Tea leaves transforming into enzymes to control sugar molecules.

Unlocking Tea's Secrets: Can Black Tea Really Help Control Carbs?

Lena Voss in Health & Wellness December 2025 • 5 min read.

"Exploring the potential of black tea and green tea in managing blood sugar and weight through enzyme inhibition."

For centuries, people have turned to plants for healing, and teas are among the most ancient and popular remedies. Green tea and black tea, both derived from the Camellia sinensis plant, are often touted for their potential to help manage hyperglycemia (high blood sugar) and obesity. But how much of this is just old wives' tales, and how much is backed by science?

The key may lie in how these teas interact with our digestive enzymes. Specifically, researchers are investigating whether compounds in tea can inhibit enzymes like alpha-amylase and glucosidases, which are responsible for breaking down carbohydrates. By blocking these enzymes, teas could potentially slow down the absorption of sugars, leading to better blood sugar control and weight management.

This article delves into a study that examined the enzyme-inhibiting properties of green and black tea. We'll explore how these teas affect carbohydrate digestion under different conditions, including simulated digestion in the stomach, and what the findings might mean for your health.

Green Tea vs. Black Tea: A Tale of Two Processing Methods and Different Effects

Tea leaves transforming into enzymes to control sugar molecules.

Both green and black tea come from the same plant, Camellia sinensis, but they undergo different processing methods that affect their chemical composition. Green tea is made from fresh leaves that are steamed or pan-fried to prevent oxidation, preserving their vibrant green color and high concentration of certain compounds. Black tea, on the other hand, is fully oxidized, giving it a darker color and a distinct flavor profile.

A study published in the journal Revista Brasileira de Plantas Medicinais investigated the impact of green and black tea on key digestive enzymes. The researchers prepared infusions of both teas and measured their ability to inhibit alpha-amylase, alpha-glucosidase, and beta-glucosidase – enzymes crucial for breaking down starches and sugars.

Phenolic Power: The study found that black tea had a significantly higher concentration of phenolic compounds (80.8 ± 0.43 mg/g) compared to green tea (32.0 ± 0.12 mg/g). Phenolic compounds are known for their antioxidant and enzyme-inhibiting properties.
Enzyme Inhibition: Both green and black tea inhibited the activity of the tested enzymes under normal conditions. Black tea, however, exhibited a stronger inhibitory effect, particularly against alpha-amylase.
Simulated Digestion: Here's where things got interesting. When the teas were subjected to simulated gastric fluid (mimicking the acidic environment of the stomach), green tea lost its inhibitory action. Black tea, however, continued to inhibit alpha- and beta-glucosidases, while its effect on alpha-amylase diminished.

These findings suggest that the compounds in black tea are more resistant to the harsh conditions of the stomach and may retain their enzyme-inhibiting properties further down the digestive tract. This could explain why some studies have shown black tea to be more effective in managing blood sugar levels.

The Bottom Line: Could Black Tea Be a Carb-Conscious Choice?

The study indicates that both green and black tea can inhibit carbohydrate-digesting enzymes in vitro, but black tea appears to maintain its inhibitory effect even after exposure to simulated stomach conditions. This suggests that black tea may be a helpful addition to diets aimed at restricting carbohydrates and managing blood sugar levels.

However, it's important to remember that this is just one study, and more research is needed to confirm these findings in humans. Factors like tea concentration, brewing time, and individual differences in digestion can all influence the effects of tea on enzyme activity.

If you're considering using tea to help manage your blood sugar or weight, talk to your doctor or a registered dietitian. They can help you determine if tea is right for you and how to incorporate it safely and effectively into your diet.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1590/s1516-05722010000400017, Alternate LINK

Title: Atividade Das Glicosidases Na Presença De Chá Verde E De Chá Preto

Subject: Complementary and alternative medicine

Journal: Revista Brasileira de Plantas Medicinais

Publisher: FapUNIFESP (SciELO)

Authors: L.L.S. Pereira, S.P. Souza, M.C Silva, G.A. Carvalho, C.D. Santos, A.D. Corrêa, C.M.P. Abreu

Published: 2010-12-01

Everything You Need To Know

How might black tea and green tea impact blood sugar and weight management?

Both green tea and black tea, which are derived from the *Camellia sinensis* plant, have shown the ability to inhibit carbohydrate-digesting enzymes like alpha-amylase and glucosidases in laboratory settings. These enzymes are responsible for breaking down starches and sugars, and inhibiting them could potentially slow down sugar absorption, potentially aiding in blood sugar control and weight management.

What distinguishes the processing of green tea from black tea, and how does it affect their properties?

The key difference lies in the processing. Green tea is minimally oxidized, which helps preserve its high concentration of certain compounds. Black tea is fully oxidized, resulting in a darker color and distinct flavor profile. A study published in the journal *Revista Brasileira de Plantas Medicinais* showed that black tea has a higher concentration of phenolic compounds than green tea. Furthermore, when subjected to simulated gastric fluid, black tea maintained its inhibitory action on alpha- and beta-glucosidases, while green tea lost its inhibitory action.

Does black tea's enzyme-inhibiting effect survive digestion, and what does this mean for managing blood sugar?

The *Revista Brasileira de Plantas Medicinais* study suggests that black tea's enzyme-inhibiting properties are more resilient to the acidic environment of the stomach compared to green tea. This means black tea may continue to impact carbohydrate digestion further down the digestive tract. Therefore, black tea might be a more effective choice for individuals seeking to manage blood sugar levels through enzyme inhibition, although individual results may vary. The study is 'in vitro'.

What are phenolic compounds, and how do they contribute to black tea's potential benefits?

Phenolic compounds are a class of chemical compounds found in plants, including *Camellia sinensis*. They're known for their antioxidant and enzyme-inhibiting properties. Black tea, with its higher concentration of phenolic compounds (80.8 ± 0.43 mg/g), demonstrates a stronger ability to inhibit enzymes like alpha-amylase, which is crucial for breaking down starches. These compounds can interact with digestive enzymes, potentially reducing their efficiency in breaking down carbohydrates.

If I'm watching my carbs, how can incorporating black tea in my diet help me, according to research?

The study suggests that incorporating black tea into a carbohydrate-conscious diet may be a helpful strategy for managing blood sugar levels. By inhibiting enzymes involved in carbohydrate digestion, black tea could slow down the absorption of sugars, leading to more stable blood sugar levels. However, it is essential to consider black tea as one component of a broader approach that includes a balanced diet, regular exercise, and, if necessary, medical supervision. Additional research is needed to confirm these findings in human trials and to determine the optimal amount and timing of black tea consumption for blood sugar management.