Abstract: The present invention provides a dietary or food supplement for healthy humans that includes a combination of 4-hydroxyisoleucine and creatine, or nutraceutically acceptable derivatives of these two compounds. The supplement may include additives such as carbohydrates or amino acids. The invention further includes a regimen for supplementing a healthy athlete's diet by administering on a regular basis to the athlete 4-hydroxyisoleucine and creatine, or nutraceutically acceptable derivatives of these two compounds. The invention also provides a method for enhancing the body's absorption and utilization of a nutrient, comprising administering 4-hydroxyisoleucine or a nutraceutically acceptable derivative thereof in combination with the nutrient.