Not All Vitamins Are Created Equal: Why Your Supplements Might Be Failing You

8. Attention to Dosage and Toxicity
A higher dose does not always mean better. Some fat-soluble vitamins (such as A,D,E,K) can accumulate in the body and cause toxicity if consumed in excess. A standard supplement should provide a dose that compensates for your deficiencies without placing an extra burden on the liver and kidneys. Study the "DV" (Daily Value) label carefully.