Like 89% of nutrition accounts on instagram, the Glucose Goddess has a supplement on sale. Obviously it is being sold alongside lots of hand-waving statements about “ingredients have been thoroughly tested in clinical trials”, but the supplement itself has not been tested in a proper trial. This is a problem in and of itself.
There are also many problems with supplements (unregulated) anyway, but particularly with a supplement like this which is sold to “limit glucose spikes”.
Read on to hear why I would not recommend anyone, people with or without diabetes - purchase this supplement right now.
Nutrition supplements are problematic anyway, and the people behind them are allergic to….standards.
One of the major problems with nutritional supplements is that they are unregulated. As much as people hate on the pharmaceutical industry - prescribed medications have to go through robust testing and quality assurance. If your doc prescribes you 100mg progesterone per day to prevent endometrial hyperplasia, by golly you want to be sure the tablet you take always contains 100mg progesterone, right? Likewise if you take any medication you want to have some confidence that tests have been carried out to make sure that medication doesn’t have toxic or harmful side effects, and that it actually is biologically and clinically efficacious. These types of things are tested via phase 1, 2/b and phase 3 clinical trials.
By contrast, there is no regulation of nutrition supplements. Maybe sometimes a tablet contains 10mg of lemongrass extract, maybe next time it doesn’t. Likewise, phase 1 and 2 trials are not done on supplements - these types of trials seek to establish a dose response effect (so you can be sure to give the lowest effective dose), and also to understand toxicity. Cos by the way, supplements are not necessarily harmless just because they’re “natural” or “nutritional”.
You can talk about “science” as much as you want, but if the actual supplement has not been tested in a clinical trial (and in the intended populations), then no, it bloody isn’t “backed by scientific research”.
Folks flogging nutrition supplements rarely attempt to test their products in a proper trial. I give a lot of kudos to those who do, because it helps provide evidence for what works and what doesn’t.
Instead, what most supplement companies do is highlight other research (of varying quality) that has been done on some of the individual ingredients. The types of research cited might include good trials, it might include really crap trials, it might include observational studies that shows use of a supplement is associated with a low incidence of a certain disease. The vast, vast majority of supplement research is utterly, utterly shit (they don’t register the protocol, they don’t have a power calculation, they don’t have a pre-defined primary outcome etc).
Nevertheless, even if there are good trials which show that an individual ingredient is effective at lowering glucose, the supplement itself MUST be tested. Why?
Because you can’t assume that different ingredients or bioactive compounds are going to work together in a way that’s complementary. For example, one ingredient may prevent the absorption of another ingredient. Or one ingredient might lead to an increase in enzymes that act to degrade another ingredient. So one ingredient might neutralise another. Even more worrying, even if you knew that one ingredient on its own is safe, it doesn’t mean that potentially deleterious properties of that ingredient could not be exacerbated by the presence of another bioactive within the same tablet.
I think you should also want to establish whether the individual ingredients complement each other in their mechanism of action. For example, if one ingredient works by promoting insulin secretion via depolarising the beta-cell membrane, adding another ingredient which also promotes insulin secretion via depolarising the beta-cell membrane may have no additional effect. So then what’s the point of that additional ingredient?
So all in all, very poor. There is a reason that no-one takes nutrition science seriously, and it’s the abject lack of will to actually test anything properly.
Let’s look at the individual ingredients, and the evidence behind them.
The “anti-spike formula” is described as having four plants for which there are “25 clinical trials” to back up the claim they reduce glucose spikes. Let’s look at some of the trials (some of these are ones highlighted on the website as “evidence”:
Mulberry Leaf Extract (250mg)
This is probably the ingredient with the strongest evidence behind it. It’s thought to work (at least one of the ways) as an α-glucosidase inhibitor. α-glucosidase digests some carbohydrates so if you inhibit its action then you don’t break down the carbohydrate as much. This means that the glucose rise after eating carbs is reduced.
