Lean Body Mass Gain Research Articles

Effect of nutritional intervention on body composition and performance in elite athletes

Strength training and positive energy intake are the most important factors related to lean body mass (LBM) gain. Most studies investigating weight-gain interventions are based recreationally active subjects and less is known about optimal weight-gain protocols in elite athletes. The purpose of this study was to evaluate the effect of nutritional guidance in an 8- to 12-week weight-gain period in elite athletes. Thirty-nine elite athletes were randomised to either a ‘nutritional counseling group’ (NCG, n=21, 19.1±2.9 years, 70.9±8.9 kg) or ‘ad libitum group’ (ALG, n=18, 19.6±2.7 years, 75.0±5.9 kg). All athletes continued their sport-specific training which included an additional four strength-training sessions per week. NCG followed a meal plan providing a positive energy balance, while the ALG athletes had an ad libitum energy intake. Body weight (BW), body composition, one repetition maximum (1RM), 40 m sprint and counter movement jump (CMJ) were measured pre- and post-intervention. Energy intake was higher in the NCG than in the ALG (3585±601 vs. 2964±884 kcal) and consequently BW increased more in NCG than in ALG (3.9±0.6% vs. 1.5±0.4%). Fat mass (FM) increased more in NCG than in ALG (15±4 vs. 3±3%), but gain in LBM was not different between groups. All 1RM results improved in both groups (6–12%), whereas 40 m sprint and CMJ remained unchanged, except for a significant decrease in 40 m sprint for the athletes in NCG. Athletes with nutritional guidance increased BW more, however, excess energy intake in a weight-gain protocol should be considered carefully due to undesirable increases in body fat.

Lean body mass gain in patients with head and neck squamous cell cancer treated perioperatively with a protein‐ and energy‐dense nutritional supplement containing eicosapentaenoic acid

Cancer-associated weight loss may be mediated by an inflammatory response to cancer. Eicosapentaenoic acid (EPA) may suppress this response. Beginning no later than 2 weeks before surgery, patients with head and neck cancer and with weight loss, who were undergoing major resection with curative intent consumed a protein- and energy-dense nutritional supplement containing EPA from fish oil, in addition to usual diet or tube feed. Thirty-one subjects consumed an average of 1.8 containers/day before surgery and 1.5/day during hospitalization (per container: 300 kilocalories, 16 grams (g) protein, 1.08 g EPA). Seventy percent of subjects maintained or gained weight before hospital admission. Mean weight gain was 0.71 kg at admission and 0.66 kg at discharge. At discharge lean body mass increased by 3.20 kg (p < .001) and fat decreased by 3.19 kg (p < .001). An EPA-containing protein- and energy-dense nutritional supplement may help increase perioperative lean body mass in patients with head and neck cancer-related weight loss.

Randomized Controlled Trial to Determine the Efficacy of Long-Term Growth Hormone Treatment in Severely Burned Children

Recovery from a massive burn is characterized by catabolic and hypermetabolic responses that persist up to 2 years and impair rehabilitation and reintegration. The objective of this study was to determine the effects of long-term treatment with recombinant human growth hormone (rhGH) on growth, hypermetabolism, body composition, bone metabolism, cardiac work, and scarring in a large prospective randomized single-center controlled clinical trial in pediatric patients with massive burns. A total of 205 pediatric patients with massive burns over 40% total body surface area were prospectively enrolled between 1998 and 2007 (clinicaltrials.gov ID NCT00675714). Patients were randomized to receive either placebo (n = 94) or long-term rhGH at 0.05, 0.1, or 0.2 mg/kg/d (n = 101). Changes in weight, body composition, bone metabolism, cardiac output, resting energy expenditure, hormones, and scar development were measured at patient discharge and at 6, 9, 12, 18, and 24 months postburn. Statistical analysis used Tukey t test or ANOVA followed by Bonferroni correction. Significance was accepted at P < 0.05. RhGH administration markedly improved growth and lean body mass, whereas hypermetabolism was significantly attenuated. Serum growth hormone, insulin-like growth factor-I, and IGFBP-3 was significantly increased, whereas percent body fat content significantly decreased when compared with placebo, P < 0.05. A subset analysis revealed most lean body mass gain in the 0.2 mg/kg group, P < 0.05. Bone mineral content showed an unexpected decrease in the 0.2 mg/kg group, along with a decrease in PTH and increase in osteocalcin levels, P < 0.05. Resting energy expenditure improved with rhGH administration, most markedly in the 0.1 mg/kg/d rhGH group, P < 0.05. Cardiac output was decreased at 12 and 18 months postburn in the rhGH group. Long-term administration of 0.1 and 0.2 mg/kg/d rhGH significantly improved scarring at 12 months postburn, P < 0.05. This large prospective clinical trial showed that long-term treatment with rhGH effectively enhances recovery of severely burned pediatric patients.

