Body image, strategies to change muscles and weight, and puberty. Do they impact on positive and negative affect among adolescent boys and girls?

The purpose of this study was to examine the impact of strategies to both decrease weight and increase muscle tone on negative (depression, anxiety) and positive affect among adolescent males and females. The respondents were 1185 adolescents (587 males, 598 females) who were enrolled in grades 7 and 9 (mean age for MALES=13.22 years; mean age for FEMALES=13.21 years). Respondents completed the Body Image and Body Change Inventory that assessed body image satisfaction, body image importance, body change strategies to decrease weight, body change strategies to increase muscle tone, and food supplements. Respondents also completed the Pubertal Development Scale, the depression and anxiety scales of the Depression Anxiety and Stress Scale, and the positive affect items from the Positive and Negative Affect Scale. Structural equation modelling was used to determine how body satisfaction and importance, body change strategies, and puberty impacted on depression, anxiety, and positive affect. The results demonstrated that for both boys and girls, there was a strong association between body change strategies and negative affect. For boys, body dissatisfaction did not predict negative affect, although this was a strong predictor for girls. Body change strategies did not strongly predict positive affect for either boys or girls, although body image satisfaction was a strong predictor for both genders. The implications of these findings for obtaining a better understanding of the role of pubertal development, body image, and body change strategies in predicting positive and negative affect among adolescent males and females are discussed.

Inadvertent doping through supplement use by athletes: assessment and management of the risk in Australia

Many athletes report using a wide range of special sports foods and supplements. In the present study of 77 elite Australian swimmers, 99% of those surveyed reported the use of these special preparations, with 94% of swimmers reporting the use of non-food supplements. The most popular dietary supplements were vitamin or mineral supplements (used by 94% of the group), herbal preparations (61%), and creatine (31%). Eighty-seven percent of swimmers reported using a sports drink or other energy-providing sports food. In total, 207 different products were reported in this survey. Sports supplements, particularly supplements presented as pills or other non-food form, are poorly regulated in most countries, with little assurance of quality control. The risk of an inadvertent "positive doping test" through the use of sports supplements or sports foods is a small but real problem facing athletes who compete in events governed by anti-doping rules. The elite swimmers in this survey reported that information about the "doping safety" of supplements was important and should be funded by supplement manufacturers. Although it is challenging to provide such information, we suggest a model to provide an accredited testing program suitable for the Australian situation, with targeted athlete education about the "sports safety" of sports supplements and foods.

A longitudinal analysis of the role of biopsychosocial factors in predicting body change strategies among adolescent boys.

In this study we examined the role of biopsychosocial factors on adolescent boys' body modification strategies over an 8-month period. Participants were 434 adolescent boys aged between 11 and 16 years. The majority of respondents were from Anglo-Australian backgrounds (83%); the others were from Asian and European non-English-speaking backgrounds. The results indicated a consistent relationship between perceived encouragement to engage in body change strategies and increases in adolescents' body modification strategies, including muscle gain, weight gain, and weight loss. In addition, poor parent relations, being younger, and higher scores on the pubertal development scale predicted increased use of food supplements. However, the stability of the body modification strategies and the examined variables over the 8-month period were low. Further studies are needed to examine the stability of adolescent self-perceptions over both longer and shorter periods. Moreover, researchers need to include other factors that may be more relevant for adolescent boys (e.g., involvement in sports).

A longitudinal study of body change strategies among adolescent males

This study was designed to examine the factors predicting a range of body change strategies among adolescent males over an 8-month time period. This is the first published longitudinal study of body change strategies to increase weight and muscles among males. The 5 body change strategies in the present study were eating and exercise to lose weight, increase weight, increase muscles, bingeing, and use of food supplements. The extent to which Body Mass Index (BMI) and these body change strategies predicted each other over an 8-month period was evaluated. The role of pressure from parents and peers to lose weight, increase weight, or increase muscles was also evaluated. After controlling for the Time 1 level of each variable, only bingeing, and use of food supplements were predicted by other Time 1 body change variables. Bingeing at Time 1, and a combination of all of the other variables predicted bingeing at Time 2; use of food supplements and bingeing at Time 1 predicted the use of food supplements at Time 2. Perceived pressure from parents and peers to lose weight at Time 1 predicted strategies to lose weight at Time 2; perceived pressure from parents and peers to increase weight at Time 1 predicted strategies to increase weight at Time 2; and perceived pressure to lose weight, increase weight, and increase muscles at Time 1 predicted the use of food supplements at Time 2. These results indicate that extreme body change strategies are predicted by the adoption of more normative body change strategies at an earlier point in time, and that a range of body change strategies among adolescent males are affected by perceived pressures from parents and peers.

