1 December 2010

Busting Food Myths with Nicole Senior

Myth: High Fructose Corn Syrup (HFCS) is worse for your health than sucrose (table or cane sugar).

[NICOLE]
Nicole Senior

Fact: HFCS is just another sugar with the same health effects as sucrose. We should be limiting all added sugars to achieve a healthy diet.
In the nutrition world there is always a ‘bad’ food of the moment and right now it is high-fructose corn syrup or HFCS. A preliminary WWW search reveals a litany of dire health consequences from scare-mongering sites including an increased risk of weight gain, diabetes and liver damage. Is there just cause to worry?

HFCS made from American corn is the most commonly used sugar in processed food and drinks in the USA, whereas in Australia it is sucrose or cane sugar (from sugar cane). We use Australian grown cane sugar in our sugar jars at home too, but in the USA beet sugar (from sugar-beets) is the more common household form of sucrose. Sucrose is a disaccharide, meaning it is composed of equal amounts of two monosaccharide (single sugars) stuck together: glucose and fructose. HFCS is made by adding enzymes to corn-starch to convert the starch into its composite monosaccharide sugars glucose and fructose. Honey is also composed of a combination of glucose and fructose monosaccharides. The term HFCS is a misnomer because it doesn’t actually contain high fructose levels. The name comes from the fact that pure corn syrup contains no fructose at all, but treatment with enzymes allows varying proportions of fructose to be obtained. The most common HFCS are 55% and 42% fructose (the remainder being glucose). Sucrose is digested to 50% fructose and 50% glucose. Incidentally, 100% pure fructose has been available for years as an alternative sweetener under various brand names.

What is the GI? Glucose has the highest GI of all the sugars and fructose has the lowest, and this is the reason sucrose (a blend of glucose and fructose) has a moderate GI. Although the GI of HFCS is not available, Professor Jennie Brand Miller from GI News says there is no reason to expect it to be any different to sucrose.

Why is it used? HFCS is widely used because US agricultural policy favours corn farmers and makes imported sugar more expensive. Food manufacturers like it because it is economical, it is liquid and easy to mix, and adds good texture and sweetness to a wide range of foods.

Is it harmful? Digestion of HFCS, cane sugar, beet sugar and honey all yield similar amounts of glucose and fructose during digestion. There is no reason to expect HFCS to have unique effects on health for this reason. Like all simple sugars, these are absorbed by the small intestine: glucose can be used for energy throughout the body whereas fructose is transported to the liver for conversion to metabolic energy. Many of the studies with adverse findings are from pure fructose feeding in animals, and cannot be separated from overfeeding with any sugar, or overfeeding in general. It seems over-eating and getting fat is bad for our metabolic health but it is not due to a specific effect of HFCS.

  • A recent review published in Nutrition Metabolism concludes that “moderate fructose consumption of no more than 50g/day or around 10% of energy has no deleterious effect on lipid and glucose control and of no more than 100g/day does not influence body weight. No fully relevant data account for a direct link between moderate dietary fructose intake and health risk markers”.
  • The American Medical Association calls for more research but says it is unlikely that HFCS contributes to obesity anymore than sucrose.
  • The Huffington Post quoted Michael Jacobson, executive director of the Center for Science in the Public Interest saying sugar and high fructose corn syrup are nutritionally the same, and there's no evidence that the sweetener is any worse for the body than sugar.
  • Even Michael Pollan in his book Food Rules says “high fructose corn syrup is no worse for you than sugar” but then says to avoid it anyway because foods made with it are highly processed.
A recent study published in the journal Obesity found US sodas (soft drinks) made with HFCS were higher in fructose than expected- on average 59% and up to 65%, which is much higher than sucrose: perhaps another reason to give these drinks a miss if you are living in the USA.

While HFCS may not have the best reputation, its adverse health effects are exaggerated. We should regard HFCS as we do other added sugars and enjoy them in moderation within a healthy balanced diet.

Nicole Senior MSc (Nut&Diet) BSc (Nut) is an Accredited Practising Dietitian and Nutritionist. For more information on heart-friendly eating and fabulous recipes low in saturated fat and high on flavour check out Nicole’s books Eat to beat Cholesterol and Heart Food HERE.

