Whatever the reason for depression (whether it’s hereditary, trauma-induced, seasonal, etc.), it’s becoming clear that homocysteine levels (an amino acid) are elevated in the blood during depression. People suffering from depression often score significantly lower on mental tests (and slower to learn new mental tasks) than their non-depressive counterparts. Homocysteine is regarded as the culprit; it either damages blood vessels in the brain or destroys brain cells, or both. It could also interfere with the successful delivery of another nutrient which builds brain cells, starving the brain of necessary building components.
Even without depression, homocysteine can be lurking around in the brain, especially if there is a lack of B vitamins in diet. In other words, depression can cause homocysteine levels to go up, but being nutritionally deficient (especially for B vitamins) can also cause homocysteine levels to increase (and lead to other depression-like symptoms). It’s a case of chicken-or-the-egg; but faithfully stocking up on B vitamins can prevent dementia from a nutritional standpoint, which makes sense because they are also the vitamin group that’s responsible for a healthy nervous system.
B vitamins are actually a family of vitamins, which is why there are different bottles for B6 and B12 or totally different names like folic acid on health food stores. There are even bottles that say B-complex, which is supposed to include the whole group. Rather than isolating B-vitamin components, or depending on pill forms, eating whole foods like chicken, fish, eggs, whole-wheat cereals, and nuts can ensure a more balanced consumption of homocysteine-correcting options.