Description: This randomized, controlled dietary intervention trial is being conducted among lactating women in order to test the hypothesis that adoption of a Mediterranean diet rich in walnuts and citrus during lactation will be associated with a significant decrease in estradiol-17-beta and SHBG as compared to usual diet and a secondary hypothesis that adherence to a Mediterranean diet rich in walnuts and citrus will decrease the oxidative stress biomarkers 8-OHdG and 8-iso-PGF2alpha. Impact: The results of this trial may have implications for dietary recommendations/practices during lactation to promote improved health in both mother and child. The recruitment manuscript was published in Contemporary Clinical Trials Stendell-Hollis NR, Laudermilk MJ, West JL,Thompson PA, Thomson CA. Recruitment of lactating women into a randomized dietary intervention: successful strategies and factors promoting enrollment and retention. Contemp Clin Trials. 32(4):505-511, 2011. [PMID: 21382511].