“I’m 51 and have been diagnosed with Vitamin B12 deficiency. How can I increase my Vitamin B12 naturally?”
Vitamin B12 deficiency is becoming increasingly common, particularly after the age of 50. Depending on the population studied, an estimated 5–20% of adults have low or deficient Vitamin B12 status, and deficiency is found not only among vegetarians and vegans but also among many people who regularly consume meat, fish, eggs and dairy products. The true prevalence of Vitamin B12 deficiency is difficult to establish because there is no single universally accepted diagnostic test or definition. Estimates vary depending on the population studied and the diagnostic criteria used, and it is likely that some cases remain undiagnosed because symptoms are non-specific and laboratory testing has recognised limitations.
Common symptoms include fatigue, weakness, reduced exercise tolerance, poor concentration, memory problems, tingling or numbness in the hands and feet, balance problems, low mood, a sore tongue, mouth ulcers and megaloblastic anaemia. Not everyone experiences symptoms, and many of these symptoms can have other causes, which is why Vitamin B12 deficiency is usually confirmed with appropriate testing rather than symptoms alone.
For some people, deficiency may simply reflect insufficient exposure to a nutrient. For others, the issue lies in the body’s ability to digest, absorb, transport, activate or utilise it. A lack of exposure is fairly easily fixed through the introduction of a supplement.
Most of us associate vitamins with plants. Vitamin C is made by plants before becoming part of our diet. But vitamin B12 is different: Plants do not make Vitamin B12. Animals do not make Vitamin B12. Humans do not make Vitamin B12.
A vitamin is an organic compound that the body needs in small amounts to support normal growth, metabolism, maintenance, and physiological function, but cannot produce in sufficient quantities itself.
Therefore, it VITAmeans is VITAL and must usually be obtained from the diet. Vitamin B12 is different to many other vitamins, as it is made by certain bacteria and archaea. Every naturally occurring molecule of Vitamin B12 begins with microorganisms. Rather than asking only which foods contain it, we can now ask where the microorganisms are that make it and what conditions they require.
Like every living organism, these microorganisms need suitable conditions in which to grow. One essential requirement is cobalt, the mineral found at the centre of every Vitamin B12 molecule. Without cobalt there can be no Vitamin B12. Scientists have already identified a number of Vitamin B12-producing bacteria, including Acidipropionibacterium freudenreichii, Propionibacterium acidipropionici, Pseudomonas denitrificans and several Streptomyces species, together with certain archaea. Research continues to identify additional microorganisms capable of making Vitamin B12 and to understand the conditions under which they thrive.
One environment attracting increasing scientific interest is fermentation. Traditional fermentations are living microbial ecosystems. Depending on the ingredients, temperature, moisture, minerals, acidity and the microorganisms present, they create conditions in which different microbial communities develop. Swiss-type cheese provides one of the best-studied examples because it contains Acidipropionibacterium freudenreichii, a bacterium capable of making biologically active Vitamin B12 during the cheese-making process.
Other traditional fermented foods are also of interest. Examples of traditional microbial ecosystems include Swiss-type cheese, Emmental, Gruyère, kefir, yoghurt, cultured buttermilk, sourdough bread, Indian idli and dosa, Ethiopian injera, tempeh, miso, natto, sauerkraut, kimchi, traditional fermented pickles, fermented beetroot, fermented carrots, kombucha, water kefir, kvass, boza, ogi and many other regional fermented foods. The microbial communities within these foods vary considerably, and so does their potential to produce Vitamin B12. Factors such as the microbial strains present, cobalt availability, ingredients, temperature, acidity and fermentation time all influence the final outcome.
Humans present another interesting puzzle. We also host Vitamin B12-producing bacteria within the digestive tract. Unfortunately, most of this production occurs in the large intestine, whereas Vitamin B12 is absorbed much earlier in the terminal small intestine. In other words, we appear to make Vitamin B12 in the wrong place.
Interestingly, modern medicine already recognises that transferring microbial communities can influence health. Faecal microbiota transplantation (FMT) is now an established treatment for recurrent Clostridioides difficile infection, demonstrating that restoring an entire microbial ecosystem can have profound clinical benefits. Although FMT is not a treatment for Vitamin B12 deficiency, it illustrates a broader principle. Microorganisms are increasingly recognised as contributors to human health rather than simply organisms to be eliminated. As our understanding of the microbiome develops, it is reasonable to ask whether the relationship between microbial ecosystems and nutrient production may reveal further opportunities for research.
Some animals, particularly ruminants such as cattle, sheep and goats, rely on complex microbial fermentation within their digestive system. This allows Vitamin B12-producing microorganisms to make the vitamin before it reaches the site of absorption. Humans are different. Although we also host Vitamin B12-producing bacteria, most of this activity occurs in the large intestine, after the principal site of Vitamin B12 absorption has been passed.
This raises an intriguing research question. What would happen if someone who had spent decades living a largely sanitised indoor lifestyle were to spend six months living within a biologically rich ecosystem? Imagine growing food, making sourdough, composting, preparing fermented foods, working with living soil and eating locally produced seasonal food every day. Would their Vitamin B12 status change? To my knowledge, this study has not yet been undertaken, but it is a question that could be investigated scientifically.
Perhaps the future of Vitamin B12 research lies not only in laboratories but also in understanding the ecological systems from which the vitamin originates. Modern biotechnology already grows Vitamin B12-producing bacteria to manufacture supplements. Traditional cultures have spent thousands of years cultivating microbial ecosystems through fermentation. Bringing these two worlds together may prove to be one of the most interesting areas of nutritional research over the coming decades.
Vitamin B12 is usually discussed as a nutrient. It may also be viewed as the product of a living ecosystem. Looking at it from that perspective does not answer every question, but it encourages us to ask some new ones.
