The purpose of this second Sugar Blog is to explain, as simply as I can, the chemical structures of the different sugars and how they can affect the body.
Briefly, let us go back to high school biology and chemistry. Remember that elements (like oxygen, hydrogen, carbon, nitrogen, sulfur, etc.) are the building blocks of molecules. The drawings of the molecules showed how the fundamental elements hook together.
When it comes to sugar, there are several types of sugars, and they are divided into three categories:
Monosaccharides – these are simple sugars, having just one molecule and generally found naturally in fruits and some vegetables.
- Glucose – a sugar found in the bloodstream. It is a six-member ring, which makes it stable
- Galactose – a “milk sugar” rarely found in the diet, usually found in lactose and complex carbohydrates
- Fructose – is found in fruits and plants and is a five-member ring which makes it less stable
Disaccharides – two simple sugar molecules joined together
- Sucrose – 1 glucose molecule + 1 fructose molecule is table sugar
- Lactose – 1 glucose molecule + 1 galactose molecule, found in milk and dairy
- Maltose – 2 galactose molecules, generally in grains
Polysaccharides – are many connected sugar molecules in chains
- Glycogen – is the storage form of glucose in the liver
- Starch – as it is found in potatoes, other vegetables, and grains
- Cellulose and Chitin – gives structural support to plants and organisms (insects and crustaceans)
Enough of high school science. Let’s talk about why all this sugar talk matters to our bodies.
Glucose is the source of energy for every cell in our bodies. It is attained from the digestion of food in our gastrointestinal tracts. Somewhere between 25% and 50% of the glucose absorbed across the small intestine goes to the liver, where excess glucose is stored as glycogen to be used in the future, as needed, for energy. An unlimited amount of glucose can be stored this way in the liver without causing harm to the liver. The remainder of the glucose goes to our muscles and brain. The body has a very intricate system for keeping our blood sugar in a normal range. But, overeating sugar can be bad for us. Remember, it is addictive. When the liver is overloaded with sugar, it is converted to fat and causes weight gain.
The biggest problem comes from the intake of fructose. Unlike glucose, fructose is metabolized only in the liver. And because it is a five-member ring molecule, it is more unstable than glucose and causes more oxidative stress (more about that in a future blog).
When we consume high levels of fructose (mainly found in sodas and hidden in processed or “manufactured” foods), the liver gets overloaded. The liver converts the fructose to fat, which results in fat deposits within muscles and around our internal organs. This inner fat is called visceral fat and is dangerous to our health, and can lead to an increased risk of diabetes.
Another consequence of too much fructose is that it causes the liver to develop fatty globules, a disorder called “fatty liver.” As many as 25% – 50% of people in the developed world are presently affected by fatty liver.
About 20% of people with fatty liver go on to develop inflammation, scarring, and fibrosis in the liver leading to cirrhosis, liver failure and sometimes even to liver cancer. In cirrhosis, the scarring and fibrosis hardens the tissues within the liver making it incapable of doing its job. This same scenario can also happen with chronic alcohol intake.
Fructose, as found in whole fruits, is not a problem because the fiber in the fruit slows down its absorption and the liver can handle that. The main source of fructose in our diets comes from the addition of high fructose corn syrup (HFCS) to processed foods, especially in sodas and fruit and sports drinks, but found in many other foods also. Liquids with calories do not satisfy hunger and fructose does not suppress the appetite as does glucose. One can of HFCS sweetened soda a day can equal a 15 pound weight gain in a year! Although, HFCS sweetened sodas, fruit juices, and sports drinks are a major source for excessive fructose intake, other foods also contain HFCS and sugars (by many names). Some of these other foods are: candy, sweetened yogurt, salad dressings, frozen junk food (pizzas and TV dinners), breads, canned fruit, boxed dinners, granola bars, breakfast cereals, store-bought baked goods, sauces and condiments, snack foods, energy bars, coffee creamer, jams and jellies, and ice cream.
Some of the disorders that can be caused by excessive sugar intake (especially via HFCS in processed foods and drinks) are: weight gain and obesity, increased risk of heart disease linked to arteriosclerosis (hardening of the arteries), acne, increased risk of diabetes, increased skin aging, kidney disease, increased risk of gout and high blood pressure from increased levels of uric acid, accelerated cognitive decline, elevation of triglycerides in the blood, possibly an increase in the risk of cancer and depression, and now concern is being raised that there might be an association between intake of HFCS and colorectal cancers.
This does not paint a pretty picture. What is one to do? Here is what I have done to clean up my personal food environment. I went through the refrigerator and cupboards and read all the food labels. I threw away anything that contained sugar or HFCS. Most was in salad dressings, but I found sugar in one jar of mustard (but not the other), and to my amazement, there was sugar in the mayonnaise. I have kept fruit juices and sodas out of the house for quite a while. Most authorities in the field of nutrition recommend discontinuing the drinking of HFCS, sugar, or artificially sweetened drinks. It is also best to stay away from processed foods, as over 80% of them have added HFCS or some other form of sugar. There are ways to impact our communities. Schools can be encouraged to eliminate soda machines. Grocery store managers can be encouraged to increase the bottled water at the check-out stands, rather than sodas, and also to add some healthy food instead of just candy. It is also known that our present American habit of grazing (eating and snacking off and on throughout the day) also contributes to the health problems caused increased sugar intake and obesity. So, I encourage you to set a good example by not grazing, but eating healthful foods at planned regular intervals and to sit down with your family to eat together at least once a day, to enjoy their companionship and try new healthy foods.
As Michael Pollan, well-known food writer, has said:
“Eat real food, not too much, mostly plants.”
“Don’t eat anything your great-grandmother would not recognize as food.”
