Diabetic? There are supplements that may help you
Cinnamon, inositol, berberine, mulberry leaf extracts. Do they help?
I was reviewing a patient’s diabetes management in clinic on Thursday, and he had questions about alternative treatment, including supplements.
I gave him information based on my research, and that is the information I am sharing with you today.
Is ‘natural’ better?
‘Natural’ alternatives are commonly on patient’s minds when it comes to treatments, and medicines have only been available for a century.
Most of the progress made with medications for type 2 diabetes, and during this period much of the medical community have come to discount supplements as potentially helping improve diabetes control.
I haven’t defined natural (it is subjective). For this article we will assume natural means a substance hasn’t been significantly altered from its original form.
They’re in common use.
Supplements are a common topic patients raise when discussing diabetes.
The interest is understandable as supplements are often perceived as more natural, safer, and closer to addressing root causes rather than symptoms.
For some, they represent a way to regain control when progress with lifestyle change or medication feels slow.
Many clinicians are hesitant to discuss supplements in depth.
It is difficult for doctors to discuss supplements. They are poorly regulated, inconsistently studied, and largely absent from formal medical training.
This lack of exposure sometimes lead to the assumption that supplements offer no meaningful benefit, and may even cause harm.
But that assumption isn’t correct.
Some supplements do demonstrate significant glucose lowering effects and may have benefit being being used in conjunction with conventional medical management and lifestyle support.
The challenge lies in separating evidence from assumption.
Let’s get some clarity on supplements
Before discussing individual supplements, a few points need to be explicit.
Supplements do not treat the root cause of type 2 diabetes.
They do not reverse insulin resistance or replace the impact of sustained lifestyle change.
Supplements are not a shortcut.
Any glucose lowering effect they have depends on continued use.
When stopped, the effect stops. In this respect, they behave much more like medications.
Supplements can still cause side effects, interact with prescribed medications, and cause harm.
They should not be assumed to be safer simply because they are plant derived or sold without a prescription.
There is no good robust evidence on the long term safety or effectiveness of combining multiple supplements.
At present, we simply do not know, although in most cases the risks may be perceived as low.
Berberine
What is it?
We don’t find it commonly in foods. It is derived from a Chinese origin plant, where it is found in small amounts.
How does it work?
It works in a number of ways including:
Increased cellular glucose uptake (increasing ‘insulin sensitivity’)
Reduced glucose production from the liver
Shift cells to break down glucose into energy
Reduce absorption of glucose
A meta-analysis shows it is effective in helping to reduce blood glucose levels.
It found the mean difference in blood glucose as 0.82mmol/L.
What does that mean?
This is not a perfect conversion but using the diabetes.co.uk conversion calculator, 0.82mmol/L is equivalent to an A1c drop from 49 to 44 mmol or from 6.6% to 6.2% DCCT.
This is quite a big drop but this implies that berberine is taken with every meal.
How much do you need?
In the meta analysis - which looked at many studies - dosing was primarily taken in tablet form, with a range of 0.9g - 2.4g per day.
Supplements are available typically in 500mg (0.5g) and 1000mg (1g) doses.
It is likely to be active in the blood stream for a few hours after taking it.
It needs to be taken frequently with meals for it to have a sustained and meaningful impact.
What are the risks?
A meta analysis, looking at over 2,500 patients did not identify any major organ-related side effects. The frequency of side effects reported was comparable to anti-diabetic drugs.
These side effects were mostly gut-related side effects, which was dose dependent.
Berberine should not be viewed as better or necessarily safer than a medicine.
Mulberry Leaf
What is it?
It comes from the leaves of the Mulberry Tree, and has traditional use in Chinese Medicine.
How does it work?
By a number of potential actions including:
slowing down absorption into the blood stream
increasing insulin activity
reducing glucose release from the liver
as an antioxidant
Results
Mulberry Leaf shows promising results when it comes to blood glucose control.
A study of 615 participants found an average Hba1c fall of 2.92 (nearly 3 mmol/mol).
For context, this could be a change from 48 to 45 mmol/mol (UK/EU)
The longer the treatment, the more effective the outcome in the studies.
What are the potential side effects or concerns?
Gastrointestinal-related side effects for some people, such as diarrhoea or bloating. Most people did not report significant side effects.
How do people take it?
Capsules.
How frequently?
