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This paper presents an overview of vitamin ${\text{B}}_6$ and exercise, including the role that vitamin ${\text{B}}_6$ plays in gluconeogenesis and glycogenolysis and changes in vitamin ${\text{B}}_6$ metabolism during exercise. The dietary vitamin ${\text{B}}_6$ intakes of athletes are also reviewed. Most studies report that male athletes have adequate dietary intakes of vitamin ${\text{B}}_6$, whereas some females, especially those with low energy intakes, appear to have low vitamin ${\text{B}}_6$ intakes. Few studies have assessed the vitamin ${\text{B}}_6$ status of nonsupplementing athletes using the recommended status criteria. The role that vitamin ${\text{B}}_6$ may play in attenuating the rise in plasma growth hormone observed during exercise is also reviewed. Finally, recomrnendations are given for further research in the area of vitamin ${\text{B}}_6$ and exercise.

The vitamin ${\text{B}}_6$ status of 13 endurance athletes was determined by whole blood ${\text{B}}_6$ (microbiological) and urine 4-pyridoxic acid (4-PA) (HPLC), serum vitamin ${\text{B}}_6$ (pyridoxal, pyridoxol, pyridoxamin) (HPLC), and erythrocyte α- EGOT measurements with the aid of 7-day records. In addition, blood and serum samples and urine were collected before (Time A), directly after (Time B), and 2 hr after a marathon race (Time C). The total energy intake was 12,303 ± 3,464 Wday (34% fat, 48% carbohydrates, 14% protein). The vitamin ${\text{B}}_6$ intake, serum concentrations, α-EGOT value, and 4-PA excretion were higher than the reference values at Time A. Only the vitamin ${\text{B}}_6$ whole blood levels were below the normal level at Time A. The vitamin B, status of the athletes corresponded essentially to reference values obtained for untrained individuals. There was a mean loss of about 1 mg vitamin ${\text{B}}_6$ as a result of the marathon race. Vitamin ${\text{B}}_6$ supplementation does not appear necessary if a balanced diet is consumed.

The B-vitamins (thiamin, ribofavin, vitamin B-6) are necessary in the energy-producing pathways of the body, while folate and vitamin B-12 are required for the synthesis of new cells, such as the red blood cells, and for the repair of damaged cells. Active individuals with poor or marginal nutritional status for a B-vitamin may have decreased ability to perform exercise at high intensities. This review focuses on the B-vitamins and their role in energy metabolism and cell regeneration. For each vitamin, function related to physical activity, requirement, and status measures are given. Research examining dietary intakes and nutritional status in active individuals is also presented. Current research suggests that exercise may increase the requirements for ribofavin and vitamin B-6, while data for folate and vitamin B-12 are limited. Athletes who have poor diets, especially those restricting energy intakes or eliminating food groups from the diet, should consider supplementing with a multivitamin/mineral supplement.

Muscle glycogen is the primary source of energy during high intensity exercise. Increasing the carbohydrate content of the diet allows more glycogen to be stored. Some adolescent female athletes (gymnasts, dancers) do not consume adequate amounts of vitamin B6, folacin, and E. Many women have low dietary intakes of calcium and iron. Low calcium intake and physical inactivity are factors associated with the development of osteoporosis. Low iron intake is associated with the development of iron deficiency and anemia. Low ferritin levels (an index of body iron stores) are commonly observed in female athletes.

The purpose of this study was to determine the dietary adequacy of 12 collegiate cross-country runners during a competitive season. Four-day diet records were collected twice during the season and analyzed for total daily energy, macronutrients, vitamin A, vitamin C, thiamin, riboflavin, niacin, vitamin ${\text{B}}_6$, folate, iron, magnesium, zinc, and calcium. Mean energy intake (3,248 ± 590 kcal) was not significantly different from estimated mean energy expenditure (3,439 ± 244 kcal). Week 8 mean prealbumin levels were within normal limits (26.8 ± 2.8 mg/dl). Mean daily CHO intake was 497 ± 134 g/day (61.2%). Three to four hours prior to competition a pre-race meal was consumed; it contained 82 ± 47 g CHO. Posteompetition CHO intake was delayed an average 2.5 hr; at that time approximately 2.6 ± 0.69 g CHO/kg body weight was consumed. The athletes appeared to demonstrate dietary adequacy with the exception of timing of posteompetition carbohydrate consumption.

This study determined the effect of training on body composition, dietary intake, and iron status of eumenorrheic female collegiate swimmers (n = 18) and divers (n = 6) preseason and after 16 wk of training. Athletes trained on dryland (resistance, strength, fexibility) 3 d/wk, 1.5 h/d and in-water 6 d/wk, nine, 2-h sessions per week (6400 to 10,000 kJ/d). Body-mass index (kg/m²; P = 0.05), waist and hip circumferences (P ≤ 0.0001), whole body fat mass (P = 0.0002), and percentage body fat (P ≤ 0.0001) decreased, whereas lean mass increased (P = 0.028). Using dual-energy X-ray absorptiometry, we found no change in regional lean mass, but fat decreased at the waist (P = 0.0002), hip (P = 0.0002), and thigh (P = 0.002). Energy intake (10,061 ± 3617 kJ/d) did not change, but dietary quality improved with training, as refected by increased intakes of fber (P = 0.036), iron (P = 0.015), vitamin C (P = 0.029), vitamin B-6 (P = 0.032), and fruit (P = 0.003). Iron status improved as refected by slight increases in hemoglobin (P = 0.046) and hematocrit (P = 0.014) and decreases in serum transferrin receptor (P ≤ 0.0001). Studies are needed to further evaluate body composition and iron status in relation to dietary intake in female swimmers.

This cross-sectional study explored the prevalence of iron deficiency (ID) and associations between dietary factors and incidence of ID in female rhythmic gymnasts during preseason periods. Participants were 60 elite collegiate rhythmic gymnasts (18.1 ± 0.3 years [M ± SD]) who were recruited every August over the course of 8 years. Participants were divided into 2 groups according to the presence or absence of ID. Presence of ID was defined either by ferritin less than 12 µg/L or percentage of transferrin saturation less than 16%. Anthropometric and hematologic data, as well as dietary intake, which was estimated via a semiquantitative food frequency questionnaire, were compared. ID was noted in 48.3% of participants. No significant group-dependent differences were observed in physical characteristics, red blood cell counts, hemoglobin, hematocrit, haptoglobin, or erythropoietin concentrations. The ID group had a significantly lower total iron-binding capacity; serum-free iron; percentage of transferrin saturation; ferritin; and intake of protein, fat, zinc, vitamin B₂, vitamin B₆, beans, and eggs but not iron or vitamin C. The recommended dietary allowance for intake of protein, iron, zinc, and various vitamins was not met by 30%, 90%, 70%, and 22%–87% of all participants, respectively. Multiple logistic analysis showed that protein intake was significantly associated with the incidence of ID (odds ratio = 0.814, 95% confidence interval [0.669, 0.990], p = .039). Participants in the preseason’s weight-loss periods showed a tendency toward insufficient nutrient intake and were at a high risk for ID, particularly because of lower protein intake.