5 Powerful Teas That Lower Blood Sugar

Dr Jedha, Host

Hello wonderful people, welcome back to another episode of Type 2 Diabetes Talk, which is all about exploring natural ways to improve blood sugar and overall diabetes health. 

While medications can be a part of treatment if necessary, natural diet and nutrition strategies provide the most powerful foundation to treat prediabetes and T2Diabetes effectively. Natural diet and nutrition strategies also provide the foundational potential to reduce your reliance on medication over time. We talk about foods quite a lot but not drinks so much. One fantastic, enjoyable, and incredibly accessible natural strategy is drinking tea. 

01:47

Tea rituals have been an integral part of various cultures throughout history, evolving into more than just a simple act of drinking. And while the drinking of tea and the ritual of tea can be equally enjoyed, today, we’re diving deep into using teas to help manage blood sugar levels, as there are some teas that are rich in polyphenols and antioxidants that have been shown to impact blood sugar regulation positively.

So, grab yourself a warm cup of your favorite tea and get comfortable because today, we’ll be exploring the incredible effects of five powerful teas. We’ll cover all three types of caffeinated tea Green tea, Oolong Tea and Black Tea under the same category. And we’ll also cover Chamomile Tea, Cinnamon Tea, Maté (mah-tay) Tea, and Mulberry Tea. We’ll delve into how each tea can help lower blood sugar levels, reduce A1c, and provide additional health benefits backed by scientific research.

02:58

Let’s kick things off with three types of tea that come from the same origin. Green tea, oolong tea, and black tea. All three of these teas are derived from the Camellia sinensis plant. Green tea is the baby of the family, undergoing minimal processing to preserve its green color and high levels of catechins, a type of antioxidant. Oolong Tea is the middle child in the tea family, while black tea is the head of the family in terms of tea processing. So while green, oolong, and black teas come from the same plant, they differ in their processing methods, which gives them unique flavors, polyphenol profiles, and potential effects on blood sugar levels. 

All three types of traditional caffeinated teas—green tea, oolong tea, and black tea—can provide significant benefits. According to research, tea polyphenolics have been suggested to possess blood glucose lowering properties by inhibiting sugar transporters in the small intestine and improving insulin sensitivity. All three types of tea, green tea, oolong tea and black tea, have been shown to inhibit glucose uptake into intestinal cells. Green tea has been shown to be most effective for inhibiting sugar transporters, followed by oolong tea then black tea. It’s interesting to note that overall the research supports both green tea and oolong tea as being the best types to support improvements in blood glucose levels, oolong tea has shown stronger outcomes.  

Let’s first look closer at green tea. 

When researchers do a systematic review and meta-analysis of randomized controlled trials, they are assessing the overall impact when they draw all the data together from clinical trials, and this is considered the highest form of evidence. A systematic review and meta-analysis of 27 clinical trials of green tea found that it lowered fasting blood glucose but only marginally, around 1.44 mg/dL or for our metric listeners, that’s around 0.1 mmol/l, but they didn’t see any effect on A1c levels. Another systematic review and meta-analysis found that green tea reduced fasting blood glucose by an average of 2.1 mg/dL or 0.1 mmol/l, particularly in those under 55 years of age, which was a strange finding.  While green tea may not be the most powerful tea to lower blood sugar levels, it does have other benefits, including its rich antioxidant content, which can help reduce oxidative stress and inflammation in the body. It also supports heart health, aids in weight management, and has been linked to improved cholesterol levels, making it a beneficial addition to your natural lifestyle plan.

Now let’s consider the benefits of oolong tea. 

Systematic review and meta-analysis indicated the average fasting blood glucose reduction from oolong tea was 39.91 mg/dL or 2.2 mmol/l for our metric listeners. I just want to note that we always include both metrics as we have listeners from all over the world. So for oolong tea, the average fasting blood glucose reduction from oolong tea was 39.91 mg/dL or 2.2 mmol/l. Now that’s quite a significant reduction and certainly much greater than green tea. I noticed this review hadn’t included one earlier trial on oolong tea in their analysis. In this study, researchers observed that participants who consumed 1500mls of oolong tea daily for 30 days experienced a significant decrease in fasting blood sugar levels. And when I say significant, I mean 67 mg/dL reduction, that’s 3.7 mmol/L. That’s a massive drop! Imagine how you’d feel if your morning blood glucose reading dropped by that much by just drinking tea. Now 1500mls is quite a lot, about 53 ounces or 6.34 cups of tea. So in the study people replaced drinking water for drinking the oolong tea, so if you were to try this I’d make a large pot of the tea, which you can purchase as both loose leaf form and convenient tea bags; then cool the tea and put it into a large BPA free drinking bottle and sip it throughout the day. 

