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Biomedical subjects

M Fogelholm

Publications and source records attributed to M Fogelholm.

52 records · Page 3Linked to original sources
PubMed1995

Indicators of vitamin and mineral status in athletes' blood: a review.

This review examines the hypothesis that vitamin and mineral status in athletes is inadequate for optimal sports performance. The review is based on indicators determined from blood and on studies published since 1980. Most of the studies did not find micronutrient status in athletes to be different from untrained controls. The serum ferritin concentration in females was lower than in males (27 vs. 78 micrograms.L-1), and the prevalence of low serum ferritin concentration was higher in female athletes than in untrained female controls (37 vs. 23%). Supplementation of water-soluble vitamins and iron was associated with an improvement in the corresponding indicators. Excluding a few studies with mildly anemic subjects, improvements in indicators of micronutrient status were not associated with enhanced athletic performance. Consequently, the levels of indicators of micronutrient status seen in athletes' blood were apparently compatible with optimal physical performance.

Female↗
PubMed1994

Healthy lifestyles of former Finnish world class athletes.

Recently, Sarna et al. (Med. Sci. Sports Exerc. 25:237-244, 1993) reported increased mean life expectancy in former world class athletes. Because lifestyle is associated with longevity, we have examined whether health habits of former Finnish male athletes (N = 1274; present mean age: 57.5, range: 36-94 yr) differed from those of noncompetitive referents (N = 788; mean age: 55.7, range: 39-87 yr). The athletes had represented Finland in international competitions in endurance (N = 177), power (N = 454), or other ("mixed") events (N = 643) from 1920-1965. Data on physical characteristics, sociodemographic factors, and health habits were obtained from questionnaires. All dependent variables in an analysis of covariance and in a logistic regression analysis were adjusted for age and occupation. Both leisure aerobic and work activity of all athlete groups was higher (P < 0.01) than that of referents. Compared with the referents, both power and "mixed" athletes were more prone to eat fruits and vegetables and to avoid vitamin supplements, but less prone to use butter and high-fat milk, and to smoke (odds ratios different from 1.0, P < 0.05). Also endurance athletes smoked less and drank less alcohol than the referents (P < 0.05). Higher leisure aerobic activity and less frequent smoking after athletic years might explain higher life expectancy of Finnish athletes.

Adult↗
PubMed1994

Effects of bodyweight reduction on sports performance.

Athletes reduce bodyweight for several reasons: to compete in a lower weight class; to improve aesthetic appearance; or to increase physical performance. Rapid bodyweight reduction (dehydration in 12 to 96 hours), typically with fluid restriction and increased exercise, is used by athletes competing in weight-class events. Gradual bodyweight reduction (over > 1 week) is usually achieved by cutting energy intake to 75 to 130 kJ/kg/day. An intake of 100 kJ/kg/day results in a weekly bodyweight loss of roughly 1kg. Aerobic endurance capacity decreases after rapid bodyweight reduction, but might increase after gradual bodyweight reduction. Maximal oxygen uptake (VO2max) measured as L/min is unchanged or decreased after bodyweight loss, but VO2max measured as ml/kg/min may increase after gradual bodyweight reduction. Anaerobic performance and muscle strength are typically decreased after rapid bodyweight reduction with or without 1 to 3 hours rehydration. When tested after 5 to 24 hours of rehydration, performance is maintained at euhydrated levels. A high carbohydrate diet during bodyweight loss may help in maintaining performance. Anaerobic performance is not affected and strength can increase after gradual bodyweight reduction. Reductions in plasma volume, muscle glycogen content and the buffer capacity of the blood explain decreased performance after rapid bodyweight reduction. During gradual bodyweight loss, slow glycogen resynthesis after training, loss of muscle protein and stress fractures (caused by endocrinological disorders) may affect performance. Athletes' bodyweight goals should be individualised rather than by comparing with other athletes. If the time between weigh-in and competition is < 5 hours, rapid bodyweight reduction should not exceed 4% of bodyweight. If the time interval is longer, a bodyweight reduction < or = 8% might be acceptable. A moderate-energy (100 to 120 kJ/kg/day) and high-carbohydrate (60 to 70% of total energy intake) diet is recommended. Gradual bodyweight reduction may be 0.5 to 1.5 kg/week. Energy intake should be 80 to 120 kJ/kg/day, with a high carbohydrate (60 to 70%) and a low fat (15 to 25%) content.

Anaerobic Threshold↗
PubMed1994

Effects of low-dose iron supplementation in women with low serum ferritin concentration.

