If you take supplements that contain mega amounts of vitamins, you may experience symptoms of toxicity. However, not all vitamins produce this reaction. Vitamin B-12, for example, is not known to cause symptoms of dizziness or other toxicity symptoms, because your body is only able to absorb a small percentage of it from the food you eat. B-12 is found in a variety of foods, including meat, eggs, milk and shell fish.
Toxicity occurs when you consume too much of a particular vitamin from natural foods and supplements. Vitamin B-12 is not associated with toxic effects from large intakes. For this reason, it does not have a tolerable upper intake level, which is the maximum amount you should consume in one day. However, vitamin B-12 does have a minimum intake level, which is known as the recommended dietary allowance. Failure to meet this level each day could result in deficiency symptoms.
Recommended Dietary Allowance
The recommended dietary allowance, or RDA, of vitamin B-12 is 2.4 micrograms for both adult males and females. Women who are pregnant or breastfeeding require a slightly higher amount -- between 2.6 and 2.8 micrograms. Young children and infants require less. A true deficiency caused by a lack of B-12 your diet is rare; symptoms usually stem from a lack of absorption in your body.
B-12 At a Glance
Vitamin B-12 is important for your metabolism, the physiology and function of your red blood cells and management of your nervous system. Because of its relationship to your nervous system, a B-12 deficiency can result in neurological symptoms, such as difficulty walking, memory loss, disorientation, numbness and tingling in your extremities and dementia with or without mood changes. Dizziness is typically not a symptom of a B-12 deficiency.
Dizziness has many causes, including a sudden drop in blood pressure, dehydration, the flu, hypoglycemia, the common cold, allergies, heart conditions and ear problems. If you experience dizziness often, you should check with your doctor to determine the cause. Although severe cases are rare, a B-12 deficiency can affect your balance and your ability to walk, which could mimic the feeling of being dizzy. To avoid this, consume a balanced diet that contains ample sources of B-12, and remember that you cannot consume too much in one day.