Not only that, but studies have shown that oolong tea can help lower A1c levels by about 0.24%. While that’s not a lot, it’s still certainly of benefit. Now, you might be wondering, “What’s happening inside my body when I drink this tea?” Well, as we touched on earlier, oolong tea appears to inhibit the uptake of glucose in cells, potentially slowing down the absorption of carbs from your meals. Other benefits of consuming oolong tea include lowering adiponectin levels and lowering LDL particle size – this was in a study where people consumed 1000mls each day for one month, that’s about 34 ounces or 4.23 cups. Adiponectin is a hormone produced primarily by fat cells (our adipocytes) that is involved in regulating glucose levels and fatty acid breakdown. It has anti-inflammatory and anti-heart disease properties, making it an essential hormone for metabolic health. And as we spoke about in episodes 42 and 44, LDL cholesterol is not bad if you have large buoyant particles, so the fact that oolong tea can help transform small particle size, so both of these are great additional benefits of drinking oolong tea. 

10:23

Before we move onto some herbal teas, let’s look closer at another caffeinated tea. Maté (mah-tay) Tea is a traditional South American beverage made from the leaves of the Yerba Maté (mah-tay) plant and is packed with antioxidants and polyphenols. One thing to note, though, is that maté (mah-tay) tea is a caffeine-heavy beverage so it’s not suited to everyone’s metabolism. But if you tolerate caffeine-rich beverages, its benefits for blood sugar levels may be worth exploring.

In a study involving people with type 2 diabetes and prediabetes, participants who drank 330 mL, about 11 ounces or 1.4 cups of roasted maté (mah-tay) tea three times per day for 60 days experienced a reduction in fasting blood glucose by 25 mg/dL (1.4 mmol/L). Even more impressive, their A1c levels dropped by 0.85%. That’s substantial for just two months of drinking tea!

Research suggests maté (mah-tay) tea works by Research suggests maté (mah-tay) tea works by helping the body manage blood sugar in a few different ways. First, it contains chlorogenic acid, which can help reduce the amount of glucose released by the liver, meaning there’s less sugar entering your bloodstream. Another compound, called caffeic acid, helps improve how well liver cells take in glucose, which is particularly useful when your body’s insulin isn’t working as effectively, such as in insulin resistance which is present for most people with pre and T2diabetes. Also, studies show that maté (mah-tay) tea extract can reduce the amount of sugar absorbed in the intestines, such as we noted earlier, and this helps keep blood sugar levels more stable. These combined effects make maté tea a great option for supporting blood sugar management naturally.

Mate(mah-tay) tea is also known for supporting heart health, and has been shown to lower LDL and triglyceride levels in both prediabetes and type 2 diabetes.  In terms of systematic reviews, there has been one conducted in 2023, which looked at 23 studies, not all were randomized clinical trials but the purpose of this review was to establish the beneficial physiological effects of yerba maté (mah-tay) tea. The review concluded that there were consistent positive effects of consuming maté (mah-tay) tea for metabolic health improvements due to its antioxidant and anti-inflammatory activities. Most of these studies did use a tea infusion but I did notice in the results that some used extract capsules, 2000 to 3000 mg with positive outcomes, although these extract studies were different populations, not in people with diabetes but still interesting to note. 

Moving on from caffeinated teas, let’s explore a few herbal teas.

13:27

Next up is Chamomile Tea, which is more than just a relaxing bedtime staple! It’s often known for its calming properties, but chamomile also provides benefits when it comes to managing blood glucose levels. Researchers asked participants who were people living with type 2 diabetes to consume chamomile tea for 8 weeks in 150 mL or 5 ounces of hot water three times per day immediately after meals. For A1c, people saw a 0.03% reduction. Now, you might be thinking, “Well, that’s not much,” but remember, this change came purely from drinking herbal tea! For something so simple and natural, that’s a fantastic contribution. 

But it doesn’t stop there. The study also reported improvements in insulin resistance and positive changes in cholesterol levels. Additionally, chamomile has strong antioxidant properties that help protect your body from oxidative stress, which is often heightened in diabetes.

Chamomile tea is incredibly easy to find, with organic options available online or in most supermarkets. Brew a cup in the evening after dinner, and not only will you be supporting your blood sugar levels, but you’ll also be setting yourself up for a restful night’s sleep.

14:55

The next tea we’re investigating is Cinnamon Tea, a sweet and satisfying tea. 

