Landahl and colleagues31 found that iron deficiency and iron deficiency anemia are common in female soccer players at the elite level. In their study of 28 female national soccer players, 57% had iron deficiency and 29% presented with iron deficiency anemia 6 months before the FIFA Women's World Cup. Testing hemoglobin alone is insufficient to detect relative anemia. Regular monitoring of hemoglobin and ferritin concentrations may be necessary to determine appropriate iron needs.
VITAMIN D
Vitamin D is required for optimal bone health, as it helps regulate calcium and phosphorus. Further research shows a link between vitamin D and non–bone-related functions, such as muscle health, immune support, and anti-inflammatory roles, which may be linked to performance. Soccer players with low levels of vitamin D (<30 ng/mL) may be more at risk for musculoskeletal injuries and stress fractures.34 In other sports, vitamin D may enhance muscle strength; however, no association between vitamin D and muscle strength has been found in soccer players.34,35 The geographic location of an athlete seems to be irrelevant to serum levels, as insufficient levels can be found at various latitudes.34,36-38
Evidence has shown that vitamin D may improve athletic performance in vitamin D-depleted athletes, thereby improving vertical jumps, lowering risks of muscle injury/strains and stress fractures, and reducing risk of colds/flu. In 2013, researchers showed for the first time a link between vitamin D and muscle aerobic metabolism by studying the energy efficiency of the mitochondria.32 Athletes with low vitamin D levels increased their ATP production within the muscle with vitamin D supplementation over 10 weeks to 12 weeks.33
CALCIUM
Soccer players present with stronger and denser bones than non-athletes due to running and jumping in their sport. Weight-bearing sites such as lumbar spine, hip, femoral neck, trochanter, intertrochanteric region, and both legs are sensitive to the impact of soccer movements.39 Calcium and vitamin D are also important for muscle contraction.
Given the variation in genetics, sports, and gender, optimal performance requires a healthy eating plan tailored to the individual athlete. A healthy eating plan allows an athlete to train longer and harder, delay the onset of fatigue, and speed recovery. Nutrition supports optimal performance through real food, proper hydration, nutrient timing, and supplementation.
Continue to: FLUID REQUIREMENTS FOR SOCCER PLAYERS