IJMS, Vol. 21, Pages 1421: Homocysteine: Its Possible Emerging Role in At-Risk Population Groups (International Journal of Molecular Sciences)

Increased plasma homocysteine is a risk factor for several pathological disorders. Thepresent review focused on the role of homocysteine (Hcy) in different population groups,especially in risk conditions (pregnancy, infancy, old age), and on its relevance as a marker oretiological factor of the diseases in these age groups, focusing on the nutritional treatment ofelevated Hcy levels. In pregnancy, Hcy levels were investigated in relation to the increased risk ofadverse pregnancy outcomes such as small size for gestational age at birth, preeclampsia, recurrentabortions, low birth weight, or intrauterine growth restriction. In pediatric populations, Hcy levelsare important not only for cardiovascular disease, obesity, and renal disease, but the mostinteresting evidence concerns study of elevated levels of Hcy in autism spectrum disorder (ASD)and attention deficit hyperactivity disorder (ADHD). Finally, a focus on the principal pathologiesof the elderly (cardiovascular and neurodegenerative disease, osteoporosis and physical function)is presented. The metabolism of Hcy is influenced by B vitamins, and Hcy-lowering vitamintreatments have been proposed. However, clinical trials have not reached a consensus about theeffectiveness of vitamin supplementation on the reduction of Hcy levels and improvement ofpathological condition, especially in elderly patients with overt pathologies, suggesting that otherdietary and non-dietary factors are involved in high Hcy levels. The importance of novelexperimental designs focusing on intra-individual variability as a complement to the typical case–control experimental designs and the study of interactions between different factors it should beemphasized.