[6] [3] [10] A mild deficiency may not cause any discernible symptoms, but moderate deficiency can cause various symptoms, such as feeling tired, lightheadedness, headaches, cold intolerance, pale skin, sore tongue, upset stomach, loss of appetite, hair and skin color changes, numbness or tingling (pins and needles) of the fingers and toes, and tinnitus, and vision, cognitive or psychological problems
The same rule applies to the 28-day open-vial rule
Role of cognitive factors in symptom induction following high and low fat meals in patients with functional dyspepsia
Animal sources include dairy products, eggs, fish, poultry, beef Liver Chicken Fish and shellfish such as trout, salmon, tuna fish and clams Fortified breakfast cereal Low-fat milk Yogurt Cheese Eggs If you are looking for a food fortified with B12, check the product's Nutrition Facts label