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High Fructose Corn Syrup & HMF
High Fructose Corn Syrup & HMF
By: Ross Conrad

HFCS and HMF aren't all they're cracked up to be for a honey bee's diet.

January 01, 2010

Sweeter and less expensive than sugar, High-Fructose Corn Syrup (HFCS) is responsible for one of the largest changes to the diets of both the average American and the average U.S. European honey bee over the last 40 years. It now accounts for more than half the refined sweeteners used in the U.S. food supply.

Health Issues Related to HFCS

Most of the corn grown in the United States today is genetically modified to produce a toxin to protect it from corn borers and other insects. This pesticide is produced in every cell in every part of the corn plant. As a result this poison also ends up in the final corn-based products that are consumed, including HFCS. Adding to this concern is a corresponding increase in human health issues and degenerative diseases such as weight gain, diabetes, and heart disease that has occurred during the past 40 years and has been linked to the consumption of HFCS by numerous researchers.1, 2, 3, 4, 5 As if all this wasn’t enough, two recent studies found toxic levels of mercury in almost half the samples of HFCS tested, and in about a third of the food products studied which contained corn syrup as an ingredient.6 The most likely sources of the mercury contamination are mercury-containing hydrochloric acid and caustic soda, both of which may be used in the production of HFCS. All of this does not reflect well on the dietary use of High Fructose Corn Syrup.

Health Issues Related to HMF

Hydroxymethylfurfural (HMF) is a compound that is formed when fructose degrades after being exposed to heat while in the presence of an acid. In general, the warmer the temperature, the greater the production of HMF in HFCS with concentrations really jumping dramatically at temperatures of 120°F (49°C) and higher.7 HMF is suspected to play a role in human obesity and heart disease. In test tube studies, high levels of HMF has been linked to significant DNA damage in human cells.8 When HMF breaks down in the human body, it can create substances that are even more harmful than HMF itself.

Industry’s Response

A visit to the Corn Refiner’s Association (CRA) website waxes poetic about the virtues of HFCS with quotes such as 'HFCS is the chemical and nutritional equivalent of table sugar (sucrose). The two substances have the same calories, the same chemical composition, and are metabolized identically.'9 The first part of this statement is basically true given the use of the word 'equivalent' which can mean similar, but not the same. Both HFCS and sugar certainly have approximately the same number of calories and both are pure carbohydrate which means that they are both virtually devoid of vitamins and minerals. For this reason alone, such sugars should be avoided since they do not promote robust health. To state that HFCS and table sugar are 'metabolized identically' is suspect however, given that sucrose is composed primarily of disaccharides and HFCS is composed of primarily mono saccharides. Such statements rely on reports that ignore the large amount of research and the epidemiological correlation showing that HFCS is metabolized differently than sucrose.

The CRA website even compares high fructose corn syrup to honey with the statement '...the saccharide composition (glucose to fructose ratio) of HFCS is approximately the same as that of honey, inverted sugar, and the disaccharide sucrose (table sugar).' This statement may be true with regard to honey, depending on the type of corn syrup you are referring to since HFCS is available in three different formulations. HFCS containing 42 percent fructose is used primarily in processed, packaged and baked goods. Fifty-five percent fructose corn syrup is used by soft drink manufacturers. Finally an extremely sweet, ninety percent HFCS is used in low-calorie 'diet' products. Honey on the other hand tends to be composed of a mixture of primarily fructose and glucose. Given that the National Honey Board lists the fructose range of honey as between 30.91- 44.26 percent the comparison of HFCS to honey may be true, but only between certain types of honey and corn syrup containing 42 percent fructose.10

The Corn Refiner’s Association goes on to attempt to refute all the negative studies and reports on HFCS and hydroxymethylfurfural. They question the quality and accuracy of the studies that point to potential human or honey bee health issues and cite other studies that seem to reach conflicting conclusions with regard to the effects of HFCS. They responded to the mercury contamination issue with misleading statements such as, 'Our industry has used mercury-free versions of the two re-agents mentioned ..., hydrochloric acid and caustic soda, for several years', without referring to the fact that not all members of the industry have made the switch to using the mercury-free processing agents. The CRA will also point to Food and Drug Administration and Environmental Protection Agency approval for genetically modified corn as proof that HFCS made from GM corn is safe for human and animal consumption.

