B vitamins are required for every process in your body. You can get them from a variety of foods, but even a carefully chosen diet may not provide the amounts of all the B vitamins you need, every single day. 

Vitamin B12 Plus is a B vitamin that is commonly deficient among people who have had weight loss surgery or other abdominal surgeries. You are at higher risk if you follow a vegan or plant-based diet. Another high-risk group includes people over age 60 who have decreased absorption of vitamin B12 from food or pills.