November is Diabetes Awareness Month, and with about 40 million people in the US living with diabetes, many of your patients are likely taking supplements too. Are you asking about everything they take, including cold remedies?
In this episode, NatMed editors Jeff Langford, Andrea Stafford, and Kelly Daniels answer important questions about supplements in patients with diabetes. They cover which supplements have evidence for glycemic control, and which ones can raise blood glucose, increase the risk of hypoglycemia, or even throw off a glucose reading. They wrap up with a lightning round of quick questions patients ask every day.
Questions we answer:
- Do supplements help with glycemic control?
- Which supplements can increase the risk of hypoglycemia with diabetes medications?
- Which supplement can raise blood glucose, and what dose?
- Can supplements throw off glucose readings?
We also cover:
- What the evidence shows for berberine and fenugreek for glycemic control.
- Why supplements taken for neuropathy, stress, or sleep can still affect blood glucose.
- Why high-dose niacin may require diabetes medication adjustments.
- How much vitamin C can cause falsely elevated glucose readings, and why it varies by device.
- A lightning round of commonly asked questions.
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NatMed / TRC Healthcare Editor Hosts:
- Jeff Langford PharmD, BCPS, BCCP (Managing Clinical Editor)
- Andrea Stafford, PharmD (Assistant Editor)
- Â Kelly Daniels, BA (News Editor & Associate Content Manager)
CE Information:
None of the speakers have anything to disclose.Â
TRC Healthcare offers CE credit for this podcast for subscribers.
Log in to your Pharmacist’s Letter, Pharmacy Technician’s Letter, or Prescriber Insights account and look for the title of this podcast in the list of available CE courses.
The clinical resources mentioned during the podcast are part of a subscription to NatMed:
- 🌱 NatMed Pro
- đź’Š TRC Healthcare
- Newsletter
- Infographic (Coming Soon)
- Monographs: Niacin, Vitamin C, Ashwagandha, Alpha-Lipoic Acid, Fenugreek, Berberine
- Tools: Effectiveness by Condition, Interaction Checker
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Transcript:
This transcript is automatically generated.
00:00:04 Kelly Daniels
November is Diabetes Awareness Month, and it’s the perfect time to talk about supplements and diabetes care.
00:00:10 Jeff Langford
Welcome back to Natural Medicines: Evidence in Practice. I’m Jeff Langford, pharmacist and managing clinical editor at NatMed.
00:00:18 Andrea Stafford
And I’m Andrea Stafford, pharmacist and assistant editor.
00:00:21 Kelly Daniels
And I’m Kelly Daniels, content production manager.
00:00:24 Jeff Langford
And on this show, we’re going to cut through trends and marketing claims to bring practical, evidence-based guidance for real patient conversations.
00:00:31 Andrea Stafford
And in honor of Diabetes Awareness Month, we are tackling some key supplement questions. For example, does any help with blood glucose control or even raise blood glucose levels? And which ones raise the risk of low blood sugar with diabetes medications?
00:00:45 Kelly Daniels
Quick reminder, this podcast offers CE credit for pharmacists, pharmacy technicians, prescribers, and nurses. Log into your NatMed account and look for this episode in the list of available courses. For disclosure, the NatMed team has nothing to disclose.
00:01:00 Jeff Langford
Well, Andrea, as we get started, certainly diabetes statistics show why the awareness of this condition is so important. For example, CDC says about 40 million people in the US have diabetes, about 12% of the population.
00:01:14 Jeff Langford
And we know that’s really impactful for people. It increases the risk of cardiovascular disease, kidney disease, liver disease, damage to nerves in eyes, and more. So that’s just some top things on that list. And Diabetes Awareness Month really puts a spotlight on identifying and managing the condition, including diet and medications. But tell me a little bit about why supplements need to be a part of this conversation too.
00:01:40 Andrea Stafford
Yeah, that’s a good question. And that’s because patients with diabetes may use supplements to help manage their blood sugar or for completely different reasons like neuropathy or stress and sleep or even a cold. Either way, diabetes management is this kind of balancing act and a supplement can raise or lower glucose or make a reading look wrong, leading to treatment decisions without a full picture.
