I made earlier is there too:

Bottom Line: For people who are inactive and eat a Western diet, large amounts of fructose from added sugars get turned into fat in the liver.

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Hi @jepc,

Diets since the evolution of human have included the gorging fruits when in season and available. In the hunter gatherer period, the diet was principally meat, fruits and honey. These fruits and honey contained significant sugars and calorific value to the peoples at that time. When such were not available or scarce, they (principally female and children) then foraged the landscape for fallback foods which had a significantly lower calorific value but was nutritious enough until preferable food sources were readily available. This popular National Geographic story provides more infornation. There are also many researchers who have also studied their diets from paintings, crypts, archaeological digs and also using that which currently exists in remote tribes throughout the world that recently have still huntered and gathered, that concur with this.

Also, many fruits have not changed much as a result of breeding in the past century as many fruits have long generation times (can be uo to 7 plus years before results of a breeding trial are known. There are some fruits such as berries which have shorter generation periods (year or less) and have been subject to greater modification through breeding. Strawberries is a good example as it is now quite different to that in the wild.

The early days of agriculture, fruits which were eaten regularly historically and easily grown were also farmed. This is confimed by many papers on the subject and is summarised here.

Expansion, intensification and mechanisation of agriculture lead to more efficient production of all crops including fruits. It has allowed more easy access to a greater range or fruits than has occurred in the past (namely, fruits now can be those sourced half a country/world away rather than those abundant in the locality). This has been the main change in the modernisation of agriculture, including fruit production. For example, one can now get cherries most of the year either sourced from Australian orchards or those on the northern hemisphere when out of season here.

If one also looks at the diet of apes, which are a close relative to homo sapiens and are are still hunters and gathers, they consume significantly more fruits and honey than modern humans.

Whilst there is an argument about the overconsumption of sugar through the relatively recent invention of highly processed foods, one can’t ignore the facts that the human digestion system has evolved with a diet containing considerablr quantities sugar. While not having medicial background, I understand that the insulin production in the human body is a result of evolution and exposure to sugar in the diet…the way the human body deals with blood glucose. Humans would not have such a evolved insulin system if humans had not been exposed to sugar over 10s thousands of years.

The issue in relation to processed foods is the sugar has no real nutritional value, only calorific value. It is also very easy to consume, is readily available and added to most processed foods (along with salts, preservatives etc). I beleive that this has been the greatest change to human diets since the worlds industrialisation, and this change has been rapid not allowing natural evolution to catch up.

It is also worth noting that fruits on the other hand have significant nutritional value and contain compounds which are essential to human life and health.

Also, Dr Lustig has not carried out his own research on much what he believes. He has read many others research papers and based his own beliefs on what he has read and his own observations. He acknowledges this himself. The article he has coauthored is " What is metabolic syndrome, and why are children getting it?",

From the information available on the net, Dr Lustig also does not endorse the restriction of fruits containing sugars (inc. fructose). This concurs with the advice of most nutritionists which I have read.

His grief appears to be about added sugars, not natural sugars…but some of the information/communications from him are somewhat confusing. Claiming that sugar is toxic is alarmist and does not recognise the part sugar has played in human diets historically - since the hunter and gatherer days.

I also understand from my own reading is that fructose consumption has increased dramatically in the past 30 years, ever since the Japanese found a way to covert corn starch into fructose (to create corn syrup). In the US corn syrup is a very cheap sweetener and used in many processed foods as the primary sweetener (unlike in Australian processed foods). An example is soft drink. In the US, corn syrup is often used as the primary sweetener whereby in countries such as Australia, it is cane or beet sugar.

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I agree @gordon and as I have mentioned before the eating of fruit is not the problem. It is the 1) adding of sugars to foods that is creating much of the problem + 2) a more sedentary life for many of us that means when we consume energy in foods we store excess typically as fat. Over consumption of any food is not a healthy lifestyle choice and if we eat more kilojoules of energy than we need even if it is not sugary then we will get fat.

Sometimes we eat more because our hunger signals are not being quieted and there is mounting evidence as pointed out in the last article that fructose can play a part in this what I will term mis-signalling of satiety. So the combined effect of more kilojoules and no easing of hunger signals is a deadly double act and this comes with an added hit of missing out on other necessary nutrients and fibre that come with eating a well balanced diet that includes unprocessed fruits and vegetables.

