The Green Tea vs. B12 Myth: Why the Confusion?
There is a persistent myth that certain plant-based foods, including green tea, are natural sources of vitamin B12. This stems from some early research that used microbiological assay methods to detect corrinoid compounds in various tea leaves. However, these methods sometimes detect inactive corrinoids that are not the same as the biologically active B12 that humans need. For practical nutritional purposes, brewed green tea contains no usable vitamin B12.
A closer look at the research
Research has investigated the presence of vitamin B12 in various types of tea leaves, including green, black, and red tea. One study found corrinoid compounds in the leaves but concluded that higher values found by microbiological methods were likely due to inactive corrinoids that don't provide a nutritional benefit to mammals. Another study on Chinese black tea found that while some fermented tea leaves contained authentic B12, you would have to drink an impractical amount (hundreds of liters) to meet the daily requirement. For green tea, the consensus remains that it is not a meaningful source.
What is vitamin B12?
Vitamin B12, also known as cobalamin, is an essential water-soluble vitamin that plays a crucial role in the health of nerve tissue, brain function, and the production of red blood cells. Unlike most other vitamins, B12 is not naturally produced by plants and is primarily found in animal products. This makes it a critical nutrient for individuals following a vegetarian or vegan diet to monitor carefully.
Where to get reliable B12 sources
Since you cannot depend on green tea for this vital nutrient, it is important to know where to find reliable sources. For those following a vegan diet, supplementation or fortified foods are essential. Non-vegans can typically obtain enough B12 from a varied diet including animal products. Here is a list of trusted B12 sources:
- Animal Products: Meat, eggs, fish (such as salmon and tuna), and dairy products are excellent natural sources of vitamin B12.
- Fortified Cereals: Many breakfast cereals are fortified with vitamins, including B12, making them a convenient option.
- Nutritional Yeast: This popular vegan staple is often fortified with B12 and has a cheesy flavor, making it a great addition to sauces and snacks.
- Plant-Based Milks and Spreads: Look for products like soy milk, almond milk, or margarine that have been fortified with B12.
-
Supplements: For consistent and reliable intake, B12 supplements are a safe and effective option, especially for vegans and older adults.
Comparison: Green Tea vs. Reliable B12 Sources
Feature Green Tea Animal Products Fortified Foods Supplements B12 Content Negligible / Inactive High / Bioavailable Variable / Fortified High / Bioavailable Source Plant-based infusion Animal-derived Plant-based or synthetic Synthetic or fermented Reliability Not reliable Excellent Reliable, if fortified Excellent Diet Suitability N/A Omnivore/Vegetarian Omnivore/Vegetarian/Vegan Omnivore/Vegetarian/Vegan Absorption None for humans Efficient Efficient, varies by product Efficient Who is at risk for B12 deficiency?
Certain groups of people are at a higher risk of developing a B12 deficiency and should be particularly mindful of their intake. This includes older adults, as absorption can decrease with age, and individuals with certain medical conditions like pernicious anemia or those who have had bariatric surgery. Vegetarians and vegans are also at high risk due to their dietary restrictions and should prioritize fortified foods and supplements. Other risk factors include long-term use of certain medications, such as some acid-blockers and metformin.
Beyond B12: The real benefits of green tea
While green tea does not offer B12, it is still a very healthy beverage. Its key benefits come from its high concentration of antioxidants, particularly polyphenols. These compounds help protect cells from damage and may contribute to a reduced risk of chronic diseases like heart disease, diabetes, and certain cancers. Green tea also contains L-theanine, an amino acid known for its relaxing effects, and catechins, which may help boost metabolism. It is important to view green tea as a valuable addition to a healthy diet for these specific benefits, and not as a cure-all.
Conclusion: Stick to reliable sources
In summary, the notion that green tea contains a meaningful amount of usable vitamin B12 for humans is false. The trace corrinoid compounds found in the leaves are either inactive or present in amounts far too small to be nutritionally significant from a brewed beverage. Individuals seeking to ensure adequate B12 intake, especially those on plant-based diets, should not rely on green tea and instead turn to fortified foods, reliable animal products, or supplements. For its other health benefits, green tea remains an excellent choice for a low-calorie, antioxidant-rich beverage.
For more information on vitamin B12, consult resources from trusted health organizations, such as the NHS guide to the vegan diet.