Exercise and lean weight: the influence of body weight.

Exercise can produce a modest gain of lean body mass (LBM) and loss of fat in weight-stable individuals, but it is important to realize that if much weight is lost during exercise there is a risk of some erosion of the LBM. Data from both human and animal experiments show that exercise cannot conserve lean weight in the face of significant energy deficit, although moderate obesity affords a modicum of protection in this respect.

Amino acid profiles in adults with growth hormone (GH) deficiency before and during GH replacement therapy

Objective GH replacement to growth hormone deficient (GHD) adults improves body composition. In a subset however, lean body mass (LBM) fails to increase despite normalization of IGF-I and amino acid availability could be of importance. We analyzed amino acid (AA) profiles in plasma and erythrocytes (RBC) and associations with LBM, serum IGF-I and IGFBP-1 before and during GH replacement. Design and methods Examinations were performed in 15 GHD patients (six women), aged 34–61 yrs before and after 12 months of GH therapy and in a control group of 20 healthy males aged 31–68 yrs. LBM was measured by dual energy X-ray absorptiometry (DXA), free AAs in plasma and RBC by high performance liquid chromatography and serum IGF-I and IGFBP-1 by in-house RIAs. Setting Tertiary care referral centre. Results At baseline, female GHD patients tended to have lower concentrations of the essential branched – chain AAs isoleucine and leucine, total essential AAs, and of the non-essential AA glutamine than the male patients. Male GHD patients tended to have higher plasma and RBC glutamate than controls. At 12 months, IGF-I had normalized in all but one patient and mean LBM gain was 1.9 ± 0.4 kg. AA levels were unchanged. The change in LBM at 12 months was positively correlated to the ratio between the sum of isoleucine, leucine and valine and baseline LBM kg/m 2 ( r = 0.76, p = 0.001, n = 15). Conclusion Our results suggest that the essential branched-chain amino acids in plasma are important for the LBM response to GH substitution. Our finding has to be confirmed in larger groups of GHD adults before making a proper selection of AAs to be measured in plasma and added as dietary supplement during GH therapy. GH administration did not change AA levels and measurements are not useful for monitoring of GH therapy at the time being.

Influence of Protein and Energy Intakes on Body Composition of Formula‐fed Preterm Infants After Term

The aim of the present study was to evaluate changes in body composition in 48 preterm infants in relation to protein and energy intakes from term up to 3 months of corrected age, using air displacement plethysmography. Protein intake (grams per kilogram per day) was negatively associated with percentage of fat mass at 1 month of corrected age. The high-protein-intake group showed greater gain in lean body mass gain than did the low-protein-intake group. This finding suggests that during the first month of corrected age, high protein intake results in a significantly different weight gain composition.

Moderators of the effects of exercise training in breast cancer patients receiving chemotherapy

Exercise training improves supportive care outcomes in patients with breast cancer who are receiving adjuvant therapy, but the responses are heterogeneous. In this study, the authors examined personal and clinical factors that may predict exercise training responses. Breast cancer patients who were initiating adjuvant chemotherapy (N=242) were assigned randomly to receive usual care (UC) (n=82), resistance exercise training (RET) (n=82), or aerobic exercise training (AET) (n=78) for the duration of chemotherapy. Endpoints were quality of life (QoL), aerobic fitness, muscular strength, lean body mass, and body fat. Moderators were patient preference for group assignment, marital status, age, disease stage, and chemotherapy regimen. Adjusted linear mixed-model analyses demonstrated that patient preference moderated QoL response (P= .005). Patients who preferred RET improved QoL when they were assigned to receive RET compared with UC (mean difference, 16.5; 95% confidence interval [95% CI], 4.3-28.7; P= .008) or AET (mean difference, 11; 95% CI, -1.1-23.4; P= .076). Patients who had no preference had improved QoL when they were assigned to receive AET compared with RET (mean difference, 23; 95% CI, 4.9-41; P= .014). Marital status also moderated QoL response (P= .026), age moderated aerobic fitness response (P= .029), chemotherapy regimen moderated strength gain (P= .009), and disease stage moderated both lean body mass gain (P< .001) and fat loss (P= .059). Unmarried, younger patients who were receiving nontaxane-based therapies and had more advanced disease stage experienced better outcomes. The findings were not explained by differences in adherence. Patient preference, demographic variables, and medical variables moderated the effects of exercise training in breast cancer patients who were receiving chemotherapy. If replicated, these results may inform clinical practice.

