Fast Facts on High Fructose Corn Syrup (HFCS)

Written by: Emily Russo, MS, RD, CDN

We’ve all heard that high-fructose corn syrup is bad for us, but how many of us can explain why? Here's the long and the short of it!

We may have heard that high-fructose corn syrup is linked to chronic disease, but how does that translate into our every day dietary choices? Here’s the long and short of it.

Last week I decided to look up #HFCS on my social media search, just to see what people were saying. The message was pretty consistent – AVOID HFCS – but no one was sharing why.

And though I appreciate quick tips as I scroll through my feed, this type of blanket advice feels more like fear mongering than it is educational. So that’s why it’s important to actually consider why HFCS gets a bad rap.

First, what is Fructose?
Fructose is a sugar found naturally in fruits, honey, maple syrup, & agave, to name a few.

What is HFCS?
It’s a bit of a misnomer, as the “high” part simply means there’s more fructose in HFCS than there is in corn syrup; but compared to sucrose, the fructose levels are actually pretty similar.

To explain further, corn syrup is 100% glucose molecules. When enzymes and water are added to corn syrup to convert some of those glucose molecules to fructose, it becomes HFCS at varying concentrations (typically 42% or 55%). Sucrose, or table sugar, is also fructose & glucose, but the ratio is 1:1, or 50% fructose.

The biggest difference between the two sugars is that unlike HFCS there is no unbound fructose and no water in a sucrose molecule.

Why is HFCS used in food products?
HFCS is an ingredient found in highly processed foods and beverages such as non-diet sodas, juices, and salad dressings or sauces to name a few. Since fructose tastes sweeter than glucose, it’s cheaper to add a smaller amount of HFCS to products while still achieving the desired level of sweetness.

Why does everyone tell us to avoid it?
Eating an excessive amount of sugar on a daily basis, whether it’s mostly from glucose, fructose, or HFCS will likely lead to weight gain. While weight gain on its own may not cause poor health outcomes, it is most certainly cause for concern when in conjunction with behaviors such as excessive intake, or bingeing. Research indicates it doesn’t matter what kind of sugar it is.

Additionally, but unrelated, some people experience gas, bloating and other signs of irritable bowel syndrome after eating foods with fructose. This can include HFCS as well as naturally occurring fructose such as those in fruits or natural sweeteners like honey or agave.

People with IBS are often encouraged to try a short-term low-FODMAP diet, which includes decreasing fructose consumption, to minimize symptoms.

What else?
Some studies have shown a link between excessive intake of fructose and higher prevalence of non-alcoholic fatty liver disease (NAFLD), Type 2 Diabetes, or GI tumor development. Some studies have shown that excessive intake of all types of sugar is also associated these conditions.

Fructose (from any source, natural or not) has a different mechanism of absorption and transport than glucose and may have a different impact on certain biomarkers after ingestion. Because HFCS contains higher amounts of unbound fructose, the thought is HFCS has more of an impact on these biomarkers than sucrose or naturally occurring fructose. This is the central focus of current research.

What’s the Bottom Line?
Most foods containing HFCS also happen to be low in vitamins, minerals, and fiber, and contain additives. A diet consistently high in HFCS-foods in the long-term is NOT beneficial to overall health.

Remember that the impact of diet on overall health is an average of all foods eaten over time. Meaning, if you want to have a cola or a packaged cookie, enjoy it, and don’t fear it. This is different than a diet that consists mostly of sugar-sweetened beverages and chocolate syrup (like Will Ferrell in the movie Elf!).

More research, especially studies comparing sucrose and HFCS, is needed to determine the more nuanced health impacts of HFCS. 

As always, I welcome any comments or questions below!

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