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I also recall seeing something recently that the issue is not consumption of sugar by itself as most of us can’t tolerate high sugar intake. The problem arises when sugar is combined with refined fats and oils. The human body seems to not recognise high sugar intake when sugar is combined with fats/oils. There is supposed to be a ‘perfect’ sugar/fat ratio which suppresses the normal human response of stopping its intake…and I also recall that ice cream has this ‘perfect’ ratio which allows its ready over-consumption. Many other ‘treat foods’ such as cakes, chocolates etc are within reach of this perfect ratio.

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Having just read the National Geographic article all I can say is that it is a typical American “puff piece”. It contains no proper scientific study and much of it is anecdotal. Certainly none of it falls into the category of “causal medical inference”.
Much can be said of the other article mentioned.

One thing is certain, until recently there was never enough fruit or honey for humans to “gorge” on them. They were always luxury foods that were sporadically available, and honey was only available in extremely small quantities. Many species of bees do not even produce honey. It is only the farmed European bee that now produces large quantities of honey. Despite what has been said elsewhere, most native fruits consumed by our ancestors were, by our taste standards of today, quite bitter and contained a very large percentage of fibre.

Whilst apes do eat fruit, in most cases this is not the fruit that you or I would eat. To us it would tase disgusting, the only exception is a few of the figs. Think of the figs on a Morton Bay Fig and I think you get the idea of the type of fruits that apes etc have to eat.

In discussing “sugar” I must repeat that we have to specify which sugar we are talking about. I will do some research on this, however from memory it is the way that fructose stuff up the insulin that is part of the problem. In other words the insulin is there for glucose, when you stuff up the natural body processes with fructose you cause problems with the insulin in the body.

Certainly processed food is a problem because not only does it have lots of fructose in it, it has less fibre in it.

With regard to Dr Lustig, he has been involved in many many studies over the years and people would be well advised to contact him for a list of references. Of course there is no problem with having a few pieces of fruit per day, but gorging on the stuff will take you down the same path as ingesting large amounts of fructose by other means.

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The problem is not just about sugar combined with fats and or oils, though this does compound the kilojoule intake. Many of the studies actually looked at high sugar content products that have little or no added fats/oils. The last article I linked to looked at Fructose and specifically in some of the referred to studies they looked at high fructose drinks that had/have negligible fats/oils and they were able to correlate just the fructose consumption to the evidenced problems.

From their conclusions:
“Although not all studies come to exactly the same conclusion, sufficient evidence has accumulated over the last 10 years to indicate that fructose, in certain concentrations and mainly in males has a significant impact on brain and cognitive functions. On the one hand, fructose intake affects appetite control by increasing ghrelin serum levels and hypothalamic CB1 mRNA, and decreasing the activation of brain satiety centers. On the other hand, it leads to brain insulin resistance, impaired learning and memory, and reduced neurogenesis (Figure ​(Figure2).2). Despite some contradictory results, care needs to be taken with respect to the intake of processed foods and beverages since recent tests showed that the free fructose content in popular soft drinks is still increasing, with some beverages containing up to 50% more fructose than glucose (3).”

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I have carried out a literature search for his articles and there is very limited number of journal papers he has written or co-authored on the subjects he now advocates. He however has written many popular articles for books and the media. These don’t constitute peer reviewed scientific research and are his beliefs/opinions.

In relation to bees, there are numerous bees in the Apis genus that produce honey and native to various parts of the world, including Africa, Australia and Asia. Indigenous peoples have used such honey as a part of their diets for many (10s) thousands of years…esp. as in the case of Australia where native bee hives were regularly raided for its honey. Same happened in other parts of the world and still occurs in tribal areas in Africia.

It is also worth noting that scientifically, it is beleived that the purpose of fruit for flowering plants is to make it attractive for birds and animals to consume to assist with the seeds distribution. A number of plants also require the seed to pass through the digestion tract of an animal to assist with its germination (passing of the seed means that the consuming animal would have most likely moved away from the parent tree). A seeds distribution is key to reduce competion with the parent tree by germinating away the parent. Competition can significantly limit the survival of plant species in the wild.

Flowering plants evolved over millions of years to have attractive fruits with an encased seed to increase the likelihood of the fruit and seed being eaten. Sugar (glucose, fructose and in other forms) in these fruits is attractive to both birds and mammals and the sweeter the fruit, the more likely the fruit would be consumed and then distributed. Plants have evolved to be sweet and contain sugar particulrly where the plants have to compete with other species in ghe same locality (e.g. in a rainforest where a fruit needs to ‘standout’ to be consumed and seed distributed).

