Facts about fructose in food you're not supposed to know...

Fructose in food - also known as high fructose corn syrup - could be a strong risk factor for a heart attack among middle-aged and elderly men.

Fructose in food

High fructose corn syrup is added to foods to make them taste sweeter. Because of its "natural" connotations, fructose in food is often perceived as a healthy alternative to other sweeteners. You'll find it in soft drinks, ice cream and frozen desserts, especially in the low-fat versions.

According to Dr. John Yudkin, former chairman of the department of nutrition at Queen Elizabeth College in London, high fructose consumption may be a risk factor for heart disease.

Yudkin first warned of the dangers of fructose in the late 1960's. Like many others, Yudkin wasn't convinced by the studies linking animal fat with heart disease, and began searching for another explanation. At first, he chose to focus on sucrose. His tests showed that sucrose increased blood levels of cholesterol, insulin, and triglycerides. All are linked with heart disease.

However, when Yudkin broke sucrose down into its constituent parts (fructose and glucose), fructose appeared to cause the majority of the problems.

In 1986, the United States Food and Drug Administration reported that there was "no conclusive evidence" suggesting that sugars (such as fructose in food) have a negative effect on your health. However, a Minnesota research team has shown that just six weeks on a high fructose diet raises plasma triglycerides in men by more than one-third [1].

Plasma triglycerides are a type of fat in your blood. There is a growing body of evidence linking plasma triglycerides to the "clogging" of your arteries, which may increase the risk of a heart attack or stroke. In fact, some researchers now think that plasma triglycerides levels may actually be more important than cholesterol levels in establishing your heart disease risk.

During the first six weeks of the study, subjects were given a diet deriving 17% of its total calories from fructose. In the second stage of the study, the fructose was replaced with glucose. The rest of the diet remained the same.

• The women showed no significant difference in plasma triglycerides in response to the changes in diet.

• In contrast, after just 7 days on the high-fructose diet, the men had significantly higher plasma triglycerides values than during the glucose diet.

Granted, this study did use large amounts of fructose - twice as much fructose as found in the typical American diet. However, based on current estimates, there are approximately 27,000,000 Americans consuming at least this much fructose on a daily basis.

Although previous research has shown that fructose has no negative effect on plasma triglycerides, many of these studies compared fructose with sucrose (table sugar). However, when sucrose is digested, it is broken down into both glucose and fructose - so the comparison isn't really valid.

In contrast, when a diet high in fructose is compared with a diet that contains virtually no fructose, there is a consistent body of evidence showing that fructose has a negative effect on plasma triglycerides.

It's also worth pointing out that some groups of people are more susceptible to the negative effects of fructose. The Minnesota study, for example, shows that fructose had no significant effect on triglyceride levels in women. People with high insulin and triglyceride levels to begin with (such as extremely overweight individuals) appear more sensitive to the negative effects of fructose [2].

Related Articles

• Belly Fat and How to Beat It
• How to Fight Fat and Win II (Members Only)
• The Maximum Muscle Plan (Members Only)
• The Myth about Muscle and Your Metabolic Rate

References
1. Bantle, J.P., Raatz, S.K., Thomas, W., & Georgopoulos, A. (2000). Effects of dietary fructose on plasma lipids in healthy subjects. American Journal of Clinical Nutrition, 72, 1128-1134
2. Henry, R.R., Crapo, P.A., & Thorburn, A.W. (1991). Current issues in fructose metabolism. Annual Review of Nutrition, 11 , 21-39