If you are looking for ways to boost glutathione levels in your body, there are plenty of foods that can deliver this critical antioxidant nutrient.
Glutathione is a critical antioxidant found in animals, plants, and humans, and it plays a key role in protecting cells from oxidative damage. Glutathione is not considered an essential nutrient for humans because it is produced in relatively large concentrations in the body. Dietary supplementation is still important, however, particularly for gastrointestinal health, as the absorbed glutathione in food can directly help to detoxify the small intestine and improve overall nutrient absorption. 
The other way to increase your levels of this antioxidant is to consume foods with the precursor amino acids for glutathione, including glutamate, glycine, and cysteine. Without these three amino acids, the body cannot synthesize glutathione, which can put your body at risk of oxidative stress and chronic disease.