Micronuclei in lymphocytes and exfoliated buccal cells of postmenopausal women with dietary changes in folate.

Folate deficiency is associated with anemia, birth defects, cancer and neuropsychiatric disorders. The purpose of this study was to determine if a moderate folate deficiency during controlled changes in folate intake would affect chromosomal damage in lymphocytes and buccal cells. A study of nine healthy postmenopausal women volunteers (age 49-63 years) was carried out in a metabolic unit (baseline week with folate intake of 195 microg/day, five-week depletion at 56 microg/day, and gradual repletion including four weeks at 111 microg/day, 11 days at 286 microg/day and 9 days at 516 microg/day). Plasma folate, vitamin B-12, and homocysteine were measured weekly. Cytogenetic damage was assessed by scoring micronucleus (MN) frequency in lymphocytes and buccal cells three times: (1) at the beginning of the study, (2) at the end of depletion, and (3) after repletion. The MN frequency increased in binucleated lymphocytes, as well as in all lymphocytes, after depletion (p=0.037), and later decreased following repletion (p=0. 028). Both kinetochore-positive and kinetochore-negative MN were increased after depletion (p=0.015 and 0.028), but after repletion only the change in kinetochore-positive MN was statistically significant (p=0.048). The main variables affecting MN were: (1) vitamin B-12 level, (2) plasma folate level, and (3) baseline frequency of MN. The MN frequency in exfoliated buccal cells was decreased after dietary supplementation of 516 microg/day folate (p=0.010). Thus, low folate, without clinical symptoms of anemia, results in higher levels of cytogenetic damage in both the blood and oral cavity of postmenopausal women.