Far too many people still believe that a glass of orange juice in the morning is right for you.  Similarly, far too many still believe that downing a sports drink during running, tennis, soccer, etc. is right for you. Much to the contrary—why are juices, sports drinks, and other sugary beverages harmful to our health?  

It has long been suspected that fructose is capable of causing significant harm when ingested in powder and liquid forms such as juice and sports drinks.  The food industries’ development of high fructose corn syrup only made this worse.  The human body does not need fructose.  It is not an essential sugar necessary for us to survive or thrive. 

Over the last few years, many scientists have theorized that fructose might be one of the leading cause of diseases such as cardiac disease, insulin resistance, elevated LDL, elevated triglycerides, fatty liver and the metabolic syndrome seen in adults and children throughout our country.  These are harmful diseases that could significantly shorten our lifespan.  The effect of fructose on our health is an important topic to cover.  One of the most recent articles which I will discuss later comes close to proving just how harmful fructose can be.  

History Of Fructose and Why It Is In Our Diet

Fructose was discovered in the late 1800s.  Fructose has been used as the primary sweetener of foods because it is straightforward and very cheap to manufacture.  Fructose is twice as sweet as sucrose or table sugar, so it makes food more palatable, and arguably more addictive. The food industry uses various forms of fructose.  A widespread form is high fructose corn syrup (HFCS). 

Recent data (NHANES) shows that nearly half of all Americans consume HFCS in a sugary beverage every day.  Many will consume between 200-500 calories per day of fructose.  There are 15 calories in a single teaspoon of fructose!  So, Americans are taking in a lot of fructose.  This is considered an “added sugar” when you read a food label.  The added sugar US RDA (100 calories) and the World Health Organization (WHO) recommendation (<10% of total calories) both suggest significantly limiting “added sugar” in our diets. If there wasn’t tremendous political pressure put on both the US RDA recommendations and the WHO, I imagine those recommended numbers would drop much further.  


First some useful definitions. 

Fructose. A 5 carbon ring sugar found in fruit.  Human evolution gave us a way to get rid of it… but evolution has declared that fructose is not a necessary part of the human diet.  We need glucose, vitamins, minerals, protein, and fats to survive.  We do not need fructose.  

NAFLD: Non-alcoholic fatty liver or NAFLD is thought to affect nearly 40% of Americans.  It is characterized by excess fat accumulation in the liver.  It is more commonly seen in obese adults and obese children.  NAFLD is frequently seen in association with type 2 diabetes as well as lipid-related issues such as an elevated LDL and triglycerides.  NAFLD is not as dangerous as NASH. 

NASH: In a certain percentag4e of patients with NAFLD, they will also go on to develop inflammation within the liver.  This inflammation scars the liver and in time, may lead to cirrhosis.  Many patients with end-stage cirrhosis might go on to require a liver transplant.  NASH is far more severe than NAFLD.  

Microbiome: The microbiome is composed of trillions of bacteria within your gut.  It has become abundantly clear that these bacteria play a significant role in obesity, depression, certain diseases, and how we metabolize many of the foods we eat.  

Metabolic syndrome: Metabolic syndrome is a set of issues that occur together. These conditions include hypertension, elevated blood sugar (insulin resistance), excess body fat around the waist (visceral fat), and triglyceride levels. When present, these conditions increase your risk of heart disease, stroke, and type 2 diabetes. 

LPS: THis is known as an endotoxin.  It is part of the cell wall in particular bacterium.  When they are in our bloodstream or tissues, they induce a severe inflammatory reaction.  


Why is Fructose Bad For Us? 

Fructose and Human DiseaseWhat happens to fructose when you eat it?  If you glance at the diagram to the right, you will see the two pathways that glucose and fructose follow in the liver once we ingest them.  Notice how Uric Acid is produced during the metabolism of fructose.  That is why we can use your uric acid level as a biomarker for the amount of fructose you ingest.  For those of you who suffer from gout, this increase could initiate a gout attack. 

