As per the nutritionist, several factors can affect the level of glutathione in the body. The most common one is age. She said that as we age, our body starts making less glutathione, making us more prone to diseases. “After 45 years, it starts decreasing and after 60 it is diminished,” she added. Besides, smoking, alcohol intake, pollution and consumption of processed food can also decrease the level of glutathione in the body.