Intermediates of the methylation pathway are known to decrease with age along with a decline in methylation pathway function. DNA methylation is also known to decrease with aging. Age related decreases in methylation can lead to decreased methylation of T cells which may in part explain changes in immune function with age. Age related decreases in methylation can result in increased levels of homocysteine, increasing the risk of arthritis, cancer depression and heart disease. This would suggest that increasing the body’s level of methylation through supplementation may extend healthy life span.