Homocysteine and B vitamins in mild cognitive impairment and dementia

Abstract

Elderly subjects with mild cognitive impairment have a high risk for conversion to Alzheimer's disease or are already in a preclinical dementia stage. By cross-sectionally comparing subjects in prodromal and early phases of dementia with non-demented controls, we tested the hypothesis whether low serum vitamin B12 and folate and high plasma total homocysteine concentrations precede or are a consequence of dementia onset. From a large population of 623 consecutive subjects seen at the Memory Clinic (Ospedale Beata Vergine, Mendrisio, Switzerland), 433 subjects could be included in the analyses: 79 elderly controls, 218 Clinical Dementia Rating 0.5 subjects, and 136 demented patients (111 with Alzheimer's disease and 25 with vascular dementia). As in an earlier report on a smaller sample of the same population (n=228), the lowest folate tertile was strongly associated with mild cognitive impairment (adjusted OR=3.1) and Alzheimer's disease (adjusted OR=4.0). Hyperhomocysteinemia showed a significant association not only with Alzheimer's disease (adjusted OR=3.1) but, at variance with the previous report, also with mild cognitive impairment (adjusted OR=2.6). Present reanalysis results suggest that subclinical folate deficiency and hyperhomocysteinemia might predate dementia onset, findings to be confirmed by longitudinal studies.

Assessment of tailor-made prevention of atherosclerosis with folic acid supplementation: randomized, double-blind, placebo-controlled trials in each MTHFR C677T genotype

“…Since hyperhomocysteinemia is suspected as being a risk factor for many diseases (oral clefts, Down syndrome, placenta-mediated diseases, colorectal neoplasias, Alzheimer's disease, etc.) in addition to vascular diseases and neural-tube defects (Ray and Laskin 1999;Ames 1999;Botto and Yang 2000;Ueland et al 2001;Ames et al 2002;Quadri et al 2004), this information is useful not only for the prevention of atherosclerosis but also for that of other diseases when considering a tailormade preventative approach.…”

Alzheimer’s disease and gut microbiota

“…Studies confirm that a lack of vitamin B12 is an important risk factor of dementia. Low levels of vitamin B12 in serum is associated with an increased risk of AD and MCI (Quadri et al, 2004). In the healthy elderly population, the levels of vitamin B12 in serum are positively related to cognitive ability (Duthie et al, 2002).…”

Folic Acid - The Occurrence and the Role in Human Nutrition

“…Its beneficial effects on the function of this system is associated with its participation in the formation of neuro-stimulating substances in the body such as dopamine, norepinephrine and epinephrine (Paul et al 2004, Coppen & Bolander-Gouaille 2005, Reynolds 2006). Many clinical and epidemiological studies have shown that folate deficiency in the diet leads to a number of neuropsychiatric disorders such as depression, psychosis, dementia and seizures (Quadri et al 2004, Luchsinger et al 2007.…”