Researchers tested eight different brands of furu, a traditional Chinese fermented tofu product, to see if it could be a good source of vitamin B12 for vegetarians and vegans. They found that while some furu products contain B12, most of it is in a form the body can’t actually use. Only grey furu had meaningful amounts of usable B12, and even then, just 9% was in the right form. This means furu probably shouldn’t be your main source of B12 if you’re vegetarian or vegan, and you might need to look for other options like supplements or fortified foods.

The Quick Take

  • What they studied: Whether fermented tofu (furu) products sold in stores contain enough usable vitamin B12 to help vegetarians and vegans meet their daily needs
  • Who participated: Eight different commercial brands of furu products purchased from stores, tested in a laboratory
  • Key finding: Grey furu had the most B12 at about 1.1 micrograms per 100 grams, but only 9% of it was in a form the body can use. Other furu types had even less, with most containing less than 0.4 micrograms per 100 grams
  • What it means for you: If you’re vegetarian or vegan, furu alone probably won’t give you enough usable B12. You should consider other reliable sources like B12 supplements, fortified plant milks, or nutritional yeast to make sure you’re getting enough

The Research Details

Scientists bought eight different commercial furu products and tested them in a laboratory using two advanced techniques. First, they used high-performance liquid chromatography (think of it like a machine that separates and measures different chemicals) to measure the total amount of B12 in each product. Then they used an even more detailed technique called liquid chromatography-tandem mass spectrometry to identify exactly which types of B12 compounds were present and whether they were the active form the body can use.

This two-step approach was important because vitamin B12 exists in different chemical forms. Some forms are “active” and work in your body, while others are “inactive” and your body can’t use them. Previous studies had suggested furu might have B12, but nobody had checked whether it was the usable kind.

This research matters because millions of vegetarians and vegans worldwide struggle to get enough B12, which is crucial for nerve function and making red blood cells. If furu could be a reliable plant-based source, it would be great news. However, this study shows we need to be careful about assuming plant foods contain usable B12 without actually testing them properly. It’s a good reminder that just because something contains a nutrient doesn’t mean your body can actually use it.

This study used well-established laboratory techniques that are considered the gold standard for measuring vitamins. The researchers tested multiple products to see if results were consistent across brands. However, the study only looked at eight products, so we can’t be completely sure these results apply to all furu products everywhere. The study was published in a peer-reviewed scientific journal, meaning other experts reviewed it before publication.

What the Results Show

The researchers found big differences between furu products. Grey furu was the winner with about 1.1 micrograms of B12 per 100 grams, which is actually a decent amount. However, when they looked more closely at what type of B12 it was, they discovered something disappointing: only about 9% of the total B12 in grey furu was in the active form the body can use. The rest was inactive forms called corrinoids that your body can’t use.

The other seven furu products were even less impressive. They contained less than 0.4 micrograms per 100 grams total, and they had similar problems with most of the B12 being in inactive forms. This means that even if you ate a lot of regular furu, you probably wouldn’t get much usable B12 from it.

To put this in perspective, adults need about 2.4 micrograms of B12 per day. Even the best-performing grey furu would only provide a small fraction of that amount per serving, and most of what’s there wouldn’t help you anyway.

The study found that the pattern of having mostly inactive B12 was consistent across all the products tested. This suggests it’s not just a problem with one brand or type of furu, but rather something about how furu is made or stored that creates these inactive forms. The researchers also noted that grey furu stood out as having more total B12 than other varieties, which might be due to differences in fermentation time or the specific bacteria used in the fermentation process.

Earlier studies had suggested that furu might contain B12, which made sense because fermentation by bacteria can sometimes create B12. However, this is the first study to carefully check whether that B12 is actually usable by the human body. This research shows why it’s important to dig deeper than just measuring total nutrient content. Some plant foods that seemed promising for B12 have turned out to have mostly inactive forms, and furu appears to be another example of this.

The study only tested eight commercial products, so we don’t know if all furu products worldwide have the same problem. The researchers didn’t test homemade furu or products from all regions where furu is made. They also didn’t do any studies with actual people eating furu to see if the small amount of active B12 present would make any real difference in their B12 levels. Additionally, the study was done at one point in time, so we don’t know if B12 levels change over time as products sit on store shelves.

The Bottom Line

Vegetarians and vegans should not rely on furu as their main source of B12. Instead, consider these more reliable options: B12 supplements (either daily or weekly doses), fortified plant-based milks, fortified cereals, nutritional yeast, or fortified meat substitutes. If you do eat furu, enjoy it for its taste and nutrition, but don’t count on it for your B12 needs. This recommendation is based on strong evidence from this study.

This research is most important for vegetarians and vegans who are looking for plant-based B12 sources. It’s also relevant for people who follow plant-based diets for health or environmental reasons. Healthcare providers who work with vegetarian and vegan patients should know about this finding. People who eat furu occasionally as part of a varied diet probably don’t need to worry, but those relying on it as a B12 source should reconsider. This doesn’t apply to people who eat meat, fish, or dairy regularly, as they typically get enough B12 from those sources.

B12 deficiency develops slowly over months to years, so you won’t notice a problem immediately if you’re not getting enough. However, once you start taking a reliable B12 source like supplements or fortified foods, your body can build up its stores relatively quickly. Most people see their B12 levels improve within a few weeks to months of consistent supplementation.

Want to Apply This Research?

  • Track your daily B12 intake in micrograms, aiming for at least 2.4 mcg per day. Log all B12 sources including supplements, fortified foods, and animal products if applicable. Set a weekly reminder to check that you’re meeting your target.
  • If you’re vegetarian or vegan, add one reliable B12 source to your daily routine: take a B12 supplement, drink a glass of fortified plant milk, or eat a serving of fortified cereal. Make this a non-negotiable daily habit, just like brushing your teeth.
  • Set a monthly reminder to review your B12 intake log. Every 6-12 months, consider getting your B12 levels checked by a doctor with a simple blood test. This helps you know if your current strategy is working or if you need to adjust your approach.

This research is informational and should not replace professional medical advice. If you are vegetarian or vegan and concerned about B12 deficiency, consult with a healthcare provider or registered dietitian who can assess your individual needs and recommend appropriate testing or supplementation. B12 deficiency can have serious health consequences if left untreated, so professional guidance is important. This study suggests furu is not a reliable B12 source, but individual circumstances may vary.