By Stephen T. Sinatra, M.D., F.A.C.C., F.A.C.N., C.N.S., C.B.T.
If you haven’t heard of high fructose corn syrup, then I’m convinced you live on a self-sustainable farm and haven’t shopped in a grocery store in 40 years! This sweetener is a top ingredient in countless packaged foods, including sodas, juices, yogurt, bread, cereals, baked goods, and more.
Despite its widespread prevalence, high fructose corn syrup (HFCS) is a polarizing ingredient. While plenty of food manufacturers and lobbyists insist it’s no different than regular table sugar, I personally believe it’s worse than regular sugar and recommend avoiding it at all costs. And I know I’m not alone in this belief among my peers in the medical community.
Why? Well, there are many downsides to HFCS, and very few, if any, benefits. Before getting into those, here’s a little background on how HFCS became so commonplace in the American diet.
The History of HFCS
HFCS was introduced into the US food supply in the early 1970s in response to the rising prices of cane and beet sugars, which are used to make traditional table sugar. By the mid-1970s, it became the go-to sweetener of food and beverage manufacturers because it provided the sweetness of table sugar, but at a fraction of the cost.
This, by the way, is the only real “benefit” of HFCS…if you can call it that. It is so cheap because it is made from an inexpensive, ubiquitous crop: corn.
Specifically, HFCS is a liquid sweetener derived from cornstarch. Corn syrup is comprised of glucose, a simple sugar. Enzymes are then added to convert some of those glucose molecules into another, much sweeter type of simple sugar—fructose. The most common form of HFCS contains 55% fructose and 45% glucose in an “unbound union.” (This is important, I promise!)
In contrast, the simple sugar sucrose (table sugar) is made by crystallizing beet juice or sugar cane. It consists of two molecules—glucose and fructose—tightly bound together in an exact one-to-one ratio.
This may seem like splitting hairs, but it does matter. Here’s why…
Even though manufacturers like to say there’s no difference between HFCS and table sugar/sucrose, they are not chemically the same, nor does the body process them the same way.
When sucrose enters the body, the enzymes in our digestive tract need to break down the tightly bound molecules into the glucose and fructose building blocks. Once this happens, they’re absorbed into the body.
However, when HFCS is consumed, no initial digestion/breakdown is required because the molecules aren’t bound together. As such, it immediately rushes into the bloodstream, and this is where problems unique to HFCS begin…
HFCS, Liver Disease & Leaky Gut
Regular consumption of high fructose corn syrup has been linked to the rising incidence of nonalcoholic fatty liver disease (NAFLD), a condition where excess fat is stored in the liver. NAFLD can lead to liver inflammation, which can then cause more aggressive conditions like nonalcoholic steatohepatitis (NASH), cirrhosis, liver cancer, and liver failure.
Simply put, the body breaks down fructose differently than glucose. Metabolism occurs mainly in the liver, where it is quickly converted into fat. The more fructose you eat, the fattier your liver becomes.
But research shows the gut plays a role in fructose digestion too—and is just as negatively affected.
An enzyme produced in both the liver and gut, called fructokinase, helps to break down fructose. The harder your gut works to digest excessive amounts of fructose, the weaker your intestinal barrier becomes.
Your intestinal barrier prevents bacteria and other toxins from leaking into your bloodstream. When it deteriorates, toxins are able to migrate into the blood (a condition known as leaky gut). Eventually this leads to endotoxemia, which literally means “toxins inside the blood.”
When they reach the liver, these leaked toxins prompt a swift immune response, which results in liver inflammation, and eventually disease.
HFCS and Heart-Related Problems
High fructose corn syrup is also linked to increased risk of high cholesterol, hypertension, and cardiovascular disease.
One study compared the effects of moderate glucose, fructose, and HFCS on risk factors for cardiovascular disease. After only two weeks, those in the fructose and HFCS groups experienced a significant rise in both cholesterol and triglyceride levels compared to those in the glucose group.
By moderate levels, we’re talking about roughly the equivalent of half a can of soda at breakfast, lunch, and dinner. Amazing that such a small of an amount can have that much of an impact.
HFCS can raise blood pressure, too. This is often due to increased sodium absorption, as well as HFCS’ propensity to stimulate the sympathetic nervous system.
An analysis of adults with no history of hypertension who took part in the National Health and Nutrition Examination Survey found that consuming 74 grams of added fructose (roughly 2.5 sodas) a day was “significantly associated with higher odds of elevated blood pressure levels.” It led to a 30% greater risk of blood pressure above 140/90, and a 77% greater risk of blood pressure over 160/100.
HFCS and Diabetes
Diabetes is a huge problem in the US, and high fructose corn syrup is largely to blame.