00:02:06 Kelly Daniels
Right, and patients may not even think about mentioning them, especially if they’re not taking them for diabetes.
00:02:12 Jeff Langford
Yeah, so it’s definitely worth asking patients with diabetes what supplements they’re taking, and that includes things that they might not consider a supplement, like cold remedies.
00:02:22 Andrea Stafford
So with that in mind, let’s dive into our FAQs.
00:02:26 Kelly Daniels
Okay, so let’s start with the questions patients probably ask the most. Do any supplements actually help with glycemic control?
00:02:34 Andrea Stafford
Yes, there are several that have evidence, but we’re going to look at berberine right now specifically. There are several studies that show taking berberine 500 milligrams 2 to three times daily for two to four months can reduce A1C, fasting plasma glucose, and postprandial glucose in people with type 2 diabetes. And it might even be similarly effective as metformin 500 milligrams 2 to three times daily.
00:03:00 Andrea Stafford
And for patients already on a diabetes medication, meta-analyses show that adding berberine to oral hypoglycemic drugs lowers fasting glucose by about 15 milligrams per deciliter, postprandial glucose by about 20 milligrams per deciliter, and A1C by about 0.7% when compared with those oral hypoglycemic drugs alone.
00:03:25 Jeff Langford
And I’ll add fenugreek to this list. Lots of supplements have been studied for their effects on blood glucose, but fenugreek is one that also has some encouraging data. It’s shown to lower fasting glucose by about 20 milligrams per deciliter, for example, and A1C by about 1% compared to different controls.
00:03:43 Andrea Stafford
But just to call out, the American Diabetes Association’s 2026 standards of care don’t generally recommend supplements for glycemic control in people without an underlying nutrient deficiency because the evidence just isn’t strong enough.
00:03:59 Kelly Daniels
Right, so it sounds like clinical studies results sound meaningful, but they’re still not a substitute for guideline-directed therapy. What do you think is the key takeaway for patients on this?
00:04:09 Jeff Langford
I think one thing, Kelly, it’s really helpful to try to direct the conversation in a way that patients can see that diabetes management is more than just regulating blood glucose for many patients. Some newer diabetes medications, like SGLT2 inhibitors and GLP-1 agonists, for example, have been shown to have other benefits like reducing cardiovascular risk in some patients.
00:04:31 Jeff Langford
So as we try to work through those conversations and guide decisions about prescription meds and supplements, we really want to take that big picture and weigh all of the risks and benefits of the meds and supplements.
00:04:43 Andrea Stafford
Exactly. So even when a patient strongly prefers a supplement, we want to keep that big picture that Jeff spoke about in mind and not swap out a medication that’s also offering that protection.
00:04:54 Andrea Stafford
And there’s another side to this as well. The same glucose-lowering effect that makes these supplements look promising is exactly what can raise the risk of hypoglycemia when they’re combined with these diabetes medications. Which brings us to our next question about which supplements interact with them.
00:05:12 Kelly Daniels
Right, and that risk is easier to catch with berberine and fenugreek, as you mentioned, since patients are usually taking them for blood sugar to begin with. But what about supplements taken for something else entirely, like a cold, but it still interacts with diabetes medications?
00:05:26 Andrea Stafford
Good question. A few to watch for are alpha lipoic acid, ashwagandha, ginger, or melatonin. They can all lower blood glucose, so taking them with diabetes medications might increase the risk of hypoglycemia.
00:05:41 Jeff Langford
And what makes these a little easier to miss is the reason that patients are taking them in the 1st place, like Kelly alluded to. So alpha-lipoic acid, for example, is used for diabetic neuropathy. And it’s likely commonly used in our patient population with diabetes. Ashwagandha and melatonin are popular for stress and sleep. Ginger is go-to for nausea. So patients may be using any of these things alongside their diabetes medications, but they may not be using some of these supplements specifically for diabetes, and they may not connect the impact of these supplements to a change in their blood sugar.
00:06:18 Kelly Daniels
So it might be something you really have to ask about directly because the patient probably isn’t going to think about it and volunteer it on their own.
00:06:26 Andrea Stafford
Right. And it’s especially important to have this conversation with patients on insulin or sulfonylureas, where the hypoglycemia risk is already higher. But not every supplement lowers blood glucose. Some can raise it.
