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Vitamin B12 – animal-based foods or supplements
Vitamin B12, also known as cobalamin, is an essential nutrient for the body’s metabolism, blood formation, and nervous system function. It is primarily found in animal products such as fish, meat, eggs, and dairy. Individuals following a vegan or strictly plant-based diet are at risk of developing a B12 deficiency, as these foods are the primary sources of the vitamin. Therefore, supplementation or consumption of fortified foods is recommended for these individuals.
Requirements and Recommended Daily Intake
The recommended daily intake for adults is around 4 micrograms. Pregnant and breastfeeding women have a slightly higher requirement, as the vitamin is important for fetal development and milk production. Older individuals may have a reduced ability to absorb B12, often due to gastric issues such as atrophic gastritis or long-term use of acid-reducing medications. These individuals may need supplements to maintain adequate levels.
B12 Deficiency and Causes
Vitamin B12 deficiency can be caused by an insufficient diet, particularly among vegans and vegetarians, or due to impaired absorption of the vitamin in the intestines. Pernicious anemia, an autoimmune disease where the body does not produce enough intrinsic factor, is a common cause of B12 deficiency. Older individuals, those who have undergone gastrointestinal surgeries (such as gastric bypass), and people with gastrointestinal disorders such as Crohn’s disease or celiac disease are also at risk. Certain medications, such as metformin (used for diabetes), can affect the body's absorption of B12 and contribute to deficiency.
Symptoms of B12 Deficiency
Symptoms of vitamin B12 deficiency develop gradually and can affect multiple organ systems. Many individuals experience persistent fatigue and weakness, often accompanied by memory problems and decreased concentration. Dizziness and muscle weakness are also common, and the nervous system may be affected, leading to tingling and numbness in the hands and feet. The skin may change color, often becoming pale or slightly yellowish, and oral health issues may arise, such as an enlarged tongue or mouth ulcers. Severe B12 deficiency can lead to megaloblastic anemia, where red blood cells become larger than normal and ineffective, which worsens symptoms of fatigue and weakness. Blood tests may show elevated mean corpuscular volume (MCV), and in some cases, low levels of neutrophils and platelets.
Do you have symptoms of B12 deficiency? Test your levels and see if you have a B12 deficiency through a blood test.
Reference Range and Diagnosis
Vitamin B12 levels in the blood should normally range between 175 and 700 pmol/L. Values below 250 pmol/L are considered a "gray zone" and may indicate deficiency, especially if symptoms are present. In uncertain cases, further investigation with plasma or testing is recommended, as it provides a more specific indication of cellular B12 status. It is also important to note that elevated B12 levels may occur with supplementation, but also in association with certain medical conditions, such as liver damage and certain blood disorders. Therefore, B12 levels should always be assessed in conjunction with the clinical picture.