Corn processors would like the public to believe that the fructose in HFCS is the same as the fructose found in natural foods like fruit and honey. Most of the fructose found in fruit and honey is in the form of L-fructose or levulose; the fructose in HFCS is D-fructose which has a slightly different chemical structure. Fresh fruits can contain small amounts of D-fructose but 'the D-fructose in HFCS has the reversed isomerization and polarity of a refined fructose molecule.'11 As a result, the fructose in HFCS is not used as an energy source by the human body because the body does not recognize the molecule and is not able to convert significant amounts of the fructose into glucose.12 Instead the highly refined sweetener is converted primarily into triglycerides and body fat. This is supported by recent research that found that obese people who consumed a beverage containing D-fructose at a meal had triglyceride levels about 200 percent higher than those that drank a glucose sweetened beverage with a meal.13

What’s A Consumer To Do?

All in all, the industry response to the growing concerns over High Fructose Corn Syrup is eerily similar to the tobacco industry’s efforts that deceived consumers into believing that cigarettes were safe and in some cases even healthy to smoke. After looking at the evidence it seems that the prudent approach would be to avoid human consumption of HFCS in all its forms. Food products containing corn syrup that are cooked or heated up before being consumed are especially risky due to the increase in HMF formation. As individuals with free will, we can make such choices for ourselves. Unfortunately, the honey bees in our care do not get to make an informed choice when we feed HFCS to them.

What’s A Beekeeper To Do?

The toxic effects of HFCS have the potential to harm bees as well as humans. Not only does corn syrup contain two types of sugar that are mildly toxic to honey bees; stachyose and farrinose,14 but high levels of HMF have been shown to cause ulceration of the honey bee gut leading to dysentery issues and premature death.

The best food to feed a honey bee is unheated honey. Since both fructose and acids are naturally present in honey, the production of HMF is always taking place in honey and accelerates when honey is heated. As a result the level of hydroxymethylfurfural in honey is sometimes used as a gauge to determine how old a sample of honey is and whether it has been exposed to heat either during processing or while in storage. The international tolerance for HMF in honey is 40 mg/kg (or 4 mg/100g) which can be reached after 230 days at 68°F (20°C).15 The ease of HMF formation in honey depends upon the botanical origins of the honey, with locust, fir-tree, and chestnut honey being among those most resistant to HMF buildup.16,17 In general, honey heated to around 122°F (50°C) experiences a relatively slow increase in HMF. Honey has a high increase of HMF when heated up to about 144°F (62°C), and honey becomes seriously impaired with excess HMF when exposed to temperatures of 180°F (82°C) and above.18

If adequate amounts of unheated honey are not available for feeding bees, syrup made from white cane sugar is the next best thing to use. (see The Honey Bee Diet, May 2009 Bee Culture for ideas on how to improve the nutritional content of cane sugar syrup). If you insist on using HFCS to feed your bees, be sure to purchase syrup that is produced using the enzyme hydrolysis process that tends to result in less HMF ending up in the syrup and avoids the opportunity for mercury contamination as opposed to acid hydrolyzed inverted sugars. HFCS purchased as bee feed should be used up ASAP and stored at temperatures well below 120°F (49°C) in order to limit the build-up of HMF that occurs with time and temperature.

Since the heating of honey is standard practice during honey harvesting and processing, this is something that our beekeeping industry should take a long hard look at. When hot, honey thins out it flows easier through pumps and filters during processing. Heating and filtering delays honey’s natural crystallization process. Unfortunately, heat also tends to change the color of honey. The flavor of honey is affected by heating, and as we have seen above, heat degrades the quality of honey through the increased formation of hydroxymethylfurfural. Considering the growing evidence that HMF is harmful to robust health, beekeepers and honey processors that are concerned with maximizing the quality of their honey will modify their operations in order to use as little heat as possible.

This also means that when used in the kitchen, it is more desirable to use honey in recipes that call for little or no heating, such as salad dressings, dips, spreads, and toppings. What to do if you are a tea or coffee drinker who likes to sweeten your beverage of choice with honey? Luckily you can continue to do so without worrying about HMF’s health effects, since the dilution of the fructose and acids in the honey would prevent the formation of HMF.