00:06:41 Kelly Daniels
Okay, so which supplements increase glucose?
00:06:45 Jeff Langford
niacin is a big one to watch for, Kelly. Niacin is commonly used to lower triglycerides, so it may turn up in our patient population with diabetes since often they do have elevated triglycerides as well. The catch is that niacin, especially at high doses, can raise blood glucose, likely by increasing insulin resistance or the amount of glucose the liver releases.
00:07:07 Kelly Daniels
How much of an effect are we talking about here?
00:07:10 Andrea Stafford
some data suggests that up to 35% of patients with diabetes may need to increase the dose of their diabetes medication when taking niacin.
00:07:19 Kelly Daniels
Okay, that’s a lot, 35%. That’s more than one in three patients taking niacin.
00:07:24 Jeff Langford
Yeah, right. It’s attention getting. There is a little nuance we want to add in here, and that is the effects of niacin on blood glucose are dose dependent.
00:07:33 Jeff Langford
And that means that the really high doses like 4 1/2 grams daily in some studies is linked to an increase in blood glucose of about 16% and over a 20% increase in A1C. But lower doses around 1 1/2 grams per day seem to have a much smaller effect on blood glucose. And that’s the range that many people are going to be using, especially if they’re using prescription niacins for triglyceride management.
00:08:00 Andrea Stafford
So the practical question isn’t just, are you taking niacin? It’s really how much the amount in a typical multivitamin or B complex is below that 4.5 grams daily.
00:08:10 Kelly Daniels
Okay, but what if a patient is taking a high dose?
00:08:14 Jeff Langford
Yes, I think in that case, it’s not automatically a reason to stop using it if the therapy is needed at that dose, but it really is a reason to coordinate with the prescriber, make sure we’re monitoring glucose closely and frequently, especially when we’re initiating niacin or changing the dose. But while we’re thinking about monitoring, the next supplement that we’re going to discuss doesn’t change glucose like niacin does, but it does change the number on some glucose monitoring devices.
00:08:46 Kelly Daniels
This one really surprised me. Can supplements really interfere with continuous glucose monitor readings?
00:08:53 Andrea Stafford
Yeah, they can. Large amounts of vitamin C can cause falsely elevated results on some continuous glucose monitoring devices. These sensors detect glucose through this electrical signal, and essentially vitamin C can add to that signal, so the sensor mistakes it for extra glucose.
00:09:12 Andrea Stafford
And depending upon the type of monitor, the user guide may warn about vitamin C intakes of more than 500 milligrams or more than 1,000 milligrams daily.
00:09:22 Kelly Daniels
Yeah, and that does not sound like very much vitamin C at all, especially this time of year, cold season, I’m sure I can reach 500 milligrams very easily.
00:09:31 Jeff Langford
Yeah, exactly. Vitamin C use tends to climb this time of year, as you mentioned, Kelly, with cold and flu. A lot of people are going to reach for a product like Emergen-C, for example. One packet of that has 1000 milligrams of vitamin C.
00:09:44 Andrea Stafford
And here’s why this is a safety concern. The patient sees this high reading. It looks real.
00:09:51 Andrea Stafford
And they take a correction dose of insulin they didn’t need if they’re on insulin. So the high was false, but that risk of hypoglycemia is real.
00:10:00 Kelly Daniels
So are there cases of these false readings actually happening in patients?
00:10:05 Jeff Langford
Yeah, there really are case reports of this occurring. And one case is just an illustration of how impactful this can be. So a patient with type 2 diabetes was hospitalized for management of diabetic retinopathy and was prescribed during that hospitalization a high-dose course of vitamin C using 10 grams per day. After about 10 days of treatment, she lost consciousness.
00:10:29 Jeff Langford
Now, her CGM reading, which she still was using or still had access to, was reporting her glucose as 291 milligrams per deciliter. So it looked like her blood glucose was high. But when they did a venous blood draw, blood glucose in that case was actually 12 milligrams per deciliter, so profoundly low. The patient was treated. Vitamin C was discontinued.
