The truth is that if you get enough vitamin B12 in your daily diet, you don't need to take any additional vitamin B12 supplements. But, you may need to take vitamin B12 if you are not getting enough of it.Here are some signs that you may need to take a vitamin B12 supplement:itamin B12 can help your body to reduce your homocysteine levels. And because homocysteine is one thing that can cause heart disease, vitamin B12 will be helping you to reduce your chance of getting it. Taking a Vitamin B12 Supplement. If you feel as though vitamin B12 can help you and your body.