1. Bray, G.A., et. al., Consumption of High-Fructose Corn Syrup in Beverages May Play A Role In The Epidemic Of Obesity, American Journal of Clinical Nutrition, April 2004, Vol. 79, No. 4, 537-543

2. Forshee, R.A., A Critical Examination of the Evidence Relating High Fructose Corn Syrup and Weight Gain, Critical Reviews in Food Science and Nutrition, 2007, 47:561-582

3. Hollenbeck, Claire B., Dietary Fructose Effects on Lipoprotein Metabolism and Risk for Coronary Artery Disease, American Journal of Clinical Nutrition, 58 (suppl), 1993, 800S-807S

4. Choi, H.K., Curhan, G., Soft Drinks, Fructose Consumption, and the Risk of Gout in Men: Prospective Cohort Study, British Medical Journal, February 9, 2008; 336(7639):309-312

5. Stranahan, A.M., et. al., Diet-induced insulin resistance impairs hippocampal synaptic plasticity and dognition in mid aged rats. Hippocampus, July 23, 2008.

6. Dufault, R., et al., Mercury From Chlor-alkalai Plants: Measured Concentrations In Food Product Sugar, Environmental Health, 2009 8:2

7. Blaise W. LeBlanc, et. al., Formation of Hydroxymethylfurfural in Domestic High-Fructose Corn Syrup and Its Toxicity to the Honey Bee (Apis mellifera), J. Agric. Food Chem., July, 31, (2009), 57 (16), pp 7369-7376

8. Durling, L.J., Busk, L., Hellman, B.E., Evaluation of the DNA damaging effect of the heat-induced food toxicant 5-hydroxymethylfurfural (HMF) in various cell lines with different activities of sulfotransferases, Food Chem Toxicology, January 20, 2009

9. Corn Refiner’s Association:

10. National Honey Board:

11. Los Altos Health Research Clinic Study conducted by Dr. Gene Spiller. Polarimetry Saccharimetry and the Sugars, Circular C440, US National Bureau Of Standards, by Frederick J. Bates & Assoc., May 1, 1942, taken from Fallon Morell, S., Nagel, R.,Worse Than We Thought, The Lowdown on High Fructose Corn Syrup and Agave 'Nectar' Wise Traditions, Spring 2009, pg. 52, Published by the Weston A. Price Foundation.

12. The Metabolic Basis Of Inherited Disease, McGraw Hill, ISBN 0-07-060726-5, Editors Richard S. Lauffer, Ellen Warren & Donna McIvor, Chapter 5, The Metabolism Of Fructose, and Chapter 12, Some Specific Pathways Of Metabolism Of Carbohydrates And Lipids, taken from Fallon Morell, S., Nagel, R.,Worse Than We Thought, The Lowdown on High Fructose Corn Syrup and Agave 'Nectar' Wise Traditions, Spring 2009, pg. 52, Published by the Weston A. Price Foundation.

13. Teff, K.L., et. al., Endocrine and metabolic effects of consuming fructose- and glucose-sweetened beverages with meals in obese men and women: influence of insulin resistance on plasma triglyceride responses, Journal of Clinical Endocrinology and Metabolism, doi:10.1210/jc.2008-2192, taken from Fallon Morell, S., Nagel, R.,Worse Than We Thought, The Lowdown on High Fructose Corn Syrup and Agave 'Nectar' Wise Traditions, Spring 2009, pg. 52, Published by the Weston A. Price Foundation.

14. Bob Harrison, 'Weslaco Bee Lab and Current Research,' American Bee Journal, 147 (4): 323-326

15. Juarez-Salomo, A., Valle-Vega, P., Hydroxymethylfuraldehyde thermogeneration as honey quality parameter, Tecnologia-de-Alimentos; 30(6) 13-17, 17 ref. NU: ISSN: 0564-6758 accessed on line at

16. Thrasyvoulou, A., Heating Times For Greek Honey’s, Melissokomiki-Epitheorisi, 1997, 11:2, 79-80, Bj. 1997 accessed on line at

17. Kubis, I, Ingr, I, Effects Inducing Changes In Hydroxymethylfurfural Content In Honey, Czec. Journal of Animal Science, 43 (8), 379-383, 11 ref. NU: ISSN: 0044-4847 accessed on line at

18. Ibid


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