00:10:53 Andrea Stafford
That is an extreme example, but it shows how serious this interference can be. And since device user guides flag doses as low as 500 milligrams, even everyday vitamin C use is worth a conversation.
00:11:06 Kelly Daniels
So what guidance would you provide patients on this?
00:11:10 Jeff Langford
Yeah, first check instructions for the specific continuous glucose monitor device that the patient has or refer to those instructions. The issue varies from device to device. For example, the FreeStyle Libre 2 Plus and 3 Plus user guide say that taking more than 1000 milligrams of vitamin C per day can falsely raise sensor readings.
00:11:32 Jeff Langford
This could make patients miss a severely low glucose event like we described. However, it doesn’t impact every CGM. Dexcom, another big player in this area, has different substances that interfere with their readings, but vitamin C is not one of them.
00:11:48 Andrea Stafford
And we also want to ask about vitamin C directly. Powders, gummies, effervescent tablets, and immune support blends all count.
00:11:56 Andrea Stafford
And third, if they are taking it, an unexpected high reading, especially if it doesn’t match how they’re feeling, is a reason to follow up with a finger stick.
00:12:05 Jeff Langford
Whether a patient with diabetes is asking about berberine for glucose control, or you’re checking whether their cold remedy could affect their CGM readings, NatMed Pro has clinical tools to help. Use Effectiveness by Condition to see which supplements have real evidence for diabetes.
00:12:21 Andrea Stafford
And don’t forget to review all the sections within our individual monographs, including adverse effects, safety, and interactions with conditions.
00:12:29 Kelly Daniels
NatMed also offers CE credit and our monthly newsletter. Listeners can save 10% off a new or upgraded subscription with code NATMED1026 at checkout. Links are in the show notes.
00:12:41 Kelly Daniels
We’ve covered several important questions for patients with diabetes, but I think it’d be fun to do a quick lightning round to address questions that are likely to come up as well. We’ll keep these answers short. So you ready, Andrea and Jeff?
00:12:52 Andrea Stafford
Yes.
00:12:53 Jeff Langford
Let’s do it.
00:12:54 Kelly Daniels
Okay. First question, a patient’s been on metformin for years. Do they need a vitamin B12 supplement?
00:13:01 Andrea Stafford
That’s a fair question because long-term metformin use is associated with lower vitamin B12 levels. The ADA standards of care recommend considering periodic B12 checks for people on long-term metformin, and checking about once a year is reasonable for many of them. Then a supplement can be added if the level is low rather than just starting one automatically.
00:13:22 Kelly Daniels
Next question. Are gummy vitamins okay?
00:13:25 Jeff Langford
It depends on the specific gummy and how many a patient uses.
00:13:29 Jeff Langford
So gummy vitamins can contain anywhere from like 2 to 8 grams of sugar per serving. That’s going to depend on the brand and the type. But if patients are taking multiple of those gummies every day, the sugar content can certainly add up. So for example, if you took four gummies and they had that upper end of the sugar content, that would roughly equal like a piece of frosted birthday cake in terms of the amount of sugar. So it definitely could be impactful. Sugar-free gummies are available. Oftentimes they use sugar alcohols. It can still cause a minor elevation in blood glucose. So I’d say check the label and in many cases it’s probably going to be prudent just to suggest a tablet or a capsule if sugar intake is a real concern.
00:14:11 Kelly Daniels
Okay, what if a supplement bottle says supports healthy blood sugar? Does that mean it actually works?
00:14:17 Andrea Stafford
Not necessarily. That’s what’s called a structure function claim. It describes how a supplement may affect the body’s normal structure or function, and supplement makers don’t need FDA approval to use one, but the label must include a disclaimer saying the FDA hasn’t evaluated the claim and that the product isn’t intended to diagnose, treat, cure, or prevent any disease.
00:14:38 Jeff Langford
I’m going to sneak in here, Kelly, and just say that I think it’s really important to know that the supplements can’t legally claim to treat a condition like diabetes. So it’s going to use that language Andrea mentioned about supporting healthy blood sugar. So it sounds similar, but it’s really different. And we do want to help patients understand these really broad statements and what they are and are not saying and help them look for the evidence before they rely on the benefit.
