Isolated elevation in ALP level, especially if marginal and transient in nature without any elevation in the other liver enzymes and serum bilirubin level usually does not signify a serious medical problem.
Some teenagers and young adults may have marginally elevated ALP levels due to more active bone metabolism. This is considered a normal variant. Drugs and fatty liver can also cause ALP elevation without a concurrently higher GGT level.
However, if the elevation is persistent and significant or trending upwards, it will be prudent to perform more studies to exclude bile duct or liver related conditions and other significant bone or endocrine problems.
If you are taking any health supplement, you can consider stopping for a whole and repeat the ALP level. Weight reduction, exercise and cutting down on alcohol consumption will help in managing your fatty liver.