Notice that glucose typically follows a pathway resulting in glycogen, which is how our body stores energy needed to live.  The metabolism of fructose ends in the production of fatty acids.  That is how fructose increases the amount of fat in your liver.  That can lead to a fatty liver or NAFLD. 

The liver will try its hardest to get rid of those extra fats.  The liver will package the fat into a particle known as a VLDL.  Those VLDLs are full of triglycerides from your liver.  During their trip through your bloodstream, those lipids can find their way into your blood vessel walls.  When combined with inflammation, which is produced by high sugar loads,  the combination will cause atherosclerosis.  That is how fructose can cause fatty liver, increased triglycerides, increased uric acid, and cardiac disease.  

This article in JAMA showed that a single 12-ounce glass of juice or a sugary beverage was associated with an 11% increase in all-cause mortality (death due to any reason).  2 servings a day increased that risk to 24%!  

Fructose and Other Harmful Effects

One of the more recent studies into the metabolism of fructose revealed how fructose could potentially cause severe disease, which would threaten our well-being.  I’m certainly not saying that fatty liver and excess lipids such as triglycerides aren’t bad enough, but the story goes much deeper.  

leaky gut due to fructoseFructose has now been shown to cause a “leaky gut.”  You may have heard that term before.  Your cells in your intestine are very tightly bound or attached to each other.  That serves a vital function, keeping whatever is in your intestine out of your blood.  Various issues or diseases can cause a leaky gut.  When you develop a leaky gut, your intestinal cells are no longer tightly bound to one another. Therefore, bacteria can enter the space between the cells and get into your bloodstream. 

Many of the bacteria within our intestine have LPS in their cell wall. As I mentioned earlier, that can cause a severe inflammatory reaction in your body.   Diseases such as NASH and atherosclerosis are very complex.  No one issue is necessary AND sufficient to produce them.  For example, in your liver, you need both inflammation and high fat to cause NASH.  Both inflammation and fat are necessary, but neither alone is sufficient.  The same goes for heart disease.  To develop atherosclerosis, you need an increased lifetime exposure to elevated lipids, and you need inflammation to be present. 

If your gut is leaky due to excess fructose, then bacterial LPS and potentially other substances which cause inflammation are getting into your body. They will create an inflammatory reaction and can trigger NASH, atherosclerosis, dementia, and other disease states.   


The Bottom Line 

Fructose is a very commonly used sweetener.  You have no biological need for it.  Fructose appears to cause significant disease in humans and animals.  It is a common misconception that Sports Drinks or Vitamin Drinks are healthy. They are not. They are full of fructose and other forms of sugar. Most exercise does not require immediate replenishment of your energy expenditure.  That means that if you go for a 10-mile run, you can drink water, and wait until you get home so you can make yourself a much healthier meal.  For marathon training and runs longer than 15 miles, you may need minerals and calories as well.  But this article is not being written to address the needs of the 1% of you who are running that far. The other 99% of us do not need these sugar-laden sports drinks, sodas, and iced teas.  

The same goes for your children on the ballfield.  They do not require Gatorade or other sports drinks. They should be drinking water. 

Water should be the primary beverage we choose throughout the day. The food industry will try very, very hard to convince you that the opposite is true. They are not vested in your health and well being.  Prioritize your health.  Prioritize your health long into the future. Water should be your first drink of choice.  



Disclaimer:  this information is for your education and should not be considered medical advice regarding diagnosis or treatment recommendations. Some links on this page may be affiliate links. Read the full disclaimer.

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About the author:

Howard J. Luks, MD

Howard J. Luks, MD

A Board Certified Orthopedic Surgeon in Hawthorne, NY. Dr. Howard Luks specializes in the treatment of the shoulder, knee, elbow, and ankle. He has a very "social" patient centric approach and believes that the more you understand about your issue, the more informed your decisions will be. Ultimately your treatments and his recommendations will be based on proper communications, proper understanding, and shared decision-making principles – all geared to improve your quality of life.