We studied effects of dose and treatment duration during low-dose iron supplementation in premenopausal, non-pregnant women, with initial serum ferritin and haemoglobin concentrations < 20 micrograms x l-1 and > or = 120 g x l-1, respectively. The study was randomized, double-blind and placebo-controlled. Three groups completed a 6-month study: placebo (n = 27), FE-9 (9 mg iron x day-1, n = 18) and FE-27 group (27 mg iron x day-1, n = 19). The supplement consisted of 11% heme and 89% inorganic iron. In FE-27, serum ferritin increased from (mean, 95% confidence interval) 11.8 (9.7; 14.4) to 25.3 (18.6; 34.4) micrograms x l-1 in 1 month, and remained stable after that (ANOVA: group effect, P = 0.0003). In both FE-9 and FE-27, blood haemoglobin levels increased from 136 (132; 140) to 142 (139; 145) g x l-1 in 1 month, remaining constant after that (group effect, P = 0.001). Hence, the 27 mg daily dose of organic/inorganic iron corrected both mild anaemia and storage iron depletion, whereas the 9 mg dose did not affect iron stores. Elongation of treatment duration above 1 month brought about only minor changes.

Adult↗
PubMed1994

Vitamins, minerals and supplementation in soccer.

Despite low mineral intakes in several groups of female 'ball-game' players, investigations of blood profiles and physical performance do not indicate any evident physiological benefits of micronutrient supplementation. Nevertheless, measurements of iron status are warranted, particularly in female athletes. Iron therapy may be beneficial for iron-depleted (serum ferritin < 12 micrograms l-1) individuals. In athletes with infrequent or irregular menstruation, supplementary calcium might help to preserve bone density.

Calcium↗
PubMed1993

Lack of association between indices of vitamin B1, B2, and B6 status and exercise-induced blood lactate in young adults.

By means of a 5-week vitamin B-complex supplementation, associations between indices of vitamin B1, B2, and B6 status (activation coefficients [AC] for erythrocyte transketolase, glutathione reductase, and aspartate aminotransferase) and exercise-induced blood lactate concentration were studied. Subjects, 42 physically active college students (18-32 yrs), were randomized into vitamin (n = 22) and placebo (n = 20) groups. Before the supplementation there were no differences in ACs or basal enzyme activities between the groups. The ACs were relatively high, suggesting marginal vitamin status. In the vitamin group, all three ACs were lower (p < 0.0001) after supplementation: transketolase decreased from 1.16 (1.14-1.18) (mean and 95% confidence interval) to 1.08 (1.06-1.10); glutathione reductase decreased from 1.33 (1.28-1.39) to 1.14 (1.11-1.17); and aspartate aminotransferase decreased from 2.04 (1.94-2.14) to 1.73 (1.67-1.80). No changes were found after placebo. Despite improved indices of vitamin status, supplementation did not affect exercise-induced blood lactate concentration. Hence no association was found between ACs and blood lactate. It seems that marginally high ACs do not necessarily predict altered lactate metabolism.

Adolescent↗
PubMed1993

Factors affecting iron status in non-pregnant women from urban south Finland.

Iron status was evaluated in 446 non-pregnant urban Finnish women, aged 17-50 years. The mean results (95% ranges) for blood haemoglobin concentrations, mean corpuscular volumes (MCV) and serum ferritin concentrations were 139 g/l (121-155), 89 fl (79-97) and 28 micrograms/l (7-120), respectively. Serum ferritin was < 12 and < 20 micrograms/l in 11% and 30% of the subjects, respectively. In analyses of covariance, high frequency of menstruation, prolonged menstrual bleeding time, blood donation and use of intrauterine devices had negative effects (P < 0.05) on iron status. Dietary habits or participation in very hard physical exercise did not affect iron status. Factors predicting low iron stores were evaluated in a logistic regression analysis. Blood donation (odds ratio and its 95% confidence interval: 2.53; 1.22-4.82) and very prolonged (> or = 8 days) menstrual bleeding (4.93; 1.63-14.9) increased the likelihood for low serum ferritin, whereas daily physical activity (0.02; 0.01-0.88) and use of multivitamin and mineral supplements (0.57; 0.33-0.98) were associated with higher concentration. In conclusion, blood losses increase the risk for iron depletion, while higher physical activity (presumably because of the positive effects on energy and iron intake) may prevent iron depletion.

Adolescent↗
PubMed1992

Effects of iron supplementation in female athletes with low serum ferritin concentration.

Low serum ferritin concentrations are commonly found in female athletes. By studying the effects of an 8-week iron or placebo supplementation in 31 female athletes (aged 17-31 years), with an initial serum ferritin concentration less than or equal to 25 micrograms/l and blood hemoglobin 120 g/l, we investigated whether low serum ferritin values hinder aerobic performance. Serum ferritin concentration increased from 14 (25th and 75th percentile: 11, 21) to 26 (18, 36) micrograms/l in the iron-supplemented group, but remained at a low 11 (9, 17) micrograms/l in the placebo group (group difference after supplementation: p = 0.001). Before supplementation, blood hemoglobin concentration was not different in the two groups. After supplementation, however, the concentration in the iron group was 139 (135, 144) g/l and 128 (126, 134) g/l in the placebo group (group difference: p = 0.001). Iron supplementation did not affect blood lactate concentration or VO2max during an incremental ergometer test. Hence, aerobic performance was not impaired in nonanemic female athletes with serum ferritin 25 micrograms/l.

