Vitamin B12 Deficiency
Assess whether you show clinical signs of vitamin B12 (cobalamin) deficiency: fatigue, pale complexion, stomach problems, lower back pain.
Keyboard: the number of the answer, left arrow to go back.
Keeping your balance
Metabolic role of B12
Cobalamin is the cofactor for methionine synthase (methylation cycle, reconversion of homocysteine to methionine with folates) and methylmalonyl-CoA mutase (catabolism of odd-chain fatty acids). It is essential for myelin synthesis, red blood cell formation, and proper neurological function.
Populations at risk of deficiency
Vegetarians and vegans, elderly people (atrophic gastritis reducing intrinsic factor), chronic users of proton pump inhibitors (PPIs) and metformin are particularly exposed to B12 deficiency. Annual testing is recommended for these groups.
Maintain absorption capacity
B12 absorption depends on gastric intrinsic factor. Preserve your stomach acidity by eating calmly and chewing thoroughly. If you take a long-term antacid, never stop it on your own: that decision belongs to your doctor. A functional stomach is key to good dietary cobalamin assimilation.
What you can do
Understanding B12 deficiency
B12 is the cofactor for methionine synthase (methylation cycle) and methylmalonyl-CoA mutase (lipid catabolism). A deficit causes accumulation of homocysteine and methylmalonic acid, progressive nerve demyelination, and blockade of cell division in bone marrow (megaloblastic anemia).
Biological markers to request
Serum B12 alone is insufficient: the classic threshold of 200 pg/mL misses many functional deficiencies. Request methylmalonic acid (MMA), the most sensitive marker of tissue deficit (elevated even before serum B12 falls), and holotranscobalamin (active B12, the truly available fraction). Homocysteine completes the picture. Target: B12 above 400 pg/mL.
Most B12-rich foods
Cooked veal liver is the most concentrated source (60 mcg/100g), followed by cooked octopus (36 mcg/100g), beef kidney (31 mcg/100g), cooked mussels (24 mcg/100g), and mackerel (19 mcg/100g). Sardines, smoked herring, salmon, eggs, and aged cheeses complete daily intake.
Supplementation in active form
Sublingual methylcobalamin is the active form directly usable in the methylation cycle. The sublingual route bypasses gastric absorption problems. Hydroxocobalamin in intramuscular injections is indicated in case of severe malabsorption or advanced atrophic gastritis. Doses are set with your doctor or your naturopath, all the more so if you already take a medication.
Preserve gastric acidity
B12 absorption depends on gastric intrinsic factor, itself secreted in acidic conditions. Reevaluate with your doctor the necessity of long-term PPIs. Eat calmly, chew thoroughly, and avoid drinking during meals to preserve stomach acidity. A hypochlorhydric stomach is the leading cause of B12 malabsorption.
Gentian to support the stomach
Gentian (Gentiana lutea) is the reference bitter plant to stimulate gastric secretion, including hydrochloric acid and intrinsic factor necessary for B12 absorption. In tincture form (before meals) or as root decoction, it prepares the stomach for better dietary cobalamin assimilation. Doses are set with your doctor or your naturopath, all the more so if you already take a medication.
What you can do
Pathophysiology of B12 deficiency
B12 deficiency blocks methionine synthase (homocysteine accumulation, folate trap disrupting DNA synthesis) and methylmalonyl-CoA mutase (neurotoxic methylmalonic acid accumulation). The resulting demyelination affects the posterior and lateral columns of the spinal cord (subacute combined sclerosis), causing potentially lasting neurological damage if not corrected in time.
Priority biological assessment
Request serum B12 (optimal threshold above 400 pg/mL, not 200), holotranscobalamin (active B12, the earliest depletion marker), urinary or serum methylmalonic acid (elevated confirms tissue deficit even with normal serum B12), and homocysteine. CBC reveals macrocytosis (MCV above 100 fL) if established megaloblastic anemia.
Most concentrated B12-containing foods
Focus on the densest sources: cooked veal liver (60 mcg/100g), cooked octopus (36 mcg/100g), beef kidney (31 mcg/100g), cooked mussels (24 mcg/100g), mackerel (19 mcg/100g), oysters (16 mcg/100g). As daily supplements, sardines, eggs, aged cheeses, and red meat complete intake. No reliable plant-based source contains bioavailable B12.
Methylcobalamin supplementation
Sublingual methylcobalamin is the active form directly usable in the methylation cycle, which bypasses gastric absorption problems. In case of atrophic gastritis, Biermer disease, or severe malabsorption, hydroxocobalamin in intramuscular injections (loading course then monthly maintenance) is the standard. Doses are set with your doctor or your naturopath, all the more so if you already take a medication.
Restore gastric function
B12 absorption requires intrinsic factor secreted by parietal cells in acidic conditions. Reevaluate with your doctor the necessity of long-term PPIs. Chew thoroughly, eat calmly, and avoid excess liquid during meals. A functional stomach is the primary condition for good cobalamin assimilation.
Gentian to stimulate intrinsic factor
Gentian (Gentiana lutea) is the quintessential bitter plant to stimulate gastric secretions, including hydrochloric acid and intrinsic factor essential for B12 absorption. In tincture form (15 minutes before meals) or as root decoction, it restores upper digestive capacity and optimizes dietary cobalamin assimilation. Doses are set with your doctor or your naturopath, all the more so if you already take a medication.
Le Cabinet
The Friday morning letter. One topic on the body’s terrain, sourced, no shortcuts.
Unsubscribe in one click. Your data is handled according to our privacy policy.
Related tests
This result is an educational naturopathic self-assessment. It is neither a diagnosis nor medical advice, and it does not replace a consultation. Only a health professional can confirm or rule out a disorder. If symptoms persist, or if you are pregnant, breastfeeding or on any treatment, talk to your doctor before taking any supplement or herbal preparation, and never stop a treatment without medical advice.
How to read this test
Assess whether you show clinical signs of vitamin B12 (cobalamin) deficiency: fatigue, pale complexion, stomach problems, lower back pain. Free, 5 questions.
Vitamin B12, or cobalamin, is essential for proper nervous system function and red blood cell formation. Its absorption depends on gastric intrinsic factor, making it vulnerable to digestive disorders. Vegetarians and vegans are particularly at risk of deficiency, which can lead to pernicious anemia and lasting neurological damage if left uncorrected.
Strengths
- Rapid identification of clinical signs
- Simple self-assessment test
- Essential for vegetarians and vegans
Limitations
- Does not replace blood testing
- Some signs may have other causes
- Limited sensitivity for subclinical deficiencies