Date

2006-01-01

Author

Troen, AM
Mitchell, B
Sorensen, B
Wener, MH
Johnston, A
Wood, B
Selhub, J
McTiernan, A
Yasui, Y
Oral, E
Potter, JD
Ulrich, CM

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

103
views

0
downloads

Cite This

Folic acid (FA) supplements and food fortification are used to prevent neural tube defects and to lower plasma homocysteine. Through exposure to food fortification and vitamin supplement use, large populations in the United States and elsewhere have an unprecedented high FA intake. We evaluated dietary and supplemental intakes of folate and FA in relation to an index of immune function, natural killer cell (NK) cytotoxicity, among 105 healthy, postmenopausal women. Among women with a diet low in folate ( 400 mu g/d had reduced NK cytotoxicity compared with those consuming a low-folate diet and no supplements (P = 0.02). Prompted by this observation, we assessed the presence of unmetabolized FA in plasma as a biochemical marker of excess FA. Unmetabolized folic acid was detected in 78% of plasma samples from fasting participants. We found an inverse relation between the presence of unmetabolized FA in plasma and NK cytotoxicity. NK cytotoxicity was similar to 23% lower among women with detectable folic acid (P = 0.04). This inverse relation was stronger among women >= 60 y old and more pronounced with increasing unmetabolized FA concentrations (P-trend = 0.002). Because of the increased intake of FA in many countries, our findings highlight the need for further studies on the effect of long-term high FA intake on immune function and health.

Subject Keywords

Carcinogenesis, Folic acid, Immune function, Natural killer cells

URI

https://hdl.handle.net/11511/68583

Collections

Department of Statistics, Article