The loss of ability to absorb vitamin B 12 (B 12) is the most common cause of adult B 12 deficiency. Impaired absorption of vitamin B 12 may be due to a loss of intrinsic factor or to a number of other conditions that decrease production of gastric acid, which also plays a part in the absorption of B 12 from foods.
One of the best natural insect repellent is Lemon Balm. If you insist to go for organic route, Lemon Balm which contains high Citronellal contents is able to repel insects such as mosquitoes, flies, ants and etc. However, Lemon Balm does not deter butterflies or bees.
Recent research suggests that elemol, another component extractable from the fruit, shows promise as a mosquito repellent with similar activity to DEET in contact and residual repellency. The trees range from 40-60 feet (12-18 m) high with short trunk and round-topped head.