Vitamin Duos That Work Better Together Folate and Vitamin B12 Homocysteine is a toxic amino acid produced in the body that appears to increase the risks for dementia and heart disease. Vitamin B12 and folate are both needed to process homocysteine. When present in adequate amounts, they can effectively decrease homocysteine levels. While the data for heart disease benefits from folate and vitamin B12 remain less clear, with respect to dementia, an international consensus statement in 2018 concluded that even moderate elevations of homocysteine in the elderly is a cause of cognitive decline and dementia. Further, the statement notes that the risks from elevated homocysteine should not be underestimated, especially because treating it with B vitamins, such as folate and vitamin B12, is cheap, safe, and effective. As such, these nutrients appear to have anti-aging benefits for the brain. Vitamin B12 and folate are two B vitamins that function together in what is called the methylation cycle. The methylation cycle is a complex but critical system in the body. It plays a part in attaching methyl groups to different compounds. A methyl group is a carbon atom bonded to three hydrogens. Methyl groups are important for deoxyribonucleic acid (DNA), the production of neurotransmitters, the functioning of nerves, and other systems throughout the body. Homocysteine is naturally produced in the methylation cycle and is effectively reduced when folate and vitamin B12 are in good supply. Deficiency of either vitamin B12 or folate can present similarly. If severe, a deficiency in either vitamin can cause permanent nerve damage. If a B12 deficiency is mistakenly treated with folate, it can mask the symptoms while underlying nerve damage continues to progress. Whenever supplementing with folate, it is always best to include vitamin B12 to prevent any risk of nerve damage from a vitamin B12 deficiency.