Folate Metabolism in Normal Weight and Obese Women of Child-bearing Age

The purpose of this study is to determine if there is a difference in the short term response in serum folate after a single dose of folic acid in normal weight and obese women of childbearing age.

Current recommendations established in 1998, specify that all women capable of becoming pregnant consume 400 micrograms of folate daily from supplements, fortified foods, or both, in addition to consuming food folate from a varied diet. Despite this recommendation, obese women have a lower folate status than women of normal weight which suggests that obesity may have a negative impact on folate metabolism. Therefore, the objective of this study is to determine if there are differences in the metabolic response to a single dose of folate between normal weight and obese women of child bearing age. The two groups of women will be given the currently recommended amount of folic acid, 400 micrograms, and blood samples will be taken before the vitamin is given and at various points afterwards to determine serum folate response to the folate dose. Results of this research should help determine if folate requirements are higher for obese than for non-obese women. The long-term goal of this and follow-up studies is to generate data that will contribute to the evidence base used by scientific advisory panels to determine whether dietary folate intake recommendations should be based on body weight.

Change from baseline in serum folate response at the indicated time points following oral intake of a 400 ug dose of folic acid will be calculated by subtracting the baseline concentrations from the folate value at each subsequent time point. Individual response-time curves will be generated and area-under-the-curve (AUC) calculated using the trapezoidal rule.

Maximum folate concentration in response to an oral dose of 400 ug folic acid. Values are derived from the individual response curves.

Time to peak serum concentration of folate following the oral administration of a 400 ug dose of folic acid. Values are derived from the individual response curves.

Inclusion Criteria: Female 18-35 yr Caucasian Body mass index 18.5 - 24.9 or > 30 kg/m2 Exclusion Criteria: Currently pregnant, pregnancy within the past 12 months Greater than 2 previous pregnancies Use of prescription drugs other than oral contraceptives Chronic disease (diabetes, hypertension, epilepsy, cancer, kidney disease, cardiovascular disease) Acute illness (e.g. pneumonia, urinary tract infection, mononucleosis) Use of antibiotics in past 30 days Current smoker Use of dietary supplements including multivitamins in the past 30 days Significant weight change in past 12 months Typical alcohol consumption of 2 or more drinks per day Consumption of any alcohol in the week preceding testing

da Silva VR, Hausman DB, Kauwell GP, Sokolow A, Tackett RL, Rathbun SL, Bailey LB. Obesity affects short-term folate pharmacokinetics in women of childbearing age. Int J Obes (Lond). 2013 Dec;37(12):1608-10. doi: 10.1038/ijo.2013.41. Epub 2013 Apr 9.