Can sugar substitutes cause heart attacks and strokes?

You might have heard by now about a new study that has implicated the sugar substitute, erythritol, as a major causative factor for heart attacks and strokes. My own local newspaper, The OC Register reported on this, and you can find the source research paper at nature.com (paywalled unfortunately).

After hearing from clients and friends wanting to know more about this, I decided I should write up a full post to share my thoughts.

There’s certainly a great deal of consternation about this, as well as a great deal of confusion and muddying of the waters.

NOTE: If you don’t need a primer on sugar alcohols and erythritol, just skip ahead to the section ‘Cause for alarm?’ for the analysis and recommendations.

OMG! Fake sugars = bad… right?

The first and most important thing to note is: this is not about all (or any other) sugar substitutes. However, there are a great many sugar substitutes on the market today that are based on erythritol because it is granular, like sugar, and is almost identical to sugar when it comes to measuring, mixing, and dissolving. However, because erythritol is not quite as sweet as normal sugar, the distributors of these products frequently mix stevia or monk fruit -derived sweeteners with the erythritol. Both of these are so much sweeter than sugar that you only need minuscule amounts to get the same sweetness. Therefore, by adding a tiny bit to erythritol, you end up with a product that looks and measures like sugar, with the same exact level of sweetness. But this has led to a lot of (often purposeful) consumer confusion. Many of these products are specifically marked on packaging to highlight and extol the tiny additive sweeteners (monk fruit or stevia) while there’s zero mention at all regarding erythritol, which you’ll only discover is the primary ingredient by reading the ingredients.

Anyway, the bottom line is that neither monk fruit nor stevia are implicated by this recent study. No other sweeteners are, in fact. This study, and any concern you should have, are entirely and solely regarding erythritol.

Erythritol is a sugar alcohol. Sugar alcohols are not alcoholic substances as we know them. They are just called ‘alcohols’ because, chemically speaking, they are sugars that carry a hydroxyl group (an oxygen and hydrogen bonded to a carbon), which is a defining characteristic in organic chemistry for alcohols. So, what ends up happening with sugar alcohols is that they taste sweet, like sugars, but are non-digestible due to their unique molecular makeup. A few other popular sugar alcohols you may see listed as ingredients in products are mannitol, sorbitol, and xylitol.

With the intriguing exception of erythritol, as non-digestible carbohydrates, most sugar alcohols are essentially like fiber. They feed bacteria in our gut. That’s one reason they can give people stomach cramps, gas, or even diarrhea. Our expectation with sugar alcohols is that they’ll sweeten foods without affecting our metabolism. However, because they’re still carbohydrates, even though we can’t digest them, just like fiber, they can affect our microbiota. More research is needed to determine if or when those effects could be health promoting or bad, likely depending on the specific sugar alcohol.

So, are any other sugar alcohols implicated? Not at this time. Maybe it’s because erythritol seems unique among sugar alcohols in how it gets absorbed into the bloodstream to circulate for a while before elimination. However, it would be prudent to re-investigate other sugar alcohols to see if they too might have similar effects (perhaps small amounts absorbed into blood?) even if at a smaller level.

This is NOT the same problem as atherosclerosis or high blood pressure and cholesterol, etc.

It’s important to point out that the researchers claim to have uncovered elevated heart attack and stroke risk due to enhanced clotting of the blood. This is not at all the same thing as having lesions or plaques in your arteries, or them being stiff and under too much pressure. This is not the same as narrowed arteries or veins. Not the same as cholesterol deposits.

However, if you already have narrowed blood vessels, plaques, calcified buildup etc… then blood clotting is something you need to be careful about. That’s the reason taking a baby aspirin daily was so popular not too long ago. The aspirin makes the blood less “clotty.”

But it’s important to point this distinction out because consumption of erythritol —at least going by the results of this paper— IS NOT causing lesions or plaques… or inflammation… or narrowed arteries… none of that usual stuff we should worry about when it comes to cardiovascular health or the typical age and obesity -associated risks.

Cause for alarm?

First, let’s temper some of the panic with possible evidence for us to be cautiously skeptical about the research.

First: The primary concern, namely that erythritol causes heart attacks and strokes, was discovered within a highly susceptible sample: people with existing disease. That’s not a reliable bedrock upon which to draw population-wide conclusions. Even among those with disease, this is a confounding factor that makes it less reliable to extrapolate findings. It’s like saying a study found people who play violent video games got into more car accidents, but this study was conducted among people who speed or tailgate.

Second: The research claims something extremely unusual: in a followup study, they said they found erythritol at elevated levels in the subjects’ blood samples THREE DAYS after ingesting a relatively normal amount. That’s an awfully long time. This makes me wonder whether there could have been a flaw in the study.

Third: A lead author of the study has some potential conflicts of interest, albeit not clearly so — and he claims they are not.

Fourth: Millions upon millions of people have been consuming erythritol for years with no apparent ill effects so far. I’d love to see a study test their blood for both erythritol levels and clotting behaviors.

