What Does Vitamin B Do for You?. Part of the series: Nutrition Tips for Healthy Living. Vitamin B helps the body to function properly by aiding with digestion, cell growth, muscle development and the formation of regular sleep patterns. Find out how the B vitamins such as B1, B2, B3, B5, B6, B12, B15 and B17, found in fruits and vegetables, help with the growth and development of the body in this free video on nutrition from a professional wellness counselor.