WHAT IS IT? High-fructose corn syrup is produced by milling corn to produce corn starch then processing the corn starch to yield corn syrup. The corn syrup at that point is almost entirely glucose. Enzymes that change the glucose into fructose, which is sweeter than glucose, are added. The resulting syrup (after enzyme conversion) contains approximately 90% fructose and is known as HFCS 90. To make the other common forms of HFCS, the HFCS 90 is mixed with 100% glucose corn syrup in the appropriate ratios to form the desired HFCS. The typical types of HFCS are: HFCS 90 (most commonly used in baked goods) which is approximately 90% fructose and 10% glucose; HFCS 55 (most commonly used in soft drinks and comparable in sweetness to table sugar) which is approximately 55% fructose and 45% glucose; and HFCS 42 (most commonly used in sports drinks) which is approximately 42% fructose and 58% glucose.
The process by which HFCS is produced was first developed in 1957, then refined in the 1970s. Over the period of about 1975-1985, HFCS was rapidly introduced in many processed foods and soft drinks in the US. Since that time, HFCS has replaced cane sugar in a large variety of foods in the USA. The main reasons for this switch are:
- HFCS blends easily with sweeteners, acids, and flavorings and is easier to transport because it is a liquid.
- HFCS usage leads to products with a much longer shelf life because it retains moisture, resists drying out, controls crystallization, and prevents microbiological growth.
- HFCS is cheaper due to the relative abundance of corn, farm subsidies, and sugar import tariffs in the United States.
From a manufacturer's point of view, HFCS is a revolutionary advance in food science!
WHY IS THIS A CONCERN? Fructose is one component of sucrose (cane or table sugar), which also naturally contains glucose. In laboratory and human tests, it has been found that excess sucrose increases blood levels of cholesterol, triglyceride (another type of fat), uric acid, insulin, and cortisol--all associated with an increased risk of heart disease. Sucrose also raises blood pressure and increases the fragility of blood platelet cells, making them more prone to clotting. As dramatic as those findings were, when substituting pure fructose for sucrose in the same experiments, the effects are magnified with fructose. Fructose was determined to be, in effect, "the dangerous part" of sucrose. In contrast, glucose did little more than cause cavities. Studies have also concluded that pure fructose produces significantly higher fasting plasma triacylglycerol values (a risk factor for cardiovascular disease) than a pure glucose diet. While fructose has been advocated for years as a safe sugar for diabetics because it doesn't trigger a rapid rise in blood sugar, the cardiovascular consequences of consuming large amounts of fructose may outweigh the benefits for diabetics who already face a higher than average risk of developing heart disease.
It is an interesting thing about fructose, that it does not stimulate insulin secretion and does not require insulin to be transported into cells like other carbohydrates, and at first this may seem like a great thing. However, the lack of insulin response can be viewed by some as a double-edged sword because insulin also controls the fate of another hormone--leptin. Essentially, leptin signals the brain to stop sending hunger signals when you've had enough to eat. Since fructose doesn't stimulate insulin, there will be no subsequent increase in leptin levels, thus no feeling of satiety achieved by consuming fructose alone.
Some advocates of HFCS (notably, those who manufacture goods containing HFCS or benefiting from it's production) regard such findings as "media hype", stating that information about the effects of HFCS have been "blown out of proportion" because the aforementioned studies looked at the effects of fructose alone and not actual HFCS in a relastic context. High fructose corn syrup, they proclaim, actually contains varying ratios of fructose and glucose, which are roughly the same products produced by the breakdown of natural sucrose in the body. Still, as evidenced by a myriad of other independant lab experiments, even large quantities of the natural from sucrose are known to stimulate the liver to produce triglycerides, promote glycation of proteins, and induce insulin resistance which can be a contributing factor in developing diabetes. We now know this to be especially true of fructose, regardless of whether it is 100% pure fructose or a mixture of fructose and glucose.
While some forms of HFCS may not inherently be more dangerous than natural sucrose, the problem comes with the sheer quantity of "hidden" fructose being consumed through the HFCS in processed foods: most people are surprised to learn of the abundance of HFCS in foods we don't normally associate with being "sweet", from breads to pasta sauces to bacon and even beer. Its commonly used in so-called "health products" like protein bars and energy drinks, and of course in candy and soda pop. Overall sweetener consumption, and in particular high-fructose mixtures, has increased since the introduction of HFCS. Thus, the proportion of fructose as a component of overall sweetener intake in the United States has increased since the early 1980s.
WHAT ABOUT FRUIT? Fructose is commonly known as "fruit sugar." So does this mean fruit has the same effects on the body as HFCS?
Fortunately, natural sources are much less potent simply because the quantity of pure fructose consumed is significantly less than found in most processed foods. Fructose accounts for only 5 to 7 percent of the weight of cherries, pears, bananas, grapes, and apples. That's about 5 to 8 teaspoons per pound of fresh fruit. There's even less fructose--2 to 3 percent, or roughly 2 to 3 teaspoons per pound--in strawberries, blackberries, blueberries, oranges, and grapefruit. Compare this to conventional soft drinks, which almost universally contain 11 percent HFCS by weight--a whopping 2.2 pounds per case. Honey, refined by bees, contains 40 percent fructose, but its extreme sweetness deters most people from consuming it in large amounts.
THE FINAL VERDICT: Though many hazards are associated with fructose and HFCS, the overall ill effects appear to be largely dose dependent, according to experts. There is very real concern with a diet that is comprised predominantly of processed foods, especially as younger generations become more frequently exposed to convenience diets. Conversely, if you eat primarily whole, natural foods, and avoid large quantities of processed or sweetened foods, you have little to worry about with an occasional sugary treat. "We have not taken a no-sugar stance," one nutritionist says. "We have taken a no-excessive-sugar stance."