This was the title of a lecture given by a Professor of Pediatrics at UCSF last year. It was just the latest in a series of shocking summaries of the risks of sugar (sucrose) and high-fructose corn syrup, which are probably responsible for a large part of the epidemics of high blood pressure, diabetes, obesity, cardiovascular disease and cancer.

The reason that sugar is toxic is that it contains fructose. This is the sugar in fruit, but fruit is not harmful. Fruit is safer because it contains a huge amount of fiber and is enriched with many vitamins, minerals and phytonutrients that the body thrives on (particularly when it is organic) ... although too much fruit can still trigger gout.

 

What happens to sugar in the body

 

Sucrose is a disaccharide. This means it is made of two simple sugars - glucose and fructose. When you eat sugar, an enzyme in the small intestine named sucrase splits sucrose into its two parts, and they are then available for use. While glucose is an essential source of energy for human beings (and all living things), fructose is not. Fructose is actually a toxin that is not used by any body part or organ. It must be detoxified by the liver, causing a lot of damage in the process.

There is a lot of biochemistry to understand, but the damage caused by fructose can only be understood in these terms. While glucose is used as energy by muscle cells, fructose is not. Virtually all of it must be processed by the liver, and this results in:

• Production of VLDL by a process called de novo lipogenesis, which is how sugar is turned into fat
• Production of uric acid, which causes gout and has recently been shown to raise blood pressure by inhibiting nitrogen oxide synthase (NOS) in the blood vessel wall
• Upregulation of JNK-1, a major signal for increasing inflammation
• Production of serine-IRS-1, a second messenger that causes insulin resistance (diabetes)

Additionally, fructose leads to the formation of seven times (7x) the amount of advanced glycation end-products (AGEs) as glucose. These are produced when fructose forms cross-links with proteins, and they cause cancer. They are the reason you are advised not to eat meat that is charred or cooked at high temperature.

 

The end result

 

Glucose triggers the release of insulin, but fructose does not. This means it does not trigger the release of leptin either. Leptin is the hormone released by fat cells that tells the brain you have had enough to eat – it is a satiety signal. So fructose will never satisfy your hunger. Leptin has been linked to obesity in hundreds of studies.

Much of the fat that is produced in the liver as it attempts to break down fructose never makes it out. It remains trapped inside, leading to fatty liver and hepatitis. This is called non-alcoholic fatty liver disease (NAFLD) and it is still widely misunderstood by the medical profession. NAFLD is caused by fructose. Period.

As you can see, fructose damages many biochemical pathways, leading to all the problems that make up the metabolic syndrome. This is the reason for the dramatic rise in childhood obesity. It is not caused by lack of exercise or overeating. If this were the case, there would not be an epidemic of obese six-month old infants.

 

Politics and Money

 

High-fructose corn syrup (HFCS) is one reason that these problems are on the rise. HFCS is a sweetener that was developed in 1975, and it has gotten a lot of bad press because it is said to be more dangerous than sugar. This is not really true. Sucrose is 50% fructose, and HFCS contains about the same amount. They both cause the same amount of damage.

HFCS is dangerous because it is cheap. It is half the price of sugar because of US government corn subsidies. A cheaper sweetener made it possible for the food industry to put HFCS in everything, from pretzels to hamburger buns, and this led to a huge increase in the amount of fructose consumed each year. People like sugar. Animal studies have demonstrated that very sweet tastes are more addictive than cocaine.

Another reason that sugar intake has increased is that 25 years ago we were all told that fat is bad and we were supposed to eat less of it. The only way to accomplish this was to eat more carbohydrate, much of it in the form of sugar.

 

What to do

 

• Make water your main beverage. If you don’t like the taste of water, add a few drops of lemon juice.
• Avoid fruit juice. Even ‘unsweetened’ fruit juice contains pure fructose, without the fiber to limit its absorption. The ‘natural sugars’ in fruit juice are very rapidly absorbed by the bloodstream, so juice is nothing like real fruit. It is a health hazard, and fruit juice consumption has been linked to childhood obesity, diabetes, gout and gallstones.
• Avoid soft drinks. This should be obvious. Diet drinks cause less damage than regular ones, but they also have their problems.
• Avoid processed foods that contain sugar. If it has a label or a long list of ingredients you cannot pronounce, it is not real food. Real food is found in nature, not in plastic packages.

While the research linking sugar to chronic disease has not been given much media attention, there is plenty of it out there. A well-referenced list of the risks of sugar appears on a website run by Dr Joe Mercola. View it here. Every person should be made aware of the risks of sugar, even in its ‘natural’ form in fruit juice. Spread the word.