#b12deficiency #vitaminb12deficiency #vitaminb12
Many people take Vitamin B12 or even show “normal” blood test results — yet still feel exhausted, foggy, or notice tingling hands and feet. The real issue often isn’t how much you take, but whether your body can actually absorb and use B12.
I’m Sonia Hollis, a qualified Nutritional Therapist, and in this video I’ll walk you through 6 hidden reasons why B12 absorption fails — from low stomach acid, gut conditions, and common medications, to genetics, alcohol, and diet misconceptions. More importantly, you’ll learn practical steps you can take to support absorption, choose the right form of B12, and finally start feeling better.
If you’ve been struggling with fatigue, low mood, or unexplained health issues, this could be the missing link.
✨ Want to boost your energy & brain health?
I’ve made a FREE Vitamin B12 Guide that shows you the key signs of deficiency, top food sources, and supplement tips.
👉 Grab it here: https://personalised-nutritional-therapy.co.uk/yt-b12-guide
Don’t miss it — it’s a quick, science-backed guide that could make a real difference if you’ve been feeling tired or foggy. 💡
Thanks for watching, and take care of your health 💚
— Sonia
(MSc Personalised Nutrition)
🔗 Explore my nutrigenomic testing here:
https://personalised-nutritional-therapy.co.uk/dna-testing-nutrigenomics/
🔗 Explore my Nutrition & Health Toolkit here:
https://personalised-nutritional-therapy.co.uk/product/nutrition-health-toolkit-lifetime-access/
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Disclaimer: The material on this channel is offered for general and educational reasons only and should never be used in place of medical advice from a certified medical practitioner. Before commencing any nutrition or lifestyle regimen, all readers of this information, especially those using prescription medications, should consult their doctors or trained health specialists.
https://pmc.ncbi.nlm.nih.gov/articles/PMC3262614/ Vitamin B-12
https://pmc.ncbi.nlm.nih.gov/articles/PMC6024521/ Foods and Supplements Associated with Vitamin B12 Biomarkers among Vegetarian and Non-Vegetarian Participants of the Adventist Health Study-2 (AHS-2) Calibration Study
https://pmc.ncbi.nlm.nih.gov/articles/PMC11050313/ Diagnosis, Treatment and Long-Term Management of Vitamin B12 Deficiency in Adults: A Delphi Expert Consensus
https://pmc.ncbi.nlm.nih.gov/articles/PMC7581105/ Association between frailty and vitamin B12 in the older Korean population
https://pmc.ncbi.nlm.nih.gov/articles/PMC4921487/ Biomarkers and Algorithms for the Diagnosis of Vitamin B12 Deficiency
https://pmc.ncbi.nlm.nih.gov/articles/PMC8311483/ Long-term metformin therapy and vitamin B12 deficiency: An association to bear in mind
https://pmc.ncbi.nlm.nih.gov/articles/PMC4042564/ Vitamin B12-Containing Plant Food Sources for Vegetarians
https://pmc.ncbi.nlm.nih.gov/articles/PMC4850488/ Cyanobacteria and Eukaryotic Algae Use Different Chemical Variants of Vitamin B12
https://pmc.ncbi.nlm.nih.gov/articles/PMC4850488/figure/undfig1/
https://pmc.ncbi.nlm.nih.gov/articles/PMC7396987/ Biological Activity of Pseudovitamin B12 on Cobalamin-Dependent Methylmalonyl-CoA Mutase and Methionine Synthase in Mammalian Cultured COS-7 Cells
https://pmc.ncbi.nlm.nih.gov/articles/PMC11128391/ Efficacy of different routes of vitamin B12 supplementation for the treatment of patients with vitamin B12 deficiency: A systematic review and network meta-analysis
https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/ Vitamin B12 Health Professional Fact Sheet
https://pmc.ncbi.nlm.nih.gov/articles/PMC11124153/ Exploring Vitamin B12 Supplementation in the Vegan Population: A Scoping Review of the Evidence
00:00 Introduction
01:00 Low Stomach Acid & Intrinsic Factor
02:41 Gut Conditions (Celiac, Crohn’s & SIBO)
04:34 Medications That Block Absorption
06:31 Genetics – FUT2 & MTHFR
08:25 Alcohol & Lifestyle Factors
10:26 Diet & Misconceptions
Do you often feel tired, foggy, or notice tingling hands and feet, yet your blood tests say that your vitamin B12 is normal? Or maybe you’ve been taking supplements and still don’t feel any better. The problem might not be what you’re taking, but whether your body can actually absorb and use it. Hi, I’m Sonia Hollis, a qualified nutritional therapist, and in today’s video, we’re going to be diving into the real science of B12 absorption. I’ll walk you through the six hidden reasons why your body might not be absorbing vitamin B12 properly. You’ll learn about gut health, genetics, medications, and lifestyle factors that can block absorption, and most importantly, what you can do to fix it safely and effectively. But before we begin, don’t forget to hit that like and subscribe button, turn on your notifications so you never miss any of our scienceback tips. Okay, let’s get started. To absorb vitamin B12 from food, your stomach acid must first release it from protein, then a special protein called intrinsic factor made in the stomach lining helps transport it into the small intestine. But here’s the problem. As we age, stomach acid naturally declines. If you’re on antacid or protein pump inhibitors like omerazole, this reduces acid even further. Atrophic gastritis or autoimmune conditions can also damage the stomach lining. So intrinsic factor isn’t produced leading to penicious anemia. If your stomach acid is low, you won’t absorb B12 from food effectively even from rich sources like meat, fish, dairy, or eggs. So, what can you do about it? You’ll often see advice online to drink apple cider vinegar or take acid pills, but these can be risky if you have reflux, ulcers, or are on certain medications. So, it’s best to work with a practitioner rather than