Relationship between GH-induced metabolic changes and changes in body composition: A dose and time course study in GH-deficient adults

Objective Although growth hormone (GH)-induced changes in fat and protein metabolism are likely to underlie changes in body composition, the relationship has not been clearly defined. The aim was to study the effects of dose and time course on substrate metabolism and relate to body compositional changes during GH treatment. Design In an open randomised-controlled study, 16 GH-deficient adults were randomised to treatment with GH 3 μg/kg/d (low dose, n = 6) or 6 μg/kg/d (higher dose, n = 10) for 12 weeks. Changes in whole body protein metabolism, estimated using the leucine turnover technique, and resting energy expenditure (REE) were assessed after short-term GH (two weeks) and longer-term GH (12 weeks). Changes in lean body mass (LBM) and fat mass (FM) over 12 weeks were assessed by DXA. Results The maximal changes in leucine oxidation (Lox) (−3.9 ± 1.1 versus +0.8 ± 1.8 μmol/min, p = 0.03) and REE (+132 ± 36 versus −28 ± 41 kcal/d, p = 0.01) were significantly greater in the higher, than the low dose group. FM fell (−1.4 ± 0.4 kg, p = 0.005) and LBM increased (+2.2 ± 0.7 kg, p = 0.01) significantly in the higher dose group only. The acute reduction in Lox at two weeks in the higher dose group was no longer significant after 12 weeks. The change in Lox after two ( r = −0.53, p = 0.035), but not 12, weeks was significantly correlated with the change in LBM. Conclusions GH-induced changes in protein metabolism were influenced by the dose and duration of GH treatment. Suppression of protein oxidation occured soon after initiation of GH in the higher dose group and predicted a later gain in LBM. Early assessment of whole body protein metabolism may allow prediction of the anabolic potential of GH.

Omega-3 polyunsaturated fatty acids improve host response in chronicPseudomonas aeruginosalung infection in mice

Pseudomonas aeruginosa is a gram-negative bacilli frequently encountered in human pathology. This pathogen is involved in a large number of nosocomial infections and chronic diseases. Herein we investigated the effects of polyunsaturated fatty acids (PUFA) in chronic Pseudomonas aeruginosa lung infection. C57BL/6 mice were fed for 5 wk with specifically designed diets with high contents in either omega-3 (omega-3) or omega-6 PUFA and compared to a control diet. P. aeruginosa included in agarose beads was then instilled intratracheally, and the animals were studied for 7 days. On the 4th day, the mice fed with the omega-3 diet had a higher lean body mass gain and a lower omega-6:omega-3 ratio of fatty acids extracted from the lung tissue compared with the other groups (P < 0.05). The omega-3 group had the lowest mortality. Distal alveolar fluid clearance (DAFC) as well as the inflammatory response and the cellular recruitment were higher in the omega-3 group on the 4th day. The effect on DAFC was independent of alpha-epithelial Na(+) channels (alpha-ENaC), beta-ENaC, and alpha(1)-Na-K-ATPase mRNA expressions, which were not altered by the different diets. In conclusion, a diet enriched in omega-3 PUFA can change lung membrane composition and improve survival in chronic pneumonia. This effect on survival is probably multifactorial involving the increased DAFC capacity as well as the optimization of the initial inflammatory response. This work suggests that a better control of the omega-6/omega-3 PUFA balance may represent an interesting target in the prevention and/or control of P. aeruginosa infection in patients.

Body composition in pregnancies of adolescents and mature women and the relationship to birth anthropometry

