A composition can treat or prevent at least one physical state selected from the group consisting of oxidative stress, a condition associated with oxidative stress, a reduced level of glutathione, and a condition associated with a reduced level of glutathione. The composition contains an effective amount of a combination of a Nicotinamide Adenine Dinucleotide (NAD+) precursor and at least one ketone or ketone precursor. The composition can be an enterally administered composition such as an orally administered food product or food supplement.