A prospective study of extreme weight change behaviors among adolescent boys and girls.

This study examined changes in extreme weight change attitudes and behaviors (exercise dependence, food supplements, drive for thinness, bulimia) among adolescent boys and girls over a 16 month period. It also investigated the impact of body mass index, puberty, body image, depression and positive affect on these attitudes and behaviors 16 months later. The participants were 847 young adolescents (411 boys, 436 girls). Participants completed questionnaires evaluating the above variables on three occasions, eight months apart. Girls obtained higher scores on exercise dependence, drive for thinness and bulimia. Changes in depression and body image importance were the strongest predictors of changes in these extreme attitudes and behaviors among boys; changes in depression, body dissatisfaction and body image importance were the strongest predictors for girls. The need for gender specific educational and intervention programs for adolescents are discussed.

A longitudinal study of body change strategies of fitness center attendees

This study evaluated predictors of strategies to change weight and muscles among men and women who attend fitness centers. A questionnaire was completed by 107 men (mean age = 39.17, SD = 13.14), and 151 women (mean age = 35.31, SD = 11.38) who regularly attended fitness centers at two points in time, one year apart. The only unique predictor of body change strategies over time for men was body dissatisfaction predicting drive for thinness; for women, body dissatisfaction predicted strategies to lose weight, drive for thinness, use of food supplements to lose weight and levels of bulimia. Media messages also predicted drive for thinness and bulimia among women. These findings would suggest that attendance body dissatisfaction is an important factor predicting other normative and health risk behaviors among fitness center attendees, particularly women at a fitness center over a 12 month period was not generally associated with adverse health risk behaviors.

Effect of diets containing n-3 fatty acids on muscle long-chain n-3 fatty acid content in lambs fed low- and medium-quality roughage diets

In two experiments, each with 32 crossbred ([Merino x Border Leicester] x Poll Dorset) wether lambs (26 to 33 kg weight range), animals were randomly assigned to one of four treatments. A mixture of lucerne chaff:oaten chaff was used as a basal diet, offered in different ratios. Animals were allowed to consume on a free-access basis in Exp. 1 or 90% of ad libitum intake in Exp. 2 in order to provide a low- (6.5 MJ ME/d) and medium- (9.5 MJ ME/d) quality basal diet, respectively. Isoenergetic amounts of lipid supplements, fish meal (80 g DM), canola meal (84 g DM), and soy meal (75 g DM) were tested in Exp. 1. In Exp. 2, fish meal (9% DM), unprotected rapeseed (7% DM), and protected canola seed (6% DM) were fed as supplements. At the end of 53-d (Exp. 1) or 46-d (Exp. 2) experimental periods, lambs were slaughtered at a commercial abattoir and at 24 h postmortem longissimus thoracis (LT) muscle was collected for the analysis of fatty acid (FA) composition of structural phospholipid and storage triglyceride fractions. Fish meal diet increased LT muscle long-chain n-3 FA content by 27% (P < 0.02) in Exp. I and 30% (P < 0.001) in Exp. 2 compared with lambs fed the basal diet, but fish meal decreased (P < 0.01) the n-6 FA content only in Exp. 1. Soy meal and protected canola seed diets increased (P < 0.01) LT muscle n-6 FA content but did not affect long-chain n-3 FA content. Longissimus thoracis muscle long-chain n-3 FA were mainly deposited in structural phospholipid, rather than in storage triglyceride. In both Exp. 1 and Exp. 2, the ratio of n-6:n-3 FA in LT muscle was lowest (P < 0.01) in lambs fed fish meal supplement compared with all other treatments. Protected canola seed diet increased the ratio of n-6:n-3 FA (P < 0.01) and PUFA:saturated fatty acid (P < 0.03) content from those animals fed the basal, fish meal, and unprotected rapeseed diets in Exp. 2. This was due to an increase in muscle n-6 FA content, mainly linoleic acid, of both phospholipid (P < 0.001) and triglyceride (P < 0.01) fractions and not to an increase in muscle n3 FA content. The results indicate that by feeding fish meal supplement, the essential n-3 FA can be increased while lowering the ratio of n-6:n-3 content in lamb meat to an extent that could affect nutritional value, attractiveness, and the economic value of meat.