Between 1-3 times per day. One of the drawbacks of the study is that it doesn’t clarify exactly the differences in dosing in many of the research papers they reviewed.
What’s the dose?
There is a dosing range of 600-2500mg per day. Higher doses are usually split throughout the day.
You need to continue the supplement for it to have an impact much like typical medicines.
Cinnamon
What is it?
A spice commonly used in cooking. Many people will be familiar with its look & taste.
Specifically you should look at the ceylon variety of cinnamon, and avoid the cassia variety.
The benefits associated with ceylon cinnamon are not consistently replicated with cassia cinnamon.
How does it work?
Through a number of actions including:
improving glucose uptake in cells
mimicking insulin’s activity
including prevention of glucose release from the liver
What’s the impact data?
One study has reviewed multiple research papers totalling 1,100 participants.
Key Findings
There is an overall small reduction in HbA1c levels by up to 2.6 mmol/mol.
You need to continue to taking this supplement for it to have impact. There was no impact on weight.
What is the dose needed?
It depends whether you are using powder or capsule form and there is a wide range.
Based on the clinical studies reviewed:
Cinnamon Powder - 1-6g per day
Cinnamon extract - 0.12 - 0.5 grams per day
Side Effects
There is generally a lower risk of side effects reported with Cinnamon.
Inositol
Inositol is a form of sugar that is found in small amounts in many different foods.
This includes brown rice, legumes, nuts and citrus fruits.
As with many other supplements, to turn it into a supplement it is created using industrial techniques to produce in large quantities.
There are two main forms of inositol that are used as supplements. Myo-inositol and D-chiro-inositol,
Supplements available will usually contain both of these.
How does it work?
It’s also known as vitamin B8 - but it is not a vitamin! It is a carbohydrate and a type of sugar.
It’s full mechanism of action is not fully known but it has a number of impacts including improving the action of insulin in being able to move glucose into cells.
This impact has been shown to lower blood glucose levels after eating and at night time.
There also appears to be an impact in reducing inflammatory effects, which may contribute to weight loss.
It may also help to reduce glucose production from the liver, and reducing fat accumulation in the liver too.
Inositol studies are commonly done in gestational diabetes, who are women who develop diabetes during pregnancy.
They also looked at patients with Polycystic Ovarian Syndrome
What’s the evidence?
The evidence is good for inositol and appears to be quite safe.
It is noted as having significant improvement for blood glucose control in gestational diabetes and type 2 diabetes.
One study (Pintaudi et al) looked at 20 patients who had type 2 diabetes with inositol supplementation. They found a significant average reduction in blood glucose Hba1c from 8.6 - 7.7% (DCCT) - equivalent to a shift in mmol/mol from 70 down to 61.
Remember, shifts are likelier to be bigger if there is poor diabetes control.
This is a significant shift.
Another study specifically looking at reduction in weight found a significant impact too.
How do you take it?
It comes in supplements, typically split between the two types of inositol mentioned.
It does still have calories - but at 5 calories a teaspoon, a supplement will contribute significantly.
Typically a supplement would be taken once or twice a day.
Less effective supplements
Several other supplements are commonly marketed for blood glucose control, but the current human evidence supporting their use is limited.
Eriomin
A flavonoid derived from citrus, has been evaluated in a small number of randomised controlled trials.
These studies report reductions in HbA1c of around 1 to 1.5 mmol/mol, changes that were not consistently statistically or clinically significant.
It appears to me that studies may be influenced by industry involvement.
Hesperidin
Another citrus flavonoid, has been assessed in systematic reviews and meta analyses of randomised controlled trials. These analyses show no meaningful effect on blood glucose control.
Naringenin
has shown some glucose lowering effects in animal studies, but there is currently insufficient human trial data to draw reliable clinical conclusions.
Based on the available evidence, these supplements do not appear to offer meaningful benefit for most people with type 2 diabetes.
Key take homes
No supplements treat the root cause. Without looking to the root cause (lifestyle as a major component), you’re stuck taking supplements and your blood glucose will continue to rise.
There is no clear testing on combining these ingredients together and the potential long term risks and harms.
They have variable impact, can still have side effects, and cause toxicity in high doses
You would need to keep taking them all the time like your standard medicines.
If you choose to take supplements, your doctor should know. Adjustments to medication may be needed.