But there are some very worrying truths, regardless:

• The researchers report that the degree of risk was proportionate to the plasma concentration level. That’s highly implicative for erythritol.
• The researchers found an extremely high degree of risk at the higher plasma levels (double the risk!). And we’re not talking about absurd intake levels you might only see with laboratory rats. They used fairly normal dosages. This, coupled with the first point, means the risk is substantially high on top of being tightly correlated. The more you consume, the higher your risk, AND the risk is very high.
• The researchers are not merely reporting an association between intake and incidents, which is typically (and tragically) how so many bad takes regarding nutrition and medicine end up being declared. No, they claim to have discovered an actual mechanism of action (albeit one NOT well explained or defined). What they are saying they witnessed is that erythritol turns up the body’s natural blood-clotting response in a dose-dependent fashion. That means clots are much more likely to form or be larger or stronger than normal with higher erythritol levels. Clots happen all the time. What causes strokes and heart attacks is when there’s too much clotting and a piece breaks off and ends up in a narrowed blood vessel. The researchers assert they witnessed this pro-clotting effect both in test tubes and in living bodies. That’s pretty big.

What’s really bugging me…

I also want to repeat a point from the reasons to be cautiously skeptical —except this time, add this to the list of reasons to be alarmed (potentially). Recall that the researchers state they witnessed elevated blood levels of erythritol three days after consumption!

This is quite alarming.

To me, this finding should share center stage! I’m amazed not to see more pixels spilled about this. Prior to now, it could be taken for granted that erythritol is excreted in urine at a “fairly normal” rate, with a large amount gone within 3 hours and the vast majority within 24 hours [*].

As stated earlier, erythritol behaves uniquely compared to most non-digestible carbohydrates. Most of it DOES get absorbed into the blood; very little ends up in our digestive tract (this is likely the reason it’s better tolerated at high doses).

But why does this study claim it takes so long for it to get eliminated? Whereas the research I referenced suggests a half-life of about 5 hours (expected) this new study seems to suggest a flabbergasting half life of over 24 hours… possibly more than 48 hours!

Unlike actual sugar, erythritol can’t be metabolized. It’s, ultimately, a “waste product” and the only way to clear it is to filter it out with the kidneys. So I’m extremely unsettled this research implies it’s taking so incredibly long to clear. Even without concern for proposed harmful effects at a given concentration, no foreign substance should be accumulating like this. It implies we suffer a deficiency with clearing it. At high enough concentrations, anything in our blood will become harmful.

I’d like to see research digging into this aspect and either verifying or refuting it. If found to be true, perhaps this factor is directly associated to the proposed pro-clotting behavior.

For now, my feeling is either something is amiss with this research or something is very amiss with erythritol. Which would be concerning, considering its GRAS (generally recognized as safe) status.

Getting to the bottom of this is urgent, because of erythritol’s widespread use in the market. The fact that this study is locked behind a paywall, given how urgent and widely applicable a clear understanding is, how significant the potential for widespread harm is, and how unusual these findings are, is frankly scandalous. Consider this fact (this money-grab) yet another reason I’m “cautiously skeptical”. However, being skeptical, while logical, unfortunately seems to carry too much risk in this case. And that is why this research needs to be made publicly accessible for free, immediately, and more investigations corroborating or disproving the claimed outrageous half-life needs to be conducted.

The public needs to know ASAP:

1. To what extent can erythritol continue to build up in the blood stream while defying elimination?
2. What happens to plasma concentrations if an individual consumes 30g daily for an extended period of time?
3. How long does it take to completely clear just 30g of ingested erythritol?
4. What is the threshold plasma concentration at which clotting begins to get affected?

My Takeaway Advice

Unfortunately, I have to say that you really should stop buying products with erythritol for regular consumption effective now.

Occasional consumption is perhaps an ok risk for you. For most persons of good health, it’s probably ok to take that occasional risk until more is known. This would highly depend on your other risk factors (is clotting already a concern for you?).

Likewise, you are probably ok to finish off any left in your pantry. After all, how long have you been consuming those without issue? But again, personal risk is important to weigh.

You can and should switch to 100% stevia and monk fruit sweeteners, even those laced with a tiny bit of normal carbohydrate. Allulose is another option (also some controversy on this one regarding microbiota, but we’ll examine that some other time). Keep in mind that both stevia and monk fruit are so incredibly sweet they’re all but impossible to properly measure and dose in their pure forms. They need to be diluted in some kind of medium. So, when I say 100% of either, I mean that 100% of the sweetness comes from either of those two natural (and somewhat beneficial) ingredients. Not that 100% of the mass of the product is one of those two.

Also, I personally don’t have much of an issue recommending aspartame and Sucralose over sucrose (sugar). To be clear, neither is an ingredient I think anyone should consume much of — if any. However, when the only other alternative is consuming actual sugar, then, in most contexts, even artificial sweeteners like these two are the option I strongly recommend.

In future posts, you will get to see exactly why I feel sucrose (sugar) is so categorically awful that even fake chemical based sweeteners are often preferable for longevity and wellbeing.