To investigate differences in body composition between adolescent girls and mature women during pregnancy and the relationship to newborn anthropometry. A prospective study. The antenatal clinic at the University Hospital of the West Indies, Kingston, Jamaica. Four hundred and twenty-five women were invited to join the study. Three hundred and sixty-one women (84.9%) completed the study. Study participants were divided into two groups: adolescents and mature women, who were all less than 15 weeks pregnant and had no systemic illness at the time of entry into the study. A questionnaire was administered which retrieved information on demographics, age, marital status, menstrual history, parity, socio-economic status, medical history and smoking/drinking habits. Anthropometric measurements including weight, height, triceps, biceps, subscapular and suprailiac skinfolds, as well as blood pressure measurements and urine analysis were performed at the first antenatal visit and repeated at 15, 25 and 35 weeks gestation. Anthropometric measurements of the newborn were performed at birth. There were significant differences between anthropometry and skinfold thickness at the first antenatal visit between the adolescents and the mature women where the adolescents had lower measurements compared to the mature women. In the newborn anthropometry, the only significant difference seen was in the triceps skinfold thickness and the mid-upper arm circumference where the newborn of the adolescents had significantly smaller values (P=0.04; P=0.02, respectively). The percentage fat, fat mass and lean body mass were significantly lower in the adolescent compared to the mature women (P<0.0001), both at the first antenatal visit and at 35 weeks gestation. A greater gain was seen in these measurements throughout the pregnancy in the adolescents (P<0.0001). Linear regression analyses showed that the gain in lean body mass was the most important predictor of birth anthropometry. Body composition differs in pregnancy between adolescents and mature woman, and if adequate weight and lean body mass are attained, it impacts positively on birth size irrespective of age.

Dietary Fat Intake Predicts 1-Year Change in Body Fat in Adolescent Girls With Type 1 Diabetes

The purpose of this study was to determine whether objectively measured physical activity and dietary macronutrient intake differentially predict body fat in adolescent girls with type 1 diabetes and control girls. This study comprised 23 girls (12-19 years) with type 1 diabetes and 19 age-matched healthy control girls. At baseline, physical activity and energy intake were assessed for 7 consecutive days by accelerometry and a structured food diary, respectively. Body composition was measured by dual-energy X-ray absorptiometry at baseline and after 1 year. Fat intake was positively related to a 1-year change in percentage body fat (P = 0.006), after adjustment for total energy intake. No significant interaction was observed (case-control group x main exposure), indicating that the association between fat intake and gain in body fat was similar in both groups. Physical activity did not predict gain in body fat; however, total physical activity was positively associated with a gain in lean body mass (P < 0.01). Girls treated with six daily dosages of insulin increased their percentage of body fat significantly more than those treated with four daily injections (P < 0.05). In this prospective case-control study, we found that fat intake predicted gain in percentage of body fat in both adolescent girls with type 1 diabetes and healthy control girls. The number of daily insulin injections seems to influence the accumulation of body fat in girls with type 1 diabetes.

Potential causes of weight gain in type 1 diabetes mellitus

To investigate the potential causes of weight gain with insulin therapy and improved diabetic control in type 1 diabetes mellitus. This was an open-label prospective study of insulin therapy of 6 months duration in an academic medical centre. Twenty-one subjects with type 1 diabetes were enrolled. The goal was to achieve an haemoglobin A1c (HbA1c) in the range of individuals without diabetes (<5.6%). At baseline, 3 and 6 months, weight, resting energy expenditure, appetite assessment, food intake, activity level, HbA1c and 24-h glycosuria and urea nitrogen were measured. Plasma leptin, ghrelin and adiponectin levels and body fat were measured at baseline and 6 months. At baseline, average weight was 73.7 +/- 17.4 kg and HbA1c was 10.0 +/- 2.2%. Weight increased by 2.15 kg (2.69% of baseline) by 6 months whereas the HbA1c dropped by 1.71% (16.3%) to 7.9%. Energy intake differences between 3 and 6 months had a negative correlation with weight gain, but the changes in glycosuria, appetite scores and the frequency of hypoglycaemia did not correlate with weight gain. Glycaemic control did not correlate with weight change but tended to correlate with fat mass increase (p = 0.064; r = -0.51). An increase in the activity levels between 3 and 6 months correlated with decreasing fat mass (p = 0.037; r = -0.74). The changes in the appetite scores had a negative correlation with fat mass gain (p = 0.035; r = -0.61). The changes in lean body mass correlated with protein and total energy intake (p = 0.007, r = 0.85 and p = 0.003, r = 0.73 respectively). The changes in leptin levels correlated with weight gain. The lipogenic effect of insulin with subsequent increase in fat mass may be the primary cause of this weight gain that can be attenuated by the increases in the activity levels. The negative correlation of energy intake and appetite scores with fat mass gain suggests that they do not play a significant role in fat mass gain whereas energy intake did correlate with lean body mass gain.

