Written by Connie Zheng, PharmD | Reviewed by Stacia Woodcock, PharmD Published on October 13, 2022
Key takeaways:
- Dietary supplements include products like vitamins, herbal supplements, and botanicals. While evidence is limited, some studies suggest they can interact with diabetes medications.
- Check with your healthcare provider before you start taking a dietary supplement like niacin, ginseng, or ginger. You might need to track your blood sugar more often if you add one to your routine.
- Try to choose a supplement that has the USP-verified or NSF-certified mark on the label. This tells you the product’s purity and quality has been tested by an independent organization.
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If you have diabetes, you’re probably careful about taking care of your body. Perhaps you glance at food labels before filling your cart at the grocery store. Or maybe you’ve set up reminders to help you take your diabetes medications on time. You might even be considering dietary supplements to help boost your health.
In general, these are all smart steps to take. But before you add any supplements to your daily routine, it’s best to check in with your healthcare provider. Certain supplements can interact with your diabetes medications and affect your blood sugar levels. As a precaution, it’s important to keep some drug-supplement interactions in mind if you’re living with diabetes.
What medications are commonly used to treat diabetes?
Many diabetes medications are approved and recommended to lower your blood sugar. Metformin is a common first-choice medication, but other medications are also available. Top examples include:
- Sulfonylureas, like glipizide
- Thiazolidinediones, like pioglitazone (Actos)
- Dipeptidyl peptidase-4 (DDP-4) inhibitors, like Januvia (sitagliptin)
- Sodium-glucose cotransporter-2 (SGLT2) inhibitors, like Jardiance (empagliflozin)
- Insulin
6 vitamins and supplements that interact with diabetes medications
“Dietary supplement” is a broad term. It describes products that people add to their diet to improve their health. They’re primarily available over the counter. Common types of supplements include vitamins and minerals, herbals and botanicals, and probiotics.
While countless supplements are available, some of them can interact with diabetes medications. Many can change the way your body metabolizes (breaks down) diabetes medications. Others can affect the way your body responds to insulin.
And yet, there aren’t many studies that focus on the interactions between supplements and diabetes medications. And of the research that’s out there, results are often mixed. Here, we’ll break down the evidence behind possible interactions to be aware of.
1. Niacin
Niacin (vitamin B3) is found in many foods, such as beef, chicken, and marinara sauce. It’s also used as a supplement to help lower high cholesterol, which can help prevent heart problems down the line. Still, niacin and diabetes may not be the best mix.
Some studies have found that niacin can raise your blood sugar. It may also slightly elevate the risk for developing diabetes. Researchers believe this happens because niacin makes your body less sensitive to insulin, but this isn’t fully clear.
It’s recommended to use caution with niacin. You should monitor your blood sugar more closely if you start taking it. Niacin can make it harder for your diabetes medications to do their job. So be sure to let your healthcare provider know if you’re noticing symptoms of high blood sugar (hyperglycemia), such as headache, feeling thirsty, and urinating more often. They may also adjust your diabetes medication doses to account for niacin’s effects.
Keep in mind: Some multivitamins also contain niacin. This includes niacin in other forms, such as nicotinic acid and nicotinamide. The dose of niacin in a multivitamin is unlikely to lead to a noticeable change in your blood sugar levels.
2. St. John’s wort
St. John’s wort is an herbal product that’s marketed to help improve mood. Researchers are also looking into its use for other conditions, such as obsessive-compulsive disorder and premenstrual syndrome.
It’s also notorious for interacting with medications. In most cases, it makes them leave your body faster, lowering their effectiveness. But it can also amplify the effects of other medications, too.
There haven’t been many studies that look into how St. John’s wort affects diabetes medications. But based on how it works, it may make medications like sulfonylureas, thiazolidinediones, and DPP-4’s less effective. This could lead to higher blood sugar levels. What’s more, another study found that St. John’s wort can raise the level of metformin in your body. This can change your blood sugar control by raising the amount of insulin released by your body.
