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Insulin is an independent correlate of plasma homocysteine levels in obese children and adolescents. S Gallistl , K Sudi , H Mangge , W Erwa and M Borkenstein Ludwig-Boltzmann Research Institute for Pediatric Haemostasis and Thrombosis, University of Graz, Austria. siegfried.gallistl@kfunigraz.ac.at Abstract OBJECTIVE: The aim of the study was to investigate whether anthropometric and metabolic risk factors for coronary heart disease (CHD) contribute to the variation in homocysteine levels in obese children and adolescents. RESEARCH DESIGN AND METHODS: A total of 84 children and adolescents were assessed for fasting total homocysteine, methylenetetrahydrofolate reductase polymorphism (C677T mutation), folate and vitamin B12 status, and anthropometric and metabolic risk factors for CHD. RESULTS: No significant sex differences were found for all available anthropometric and metabolic characteristics except for homocysteine, which was significantly higher in boys than in girls (7.1 vs. 6.3 micromol/l; P<0.05). After adjustment for age and sex, homocysteine correlated significantly with BMI, fat mass, percentage of fat mass, and insulin and showed an inverse correlation with folate levels. Homocysteine did not correlate with vitamin B12; total cholesterol; LDL, HDL, and VLDL; triglycerides; and glucose. BMI and fat mass correlated significantly with insulin and showed a significant inverse correlation with folate. We found no association between homocysteine and the C677T mutation. In multiple regression analyses, insulin was found to be the main correlate of homocysteine. CONCLUSIONS: Our study demonstrates for the first time that insulin is a main correlate of homocysteine in obese children and adolescents and suggests that fat mass-associated hyper-insulinism may contribute to impairment of homocysteine metabolism in childhood obesity

The regulatory effect of ghrelin on growth hormone (GH) is limited in describing ghrelin response to acute submaximal exercise intensities in elite athletes. We investigated the effects of a single sculling exercise performed above and below the individual anaerobic threshold (IAT) on total ghrelin concentration in highly trained male rowers. Nine elite male rowers (20.1 +/- 3.7 years; 190.0 +/- 5.2 cm; 89.6 +/- 4.6 kg; %body fat: 9.9 +/- 2.5%) volunteered for this study. Single scull rowing was performed below and above IAT using a mean of 5 bpm above and below the heart rate of the IAT during graded exercise test. Ghrelin, leptin, GH, insulin, and glucose were measured before, immediately after, and after 30 min of recovery. Plasma ghrelin concentration did not increase significantly in either exercise but was approaching significance after 30 min of recovery (P = 0.051) when the constant load sculling was performed at the intensity above the IAT. There were no changes in plasma leptin levels. GH increased significantly immediately after exercise and remained elevated during the 30 min of recovery in both exercise conditions, while insulin decreased significantly immediately after exercise and remained significantly lower after the 30 min of recovery in both exercise intensities. Baseline ghrelin was not correlated with the body composition, physical performance, or blood biochemical data. There was no significant relationship between plasma ghrelin and other blood variables immediately after the 30 min of recovery in both exercise tests and changes in ghrelin were not related to blood biochemical variables after the exercise tests. The acute constant load sculling exercise above or below IAT that increased GH concentrations did not significantly increase the circulating plasma ghrelin levels.

OBJECTIVE To study the effect of a standardised training programme focusing on maintenance of fat free mass during weight reduction by energy reduction in obese children. DESIGN Randomised trial of physical training programme and dietary advice (group A) versus dietary advice alone (group B). SUBJECTS Thirty obese children and adolescents (14 group A, 16 group B) participated in the 12 week long programme; 20 children (10 group A, 10 group B) were also reassessed after one year. MEASUREMENTS Fat free mass was estimated from the resistance index, obtained by bioelectrical impedance analysis at baseline, after four, eight, and 12 weeks in all subjects, and after one year in 20 subjects. RESULTS The mean (SD) change in fat free mass was significantly different between the two groups after 12 weeks (group A, 2.68 (3.74) kg; group B, 0.43 (1.65) kg). The change in body weight after one year was inversely correlated with the change in fat free mass after 12 weeks (r = −0.44), as assessed in the 20 subjects. CONCLUSIONS A standardised training programme as used in this study can prevent reduction in fat free mass during weight loss in obese children. Reduction in fat free mass during weight reduction might be a risk factor for regain of weight.

In many sports, athletes with low body weight have a distinct advantage over their opponents; however, this advantage can easily turn into a noticeable disadvantage because low body weight may also be associated with health problems. The present review focuses on the problem of anorexia athletica, with its emphasis on leanness and thinness in female and male sports athletes. Athletes often restrict calories and/or overexercise to achieve or maintain low body and fat masses. There is a growing body of evidence that several metabolic and endocrine disturbances are the result of prolonged energy restriction. However, the long-term outcome of such sport-related disordered eating has not been thoroughly studied. Effective methods of treatment are scarce and similar to treatment of eating disorders. Scientific studies are needed that help establish alternative regulations for sports in which a low body weight is a primary advantage for performance.