How do you feel when you don't take your Centrum Silver vitamin? If you feel that you have less energy then you know that your vitamin is having an affect on your body.
By the way, the article you read says that vitamins are absorbed in the stomach. I don't think so. If you want help choosing the right supplement for you, it is often a good idea to go down to your local health food store and start a dialogue with those that work with the community and earn no commission. Also, your primary physician may have some great advice on what may be great too.
But, nothing compares to listening to how your body responds to what you consume.