Unlike other substances, vitamin B12 is considered a harmless substance and cases of poisoning are very rare. And max dose per day is not necessarily pointed out. When you ingest a large amount of B12, your body’s homeostasis will act by eliminating the extra in the bowels or store it in your liver for use later if needed. Your liver stores can last up to 3-5 years in case you stop consuming VitaminB12. Recommended daily intake for B12 for adults is 2.4-2.8 microgram per day.
In our body, homeostasis keeps our body intact by maintaining internal conditions normal with the aid of different feedback mechanisms. For example, when you got too much calcium in your blood, your thyroid gland will secrete a hormone called calcitonin which will act to get the excess calcium in your blood to be deposited in your bones. In contrast, when your blood is low in calcium, your parathyroid gland secretes parathormone that will act to release calcium from your bones into the blood. This is one of the feedback mechanisms that maintain balance in your body.
When you consumed B12 in large amount, symptoms of B12 overdose may or may not appear. Even there are symptoms, it is doubt to cause great farm to your body. Symptoms that may be experience are feelings of inflammation in some parts of the body, frequent and excessive bowel movements, and signs of hypersensitivity such as itchiness, chest pain or labored breathing, rashes, inflammation. There are studies that link vitamin B12 to cancer, due to B12’s role in DNA synthesis. It is also believed to cause abnormality to blood vessels and red blood cells; it can cause clotting of blood, and increased production of red blood cells.
Although B12 is considered harmless, consulting a physician before consuming large doses like vitamin B12 injections is recommended especially to people with underlying medical condition. When you start experiencing symptoms, it is better to stop taking the vitamin and then contact your health provider.