Vitamin B12 deficiency is a serious health concern that can affect multiple systems in the body. Vitamin B12, also known as cobalamin, plays a crucial role in maintaining nervous system function, supporting red blood cell formation, and preserving cognitive health. When left unaddressed, a deficiency in this vital nutrient can lead to anemia, neurological impairments, and even dementia. One of the key consequences of vitamin B12 deficiency is the accumulation of two harmful substances: methylmalonic acid (MMA) and homocysteine. Elevated MMA disrupts mitochondrial function—the energy-producing centers of cells—resulting in fatigue, impaired cellular performance, and neurological symptoms such as weakness, numbness, poor coordination, and cognitive decline. At the same time, increased homocysteine levels have been strongly linked to a higher risk of cognitive dysfunction, depression, dementia, and cardiovascular disease. This article has not yet been reviewed. The most recent update was made on May 18, 2025. Why Is Vitamin B12 Deficiency Dangerous? A vitamin B12 deficiency primarily affects blood formation. It can lead to megaloblastic or hemolytic anemia—a condition in which the body destroys its own immature red blood cells in the bone marrow. This results in reduced oxygen delivery to tissues, causing a range of symptoms from fatigue to heart failure. Common signs of deficiency include: These symptoms may mimic other serious conditions, including idiopathic thrombocytopenic purpura—but unlike many other causes, B12 deficiency anemia is treatable. Supplementation through oral tablets or intramuscular injections can be life-saving. IN THIS ARTICLE 1 Why Is Vitamin B12 Deficiency Dangerous? 2 Vitamin B12 Deficiency – A Common but Overlooked Cause of Anemia 3 Impact on the Brain and Mental Health 4 Which Foods Contain Vitamin B12? 5 Why Should You Track Your Vitamin B12 Levels? 6 How to Test Your Vitamin B12 with Healsens Vitamin B12 Deficiency – A Common but Overlooked Cause of Anemia Vitamin B12 deficiency is a frequent and often underestimated cause of anemia. Contributing factors include: In vegans, the deficiency can be especially deceptive — high levels of folic acid in the diet may mask vitamin B12 deficiency without lowering hemoglobin levels. However, the risk of neurological damage remains high despite normal blood counts. Impact on the Brain and Mental Health Vitamin B12 plays a key role in the metabolism of neurotransmitters, including dopamine. When B12 is deficient, the activity of dopamine receptors in the brain may decrease, directly affecting cognitive function and mood. Some therapeutic approaches to depression and dementia aim to stimulate these receptors. Low vitamin B12 levels have been linked to: Why Healsens? Healsens — a Smart Approach to Longevity Harness technology to extend your healthspan: biomarkers, risk assessment, and personalized recommendations—all in one place. 🔗 Download Healsens and take control of your health today. Which Foods Contain Vitamin B12? Vitamin B12 is not synthesized by plants and is found only in animal-derived foods: For vegans, it is essential to fortify the diet or take vitamin B12 supplements in the form of methylcobalamin or cyanocobalamin. Smart interpretation based on your medical history, age, and risk profile helps you spot early warning signs and take action before it’s too late. 📲 Install the Healsens app to gain access to reliable tools for monitoring and supporting your health. How to Test Your Vitamin B12 with Healsens The most reliable way to detect a vitamin B12 deficiency is through a blood test measuring total vitamin B12. In some cases, it’s also recommended to check additional markers like methylmalonic acid (MMA) and homocysteine to rule out a hidden deficiency at the cellular level. Living in the Netherlands, Belgium, or Germany? You can easily check your vitamin B12 levels through the Healsens app. Here’s how to order the test: 1. Download the Healsens app from the Google Play or the App Store, depending on your device. 2. Register in the app to unlock personalized features. 3. Go to “Browse Tests” and search for the Vitamin B12 test. 4. Tap “Add to Cart” and complete your order. 5. Want deeper insight? Add the MMA test as well for a more accurate diagnosis of functional deficiency. » This test is also included in the Vitality Check: 21 Biomarkers & Biological Age Kit — a popular starting point if you want a broader overview of your micronutrient status, energy, and biological aging. Note Not in the Netherlands, Belgium, or Germany, or using a different lab? No problem — you can have the recommended blood tests done at any local lab. Then, manually enter your results in the Healsens app. Based on your data, you’ll receive: ✦ natural recommendations to help improve your values✦ a complete health risk assessment✦ personalized insights and follow-up guidance Healsens remains your personal guide to preventive health — no matter where you are.