self-experiment. Now, I’ve got a whole video on apple cider vinegar, which I’ll link in the description below. Focus on supporting digestion naturally with balanced meals, enough protein, around 25 to 30 grams per meal, and bitter greens. I’ve also done a video on protein if you want to look more into it. Again, it’s in the description below. And if you’re on long-term acid suppressing medication, ask your doctor about yearly B12 monitoring. Your small intestine, especially the illiam, is where vitamin B12 is absorbed. But if the gut lining is damaged or inflamed, absorption can drop dramatically. With celiac disease or Crohn’s, ongoing inflammation damages the villi, the tiny finger-like structures that absorbs nutrients. Without healthy villi, your body struggles not only with B12, but also with iron, folate, and other key nutrients. With SIBO, small intestinal bacterial overgrowth, bacteria living in the wrong part of your gut can actually steal B12 before your cells get the chance to use it. So, how do you know if this could be part of your picture? If you’ve had long-standing digestive symptoms like bloating, diarrhea, constipation, unexplained nutrient deficiencies, or food sensitivities, it may be worth exploring gut health alongside your B12 levels. And while every case is different, there are some simple steps that you can do to help to create a healthier gut environment. So look for eating enough fiber and diverse plants to help feed beneficial bacteria including fermented foods like kafir, sauerkraut or miso if tolerated, reducing processed foods, refined sugar and alcohol which fuel the gut inflammation and in some cases targeted probiotics or medical treatment may be needed. I’ve covered the gut hormone connection in menopause in another video which I’ll link in the description below because changes in estrogen also reshape the microbiome and can affect digestion and nutrient absorption. Certain medications are well documented to reduce vitamin B12 absorption and this often gets overlooked in routine care. So metformin, this is widely used for type 2 diabetes and even pre-diabetes, but this interferes with absorption in the small intestine. In fact, research has shown that up to 30% of long-term users develop low B12. So that’s why I recommend annual B12 testing if you’re on metformin. Protein pump inhibitors like a metrosol and H2 blockers. These also reduce stomach acid. So remember in section one where we talked about how stomach acid frees B12 from food. If that process doesn’t happen, even a good diet won’t deliver much usable B12. And nitrous oxide, sometimes used during dental work or surgery, that can inactivate B12 temporarily. Most healthy people bounce back, but if you already have low levels, this could push you into deficiency. So, what can you do if you need these medications? First of all, don’t stop them suddenly. They’re often essential, of course, but do be proactive. Ask your doctor to check your B12 yearly. If you’re on acids suppressing medication, consider whether long-term use is still needed. And many guidelines recommend reviewing this after a few months. And if you’re on metformin, you may benefit from proactive supplementation, especially in a form that bypasses the gut, like sublingual B12. And if you haven’t already, I’d recommend watching my video on insulin resistance where I share natural ways to improve your blood sugar balance because sometimes lifestyle changes can reduce the need for long-term medications like metformin. Your genes also play a big role in how well you absorb and use vitamin B12. And this explains why some people do everything right but still end up deficient. With a FUT 2 variant, the gut lining may not produce enough transport proteins to absorb B12 efficiently. And so that means even a diet that is rich in meat, fish, and eggs, you might still run low. With an NTHFR variant, your body struggles to convert B12 into an activated methylated form. And that’s where people sometimes hear you need methylcobalin. But here’s the nuance. Not everybody does best on methyl. Some actually tolerate hydroxycobalin or adinosylcobalin better. So depending on your other genes and enzymes involved. And just to make this a little bit more real, this is my own DNA results. So I carry two FT2 variants that reduce the B12 absorption and increase susceptibility to gut issues like H pylori plus an MTHFR variant that slows folate activation. So that means that I’m more prone to low B12 even with a balanced diet. So I need to pay closer attention to the form and co-actors that I use. So, if you’ve ever taken a B12 supplement and you still feel tired, foggyheaded, you’ve got tingling in your hands and feet, it may not be all in your head. It could be how your body processes it. So, this is where Neutrogenomics testing can be really powerful. It helps you understand which forms of nutrients that your body is more likely to use effectively and where you might need extra support. So, I’m going to leave a link in the description below if you want to learn more about neutrogenomics. It’s not just your gut or genetics that affect B12. Lifestyle plays a huge role, too. So, alcohol. Your liver is the main storage site for vitamin B12. And in healthy people, it can hold years worth of reserves. But with daily alcohol use, these stores run down faster. Alcohol also irritates the stomach lining, lowers stomach acid, and increases the risk of infections like H. pylori, which we already talked about as a blocker of intrinsic factor. The key thing here is frequency. An occasional glass of wine is unlikely to wipe out your B12, but daily or heavy drinking can help to tip the balance. Stress. So chronic stress activates your fightor-flight