Weight Loss Composition: The Effects of Exercise following Obesity Surgery as Measured by Bioelectrical Impedance Analysis

Sudden weight loss following bariatric operations for morbid obesity, such as the duodenal switch (DS), can result in a concurrent decrease in lean body mass. Several methods for tracking body composition, such as bioelectrical impedance analysis (BIA), are available to monitor these changes. One method to offset the negative effects of sudden weight loss on body mass composition may be exercise. 100 patients who had undergone the DS operation for morbid obesity were classified as exercisers and non-exercisers based on self-reporting. Their body mass compositions were measured using BIA preoperatively and at 0.75, 1.5, 3, 6, 9, 12, and 18 months postoperatively. At no study interval did postoperative percent changes in weight loss differ between the exercise and non-exercise groups. At 18 months postoperatively, the exercise group showed a 28% higher loss of fat mass and an 8% higher gain in lean body mass than the non-exercise group. Exercise positively influences body mass composition following the DS. BIA can be successfully employed to monitor changes, diagnose deficiencies, and formulate treatment recommendations.

Soy versus whey protein bars: Effects on exercise training impact on lean body mass and antioxidant status

BackgroundAlthough soy protein may have many health benefits derived from its associated antioxidants, many male exercisers avoid soy protein. This is due partly to a popular, but untested notion that in males, soy is inferior to whey in promoting muscle weight gain. This study provided a direct comparison between a soy product and a whey product.MethodsLean body mass gain was examined in males from a university weight training class given daily servings of micronutrient-fortified protein bars containing soy or whey protein (33 g protein/day, 9 weeks, n = 9 for each protein treatment group). Training used workouts with fairly low repetition numbers per set. A control group from the class (N = 9) did the training, but did not consume either type protein bar.ResultsBoth the soy and whey treatment groups showed a gain in lean body mass, but the training-only group did not. The whey and training only groups, but not the soy group, showed a potentially deleterious post-training effect on two antioxidant-related related parameters.ConclusionsSoy and whey protein bar products both promoted exercise training-induced lean body mass gain, but the soy had the added benefit of preserving two aspects of antioxidant function.

Nutrition in hemodialysis patients previously on a supplemented very low protein diet

Nutritional safety of protein-restricted diets in patients with chronic renal failure is controversial. In the present study, we have assessed the evolution of nutritional status after initiation of hemodialysis in patients previously treated by a supplemented very low protein diet (SVLPD). Nutritional data were prospectively collected during the first year of hemodialysis from 15 consecutive patients treated with a SVLPD (0.3 g protein/kg/day supplemented with essential amino acids, calcium, iron, and vitamins) and compared to 15 age- and gender-matched end-stage renal disease (ESRD) patients previously on a less-restricted diet (0.90 +/- 0.21 g protein/kg/day) who started hemodialysis during the same period. Dual-energy x-ray absorptiometry (DEXA) was used to assess body composition at 0, 6, and 12 months. Hemodialysis prescriptions, biologic data and 3-day food records were collected every 3 months. Protein intake was higher than 1.2 g/kg/day in both groups as soon as 3 months after the start of hemodialysis. Albumin and prealbumin increased significantly during the first 6 months in all patients. Body mass index (BMI) increased in all patients (+0.97 +/- 1.31 kg/m2; P < 0.001) reflecting a gain in fat mass in the overall population (+2.36 +/- 2.94 kg/m2; P < 0.001) while lean body mass remained stable overall. Once on hemodialysis, SVLPD patients rapidly increased protein intake. Nutritional status improved in all patients, with a gain in fat mass in all, and a gain in lean body mass in SVLPD men only. These data indicate that treatment with a SVLPD prior to hemodialysis initiation is nutritionally safe.

Oesophageal cancer and cachexia: the effect of short‐term treatment with thalidomide on weight loss and lean body mass

Cachexia is common in patients with advanced cancer and has a direct impact on well-being and mortality. To test the hypothesis that thalidomide can promote weight gain and lean body mass in patients with advanced oesophageal cancer. In an open-label study, 11 patients with non-obstructing and inoperable oesophageal cancer were established on an isocaloric diet for 2 weeks, followed by 2 weeks on thalidomide, 200 mg daily. The primary end-points were weight change and lean body mass. Secondary end-points were quality of life and changes in resting energy expenditure. Ten patients completed the study protocol. The average caloric intake remained the same throughout the study period in all patients. Nine of 10 patients (95% confidence interval, 0.60, 0.98) lost weight on diet alone. The mean weight gain on thalidomide in the following 2 weeks was 1.29 kg (median, 1.25 kg). A similar trend was shown in the lean body mass. Eight of nine patients (95% confidence interval, 0.57, 0.98) initially lost lean body mass on diet alone (missing data in one patient). The mean gain in lean body mass on thalidomide in the following 2 weeks was 1.75 kg (median, 1.33 kg). Thalidomide treatment appeared to reverse the loss of weight and lean body mass over the 2-week trial period.

