How can i lower my ast levels? i dont drink, dont take meds, eat a vegetarian diet and low bmi?

First of all, is it elevated ? if so, how high ? You do not do anything to lower the level which is a measurement of liver function. If it is minimally, there is nothing to do. If it is high, then the cause needs to be determined.

All laboratory results need to be interpreted in the clinical context and the doctor who ordered the tests is usually in the best position to do that. Talk to the doctor who ordered the tests. Having said that, it would have helped had you provided the actual result. Wish you good health!

Agree with the other answers but would also add that an increased AST level can also be a sign of inflammation. So, if your level is elevated, you should have the test repeated in a month or 2 to see if it normalizes on its own. Is your ALT also elevated? If you drink alcohol, limit your intake before repeating the test. If the elevation persists, get hepatitis testing and see a liver specialist.