Food sources of calcium in a sample of African-American an Euro-American collegiate athletes

Predisposing Risk Factors for Stress Fractures in Collegiate Cross-Country Runners

ABSTRACT

Giffin, KL, Knight, KB, Bass, MA, and Valliant, MW. Predisposing risk factors and stress fractures in collegiate cross-country runners. J Strength Cond Res 35(1): 227-232, 2021-The purpose of this study was to explore factors associated with increased stress fractures in collegiate cross-country runners. Subjects in this study were 42 male and female cross-country runners at a Division I university. Each athlete completed a questionnaire regarding smoking status, vitamin/mineral intake, previous stress fracture history, birth control usage, menstrual status, and demographic information. Nutritional assessment using a 3-day food record and measurements of whole body, lumbar spine, and hip bone mineral densities (BMDs) were also conducted on each athlete. Results indicated that 40% of the female and 35% of the male runners reported a history of stress fracture, and that all of them did not meet the recommended daily energy intake or adequate intakes for calcium or vitamin D required for their amount of training. Two-tailed t-test found statistically higher incidences of lumbar spine BMD in male and female runners whose daily calcium and vitamin D intakes were below minimum requirements as well as for women whose caloric intake was below the required level. When data on the lumbar spine was evaluated, 31% of subjects (31.8% of the male and 30% of the female runners) were identified as having osteopenia and 4.8% with osteoporosis. Results warrant a need for future longitudinal studies.

Nutritional Intake and Energy Availability of Collegiate Distance Runners

Objective: Research investigating the dietary habits of distance runners has presented varying results. Proper dietary intake appears to enhance distance running performance and low dietary intake may impact health. The purpose of this investigation was to perform a comprehensive evaluation of nutrient intake of collegiate distance runners with comparison to recommendations for athletes.Methods: Twenty-one men (Age: 19.6 ± 1.2 years; height: 177.1 ± 5.7 cm; body mass: 65.7 ± 4.6 kg; body fat: 15.5 ± 2.2%) and 20 women (Age: 20.2 ± 1.7 years; height: 162.9 ± 6.6 cm; body mass: 53.7 ± 6.5 kg; body fat: 23.3 ± 3.6%) volunteered to participate in the investigation. Energy intake was derived from the Block Food Frequency Questionnaire. Energy availability was calculated by subtracting exercising energy expenditure from daily energy intake, divided by bone free lean mass and fat-free mass. Macronutrient and micronutrient consumption were compared with the appropriate dietary reference intake values, U.S. Dietary Guidelines, or standards recommended for endurance athletes.Results: Dietary intake for the men was 2,741.0 ± 815.2kilocalories and for the women was 1,927.7 ± 638.2kilocalories. A majority of the runners (73%) consumed less than recommended levels of carbohydrates. All men and 75% of women met or exceeded the recommended daily protein intake. Fifty percent of women and 24% of men did not meet the recommended daily allowance for calcium. Ninety-five percent of the runners did not meet the RDA for vitamin D. All the men and 75% of the women met the RDA for iron intake, with 24 of the runners taking an iron supplement. Eight men and 10 women did not meet the recommended intake for potassium.Conclusion: The dietary intake in this group of distance runners is below that necessary for the level of energy expended in their training. Carbohydrate intake is below the recommended amount for endurance athletes, and the calcium and vitamin D intake may not be favorable for bone health in this group of distance runners.

Bone Accrual in Children and Adolescent Nonelite Swimmers: A 2-Year Longitudinal Study

OBJECTIVE

To examine differences in bone mass between children and adolescents swimming competitively at nonelite levels (locally and regionally) and nonathletes and to assess changes in bone mass in these 2 groups over 24 months after taking into consideration several known confounders of bone mass.

DESIGN

Observational prospective study.

PARTICIPANTS

White nonelite swimmers (n = 128) and nonathletes (n = 106) 8 to 18 years of age from Memphis, Tennessee, USA.

MAIN OUTCOME MEASURES

Participants underwent dual-energy x-ray absorptiometry to assess total body and hip bone mineral content (BMC) at baseline and 12 and 24 months later.