The data from people with and without type 2 diabetes is not bad. Trials seem to see some reduction in glucose, and there appears to be a dose-response effect that gives you some confidence that the extract has genuine biological activity. The effect size seems to vary in studies - the reduction in glucose was about 20-30mg/dL (1.1-1.7mmol/L) in one of the trials, but in another the dose didn’t seem to reduce glucose to a significant degree until it reached 500mg.
Even having 1000mg MLE 3 times a day was not enough to significantly lower HbA1c in people with T2D. Admittedly this was a pilot study - but many of the people taking the MLE only had very modest reductions in post-prandial glucose.
So in conclusion, there is a question about the consistency of effect, and whether the magnitude of reduction in glucose is clinically relevant.
A big problem with this extract is a lack of a safety profile. If the primary “active compound” is α-glucosidase inhibitor this can provide some confidence because α-glucosidase inhibitors have a safety profile established eg (the drug Acarbose is an α-glucosidase inhibitor). However, even investigators who have found very positive results with MLE note that it does contain many other potentially active compounds which have not been studied properly.
So we don’t have data on its long-term safety - not least at 250mg (per meal? I think the sellers of the Anti-Spike supplement advocate taking a tablet per meal) - and this is a concern. JUST BECAUSE SOMETHING IS NATURAL DOES NOT MEAN IT IS SAFE.
Lemon Extract (250mg)
Having 125ml of pure lemon juice (pull that weird OMG this is TAAAART face now) might lower glucose compared to tea but I can’t find any evidence that this ingredient does anything to glucose. There’s some suggestion that in vitro (basically in cells, or a lab-based preclinical study not in a human trial) lemon extract might also be an α-glucosidase inhibitor. But 1) this doesn’t mean it does anything in a human, and 2) why would you want an ingredient that works by the same mechanism of action as MLE?
Cinnamon Extract (85mg)
Cinnamon and cinnamon extract has been tested in a few trials - none of which (AFAIK) were what I would call robust clinical trials. Similar to the situation with MLE, while there does seem to be some anti-glycaemic action, the actual magnitude of effect is in question.
For example, at 85mg of liquid cinnamon extract there is no significant reduction in HbA1c after 4 months in people with T2D. There was no trial registration either, so the reduction in fasting glucose in the intervention group might well be a type 1 error (false positive). A separate research group who formulated their own cinnamon extract did not find any effect on glucose in people with T2D.
In a pilot study on women with PCOS, 333mg of cinnamon extract 3 times per day was described as lowering glucose (but the investigators do not compare the change to that in the control group which is weird), and there *might be* an improvement in insulin sensitivity, but honestly it looks like the effect is largely driven by one person.
The potential good news (I am trying to be positive) is that cinnamon extract is though to work via improving insulin sensitivity. So if (a big if?) it were an effective agent, at least the mechanism of action would be complementary to MLE.
“Antioxidants” (100mg)
I can’t find any info on what type of antioxidants this is. Wait, I just checked the anti-spike formula website (IT’S 46 QUID A BLOODY BOTTLE FOR THIS FORMULA HAHAHAHAHAHA) and the antioxidants are “Glucose Goddess Antioxidants”. These are a mix of natural polyphenols derived from vegetables. I mean honestly, maybe these polyphenols do something but based on the literature I have seen so far I doubt it. Maybe there is something happening when we get close to 1g per tablet of these types of compounds, but at 100mg I doubt it.
Also, WHY NOT JUST EAT BLOODY VEGETABLES??
(If you thought I was done, sorry).
What’s wrong with having a specific supplement that addresses glucose spikes?
There is certainly a clinical rationale to limiting glucose excursions in people with diabetes because the glucose rises that can occur in people with diabetes can cause harm - eg to the blood vessels, and there are obviously health benefits to limiting these excursions.
However, the effect-size of this supplement (see above) is probably not enough to have a clinically relevant impact. In other words, the supplement is very very unlikely to lower glucose to a degree significant enough in diabetes that it has any meaningful health benefits.
