High fructose corn syrup worse than sugar, finds study

It is known that both sugar and high fructose corn syrup (HFCS) used as sweeteners affect health.  But a study has now shown that table sugar is the lesser evil of the two.

The study conducted by researchers at the University of Colorado’s School of Medicine in the US suggests that both the sweeteners have different effects on the body in the first few hours after ingestion. Published in the journal Metabolism, the study shows it is the composition of the two sweeteners that results makes the difference and determines how much fructose is absorbed in the blood and its subsequent health impacts.

The difference

Table sugar or sucrose contains equal parts of fructose and glucose bond together as a disaccharide (complex carbs) while the HFCS is a mixture of free fructose (55 per cent) and free glucose (45 per cent). It is this difference in fructose that affects the body.
   
Sucrose is broken down in the gut by sucrase.  This then allows the free glucose and fructose to be absorbed and enter the systemic circulation.  Although sucrase is a fast enzyme, there are studies showing that the activity of sucrase can be inhibited by various factors, including genetic polymorphisms (diversity within a population).  This would then decrease the amount of glucose and fructose available for absorption in the body since sucrose is not being broken down as quickly or efficiently.  This would then result in lower bioavailability of fructose. 

Sugar V HFCS  Table sugar or sucrose contains equal parts of fructose and glucose bond together as a disaccharide (complex carbs) while the HFCS is a mixture of free fructose (55 per cent) and free glucose (45 per cent) Sucrose is broken down in the gut by sucrase. This then allows the free glucose and fructose to be absorbed and enter the systemic circulation. This decreases the amount of glucose and fructose available for absorption in the body since sucrose is not being broken down as quickly or efficiently. This results in lower bioavailability of fructose On the other hand, HFCS does not need to be broken down since it contains free glucose and fructose, and thus can be absorbed immediately. This may lead to fat accumulation and other adverse metabolic effects. With long-term exposure fructose could drive the pathogenesis of various health issues, including obesity and metabolic syndrome

On the other hand, HFCS does not need to be broken down since it contains free glucose and fructose, and thus can be absorbed immediately. “Unlike glucose which is highly regulated, fructose levels are not controlled.  This causes it to be metabolized very quickly resulting in the depletion of ATP (adenosine triphosphate that serves as the source for energy for muscle contraction), which is further broken down into uric acid.  Our lab has shown that this mechanism may be essential in causing fat accumulation and other adverse metabolic effects.  With long-term exposure fructose could drive the pathogenesis of various health issues, including obesity and metabolic syndrome,” explains MyPhuong T Le, of the University of Colorado’s Anschutz Medical Campus Division of renal diseases and hypertension.

The study was conducted on 40 men and women who were given 24 ounces (700 ml) of HFCS and sugar-sweetened soft drinks. Careful measurements showed that the HFCS sweetened soft drinks resulted in significantly higher fructose levels than the sugar-sweetened drinks. Fructose, known to increase uric acid levels, has been implicated in blood pressure, and the HFCS-sweetened drinks also resulted in a higher uric acid level and a 3 mm Hg greater rise in systolic blood pressure.
   
The drawbacks

However the study has its limitations. “The main limitation was that the sucrose in the soft drink was already being broken down.  This prevented us from seeing the effect of sucrase on the bioavailability of fructose.  But since soft drink is a main source of sugar in the Western diet, we believed it provided more social relevance.  Interestingly, even with the sucrose broken down, this study did still find slight differences in various factors which suggests that fructose is the key factor in driving the differences,” says Le.

The study also does not address the impact on children below 18 years, as the age group selected was 18-52 years and the long-term impact of corn syrup.  “Our study shows that there are slight differences between HFCS and sucrose. It appears that the higher consumption of sweeteners along with greater exposure of fructose may be an important driving force behind the drastic rise in various health issues, such as obesity and diabetes.  However, long-term studies are needed to ascertain if HFCS leads to greater metabolic issues than sucrose,” says the author.

HFCS is popular in the West especially the United States for a couple of reasons. First, it comes from corn.  Since this is highly subsidised by the government, the cost of corn is relatively cheap.  Thus, it is less expensive for Western societies to create HFCS from corn than it is to import sugar.  The other reason is that HFCS is very stable and is a liquid.  This makes it easier to handle and mix in various foods and consumable items.
   
What is then a good substitute for HFCS? The authors point out that there are no good substitutes for HFCS. Even artificial sweeteners have been shown to cause negative health effects.  The consumption of sugar either from HFCS or sucrose is astronomically high.  Overall, consumption of sweeteners needs to be reduced not substituted.

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