RESULTS

At baseline, swimmers had 4.2% and 6.1% higher adjusted BMC for the total body and hip, respectively, compared with nonathletes (P values < 0.027). Averaging across assessment points, swimmers had 73.5 and 2.2 g higher BMC for the total body and hip, respectively, than nonathletes. Although there was a significant annual increase in total body and hip BMC in both groups (33.5 and 0.7 g, respectively), there was no difference in annualized bone accrual between swimmers and nonathletes for either total body BMC (swim by time effect; P = 0.213) or hip BMC (P = 0.265).

CONCLUSIONS

Competitive swimming at nonelite levels during childhood and adolescence does not seem to compromise bone accrual.

Dairy foods are an important source of calcium and vitamin D among Canadian-born and Asian-born Chinese in Edmonton, Alberta

Low intakes of calcium and vitamin D increase the risk for osteoporosis, bone fracture, and other health problems. This study aimed to examine the calcium and vitamin D intakes of Canadian-born Chinese (CBC) and Asian-born Chinese (ABC) in Edmonton, Canada, and to identify usual food sources of these nutrients. We hypothesized that CBC would have higher intakes of calcium and vitamin D than ABC and that the food sources of these nutrients would differ by region of birth (Canada vs Asia). Two in-person multipass 24-hour dietary recalls were administered for 1 weekday and weekend day for 81 healthy ethnically Chinese aged 18 to 58 years. The risks for calcium and vitamin D inadequacy were calculated as were the contributions of specific foods to calcium and vitamin D intakes. Calcium intake was 781 ± 337 mg/d for CBC and 809 ± 369 mg/d for ABC (P = .737). Vitamin D intake was 3.8 ± 3.4 μg/d for CBC and 5.0 ± 3.9 μg/d for ABC (P = .158). Respective risks for calcium and vitamin D inadequacy were 36% and 98% for men and 78% and 100% for women. Dairy contributed most to the calcium (43%) and vitamin D (52%) intake of participants. For ABC, soybean products contributed to 8.1% of calcium, whereas fatty fish contributed to 16.7% of vitamin D. For CBC, red meats contributed to 11.1% of vitamin D. Dietary intakes of calcium and vitamin D need to be increased in Chinese Canadians through the promotion of dairy and culturally relevant sources of these nutrients.

Calcium and dairy intake: Longitudinal trends during the transition to young adulthood and correlates of calcium intake

OBJECTIVE

To describe changes in calcium and dairy intake during the transition from middle adolescence to young adulthood and to identify baseline correlates of calcium intake in young adulthood.

DESIGN

Population-based, 5-year follow-up study (Project EAT: Eating Among Teens).

SETTING

Baseline surveys were completed in Minneapolis/St. Paul, MN schools and by mail at follow-up.

PARTICIPANTS

Males and females (N = 1521) attending high school at baseline (mean age = 15.9 years) and with a mean age of 20.5 years at follow-up.

MAIN OUTCOME MEASURES

Calcium intake.

ANALYSIS

Mixed and linear regression methods were used to respectively examine trends and correlates of intake.

RESULTS

During the transition to young adulthood, mean daily calcium intakes of females and males decreased by an average of 153 mg and 194 mg respectively. Mealtime milk availability, health/nutrition attitudes, taste preference for milk, healthful weight control behaviors, and peer support for healthful eating at baseline were associated with better follow-up calcium intake. Time spent watching television and lactose intolerance were associated with lower intake at follow-up.

CONCLUSIONS AND IMPLICATIONS

Nutrition interventions are needed to counter longitudinal decreases in calcium intake. Interventions targeted to adolescents should address the availability of milk at meals and other identified supports for healthful eating.