In reviews of cinnamon supplementation, it has been shown to significantly reduce fasting levels and A1c. Although cinnamon is more widely studied in supplement form, primarily ceylon cinnamon, the tea still contains beneficial compounds that can have a positive impact. And the effects on blood glucose have been tested using cinnamon tea. In one study, people without diabetes were given cinnamon tea made from the cinnamon sticks. This is very easy to do and delicious. We have a recipe on our website so we’ll leave that in the show notes. People were given 100mL, 3.4 ounces, or about 1/3 cup of cinnamon tea. The most important benefit was it lowered the maximum glucose concentration, meaning the tea helped prevent sharp spikes in blood sugar. In another study with people with type 2 diabetes, people were given either cinnamon tea or normal tea. The people consuming the cinnamon tea had a lower postprandial level of 20.25 mg/dL or 1.1 mmol/l and the normal tea group had a rise of 54.2 mg/dL or 3.0 mmol/l for our metric listeners. So again, this demonstrates that cinnamon tea reduce blood glucose spikes after meals. 

While the tea itself has not been studied extensively, the benefits of cinnamon for blood glucose have. What’s great about cinnamon tea is that it’s incredibly easy to make. You can buy pre-made tea bags, or even better, make your own by simmering a cinnamon stick in water for 10-15 minutes, which is so easy to do.  The result is a wonderfully sweet and aromatic tea that you can enjoy hot or cold, so please head down to the website for the cinnamon tea recipe. 

17:53

Finally, let’s explore Mulberry Tea, a lesser-known tea that has been used in Asian traditional medicine, to promote health, relieve common colds, enhance eye, liver and kidney functions and decrease blood sugar and cholesterol.

But mulberry leaf isn’t all just folk lore. Multiple studies have looked closely at mulberry leaf to determine it has multiple bioactive compounds, including polysaccharides, phenolics, flavonoids, anthocyanins, and alkaloids. Mulberry leaves also contain a compound called DNJ, which has been shown to inhibit the digestion and absorption of carbohydrates. Reviews of mulberry leaf have concluded that mulberry leaf can be used for treating diabetes by reducing insulin resistance, protecting islet cells and regulating glucose-metabolism. There have been multiple studies in animals demonstrating positive effects, and clearly its use throughout history no doubt confirms its effects. In terms of human clinical trials in people with type 2 diabetes using the tea only (not supplementation), there is only one I could find, which is disappointing. I think studies using the tea could be one that deserves more research to investigate its impact for type 2 diabetes under different scenarios because the one clinical trial conducted did show a very significant outcome. 

In this clinical trial, participants from India were given either mulberry tea or black tea with one teaspoon of sugar after the same breakfast. Compared to those drinking black tea, the participants drinking the mulberry tea saw a difference in fasting blood sugar of 25 mg/dL (1.4 mmol/L) and an even more impressive difference in postprandial (after-meal) blood sugar levels of 77 mg/dL (4.3 mmol/L). That’s a huge difference! What’s interesting was these people were obviously not well controlled in terms of blood sugar, as their fasting ranges were already high, at around 153 – 178 mg/dL, that’s around 8.5-9.9 for our metric listeners. After their breakfast, their levels were also really high, the black tea group was 287 mg/dL (15.9 mmol/L) and the mulberry tea 210 mg/dL (11.7 mmol/l). While I know that sounds alarming, and it is, levels at 287 are ridiculously high. But, the impact of the mulberry tea was clearly visible. The participants had exactly the same breakfasts, the only difference was the teas, so the difference of 25 mg/dL for fasting levels, that’s 1.4 mmol/l, and they also saw a difference of 77 mg/dL (4.4 mmol/l) for postprandial and these are both significant outcomes. Considering these results, mulberry tea does seem to be able to inhibit the digestion and absorption of carbohydrates. So as I said, I think this tea could be one that deserves more research to investigate its impact for type 2 diabetes under different scenarios. And given its rich traditional history and the collective evidence, it can provide benefits to your regular routine. 

Mulberry tea is becoming increasingly popular and can be found online or in health food stores. We’ve also got all these teas and online options on our website or inside the members site. 

21:54

So, there you have it—five incredible teas that can support you to achieve healthier blood sugar levels. In terms of fasting levels, oolong tea has the most powerful impact and robust evidence to support it, followed by Mate Tea. In terms of postprandial levels, your after-meal blood glucose levels, cinnamon tea has the most powerful impact. In terms of A1c, Mate Tea has demonstrated the greatest impact. Overall, each of these teas offers unique benefits, and incorporating them into your daily routine can be an enjoyable and easy way to help manage your blood sugar naturally. 

Take a moment to experiment with these teas, find your favorites, and create a routine that works for you. The best part? You’re not just drinking a cup of tea—you’re actively supporting your health and well-being, one sip at a time.

Thank you for joining me today. 

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Until next time, take care of you!

Dr. Jedha over and out.