00:15:05 Kelly Daniels
Yeah, that’s good clarification for sure.
00:15:08 Kelly Daniels
Okay, next question. Does chromium lower blood sugar?
00:15:11 Andrea Stafford
Yes. Oral chromium is rated possibly effective in our NatMed Pro monograph for patients with diabetes, especially when used in doses greater than 200 micrograms daily and in patients with poorly controlled diabetes.
00:15:25 Kelly Daniels
Okay, Jeff, last but not least, cinnamon. Does it work?
00:15:29 Jeff Langford
Okay, we couldn’t leave that one unanswered, could we? There are several types of cinnamon, so the answer gets really complicated.
00:15:36 Jeff Langford
To keep it as a lightning round, we’re going to focus on Cassia cinnamon. It’s the most common type sold in North America.
00:15:43 Jeff Langford
And we rate Cassia cinnamon as insufficient in NatMed. And that’s because the evidence is really mixed. Some studies in type 2 diabetes do show a benefit. One meta analysis, for example, showed that it lowered fasting glucose by about 25 milligrams per deciliter.
00:15:59 Jeff Langford
So those kind of findings are what generate interest in cinnamon for blood glucose. But there’s a flip side to that coin. Often the data doesn’t find a benefit.
00:16:07 Jeff Langford
A more recent study looked at Cassia cinnamon powder, found no benefit. Results for A1C are also fairly mixed. So most of the studies here are small and there’s a lot of variability in dose duration and background therapy. So again, even though there’s a lot of hype around cinnamon, we still rate it as insufficient evidence to really come to a bottom line.
00:16:29 Andrea Stafford
And it’s important to always, as we should, want to consider safety and drug interactions for each patient before recommending any supplement.
00:16:38 Kelly Daniels
Absolutely. Okay, great job guys. That’s the end of our lightning round. Those are the types of questions patients ask every day though, so it’s good to just run through some of those. Let’s wrap up with our key takeaways now.
00:16:51 Jeff Langford
Sure. So first, berberine and fenugreek, for example, have evidence for lowering glucose and A1C. That same effect, however, with other supplements like alpha lipoic acid and ashwagandha can increase the risk for hypoglycemia when those supplements are combined with diabetes meds.
00:17:08 Andrea Stafford
And high-dose niacin can raise blood glucose and A1C, but doses up to 1.5 grams daily seem to have minimal effects. So ask how much they’re taking.
00:17:19 Kelly Daniels
Third, vitamin C at 500 milligrams or more can cause falsely elevated readings on some CGMs. Check the patient’s device and ask about vitamin C, especially during this time of year.
00:17:28 Jeff Langford
And I’ll toss in a couple of tips from our lightning round. I would definitely say to check B12 levels in patients on long-term metformin, like Andrea mentioned. And when we’re thinking about supplements, don’t trust a label claim over evidence.
00:17:43 Jeff Langford
Kelly and Andrea, as we wrap this episode up, I’ll say it feels a little bittersweet for me. I’m pursuing a new opportunity in clinical practice. It’s going to take me outside of the NatMed space every day. So I won’t be with you on the next episode.
00:17:55 Jeff Langford
But these are great conversations. I love having them with both of you. And I look forward to listening to that next episode and taking the information you’re going to share back into my own practice.
00:18:08 Andrea Stafford
Well, Jeff, I know I can say that you’ve helped launch this podcast and were with us on episode one and your voice will definitely be missed.
00:18:16 Kelly Daniels
Absolutely. We’ll miss you very much, Jeff.
00:18:20 Jeff Langford
Well, thanks so much, guys. That means a lot.
00:18:25 Andrea Stafford
But to claim CE credit for today’s episode, follow the instructions linked in our show notes.
00:18:31 Kelly Daniels
We’ve also included links to the original newsletter article, which covers other timely topics, including vitamin B6 and neuropathy.
00:18:38 Jeff Langford
follow and subscribe to this show in your podcast app so new episodes land automatically.
00:18:43 Andrea Stafford
Thanks for listening to Natural Medicines: Evidence in Practice. Evidence, not hype.
00:18:47 Kelly Daniels
See you next month.
Natural Medicines: Evidence in Practice