A study published in the journal Global Public Health found that countries that use HFCS in their food supply have a 20% higher prevalence of diabetes compared to countries that do not. This was even the case independent of total sugar intake and obesity rates.
Sadly—but not surprisingly—of the 42 countries studied, the US had the highest per capita consumption of HFCS (55 lb per year!), followed by Hungary (47 lbs).
HFCS and Obesity
Since high fructose corn syrup is a type of sugar, it is no surprise that overconsumption can cause obesity. But what’s truly shocking is how much worse the weight gain from HFCS is compared to other sugars.
A Princeton University study found that after eight weeks, rats fed HFCS gained significantly more weight than rats given table sugar—even though both sets of rats ate the same number of calories.
These researchers conducted a second experiment where they looked at effects of HFCS over the long term (six months), as well as differences depending on gender. Both male and female rats on HFCS diets gained more weight than the control groups. The males gained a whopping 48% more weight than rats on a normal diet! On top of that, the HFCS-fed rats gained more body (especially abdominal) fat, and had elevated triglycerides.
HFCS and Cancer
To add insult to injury, high fructose corn syrup has been linked to higher risk of certain types of cancer.
The most concerning is colorectal cancer. A study involving mice predisposed to develop tumors showed that those given HFCS had a substantial increase in tumor size and grade, even in the absence of other risk factors like obesity and metabolic syndrome.
While this research is by no means definitive, it does stand to reason that if you have a personal or family history of colorectal cancer, you should avoid HFCS at all costs.
How to Avoid HFCS
It’s clear that high fructose corn syrup has many downsides. Eating something with it once in a blue moon likely isn’t going to have much of an impact on your health, but the problem is that HFCS is in so much that it is hard to avoid it.
Hard, but not impossible.
Your number-one defense is to limit the amount of processed food items in your diet. Say no to all sodas, as well as processed sweets, candies, breads, etc.
When you do need to buy packaged foods, be sure to read ingredient labels on every single item. You’d be shocked by how many things include high fructose corn syrup.
Be aware, too, that HFCS can go by other names. (Sneaky…)
Here are some to look out for:
- Natural corn syrup
- Fructose/fructose syrup/fructose isolate
- Fructose-glucose syrup
- Maize syrup
- Fruit fructose
- Crystalline fructose
Fortunately, health food stores tend to sell non-HFCS-sweetened versions of almost all your popular favorites like peanut butter, bread, candy, ice cream, yogurt, and more.
Of course, if you follow my PAMM diet, or a similar diet like Mediterranean or Paleo, you probably limit your processed food intake—which is ultimately what I recommend. When the majority of your diet is whole, organic food, you don’t need to worry as much about the impact of high fructose corn syrup on your health because you simply aren’t consuming enough of it to harm you.
With that said, I do have one last point to make about fructose…
Fructose is the main sugar in fruit. Does that make fruit bad for you? Unless you’re eating your weight in fruit every day, absolutely not. Here’s why…
Even the sweetest fruits, like mango or watermelon, still contain less sugar than foods artificially sweetened with HFCS.
Furthermore, fruit is full of fiber, vitamins, minerals, antioxidants, and water, all of which nourish your body and slow digestion. As a result, you don’t get the wild blood sugar spikes you normally experience with processed sugar.
The moral here: HFCS should have no place in anyone’s diet. Stick with food created by Mother Nature. When it comes to the ultimate nutrition, she provides exactly what you need.
- US Food & Drug Administration. High Fructose Corn Syrup Questions and Answers. Updated 1/4/18.
- Todoric J, et al. Fructose stimulated de novo lipogenesis is promoted by inflammation. Nat Metab. 2020 Oct;2(10):1034-45.
- Stanhope K, et al. Consumption of fructose and high fructose corn syrup increase postprandial triglycerides, LDL-cholesterol and apolipoprotein-B in young men and women. J Clin Endocrinol Metab. 2011 Oct;96(10):E1596-1605.
- Jalal D, et al. Increased fructose associates with elevated blood pressure. J Am Soc Nephrol. 2010 Sep;21(9):1543-49.
- Goran M, et al. High fructose corn syrup and diabetes prevalence: a global perspective. Glob Public Health. 2013;8(1):55-64.
- Princeton University. A sweet problem: Princeton researchers find that high-fructose corn syrup prompts considerably more weight gain. 2010 Mar 22.
- Bocarsly M, et al. High fructose corn syrup causes characteristics of obesity in rats: increased body weight, body fat and triglyceride levels. Pharmacol Biochem Behav. 2010 Nov;9791):101-6.
- Goncalves M, et al. High fructose corn syrup enhances intestinal tumor growth in mice. 2019 Mar 22;363(6433):1345-49.
© Stephen Sinatra, MD. All rights reserved.