The most important nutrients that help lower homocysteine levels are folate, the vitamins B12, B6 and B2, zinc and trimethylglycine (TMG).

http://www.foodforthebrain.org/alzheimers-prevention/methylation-and-homocysteine.aspx

The good news is that homocysteine levels can be tested and high homocysteine levels can, in many cases, be normalised through diet and vitamin supplementation. The most important nutrients that help lower homocysteine levels are folate, the vitamins B12, B6 and B2, zinc and trimethylglycine (TMG).

Note: 

Trimethylglycine or TMG is also more commonly referred to as betaine (BEET-ah-een). For the chemists, as the name implies it is a trimethyl derivative of the common amino acid glycine. TMG is commonly found in our diet in beets (that's where the name betaine came from), whole grains, spinach and shellfish. Feb 4, 2015

 (Source: https://ansperformance.com/trimethylglycine-supplementation/ )