Nutrition and HIV infection.

Infection by the human immunodeficiency virus (HIV) is characterized by progressive destruction of the immune system, which leads to recurrent opportunistic infections and malignancies, progressive debilitation and death. Malnutrition is one major complication of HIV infection and is recognized as a significant prognostic factor in advanced disease. Malnutrition is multifactorial and poorly treated during the course of HIV. Even if a standardized approach to the management of active weight loss has not been well established, early nutritional intervention is important in HIV infected patients to maximize gain of lean body mass. From early in the era of highly active antiretroviral therapy (HAART), an initial decreased incidence of malnutrition was noted only in western countries while a variety of changes in the distribution of body fat and associated metabolic abnormalities have been recognized under the banner of lipodystrophy.

Weight gain composition in preterm infants with dual energy X-ray absorptiometry.

Whole body composition was investigated using dual energy x-ray absorptiometry in 54 healthy preterm infants, birth weight < 1750 g, who were fed fortified human milk (n = 20) and preterm formula (n = 34) when full enteral feeding was attained and then again 3 wk later at around the time of discharge. Weight gain composition was calculated from the difference between the earlier and later measurement. The minimal detectable changes in whole body composition over time according to the variance of the population (within groups of 20 infants) and the minimal detectable changes according to the dietary intervention (between two groups of 20 infants) were determined at 5% significance and 80% power. Whole body composition was similar in the two groups at the initial measurement, but all the measured variables differed at the time of the second measurement. Formula-fed infants showed a greater weight gain (19.9 +/- 3.2 versus 15.9 +/- 2.2 g.kg(-1).d(-1), p < 0.05), fat mass deposition (5.1 +/- 1.9 versus 3.3 +/- 1.3 g.kg(-1).d(-1), p < 0.05), bone mineral content gain (289 +/- 99 versus 214 +/- 64 mg.kg(-1).d(-1), p < 0.05), and increase in bone area (1.6 +/- 0.4 versus 1.3 +/- 0.3 cm(2).kg(-1).d(-1), p < 0.05) compared with the fortified human milk group. From these data, a minimal increase from the first measurement of 111 g lean body mass, 68 g fat mass, and 3. 1 g bone mineral content is needed to be detectable in a longitudinal study that includes 20 infants. For significance between two groups of 20 infants around the time of discharge, dietary intervention needs to achieve minimal differences of 160 g lean body mass, 86 g fat mass, and 4.1 g bone mineral content. With respect to weight gain composition, the minimal differences required to reach significance are 2.1 g.kg(-1).d(-1) for gain in lean body mass, 1.2 g.kg(-1).d(-1) for gain in fat mass, and 76 mg.kg(-1). d(-1) for gain in bone mineral content. We conclude that dual energy x-ray absorptiometry allows evaluation of the effects of dietary intervention on whole body and weight gain composition in preterm infants during the first weeks of life.

Mechanisms of action of conjugated linoleic acid: evidence and speculation.

Conjugated linoleic acid (CLA) has been shown to inhibit carcinogenesis and atherosclerosis, enhance immunologic function while protecting against the catabolic effects of immune stimulation, affect body composition change (reducing body fat gain while enhancing lean body mass gain), and stimulate the growth of young rats. We discuss possible biochemical mechanisms that underlie these physiological effects. We emphasize the importance of considering the effects, both individually and combined, of the two CLA isomers (cis-9, trans-11 CLA and trans-10, cis-12 CLA) that have been shown to exhibit biological activity and which appear to exert their effects via different biochemical mechanisms.

Mechanisms of Action of Conjugated Linoleic Acid: Evidence and Speculation

Abstract. Conjugated linoleic acid (CLA) has been shown to inhibit carcinogenesis and atherosclerosis, enhance immunologic function while protecting against the catabolic effects of immune stimulation, affect body composition change (reducing body fat gain while enhancing lean body mass gain), and stimulate the growth of young rats. We discuss possible biochemical mechanisms that underlie these physiological effects. We emphasize the importance of considering the effects, both individually and combined, of the two CLA isomers (cis‐9, trans‐11 CLA and trans‐10, cis‐12 CLA) that have been shown to exhibit biological activity and which appear to exert their effects via different biochemical mechanisms.