Talk to your healthcare provider before starting St. John’s wort. You might need to check your blood sugar more often, or they could tell you to avoid St. John’s wort altogether.
3. Ginseng
Ginseng is a plant that’s been used for thousands of years in medicine. People use it for various reasons, ranging from memory and immune system support to sexual health benefits.
Newer research also suggests that ginseng may lower fasting blood sugar and hemoglobin A1C in people with Type 2 diabetes. It’s thought that ginseng does this by telling your body to make more insulin and to remove sugar from the blood.
If you start taking ginseng with diabetes medications, you may want to watch your blood sugar more closely. It’s possible for your blood sugar levels to drop too low. Look out for symptoms of low blood sugar (hypoglycemia), such as dizziness, a fast heartbeat, and hunger. Make sure to keep a source of fast-acting sugar on hand too in case your blood sugar drops too low.
Keep in mind: Many types of ginseng are available — with the most popular ones being Asian and American ginseng. They might not all have the same effect on blood sugar. How ginseng is grown, processed, and extracted can affect how it lowers blood sugar.
4. Aloe vera
Aloe vera is a plant that’s well-known as a source of relief for conditions like sunburn. But aloe vera also comes in oral forms, like pills and juice. These are promoted to help with inflammation and gut problems.
Topical aloe vera isn’t a concern, but oral aloe vera may impact your blood sugar. Some studies found that it might lower fasting blood sugar in people with prediabetes. It may also lower A1c for people who already have diabetes.
Still, it’s a good idea to check your blood sugar more often if you’re taking oral aloe vera with your diabetes medications. Let your healthcare provider know if you’re experiencing symptoms of low blood sugar more often.
5. Ginkgo biloba
Ginkgo biloba is a supplement that people take for many health conditions, including dementia, anxiety, and tinnitus.
One study found that ginkgo biloba can raise blood sugar levels in people who take oral diabetes medications. It’s not clear why this happens, but researchers think it can cause your liver to break down insulin faster. To be safe, keep an eye out for high blood sugar symptoms, such as headache, tiredness, or urinating more often.
On the other hand, some interactions may be positive. Another study found that when taken with metformin, Ginkgo biloba can help improve blood sugar in people whose blood sugar was poorly controlled on metformin alone. Your healthcare provider can tell you if it’s a good idea to combine metformin with this supplement.
6. Ginger
Ginger is a versatile plant. It’s been used for thousands of years to flavor food, but people also use it to treat certain ailments, like nausea and menstrual cramps.
It’s not fully clear if ginger interacts with diabetes medications, but some studies show that it can lower your blood sugar and A1C. Other studies show it doesn’t affect fasting blood sugar, but it can lower your A1C.
If you add ginger to your routine, make sure to monitor your blood sugar more often. Watch out for symptoms of low blood sugar, such as dizziness, shakiness, and anxiety. Your provider might also want to check your A1C levels and see if they need to make any changes to your medication routine.
Tip: If you eat candied or pickled ginger, look for products that are sugar-free or low in salt. This may help prevent spikes in your blood sugar or blood pressure levels.
Tips for choosing a dietary supplement
The FDA doesn’t regulate supplements the same way they regulate medications. They don’t check the safety and effectiveness of supplements before they hit the market. This can make choosing a supplement stressful.
To protect yourself, choose supplement brands where the purity of their products has been verified by an independent organization. Look for the USP-verified or the NSF-verified marks on the labels.
While you’re looking at the label, also glance through the ingredient list. Some products, like gummy vitamins, contain sugar. When it comes to diabetes, sugar-free options are preferred.
The bottom line
Some supplements may interfere with how well your diabetes medications work, such as St. John’s wort and ginseng. Others, like niacin, might also change the way your body responds to insulin. Before you start taking a dietary supplement, talk with your healthcare provider. They can tell you which interactions to avoid, how to manage them, and they can also point you to a regulated supplement.
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