The effect of exercise and training status on platelet activation: do cocoa polyphenols play a role?

Sedentary and trained men respond differently to the same intensity of exercise, this is probably related to their platelet reactivity and antioxidant capacity. There is growing interest in the utilization of antioxidant-rich plant extracts as dietary food supplements. The aim of this study was to investigate the effect of an acute bout of sub maximal exercise on platelet count and differential response of platelet activation in trained and sedentary subjects and to observe if cocoa polyphenols reverse the effect of exercise on platelet function. The practical significance of this study was that many sedentary people engage in occasional strenuous exercise that may predispose them to risk of heart disease. Fasting blood samples were collected from 16 male subjects, pre and post 1-h cycling exercise at 70% of maximal aerobic power (VO2max) before and after consumption of cocoa or placebo. Agonist stimulated citrated whole blood was utilized for measuring platelet aggregation, adenosine triphosphate (ATP) release and platelet activation. Baseline platelet count (221 ± 33 times 109/L) and ATP release (1.4 ± 0.6 nmol) increased significantly (P < 0.05) after exercise in all subjects. Baseline platelet numbers in the trained were higher (P < 0.05) than in the sedentary (235 ± 37 vs. 208 ± 34 times 109/L), where as platelet activation in trained was lower (P < 0.05) than sedentary (51 ± 6 vs. 59 ± 5%). Seven days of cocoa polyphenol supplementation had little effect on any of the parameters measured. We conclude that trained subjects show decreased activation of stimulated platelets when compared to the sedentary subjects and short-term cocoa polyphenol supplementation did not decrease platelet activity in response to exercise independent of prior training status.

Prevention of body concerns and risk behaviours in adolescent boys

Overall, this thesis was designed to explore the nature of adolescent boys' body image, the effects of body image on body change strategies and psychological adjustment, and the factors that influence body image. The first study examined body image in 362 adolescent boys. Body image was considered in terms of attitudes to different body parts and attributes, including, lower, middle and upper body, as well as weight, shape and muscles. The relationships between Body Mass Index (BMI), body image, sociocultural messages, psychological adjustment and body change strategies, including strategies to decrease weight and increase muscles using food and exercise, drive for thinness, bulimic attitudes and behaviour, excessive exercise, food supplements to lose weight, increase muscles and steroids, were also investigated. Multiple regression analyses were used to examine the role of body image, sociocultural messages and psychological adjustment to predict satisfaction with different body attributes and body change strategies. The findings from study one led to the development of a program aimed at preventing the development of unhealthy attitudes and behaviours among adolescent boys. Study two involved the implementation and evaluation of this prevention program. One hundred and twenty one boys participated in the program. The program was based on social-cognitive theory, and included a focus on accepting differences and the development of self-esteem. The boys who participated in the program indicated some change in existing attitudes and showed less development of risk behaviours relative to the control group. The implications of the findings from this thesis in relation to future research, as well as the prevention of adolescent boys' body image problems are discussed.

Body image, muscularity and weight loss among people who attend gymnasiums

Biosocial models of weight loss and increased muscles were empirically tested among adult exercisers. Although women experienced greater body dissatisfaction, both genders engaged in potentially risky strategies to reach their body goals, ranging from the use of food supplements and steroids to bulimic behaviours and excessive exercise.

