Vitamins B6 and B12 are both involved in systems that keep the amino acid’s derivative homocysteine in check. Elevated homocysteine levels are associated with higher risk of many health issues, including cognitive decline and Alzheimer’s. Poor vitamin B status into one’s advanced years may lead to brain shrinkage and earlier or greater onset of cognitive impairment. Recent research using very high doses of vitamin B6 and B12 showed a reduction in homocysteine levels of almost 23 percent for those supplementing and an increase of 8 percent in the placebo group. Further, the rate of brain shrinkage in the vitamin group was 30 percent less than in those taking the placebo.