 [ Symptoms ] my shoulder pops out and in by itself [ Disease ] a vitamin deficiency is a possibility but given that there are so many other possible causes of numbness some of which can be serious you should see your doctor before assuming it is a vitamin deficiency one of the most concerning vitamin deficiencies that can cause numbness is a vitamin b12 deficiency if you eat meat or other animal products you are probably getting plenty of this in your diet however vegans those who eat no animal products do have to take extra care to be sure they are getting vitamin b12 either through fortified foods like cereal or through supplementation some people also have a medical condition called pernicious anemia that decreases their ability to absorb vitamin b12 your doctor can run tests to see if you may have this condition