Case Study: The Effect of Nutritional Intervention on Body Composition and Physical Performance of a Female Squash Player

Vitamin D and Stress Fractures in Sport: Preventive and Therapeutic Measures-A Narrative Review

There are numerous risk factors for stress fractures that have been identified in literature. Among different risk factors, a prolonged lack of vitamin D (25(OH)D) can lead to stress fractures in athletes since 25(OH)D insufficiency is associated with an increased incidence of a fracture. A 25(OH)D value of <75.8 nmol/L is a risk factor for a stress fracture. 25(OH)D deficiency is, however, only one of several potential risk factors. Well-documented risk factors for a stress fracture include female sex, white ethnicity, older age, taller stature, lower aerobic fitness, prior physical inactivity, greater amounts of current physical training, thinner bones, 25(OH)D deficiency, iron deficiency, menstrual disturbances, and inadequate intake of 25(OH)D and/or calcium. Stress fractures are not uncommon in athletes and affect around 20% of all competitors. Most athletes with a stress fracture are under 25 years of age. Stress fractures can affect every sporty person, from weekend athletes to top athletes. Stress fractures are common in certain sports disciplines such as basketball, baseball, athletics, rowing, soccer, aerobics, and classical ballet. The lower extremity is increasingly affected for stress fractures with the locations of the tibia, metatarsalia and pelvis. Regarding prevention and therapy, 25(OH)D seems to play an important role. Athletes should have an evaluation of 25(OH)D -dependent calcium homeostasis based on laboratory tests of 25-OH-D3, calcium, creatinine, and parathyroid hormone. In case of a deficiency of 25(OH)D, normal blood levels of ≥30 ng/mL may be restored by optimizing the athlete's lifestyle and, if appropriate, an oral substitution of 25(OH)D. Very recent studies suggested that the prevalence of stress fractures decreased when athletes are supplemented daily with 800 IU 25(OH)D and 2000 mg calcium. Recommendations of daily 25(OH)D intake may go up to 2000 IU of 25(OH)D per day.

Are There Benefits from the Use of Fish Oil Supplements in Athletes? A Systematic Review

Despite almost 25 y of fish oil supplementation (FS) research in athletes and widespread use by the athletic community, no systematic reviews of FS in athletes have been conducted. The objectives of this systematic review are to: 1) provide a summary of the effect of FS on the athlete's physiology, health, and performance; 2) report on the quality of the evidence; 3) document any side effects as reported in the athlete research; 4) discuss any risks associated with FS use; and 5) provide guidance for FS use and highlight gaps for future research. Electronic databases (PubMed, Embase, Web of Science, Google Scholar) were searched up until April 2019. Only randomized placebo-controlled trials (RCTs) in athletes, assessing the effect of FS on a health, physiological/biochemical, or performance variable were included. Of the 137 papers identified through searches, 32 met inclusion criteria for final analysis. Athletes varied in classification from recreational to elite, and from Olympic to professional sports. Mean age for participants was 24.9 ± 4.5 y, with 70% of RCTs in males. We report consistent effects for FS on reaction time, mood, cardiovascular dynamics in cyclists, skeletal muscle recovery, the proinflammatory cytokine TNF-α, and postexercise NO responses. No clear effects on endurance performance, lung function, muscle force, or training adaptation were evident. Methodological quality, applying the Physiotherapy Evidence Database (PEDro) scale, ranged from 6 to a maximum of 11, with only 4 RCTs reporting effect sizes. Few negative outcomes were reported. We report various effects for FS on the athlete's physiology; the most consistent findings were on the central nervous system, cardiovascular system, proinflammatory cytokines, and skeletal muscle. We provide recommendations for future research and discuss the potential risks with FS use.

Analysis of Nutritional Supplements Consumption by Squash Players

The aim of the present study is to analyse nutritional supplements (NS) consumption by squash players of different levels (international vs. national). A total of 14 international players and 28 national ones answered a NS consumption frequency questionnaire that had been previously validated. A T-Student test was used for independent samples and a χ² test was used in the comparative analysis among athletes of different levels. International level players consume NS in greater proportion vs. national level players (100% vs. 67.9% p = 0.017), with differences in the consumption of bicarbonate of soda, glutamine, branched-chain amino acids, and flaxseed oil (p < 0.05). Even though international level athletes show a greater total number of NS, as well as of the total of NS of each of the categories based on scientific evidence level (sports food, medical supplements, and ergogenic aids of groups A, B, C, and D) in relation to the national level athletes, no statistically significant differences were detected (p > 0.05). With regard to nutritional advice, there are also differences among performance levels (p = 0.003), being personal trainers (28.6%) and dietitians-nutritionists (21.4%) the greatest prescribers when it comes to international-level players, whereas 55.6% of the national-level players do not receive nutritional advice. The pattern of NS consumption, based on evidence level, is unbalanced and its performance could be favored if the dietitian-nutritionist were included as a nutritional advisor for these athletes.