Bone density and young athletic women. An update

High-school girls and collegiate women have tremendous opportunities to participate in athletic teams. Young girls are also playing in club and select teams at an early age and often, year-round. There are many benefits for participating in sport and physical activity on both the physical and mental health of girls and women. Decreased risk for heart disease and diabetes mellitus, along with improved self-esteem and body-image, were among the first reported benefits of regular physical activity. In addition, sport participation and physical activity is also associated with bone health. Athletes have a greater bone mineral density compared with non-active and physically active females. The increase in bone mass should reduce the risk of fragility fractures in later life. There appears to be a window of opportunity during the development of peak bone mass in which the bone is especially responsive to weight-bearing physical activity. Impact loading sports such as gymnastics, rugby or volleyball tend to produce a better overall osteogenic response than sports without impact loading such as cycling, rowing and swimming. Relatively little is known about the impact of retiring from athletics on bone density. It appears that former athletes continue to have a higher bone density than non-athletes; however, the rate of bone loss appears to be similar in the femoral neck. The positive impact of sports participation on bone mass can be tempered by nutritional and hormonal status. It is not known whether female athletes need additional calcium compared with the general female population. Due to the increased energy expenditure of exercise and/or the pressure to obtain an optimal training bodyweight, some female athletes may develop low energy availability or an eating disorder and subsequently amenorrhoea and a loss of bone mineral density. The three inter-related clinical disorders are referred to as the 'female athlete triad'. This article presents a review of the relationship between sports training and bone health, specifically bone mineral density, in young athletic women.

Impact of detraining on bone loss in former collegiate female gymnasts

Undesirable changes in health-related parameters are thought to occur in retiring female athletes, but this has not been examined in longitudinal studies. The purpose of this study was to examine longitudinal changes in bone mineral density (BMD), body composition, and dietary intake in gymnasts and controls. Nonathletic, college-age women (: n = 9) were selected as a control group for comparison to the gymnasts (n = 10). Initial BMDs for the gymnasts were determined by using dual energy X-ray absorptiometry (Lunar, DPX) at the beginning of their final competitive year. Initial BMDs for the controls were measured during a similar time-frame. Follow-up measurements were made at least 1-year after the initial measurement. Gymnasts had significantly greater BMD of the femoral neck (1.262 versus 1.058 g/cm2, respectively), Ward's triangle (1.230 versus 1.008 g/cm2), greater trochanter (1002 versus 0.822 g/cm2), and total body (1.232 versus 1.145 g/cm2) than controls while still competing (P < .05). Following retirement from competition, (mean years of retirement, 4 years), BMD of the gymnasts remained significantly greater than controls at total body, femoral neck, trochanter, and Ward's triangle (P < .05). Significant declines in femoral neck, Ward's triangle, and greater trochanter BMD were found in both gymnasts and controls (0.72% to 1.9% per year), but only gymnasts had a significant decline at the lumbar spine (0.87% per year). In conclusion, BMD changes in former gymnasts appear to be site-specific, and gymnasts continue to have greater proximal femur BMD than controls, despite their decreased exercise, which may help postpone or prevent osteoporosis later in life.

Reliability and validity of a brief questionnaire to assess calcium intake in female collegiate athletes

Calcium intake often is inadequate in female collegiate athletes, increasing the risk for training injuries and future osteoporosis. Thus, a brief and accurate assessment tool to quickly measure calcium intake in athletes is needed. We evaluated the reliability and validity, compared to 6 days of diet records (DRs), of the Rapid Assessment Method (RAM), a self-administered calcium checklist. Seventy-six female collegiate athletes (mean age = 18.8 yrs, range= 17- 21; 97 % Caucasian) were recruited from basketball, cross-country, field hockey, soccer, and volleyball teams. Athletes completed a RAM at the start of the training season to assess calcium intake during the past week. Two weeks later, a second RAM was completed to assess reliability, and athletes began 6 days of diet records (DRs) collection. At completion of DRs, athletes completed a final RAM, corresponding to the same time period as DRs, to assess agreement between the 2 instruments. The RAM demonstrated adequate test-retest reliability over 2 weeks (n= 56; Intraclass correlation [ICC] = 0.54, p < 0.0001) and adequate agreement with DRs (n = 34; ICC = 0.41, p = 0.0067). Calcium intake was below recommended levels, and mean estimates did not differ significantly on the RAM (823 +/- 387 mg/d) and DRs (822 +/- 330 mg/d; p = 0.988). Adequacy of calcium intake from both DRs and the RAM was classified as "inadequate" (<1000 mg/d) and "adequate" (> or = 1000 mg/d). Agreement between the RAM and DRs for adequacy classification was fair (ICC= 0.30, p = 0.042), with the RAM identifying 84% of athletes judged to have inadequate calcium intake based on DRs. The RAM briefly and accurately estimates calcium intake in female collegiate athletes compared to DRs.

