B complex vitamins are a collection of the B vitamin family recommended for a variety of reasons. Fortunately there are tips to make choosing a B complex vitamin a little easier to digest. B-1 (thiamine) is good for the heart. B-2 (riboflavin) is good for digestion and the brain. B-3 (niacin) comes in various forms but can be very helpful for cholesterol and joint issues and possibly help protect the brain from dementia.