Likewise, while the evidence for glucose excursions being harmful in prediabetes is weaker than for diabetes, in many people (eg those with impaired glucose tolerance) limiting those excursions is probably beneficial for reducing the harm to blood vessels and other things. Again, this supplement is probably unlikely to have a significant enough impact on the glucose concentrations in prediabetes to make any difference.
But there is also a bigger problem to the whole idea of “limiting glucose spikes to prevent disease”, specifically thing like type 2 diabetes or insulin resistance. This is because:
And: targeting the symptom and not the underlying pathophysiology is crazy.
You can read more detail about this than you ever wanted here and here, but basically glucose starts rising on the pathway from normal glucose tolerance to type 2 diabetes because of organ-specific insulin resistance, and defects in beta-cell function. The relative contribution of each of these primary pathophysiological defects to the rising glucose concentration differs between people. However, one thing is clear:
To prevent the year-on-year rise in glucose, and prevent type 2 diabetes from developing, you need to FIX THE UNDERLYING PATHOPHYSIOLGY.
(We have no evidence that lowering glucose itself does anything to prevent type 2 diabetes from developing).
So my concern regarding “hey you need to limit glucose spikes to prevent disease” is that it is a profound misunderstanding of how many diseases develop. And the problem with the focus on glucose spikes is that maybe trying to manage them will lead a person to make healthy lifestyle changes, but it may also lead a person to do stuff that has no effect, or that even could be harmful or unpleasant (I like my gastric lining and don’t really want to neck down vinegar thanks). I lay out this argument in more depth in this publication.
In conclusion, a supplement which is focussed on “limiting glucose rises” (and it probably doesn’t do this to any meaningful degree anyway) is going to be useless for preventing T2D (and the many other diseases relating to insulin resistance and signalling) IF IT DOES NOT FIX THE UNDERLYING PATHOPHSYIOLOGY.
The potentially useful thing about MLE is that it may improve the underlying pathophysiology in the same way acarbose might. But if this is the case, why not just get MLE (I am not advising you do this by the way for safety reasons outlined), or better yet acarbose which has been tested extensively including for type 2 diabetes prevention.
Ok just one final rant. The website says something like “have this tablet when you eat cake to limit glucose rises”. What the jiggins. Have cake if you want. But the idea that any conceivable nutritional or health damage from eating cake is going to be nulled because your glucose rise when you eat is going to be limited to 6.9mmol/L when it might have got to 7.2mmol/L is utterly, utterly moronic.
Some bullet-point recommendations for free:
Eat more plants and fibre:
Doing this will not only lower your glucose acutely - it will improve the underlying pathophysiology of T2D. It’s also going to help you be healthy generally.
Going for a walk after meals is great.
Because exercise in general is going to improve your insulin sensitivity, and have a host of other health benefits. For people who have T2D these types of exercise snacks can help lower your glucose acutely too. Win win.
Changing the order of your food can be a great way of lowering glucose to a degree that can be clinically relevant in T2D. For a few reasons, going with protein first is my recommendation.
I wouldn’t bother doing this if you don’t have prediabetes or diabetes simply because there’s no reason to worry about your glucose excursions if you eat a reasonable healthy diet, and jesus can people just enjoy their food without making everything a science project?
If you feel that this article saved you £46, feel free to send a donation to my favourite charity: The Sheldrick Foundation. LET’S TAKE BAD SCIENCE AND TURN IT INTO HABITAT FOR BABY ELEPHANTS.
If you want more info on what to do to prevent type 2 diabetes, check out this article.
If you wanna chirpse my whole series on “everything you ever wanted to know about glucose and CGMs start here.
Thank you for so eloquently explaining this!! I am a dietitian and doing my PhD, and the lack of scientific rigour in nutrition supplements is infuriating.
Thank you so much for your brillant and funny insights. We need some levity in this "optimization wellness bro-science biohacking orthorexic longevity" nightmare.