In relation to fruits and honey being a luxury food for hunters and gatherers, this goes against much of the published information on the matter. Fruit, honey and meat were the primary source of nutritious foods. This was the case as it was nutritious, highly desirable to eat due to taste and readily availble for significant periods of the year, especially when the hunter and gatherers were nomadic and moved to follow the seasons to areas where they had learnt such foods to exist. They also actively searched for bee hives and followed migtating animals for their meats.

During periods of drought or other unfavourable conditons (such as walking through open savana), other less favourable foods sources were used as the preferred foods were unavailable or in low supply.

Agriculture changed this as people were able to grow their own foods removing on the require to move and find food.

As outlined above, humans have had sugars (fructose, glucose, dextrose etc) in their diets since their evolution, the recent change has been over consumption due to added (or maybe should be hidden) sugar in processed foods.

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Brendan Mays, CHOICE Staff.
Please Brendan, can we have some sort of moderation here.

a) I have just done a Google Scholar search for RH Lustig and there are many many papers listed on the issue of sugar, obesity etc.

b) Australian Aboriginal people are greatly affected by the modern high fructose diet. Obtaining honey from native Australian bees was very difficult and then only in tiny amounts.

c) Almost all seed distribution is done by birds, some is done by mamals etc but the driver is not fructose. Think of lilly pilly fruit, we find it tart. We are talking about relative sweetness here. What we consider tart and/or sour still contains some sugars and this is what was eaten (in small amounts) by our ancestors. Not cherries, plums, apricots, apples, oranges or the like.

d) Fruit, honey and meat were not “the primary source of nutritious” foods for hunter gatherers. They would have starved if they had to rely on these foods. There is absolutely no evidence to support the notion that they survived on fruit, honey and meat.

e) We all know that many species of bees do produce honey, however the bees made it very hard for their hives to be raided, and all but the modern European bee produce relatively small quantities of honey.

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Hi @jepc,

This is a forum for open debate, among other things. We’ll remove or edit comments that revert to personal attacks, but otherwise everyone is generally welcome to share their opinions. As I mentioned above, I would like to encourage Community members to reference their sources or explain their rationale as it tends to improve the discussion. Of course we’re all aware of Google and can look things up ourselves, but including a link saves time and reduces potential confusion. One additional point I can add is that at a certain point I would also encourage Community members to ‘agree to disagree’, as we intend this forum to provide positive experiences rather than upsetting people.

From my point of view, this has been an interesting and useful topic. We have the utmost respect for those willing to discuss these important issues that people are clearly passionate about, so thanks again for the comments and conduct so far.

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a. Here is one such search on google scholar search results…while there are many links most are not peer reviewed scientific artiles.

b. There is no denying that humans, including aborigines have long term health impacts from high fructose diets. There is a difference between a modern high sugar/fructose diet and historical diets which also contained fructose. Aborigines regularly harvested native bee hives to gain the hives honey. Such has been documented by many anthropologist. Here is one such example.

c. Please read my post about flowering plant evolution. Many fruits have evolved to be sweet to assist with seed dispersal. Humans from huntering and gathering have harvested such fruits as a food source. Lilly pilly fruit is not one I am aware of being documenteded as being important historically in the human diet. Many fruits which are historically important are those which have evolved to be sweet .

d. Hunter and gatherers did not survive solely on meat, fruit or honey. Such is recognised as the primary foods of hunters and gatherers. As iindicated above, they also ate other foods. These included grains, plants, root vegetables etc, however their diet primarily was as outined and noted by many anthropologist. Here is one such article that discusses the high animal food diets.. Here is one of many articles about diets of hunters and gatherers.

e. Please undertake your own research on the Apis genus (honey bees) and the harvet of honey by African hunter and gatherer tribes people. One will see the importance of honey in their diet, when the honey was available. Honey volumes do fluctuate throughout the year and is dependent on temperature, what is flowering, the type of bees etc.

In my opinion, Dr Lustig is alarmist as he broad brushes the term sugar (fructose) is toxic without recognising humans have consumed sugar/fructose safely for generations. The danger is overconsumption of sugar (inc. fructose) no differently to the overconsumption of any foods (such as red meat which has been shown to correlate with longterm health problems). Stating red meat is toxic would be equally alarmist, especially when the human diet has involved red meat since huntering and gatherering.

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Evidence, please.

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All the evidence is contained in the videos posted in the thread “Fructose is Dangerous - A Debate”.
You have asked this question before and you have been answered before.

