Question

Q. Why do we use glucose as our energy resource and not fructose?

Answer 1

Sucrose, glucose and fructose are all simple carbohydrates or simple sugars. Glucose and fructose are individual sugar units and are also called monosaccharides. Sucrose is a sugar molecule made up of both glucose and fructose so sucrose is called a disaccharide. We get our sugar naturally from whole foods and also in processed foods where sugar is added. Although sucrose, glucose and fructose are all natural sugars and taste sweet on our tongues, there’s a huge difference in the way they are metabolized in our bodies.
Our bodies like to use glucose as its energy source (glucose is the preferred energy source for your muscles and brain) so we will use any glucose we eat and also break down most carbohydrates into glucose which is then either stored or used immediately. Insulin assists glucose to get into your cells to be used for energy so it is secreted when the body detects high levels of glucose in your blood but not when there’s high levels of sucrose or fructose. Virtually every cell in your body is able to metabolize glucose. Eating too much sugar causes high blood levels of glucose which in time damages your insulin metabolism. Diabetes damages blood vessels all over your body. High blood sugars cause heart disease, kidney failure, blindness, poor circulation to your feet leading to amputations, slow wound healing and nerve damage.
Fructose is also a naturally occurring sugar in many fruits and vegetables but fructose is metabolized primarily in your liver. Fructose is used to produce energy through glycolysis. However, unlike glucose, fructose is also involved in lipogenesis which is how fat is created. Fructose is involved in the growth of fat-filled plaques that accumulate in your arteries causing cardiovascular disease and strokes. Too much fructose also creates excess stored fat in your liver causing NASH or Non-Alcoholic Liver Disease. NASH affects 30% of Americans today and leads to cirrhosis and liver failure. New scientific studies are now indicating that fructose may also activate a specific protein leading to insulin resistance and diabetes.
Sucrose (or table sugar) is an equal combination of glucose and fructose – one molecule of each. Table sugar primarily comes from sugar cane and beets which contain sucrose. When you eat sucrose, it splits into glucose and fructose and those sugars are individually metabolized as explained above. Glucose is always the first sugar the body uses for energy. Any excess fructose not needed for energy will be used to make fat. High fructose corn syrup (HFCS) has 55% fructose and 45% glucose.
Fructose or fruit sugars used to only be ingested when we ate fruits and vegetables – we used to eat about 15 grams or 1/2 oz per day. Now we eat more than 5x that amount of fructose in the form of HFCS as well as in many added sweeteners touted to be healthy like honey (50% fructose) or agave syrup which can contain up to 97% fructose which is much higher than the 55% fructose in HFCS.
A processed food is basically a food that has been altered during preparation and most contain fructose in the form of HFCS. If your food isn’t coming from the perimeter of the food store which contains most of the fresh fruit, vegetables, meat and dairy then it is probably processed. Reading food labels is the only way to see if there’s added fructose, sucrose or glucose. Foods can be naturally high in sugar, but it’s the added sugars that really cause your health problems. For instance, a 1/2 cup of sliced apples contains the equivalent of 2.5 teaspoons of sugar but also contains phytonutrients and fiber that makes this a great natural and whole food choice. Mott’s applesauce contains 5 1/2 teaspoons of sugar per serving so it has 3 added teaspoons of sugar compared to just eating an apple. That added sugar also comes from the HFCS which is the second ingredient after the apples…so your “fat-free” applesauce may be fat-free in the jar, but once your body metabolizes this product it not only increases your sugar but it also adds to your fat metabolism.
If all of this seems confusing that’s because it is. Consumer marketing does not help you out either. Changing your diet into a healthier diet is a process that involves tasting and preparing new foods, reading labels and also taking some time to read about foods and what makes certain foods better choices for you and your family. You’ve already started the learning process if you’re reading this article. I spend a lot of time with my patients discussing diet and how foods impact their medical problems and how foods can keep them in good health – we have that time together because all of my office appointments are one hour long with no waiting time. Check us out at www.bralowmedicalgroup.com and schedule a meet & greet.