title: Improved vitamin B-6 status is positively related to lymphocyte proliferation in young women consuming a controlled diet.
abstract: To examine the effect of increased intake levels of vitamin B-6 (B-6) on lymphocyte proliferation and interleukin 2 (IL-2) concentration, young women (n = 7) consumed a constant diet containing 1 mg (5.91 micro mol) B-6/d for a 7-d adjustment period, followed by three 14-d experimental periods during which the daily B-6 intake was 1.5, 2.1 and 2.7 mg (8.86, 12.41 and 15.95 micro mol)/d, respectively. Weekly fasting blood and daily 24-h urine samples were collected. Lymphocyte proliferation and IL-2 production were measured in response to phytohemagglutinin. Vitamin B-6 status improved with increased B-6 intake as measured by plasma pyridoxal 5'-phosphate (PLP) and urinary 4-pyridoxic acid. When subjects consumed 2.1 mg B-6/d for 7 d, lymphocyte proliferation increased by 35% (P < or = 0.05) compared with the mean value after consumption of 1.5 mg B-6/d for 14 d. There was no further enhancement after an additional week of 2.1 and 2.7 mg B-6/d for 2 wk. Lymphocyte proliferation was correlated (P < or = 0.01) with vitamin B-6 intake (r = 0.757), plasma PLP (r = 0.456) and erythrocyte aminotransferase activities (r = -0.361). Plasma IL-2 concentration and in vitro production did not change throughout the study, although five of seven subjects showed increases with intakes of 2.1 and 2.7 mg B-6/d, respectively, compared with the 1.5 mg/d intake. Concentrations of PLP in peripheral blood mononuclear cells were correlated (r = 0.357, P < or = 0.01) with plasma PLP, but not with proliferation. These results show that improving vitamin B-6 status by consuming a B-6 intake higher than the current Recommended Dietary Allowance enhances lymphocyte proliferation.
authors.affiliation: Department of Nutrition and Food Management, Oregon State University, Corvallis, OR 97331, USA.
authors.forename: Ho-Kyung
authors.initials: HK
authors.lastname: Kwak
authors.forename: Christine M
authors.initials: CM
authors.lastname: Hansen
authors.forename: James E
authors.initials: JE
authors.lastname: Leklem
authors.forename: Karin
authors.initials: K
authors.lastname: Hardin
authors.forename: Terry D
authors.initials: TD
authors.lastname: Shultz
mesh_terms: D000328:Adult; D000410:Alanine Transaminase / Q000097:blood; D001827:Body Height; D004032:Diet; D004912:Erythrocytes / Q000201:enzymology; D005260:Female; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis / Q000097:blood; D007963:Leukocytes, Mononuclear / Q000737:chemistry; D008213:Lymphocyte Activation; D009752:Nutritional Status; D010835:Phytohemagglutinins / Q000494:pharmacology; D011732:Pyridoxal Phosphate / Q000097:blood; D011735:Pyridoxic Acid / Q000652:urine; D025101:Vitamin B 6 / Q000008:administration & dosage*
chemical_list: D007376:Interleukin-2; D010835:Phytohemagglutinins; D011735:Pyridoxic Acid; D011732:Pyridoxal Phosphate; D025101:Vitamin B 6; D000410:Alanine Transaminase