Values are reported as mg/100g food. Glutathione can be oxidized to various forms that can be reduced back to glutathione in the intestinal tract. “Total glutathione” includes reduced glutathione and these oxidized forms. Some foods contain substances that can react with glutathione irreversibly and prevent it from being absorbed and utilized. These are reported as “glutathione-reactive substances,” and the mg value refers to the amount of glutathione in mg that they are capable of consuming. If values for total glutathione and glutathione-reactive substances are both available, the difference is reported as “net glutathione.” If this value is positive, it refers to the amount of glutathione you can absorb from the food. If it is negative, it means that the food could prevent the utilization of glutathione from other foods contained in the same meal, or prevent you from reabsorbing glutathione from your own endogenous digestive secretions. NM, not measured. ND, not detected.