Glutathione works on the skin pigment production by inhibiting tyrosinase, an enzyme involved in making melanin
Here are some other ways to help increase levels of glutathione, along with taking care to optimize vitamin D: limit alcohol consumption decrease exposure to POPs increase intake of other antioxidants to decrease overall oxidative stress increase intake of nutrients that promote glutathione production, such as NAC (N-acetylcysteine), 1000 mg/day, whey, or SAMe get enough magnesium and selenium in the diet, as both are necessary for glutathione production foods such as almonds, cruciferous vegetables, and even alcohol-free beer have been shown to raise glutathione levels, as has meditation
Patients with vitamin B12 levels less than 100 ng/L usually have clinical or metabolic evidence of B12 deficiency
Blood or intraerythrocytic parasites like Plasmodium induce oxidative stress by generating ROS in the patients erythrocytes
However, while you can get them through natural sources, some people are still not getting enough vitamin B12 daily (like vegetarians or vegans)