6 comments:

Anonymous said...

By defining carbohydrate foods as good or bad on the basis of their glycemic index, diabetologists and public-health authorites effectively misdiagnosed the impact of fructose on human health.
The key is the influence of fructose not on the blood sugar but on the liver.
Fructose passes directly to the liver, where it is metabolized almost exclusively. As a result fructose "constitues a metabolic load targeted on the liver," the Israeli diabetogist Eleazar Shafrir says, and the liver responds by converting it into triglycerides - fat - and then shipping it out on lipoproteins for storage. The more fructose in the diet the higher the subsequent triglyceride levels in the blood.*

*For this reason fructose is referred to as the most lipogenic carbohydrate. Credit for this observation dates to 1916 to Harold Higgins of the Nutrition Laboratory of the Carnegue Institution.

S said...

^ Hmm, I think the point is though, that we generally don't just go and ingest a truckload of pure fructose at every meal, so in moderation it's fine to include HFCS in your diet. Stressing too much about all this is probably worse; high cortisol levels from chronic stress can lead to hyperlipidaemia, increased appeite/cravings, weight gain, high BGLs etc; ironically just the things people are worried about avoiding! ;) Chill people :)

The Test Engineer said...

Hmm ... I am not so sure about your beliefs that HFCS is O.K. Check out Sugar:The Bitter Truth at:

http://www.youtube.com/watch?v=dBnniua6-oM

You will be surprised.

GI Group said...

Re Test Engineer's comment:
“The point of this article in GI News is that HFCS (55 in particular) are probably no worse than sucrose as they both contain approximately the same amount of fructose and have a very similar glycemic (and lipemic) affect. Both should be consumed in moderation. If consumed in excessive amounts they will raise blood glucose and lipid levels. Moderate intake means no more than 10% of total calories from added sugars.

nutrition physician guru said...

The pathway for fructose is entirely different from glucose and sucrose, so we DO have reason to believe the effects are likely different. Basically your comments are GUESSES about reality, not actually measured pathways and outcomes on what happens in the body. The comments by "anonymous" are based in fact - fructose is sent directly to the liver and results in trigylercide formation, leading to highly oxidizing (rusting) molecules. Fructose in nature (apples) comes in small quantities and an apple has low GI index. The chemically generated fructose from corn syrup is used in extremely higher levels than seen naturally, like an apple, and this puts a load on the liver, creating a excess of triglycerides. This also creates a craving of sweetener response in the brain accounting for sodas having an "addictive" quality. Noted in "A Consumer's Dictionary of Food Additive" by Ruth Winter, MS since the intro of HFCS and its increase in use by 1000 percent from 1970 to 1990 in US, the population had a co-incident sharp rise in obesity in US. HFCS is the sole sweetener in soda, and accounts for 40% of sweeteners used in food and drink in US. This trend of coincident increase in obesity is observed to be true of other countries when HFCS sweetened food/drink use increases. The increase use of HFCS in the US (by 1000%)was a greater increase than any other food or food group increase during the same time.

GI Group said...

Re Nutrition Physician - We asked Dr Alan Barclay to respond:
"Again, this is missing the point of the article, that sucrose and HFCS are considered to be nutritionally equivalent because they contain essentially the same amount of fructose and glucose. Metabolically, the source (i.e., fruit, sucrose or HFCS) of fructose should not make any difference as once it is digested and absorbed it all ends up being metabolised exactly the same way. While the well documented rise in HFCS use and its association with rates of overweight and obesity in the USA is interesting and worthy of further investigation it is very important to note that rates of overweight and obesity have been rising around the globe, yet HFCS are primarily used only in the USA due to its surplus corn crop. We have looked at trends in total fructose consumption in the USA, the United Kingdom, Japan and Australia, and found that average consumption of fructose in the latter 3 nations has actually decreased since 1970, unlike the USA, yet rates of overweight obesity have essentially doubled in the UK and Australia over the same period. This research will be published in a scientific journal shortly."