Need a Vitamin B 12 Shot?

Why DO people get B 12 shots? As always, the answer is not exactly straight-forward. Many people get them because, well, they ask for one! There is a myth out there, quite popular with the entertainment industry, that getting a B 12 injection gives you a "shot" of energy. This idea has been around for many decades, and there are patients who absolutely swear it works. Additionally, many people believe if they are really stressed and run down- say at finals time in college- then a B 12 shot seems to keep them from getting sick. Is this true?
There are not any current evidence-based medical studies that support this theory. There is one recent study that showed high intake of Vitamin B12 (and of B6) is protective against depression in older adults living within the community. (Longitudinal association of vitamin B-6, folate, and vitamin B-12 with depressive symptoms among older adults over time.)
What we primarily use B 12 shots for, however, is the obvious- true B 12 deficiency. Why do people get this? A few get it as a side effect from bariatric surgery (a stomach bypass), but most get B 12 deficiency from making antibodies to B 12 receptors in your stomach. When this happens, you can no longer ABSORB B12 from your diet, so the only ways to get B 12 is from a shot or from a medicine that can be absorbed under your tongue, or more recently, a medicine you squirt in your nose (in the same manner as allergy nose sprays.) When you bypass the stomach receptors, the B12 can then enter your body effectively. Who is prone to getting B 12 deficiency? Anyone with other auto-immune diseases, where the body starts making antibodies to other organs or receptors. This includes adult onset diabetes, vitiligo, thyroid disease and other diseases in the rheumatic family such as lupus.
How about symptoms of B 12 deficiency? There may be none. In severe cases, the patient develops anemia. Often, we see nonspecific symptoms such as brittle fingernails, fatigue, and forgetfulness.
If you have a family history of true B 12 deficiency, that is also a risk factor.
The good news is that B12 is easily replaced, and though it will take a few months to get tanked back up, you should completely recover with time as long as you are consistent about your method of B 12 replacement. Additionally, extra B12 should not be harmful to anyone, as it is a water soluble vitamin (which means you may have lovely, expensive, bright yellow/green urine if you over-replace, but no other worries!)
BOTTOM LINE: B 12 replacement is only really necessary if your levels are low- check with your doctor if you are concerned!