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Fructose consumed by eating fresh fruit is not the danger our ancestors consumed it in ‘in season’ whilst swinging from the trees (apologies to creationists). By eating fruit in season we are also eating essential trace elements vitamin and fibre whilst consuming and the qty of fructose that could be consumed in any sitting was determined by the volume of fruit that was eaten, which is limited because quickly the stomach of the eater would be full.

The real danger is modern fructose which is created in factories by breaking down starch like corn syrup and used as a substitute for and largely replaced sucrose in most processed foods. Why do they do it because corn syrup comes from broad acre cropping it is therefore plentiful and cheaper and incidentally fructose is much sweeter than sucrose.

The body handles sucrose and fructose molecules differently, sucrose it recognises and largely converts to blood sugar for instant energy needs, fructose is largely converted to body fat reserves so the animal can survive the long lean winter when little food is around living of its fat until the next growing season and the fruit becomes available again.

If you want a fairly balanced documentary see the SBS/ABC doco ‘The men that made us fat’ it studies the relationship between the replacement of sucrose with fructose in processed foods and the rising obesity crisis in the western world.

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@Fred @jepc The video is interesting and emotive but I believe Fred is after peer-reviewed scientific literature, which is also available on this topic (and some links are posted here already as you’ve pointed out @jepc).

I have a point of interest that perhaps can be entertained here. There’s a study that suggests that High Fructose Corn Syrup is not used much in Australia, but this study has since been widely discredited due to its reliance on assumptions based on outdated FAO data (to my understanding). So is there any new reliable data or information on this point? I am trying to understand when Australians would access added fructose in isolation - as in without other added sugars.

To be clear, the current CHOICE position is to target all added sugars with our campaigning, but let’s say hypothetically we were to make a point about HFCS - a key factor in Lustig’s work - is it used prominently in Australia? Is this an important point to consider or not?

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No, the videos you posted contain opinion. As I said earlier, evidence requires peer reviewed research posted in reputable scientific journals.

Given that it would be a tremendously important public health issue, if what you claim is true there should be vast amounts of evidence for it. If you posted that evidence, and it confirmed your position, there would be little, if any, need for further discussion and bothersome skeptics like me would thank you and shut up. That you steadfastly refuse to provide any evidence could be interpreted to indicate that it doesn’t exist.

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Hi @BrendanMays,

My understanding is Australia doesn’t produce much HFCS as it has a bountiful supply of equally cheap/cheaper sugar, that being from sugar cane.

It may be worth looking at the Credit Suisse report which this website used and sourced data…click on the link on the page.

My understanding is that Australian food manufacturing has based it sweetener around cane sugar, but does not prevent HFCS goods being consumed. This consumption through imported foods where HFCS is the base sweetener or the import of raw HFCS for use in food manufacturing.

As more processed foods are imported, the risk of HFCS in foods increases. Especially from countries which produce significant quantities of HFCS (as shown in above link) and use it as a food additive.

Maybe ABS or the relevant Commonwealth agency may have data about raw HFCS imports. Such would give an indication of use in Australian food manufacturing.

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Every slide used in Dr Robert Lustig’s talks has the scientific source for the statements he makes. All the references are there if you want them. I am not paid to do a university level literature review of Dr Lustig’s work, however I have written to him asking that he supply CHOICE with this. The videos do not contain opinion, many of them are presented at Stanford University and are a lecture style presentation.

One thing that is ruining this debate is the same style/tactics used by the tobacco industry to debunk those who were trying to highlight the problems of smoking.

Since this is how the debate is going to be conducted I will no longer waste my time with CHOICE. I would, however, encourage others to watch the videos and chase the science.

I am just thankful that I didn’t join a discussion on climate change or “clean coal” which are other subjects which bring out the deniers.

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Hi @jepc,

There are two issues which have been raised in this stream of posts,

The first being that the simplified statement by Dr Lustig that ‘fructose is toxic’. This simplistic claim can easily be dismissed by evidence such as much of that outlined above.

The second is over-consumption of sugars, including fructose, can lead to long term health problems. This is the basis of the Choice campaign for better food labelling. It is well known that over-consumption has been exacerbated by the addition sugar, including fructose, in processed foods which makes average sugar intake significantly higher than has occurred historically. Sugar makes food more attractive in relation to our taste receptors. This fact is undisputable and undeniable.

If Dr Lustig was not alarmist and took the second issue as his approach, then the above stream of posts would have been very different and any criticism against him substantially diminished. I believe that it would likely have been widely supported rather than criticised.

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