Effect of increasing dietary calcium through supplements and dairy food on body weight and body composition: a meta-analysis of randomised controlled trials

This meta-analysis of randomised controlled trials assessed the effect of Ca on body weight and body composition through supplementation or increasing dairy food intake. Forty-one studies met the inclusion criteria (including fifty-one trial arms; thirty-one with dairy foods (n 2091), twenty with Ca supplements (n 2711). Ca intake was approximately 900 mg/d higher in the supplement groups compared with control. In the dairy group, Ca intake was approximately 1300 mg/d. Ca supplementation did not significantly affect body weight (mean change ( - 0·17, 95 % CI - 0·70, 0·37) kg) or body fat (mean change ( - 0·19, 95 % CI - 0·51, 0·13) kg) compared to control. Similarly, increased dairy food intake did not affect body weight ( - 0·06, 95 % CI - 0·54, 0·43) kg or body fat change ( - 0·36, 95 % CI - 0·80, 0·09) kg compared to control. Sub-analyses revealed that dairy supplementation resulted in no change in body weight (nineteen studies, n 1010) ( - 0·32, 95 % CI - 0·93, 0·30 kg, P= 0·31), but a greater reduction in body fat (thirteen studies, n 564) ( - 0·96, 95 % CI - 1·46, - 0·46 kg, P < 0·001) in the presence of energy restriction over a mean of 4 months compared to control. Increasing dietary Ca intake by 900 mg/d as supplements or increasing dairy intake to approximately 3 servings daily (approximately 1300 mg of Ca/d) is not an effective weight reduction strategy in adults. There is, however, an indication that approximately 3 servings of dairy may facilitate fat loss on weight reduction diets in the short term.

Knowledge about folate and the contribution of nutrient supplements to the intake of folic acid and vitamin B12 in Australian adults in 1995 and 1996

The present paper reports knowledge about folate and the contribution of supplements to the intake of folic acid and vitamin B12 in Australian adults during 1995 and 1996. Data were obtained from two population survey monitor surveys conducted in a sample of 5422 adults in 1995-96. The surveys were designed to complement food intake data from the 1995 National Nutrition Survey and to provide an estimate of total folate intake prior to the implementation of voluntary fortification of foods with folic acid. The proportion with knowledge about folate increased with education level and socioeconomic status and was greater in women than men. It was also greater in those who were married, and in those residing in Western Australia and the Australian Capital Territory than in other states and territories. Five per cent of men and 10% of women had taken a supplement containing folio acid on the previous day. The equivalent figures for vitamin B12 were 7.5% for men and 12.5% for women. On average, intake of folic acid from supplements was 11 micro g per day for men and 28 micro g per day for women and intake of vitamin B12 was 2.6 micro g per day for men and 4.5 micro g per day for women. For individuals who consumed a supplement containing folic acid on the day before the survey the median folic acid contribution was 200 micro g. In 1995 and 1996 only one in two adult Australians had heard of folate and only one in ten women of child-bearing age had taken a supplement containing folic acid.

Comparison of different maximum safe levels in fortified foods and supplements using a probabilistic risk assessment approach

Different European institutions have developed mathematical models to propose maximum safe levels either for fortified foods or for dietary supplements. The objective of the present study was to compare and check the safety of these different maximum safe levels (MSL) by using a probabilistic risk assessment approach. The potential maximum nutritional intakes were estimated by taking into account all sources of intakes (base diet, fortified foods and dietary supplements) and compared with the tolerable upper intake levels for vitamins and minerals. This approach simulated the consequences of both food fortification and supplementation in terms of food safety. Different scenarios were tested. They are the result of the combination of several MSL obtained using the previous models. The study was based on the second French Individual and National Study on Food Consumption performed in 2006–7, matched with the French food nutritional composition database. The analyses were based on a sample of 1918 adults aged 18–79 years. Some MSL in fortified foods and dietary supplements obtained independently were protective enough, although some others could lead to nutritional intakes above the tolerable upper intake levels. The simulation showed that it is crucial to consider the inter-individual variability of fortified food intakes when setting MSL for foods and supplements. The risk assessment approach developed here by integrating the MSL for fortified foods and dietary supplements is useful for ensuring consumer protection. It may be subsequently used to test any other MSL for vitamins and minerals proposed in the future.