Participation in this study will include 6 in-person visits. After enrollment, you will be asked to complete an online questionnaire about your diet and nutrition. At your first visit, we will check for anemia using a single finger prick test and measure characteristics of your muscle, followed by a 10-20 min exercise test on a treadmill to evaluate your fitness level. At this visit you will also be given a stool sample collection kit to use at home. At visits 2-5, we will collect stool samples obtained at home, ask you to fill out surveys regarding immune status and fatigue, and obtain blood samples. We will then ask you to perform three 3-20 minute exercise tests with rest in between each test in order to determine aerobic and anaerobic performance. A finger prick will be performed before and after each run to determine lactate levels. After visits 2 and 4 you will be asked to consume either a recombinant Bovine Lactoferrin supplement (rbLf), a bovine-milk derived Lactoferrin supplement, or a placebo supplement. At visit 6 we will collect a final blood sample. A minimum of 4 weeks will occur between visits 2 and 3 and between visits 4 and 5, and a minimum of 2 weeks will occur between visits 3 and 4 and between visits 5 and 6.