When a Calorie is More than a Calorie: Fructose The Silent Killer

Next time you are in a crowd, look to your left, now look to your right. Statistically, you will see more overweight individuals than those of normal weight. We are in the midst of a crisis in this country both financially and medically—believe it or not, they are closely related. Obese and/or overweight children have risen dramatically over the past few years now affecting 1 in 3! Yes, that’s a third of the young population. If this continues to grow, childhood obesity and diabetes (cleverly termed ‘diabesity’) will bankrupt our country. Add to that the expected 1.1 trillion dollars going to be spent by the time 2050 rolls around for Alzheimer’s disease (also a preventable disease in at least 50% of cases) and it doesn’t take a financial expert to see where we are headed.

MapleSyrupProductionIt is no mystery how we have gotten to this point—the over consumption of calories, usually from nutrient poor foodstuffs. Among the most consumed is fructose. Commonly found in your home as fruit, honey or high fructose corn syrup, HFCS. Fructose is a non-complex sugar or monosaccharide. As you may have guessed, America is the largest sugar consumer.

Now keep in mind that just because you are normal weight does not mean you do not have diabetes lurking in the background. About 20% of obese patients are metabolically normal and about 40% of normal-weight patients have clear markers of metabolic syndrome. Another way to say this is: obesity is not the cause of metabolic syndrome; rather, it’s more of a symptom.

Although over 80% of our current food supply has added sugar (mostly coming from a fructose derivative), there is not a single process in the body that needs fructose to be obtained from the diet. Sperm use fructose for energy, but it is endogenously made with glucose via the sorbitol pathway.

All sugars are not created equal in their metabolism. Nearly all ingested fructose makes its way to the liver, yet it does not get converted to glycogen like glucose would. Through a series of conversion fructose is made available to the TCA cycle to produce energy. Any left over fructose triggers the formation of new fat cells. This process is called lipogenesis. Unfortunately, the calories of fructose consumed do not match that of energy demand from the body—this causes the TCA cycle to reject much of the incoming fructose and instead of producing energy it also trigger lipogenesis. Fructose will also trigger several other proteins such as PPAR-gamma, which will also stimulate fat production. We can start to see how fructose mimics more of the metabolism of alcohol rather than glucose. This scenario is what leads to poor cholesterol profiles such as elevated triglycerides and VLDL’s. Through the process of lipid production some of the fatty acids accumulate in the liver which over time can lead to fatty liver disease.

This process continues over and over as long as fructose is still present. Through a cascade of events it will eventually cause insulinfruit-15408_640 resistance, which would put more burden on the liver to clean the extra sugar (in the case of insulin resistance, glucose also becomes a potential harmful sugar source). Once this process has begun it remains cyclical—the sugar leads to insulin resistance and the insulin resistance leads to adiposity and adiposity leads to insulin resistance.

So why do we consume so much fructose? Simple, because we are addicted. It has been cleverly added to our food to create artificial dependency. Fructose acts on some of the higher brain centers or “pleasure” centers. Studies have shown an increase in dopamine (one of the pleasure neurotransmitters) when fructose is introduced to the system. Removal of fructose from those “dependent” individuals produces drug-like withdrawal symptoms. Now we cannot transfer responsibility onto the food makers and say they are making us fat—after all we are ones who choose what foods we eat. Sticking with whole non-processed foods would allow us to avoid this entire debacle in the first place, but we will save this argument for another day. What I do have a problem with is the misinformation disseminated down from the food industry. They say that fructose does not cause an insulin spike nor does it lead to elevated HbA1c (a blood marker used for Diabetes). Although both of these statements are correct in their literal sense, if we look at the mechanisms behind the metabolism that fructose causes hepatic insulin resistance, which leads to lipogenesis, and peripheral insulin resistance, we’ll see that these claims are misleading. This is also misleading in that fructose does not raise HbA1c because fructose does not bind to hemoglobin in the same manner that glucose does. These differences do not make fructose benign; but rather a silent killer when relying on traditional medical diagnostics.

High fructose corn syrup has also been know to contain levels of mercury not required to be measured by the FDA. This most likely comes from its manufacturing and conversion process. As if targeting the dopaminergic centers of the brain is not bad enough, fructose also does not trigger the satiety centers letting our body know that we are full. The combination of insatiability and its addictive nature make this substance very dangerous, especially in children.

Image taken from: http://recipes.howstuffworks.com/high-fructose-corn-syrup2.htm

Image taken from: http://recipes.howstuffworks.com/high-fructose-corn-syrup2.htm

As always, not everyone is created equal. Depending on your current energy status and activity level you may be able to handle a different percentage of fructose than another. As always there are genetic factors that need to be accounted for as well. It is important to note that fructose is far more than just a calorie—it can be addictive, easily over consumed, and efficiently be metabolized into byproducts that cause chronic disease. Next time you are at the store, read the label and reject any product with high fructose corn syrup or any of its other synonyms such as fructose, isolated fructose, HFCS-90, and others. Remember, high fructose corn syrup by any other name is still high fructose corn syrup followed with all of its negative side effects.



Works cited:

United Nations General Assembly. Prevention and control of noncommunicable diseases. UN General Assembly. New York, 2010.

Chan JM, Rimm EB, Colditz GA, Stampfer MJ, Willett WC. Obesity, fat distribution, and weight gain as risk factors for clinical diabetes in men. Diabetes Care. 1994;17:961–9.

Abbasi F, Chu JW, Lamendola C, McLaughlin T, Hayden J, Reaven GM, Reaven PD. Discrimination between obesity and insulin resistance in the relationship with adiponectin. Diabetes. 2004;53:585–90.

Weiss R, Bremer AA, Lustig RH. What is metabolic syndrome, and why are children getting it? In: Braaten D, editor. Year in Diabetes and Obesity, 2012. New York: Annals of the New York Academy of Science; 2013.

Hudgins LC, Parker TS, Levine DM, Hellerstein MK. A dual sugar challenge test for lipogenic sensitivity to dietary fructose. J Clin Endocrinol Metab. 2011;96:861–8.

Schwarz JM, Linfoot P, Dare D, Aghajanian K. Hepatic de novo lipogenesis in normoinsulinemic and hyperinsulinemic subjects consuming high-fat, low-carbohydrate and low-fat, high-carbohydrate isoenergetic diets. Am J Clin Nutr. 2003;77:43–50.

Robert H. Lustig. Fructose: It’s “Alcohol Without the Buzz”