The 2010 Dietary Guidelines Advisory Committee did not recommend the use of multi-vitamins for the general healthy population. But there was an indication for specific diseases, like Type 2 diabetes, to use daily supplementation of the vitamin B group and antioxidant vitamins (vitamin A, C, E and carotenoids). There was also a reduced infection rate in Type 2 diabetes after patients used multi-vitamins for six months.

Patients who are using metformin are at a higher risk of developing vitamin B12 deficiency and its consequent of hyperohomysteinemia that may lead to neuropathy and other complications. Thus, supplementation of vitamin B12 can improve cognitive performance. 

Vitamin B12 is readily available in animal products, including fish, meat, poultry, eggs and milk and other dairy products. The daily recommended amount of vitamin B12 for adults is 2,4 micrograms (mcg) in supplement form or as an injection if it can’t be taken in as a food source.

Reference: Nutrients 2013; Diabetes Care, from assessed data from the National Health and Nutritional Examination Survey; The Journal of Clinical Endocrinology and Metabolism