A pilot intervention to increase calcium intake in female collegiate athletes

Calcium intake in adolescent and young adult female athletes often is inadequate to optimize peak bone mass, an important determinant of osteoporosis risk. The purpose of this study was to determine if calcium supplementation in eumenorrheic female collegiate athletes increases intake to recommended levels and promotes increases in bone mineral density (BMD). Forty-eight eumenorrheic female athletes from several college teams (15 soccer, 7 cross-country, 8 indoor track, and 18 basketball) were randomized at the beginning of a competitive season to receive either an oral calcium supplement (1000 mg calcium citrate/400 I.U. Vitamin D) or placebo daily throughout the training season (16 weeks). Self-reported daily pill intake was obtained every 2 weeks to assess adherence. Calcium intake was evaluated using the Rapid Assessment Method, and total body and leg BMD was measured at pre-, mid-, and postseason using dual energy x-ray absorptiometry (DEXA; Hologic QDR-2000). Pre-season calcium intake was lower than national recommendations for this age group (12), averaging 842 mg/d (SD = 719) and was lower in the placebo group compared to the supplemented group (649 +/- 268 vs. 1071 +/- 986 mg/d, respectively; p = .064). Adherence to supplementation was good, averaging 70% across the training season. Supplementation boosted total calcium intake to a mean of 1397 +/- 411 mg/d, which is consistent with recommended levels for this group (37). Supplementation did not influence BMD change during this 16-week intervention. Across teams, a small increase of 0.8% was observed in leg BMD. Change in total body BMD was modified by team, with a significant increase of 1.5% observed in basketball players. These results indicate that providing calcium supplements of 1000 mg/d is adequate to boost total intake to recommended levels during athletic training. Longer intervention trials are required to determine whether calcium supplementation has a positive effect on BMD.

Food mixture or ingredient sources for dietary calcium: Shifts in food group contributions using four grouping protocols

Identifying dietary sources of nutrients by assigning survey foods to food groups can under- or overestimate the contribution a group makes to the intake of specific nutrients. Using calcium and food intakes from USDA's 1994-1996, 1998 Continuing Survey of Food Intakes by Individuals, the authors determined the proportion of dietary calcium from the dairy, grains, meats, fruits, and vegetables groups using four grouping protocols. Calcium contributions from milk and cheese were higher as more ingredient sources and fewer survey food items were represented in the dairy group. Milk, cheese, and yogurt reported as separate survey food items contributed 42% of total calcium intake. An additional 21% of dietary calcium came from dairy ingredients in mixed foods such as macaroni and cheese, pizza, sandwiches, and desserts. The remaining dietary calcium sources were single grains (16%); vegetable (7%); meat, poultry, and fish (5%); fruit (3%); and miscellaneous foods (7%). Data quantifying the nutrient contributions from dairy ingredients could affect dietary guidance messages or research using dairy foods as variables.

Bone mineral density in triathletes over a competitive season

There is evidence from previous cross-sectional studies that high volumes of certain sports, including running, swimming and cycling, may have a negative impact on bone mineral density. The aim of the present study was to evaluate prospectively the effects of high athletic training in individuals who engage in high volumes of all three of these activities (triathletes). Bone mineral density for the total body, arms and legs was determined by dual-energy X-ray absorptiometry in 21 competitive triathletes (9 men, 12 women) at the beginning of the training season and 24 weeks later. Age, body mass index, calcium intake and training volume were also recorded to examine potential mediators of bone mineral density change. Men had greater bone mineral density at all sites than women. No significant changes were observed over the 24 weeks for either total body or leg bone mineral density. Bone mineral density in both arms increased by approximately 2% in men (P < 0.03), but no change was observed for women. Change in bone mineral density at all sites was unrelated to age, body mass index, calcium intake and training volume. The results suggest that adverse changes in bone mineral density do not occur over the course of 6 months of training in competitive triathletes.