Adolescent↗
PubMed1992

Dietary intake and thiamin, iron, and zinc status in elite Nordic skiers during different training periods.

This study evaluated how different training periods affect dietary intake and biochemical indices of thiamin, iron, and zinc status in elite Nordic skiers. Subjects were 17 skiers and 39 controls, ages 18-38 yrs. Dietary data were collected by 7-day food records at 3-month intervals. Coefficient of variation (CV) was used to indicate magnitude of seasonal changes. Energy intake for the year (28 food record days) was 3,802 kcal/day (CV 19.1%) in male skiers, 2,754 kcal/day (CV 3.7%) in male controls, 2,812 kcal/day (CV 9.1%) in female skiers, and 2,013 kcal/day (CV 5.9%) in female controls. CVs for thiamin, riboflavin, vitamin C, calcium, magnesium, iron, and zinc intake were 14.1-23.9% (male skiers), 2.9-15.0% (male controls), 4.8-24.5% (female skiers), and 4.3-11.5% (female controls). Seasonal changes in energy, carbohydrate, and micronutrient intakes reflected energy expenditure in male endurance athletes particularly. Erythrocyte transketolase activation coefficients and serum ferritin and zinc concentrations did not differ between skiers and controls. Seasonal variations in these biochemical indices of nutritional status were of the same magnitude in skiers and controls, despite large changes in skiers' physical activity.

Adolescent↗
PubMed1992

Micronutrient status in females during a 24-week fitness-type exercise program.

Thiamin, riboflavin, vitamin B6, magnesium, iron and zinc status, assessed from blood samples, was studied during a 24-week fitness-type exercise program. Subjects in exercise (n = 21) and control (n = 18) groups were female university students, aged 18-33 years. Erythrocyte (E) transketolase and glutathione activation coefficient, serum magnesium, zinc and ferritin, blood hemoglobin concentration and mean corpuscular volume were similar in both groups throughout the entire study. E-aspartate aminotransferase activation coefficient (vitamin B6 status) increased (4%) in exercise and decreased (7%) in control groups (p = 0.04), respectively. E-magnesium was stable in exercise but decreased (4%) in control groups (p = 0.004%). E-zinc increased (9%) in exercise subjects but remained stable in controls (p < 0.0001). A marginally altered vitamin B6 status was the only negative change found in exercise subjects.

Adult↗
PubMed1991

The validity of a food use questionnaire in assessing the nutrient intake of physically active young men.

The validity of a self-administered food use questionnaire, comprising 122 questions on food items or dishes and designed especially to assess the intake of micronutrients, was evaluated using a 7-day food record (7DR) as a reference method. The subjects kept the food record after they filled in the questionnaire. Eighty-four male athletes participated in this study. The nutrient intake from the food use questionnaires was calculated in two ways: (i) in questionnaire 1 (FUQ-1), the portion size reported by the subjects was used, and (ii) in questionnaire 2 (FUQ-2), a 'typical' portion size was used regardless of the subject's report. In FUQ-1, the reported nutrient intake tended to be overestimated in comparison to the 7DR, whereas in FUQ-2 comparable results on a group level for all nutrients, except for proteins and fats, were obtained. The percentage of subjects similarly classified into tertiles (7DR vs. FUQ-1 or FUQ-2) varied between 37 and 54 per cent. The results show that the food use questionnaire agreed well with the food record on a group level, if a typical portion size was used. However, the agreement on an individual level was not quite as good.

Adult↗
PubMed1989

High-carbohydrate diet for long distance runners--a practical view-point.

The nutritional value of a high-carbohydrate diet was evaluated. Seven male marathon runners kept a food record diary for the three days preceeding two endurance races. They were instructed in how to compose a diet which contained about 9 g carbohydrate day-1 kg body weight-1. Sixty three per cent of the subjects' total energy intake was derived from carbohydrates. The dietary intake of vitamin C was six times the Recommended Daily Dietary Allowances (RDA). Intakes of thiamin, riboflavin, calcium, magnesium and iron were more than twofold, and niacin intake 1,4-fold compared to the allowances. The diet contained sufficient amounts of carbohydrate to refill and enlarge muscle glycogen stores. Moreover the nutritional value was high, and therefore this kind of a diet can be recommended to endurance athletes even on a daily basis.

Adult↗