The Dietary Guidelines for Americans recommend that children and adolescents "consume whole-grain products often; at least half the grains should be whole grains." Few, if any studies, examine the benefit of whole grains on the health of adolescents. The purpose of this study is to determine if adolescents eating diets rich in whole grains vs. diets rich in refined grains (i.e., a typical diet) have improved markers of digestive and immune health.

Middle-school students will be recruited and randomized to receive >/=80 g of whole grains (>/=5 servings) or similar foods made with refined grains each day for six weeks. Based on treatment group, subjects will be provided either whole grain or refined grain foods and snacks. They will be instructed on how to use these foods to replace other foods already contained in the diet. Stool, blood, and saliva samples will be obtained at baseline and at study end to examine the microbiota and markers of digestive and immune health. Daily records will be maintained by the students to assess bowel habits and compliance. It is anticipated that whole grains will increase stool bulk resulting in increased stool frequency and softer stools. Additionally, fermentation of the fiber within the colon will alter the microbiota profile. Because the majority of the immune system resides within the gastrointestinal tract, improved balance of the intestinal microbiota may prime the immune system thus contributing to improved immune defense.

Inclusion Criteria:

• Middle-school student at Westwood Middle School, Gainesville, FL
• Parental/guardian consent
• Willing to eat three different study foods each day for six weeks
• Willing to provide two blood samples and two saliva samples over the course of the study

Exclusion Criteria:

• Taking medications for constipation or diarrhea
• Antibiotic therapy within the past four weeks prior to randomization
• Takes probiotics or consumes greater than three servings of yogurt per week
• Has any diseases or illnesses such as gastrointestinal disease (gastric ulcers, Crohn's, ulcerative colitis, etc.), other chronic diseases (diabetes, kidney disease, etc.) or immune-modulating diseases (HIV, AIDS, autoimmune, hepatitis, cancer, etc.)
• Has any food allergies (wheat, soy, egg, milk, gluten, nuts, or any other food or food ingredient)