nervous system. And when that’s switched on, digestion is switched off. So this means lower stomach acid, slower motility, and poorer absorptions of nutrients like vitamin B12. So that’s why people under constant pressure often feel both fatigued and nutrient depleted even if their diet looks okay. Now, our sleep and circadian rhythm also matter. Poor sleep and irregular eating patterns can affect how efficiently the gut absorbs and uses nutrients. So what can you do about it? Be mindful about alcohol. So keep it for special occasions rather than making it a daily habit. Build stress buffering habits like walking, yoga, or even simply eating meals without screens. and prioritize good sleep and consistent meal times to support digestion. And if you’d like to dive deeper into the liver’s role in storing nutrients, I’ve done a full video on fatty liver that I’ll link in the description below because your liver health and B12 status are closely connected. Yes, diet really matters, but deficiency isn’t just a vegan problem. Vegans and vegetarians are at a higher risk because natural B12 is only found in animal products like meat, fish, eggs, and dairy. So for anyone plant-based, fortified foods or supplements are essential. And B12 isn’t something that you can reliably get from plants alone. But even omnivores can become deficient because absorption is the bigger issue here. If stomach acid is low, the gut lining is inflamed, or medications are interfering, even a steak dinner won’t deliver much usable B12. And you might hear claims that plant foods like spirulina or seaweed are good sources of B12, but in reality, they contain lookalike compounds that your body can’t use. And sometimes these can even block the absorption of true active B12. So, what’s the practical takeaway? If you’re plant-based, make fortified food and supplementation non-negotiable. If you’re an omnivore but still struggling with fatigue or low B12 levels, don’t assume that diet alone is enough. Look at the underlying causes that we’ve looked at today. I’ve also done a recent video on vitamin B deficiencies where I explain how B12 interacts with folate, B6, and other key nutrients. So, it’s worth a watch if you want the full picture of how these vitamins work together. So, if you’re worried about absorption, the first step is testing. A standard serum B12 test is a start, but it doesn’t always reflect what’s happening inside your cells. That’s because most of the B12 circulating in your blood is bound to proteins your body can’t actually use. So, what really matters is active B12. Now this is the fraction that your cells can actually take up. Unfortunately, it’s not always offered on the basic panels, but it is worth asking about. Practitioners may also check the MMA and homocyine because when B12 is too low, MMA and homocyine tends to rise, giving a clearer picture of what’s actually happening inside your cells. I go into far more detail on these lab markers with reference ranges and what they mean in my other B12 video and I’ll link it in the description below. But what if you already know that absorption is an issue or your results are borderline? Here are some practical next steps. Sublingual supplements. Now, these dissolve under the tongue and bypass the stomach, which can be especially helpful if you have low stomach acid and you know that’s part of the problem. Choosing the right form. Some people do best on methylcobalene, others on hydroxycobalin or adinosolabil. If one form doesn’t help, it’s fine to try another under guidance. Injections. In cases like penicious anemia or severe gut conditions, injections are often the most reliable ways to restore levels and many people notice improvements within weeks. And food and co-actors. Don’t forget the basics. So B12 works in partnership with protein, folate, and B6 in your methylation and energy pathways. The key isn’t just raising your blood levels. is making sure that your cells can actually use B12. And that’s why personalization really matters. And if you’d like some resources to help personalize your nutrition, I’ll link my nutrition and health toolkit in the description. It’s full of step-by-step guides. So, in summary, B12 isn’t just about what you eat or even what you supplement. It’s about whether your body can actually absorb and activate it. So to recap, the six main reasons that you may not be absorbing B12 properly are low stomach acid or lack of intrinsic factor, gut conditions like cigiliac, Crohn’s or SIBO, medications such as metformin and PPIs, genetic varants like FUTU and MTHFR, alcohol and lifestyle factors, and lastly, diet choices and plant-based misconceptions. So get the right tests, choose the supplement form that suits your body, and always address the underlying causes, not just the symptoms. This is actually the third video in our B12 series. In the first one, I covered the early warning signs of deficiency. And in the second one, I explained the best and worst supplement forms. So I’m going to link both of those in the description below so you can get the full picture. And remember, if you’ve been struggling with fatigue, brain fog, or unexplained symptoms, you’re not alone. But with the right testing, personalization, and support, you can get to the root cause and start feeling more like yourself again. If you’d like some more resources, I’m going to leave the links below to our nutrition and health toolkit and also my page on neutrogenomic testing, which can help you personalize your approach. So, that’s it for today. I hope you found this helpful. Don’t forget to like and subscribe and check out our channel for our other scienceback tips. All right, take care and I’ll see you soon. Bye-bye.
