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Originally Posted by Todd
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The studies i looked at for cla were for healthy individuals ie no weight problem. I have further educated myself now and have to agree it can be very beneficial at the moment i would limit that to overweight people till i see more. Here are some studies that did not come from ast or max ot or some other supplement site
summary - as i know it can be tedious reading through all them studies
- Conjugated linoleic acid (CLA) reduced body
fat and changed fatty acid metabolism in
some human studies but had no effect in
others
- CLA reduced leptin levels in one human study
- CLA reduced body fat, increased lean body
mass, improved glucose tolerance, and
upregulated uncoupling protein-2 in mice and
rats
- CLA increased apoptosis and reduced fatty acid
composition of white adipose tissue and
reduced adipocyte cell size in rats
Conjugated linoleic acid (CLA) 0.7 grams daily for 4 weeks followed by 1.4 grams daily for 4 weeks reduced body fat percentages in 21 adult male and female volunteers. Volunteers consumed a controlled diet (no significant differences in energy or macronutrient intake). A significant reduction in high-density lipoprotein was observed during the first 4 weeks compared to placebo (p less than 0.001). A significant decrease in the sum of thickness of ten skinfold measurements and percentage body fat and fat mass (calculated from skinfold measurements) was observed during the second 4 weeks compared to placebo (p less than 0.001). A nonsignificant trend toward lower triglycerides and total cholesterol was observed with CLA. CLA was incorporated into serum total lipids at all CLA doses (Mougios et al, 2001).
b. Conjugated linoleic acid (CLA) significantly reduced sagittal abdominal diameter (SAD) as compared with placebo in a double- blind, randomized, placebo-controlled study of 24 obese men. Twenty-five obese men (39 to 64 years old) with a waist-to-hip ratio of 1.05 and a body mass index 32 kilograms/meter squared were enrolled in the study; one subject did not complete the study. Subjects received 4.2 grams CLA daily or placebo (olive oil). After four weeks of supplementation, a significant reduction in abdominal adipose tissue was seen in the subjects treated with CLA (p = 0.041). Other measurements of anthropometry or metabolism showed no significant differences between the two groups (Riserus et al, 2001).
c. Conjugated linoleic acid (CLA) decreased body fat by 3.8% (p = 0.05) in a randomized, double-blind, placebo-controlled study. Body weight, body mass index (BMI), and sagittal abdominal diameter were unchanged. Fifty-three nonobese, normolipidemic subjects received CLA 4.2 grams daily or placebo (olive oil) for 12 weeks. No differences were noted in serum lipoproteins, nonesterified fatty acids, or plasminogen activator inhibitor 1 (PAI-1). A trend toward increased glucose levels was seen in the CLA-treated group as compared to the control group. CLA increased apolipoprotein B and decreased triglycerides and low-density lipoprotein compared to placebo (p=0.044 and p=0.039, respectively). No significant differences were observed between the two groups with regard to changes in fasting glucose, plasma insulin, nonesterified fatty acids, or PAI-1 (plasminogen activator inhibitor). The authors suggest that the diverging results of this study, as compared to others, could be due to the use of different isomers or differing effects of CLA on obese as compared to normal weight individuals (Smedman & Vessby, 2001).
d. Conjugated linoleic acid (CLA) 3.9 grams daily for 4 weeks did not change lipolytic rates in 6 weight-stable women as measured by glycerol rate of appearance (Ra) and free fatty acid release from adipocytes at rest or during exercise. The women (21 to 41 years old) were confined to a metabolic ward for 94 days and their diet was controlled and held constant. After a stabilization period, CLA supplementation was initiated. The authors noted that non-pure CLA was used and that the trans-10,cis-12 isomer may be more active in terms of body composition (Zambell et al, 2001).
e. Conjugated linoleic acid (CLA) significantly reduced body fat mass in a twelve-week, randomized, double-blind, placebo- controlled study of 60 overweight or moderately obese individuals. Subjects received placebo (9 grams olive oil daily) or CLA 1.7, 3.4, 5.1, or 6.8 grams daily in addition to olive oil in order to bring the total fatty acid intake to 9 grams daily. After twelve weeks of treatment, no group showed a significant reduction in weight or body mass index (BMI). However, a significant reduction in body fat mass (BFM) was seen with CLA 3.4 grams (p = 0.05) and 6.8 grams daily (p = 0.02). A trend was seen in CLA groups toward increased lean body mass (LBM) but this was only significant with CLA 6.8 grams daily (p less than or equal to 0.05). Since the subjects were exposed to either light or intensive exercise training during the course of the study, the authors point out that it is difficult to distinguish if the increase in LBM was due to CLA or training activities (Blankson et al, 2000).
f. Conjugated linoleic acid (CLA) 3 grams daily transiently lowered circulating leptin levels in healthy female volunteers. In other studies, leptin directly stimulated lipolysis in adipose tissue in vitro, and reduced food intake and increased metabolic rates in animals. Leptin levels initially significantly decreased (p=0.05) in CLA-treated subjects but returned to baseline levels by the end of the 57-day study. The lowest leptin level was observed on day 49 of the study. No significant differences were observed for plasma insulin levels although there was a trend toward increased insulin levels in the CLA-fed group that peaked at day 49. No significant changes in body fat or appetite were observed (Medina et al, 2000).
g. Conjugated linoleic acid (CLA) 3 grams daily did not change body composition or
energy expenditure in 17 female adults confined to a metabolic suite for 64 days. Fat-free mass, fat mass, and
body fat percentage were unchanged at the close of the study. Determination of body composition was achieved by total body electrical conductivity and dual x-ray absorptiometry. Body composition was measured three times per week during the study period. No significant changes in energy expenditure and utilization were reported. Sunflower oil was used as placebo. Authors cited use of a metabolic suite for control of diet, more accurate equipment, and more frequent measurement of body composition for their results conflicting with positive body composition changes reported by other studies. Researchers reported the use of a non-pure form of CLA with the trans-10, cis- 12 isomer being the most abundant isomer (Zambell et al, 2000).
4. ANIMAL:
a. Mice fed CLA at 1% and 2% of their diet by weight for 5 days had increased apoptosis of white adipose tissue. Apoptosis, measured by internucleosomal DNA degradation, was increased in the retroperitoneal fat pads of mice fed 2% CLA compared to control (p less than 0.01). A reduction of 10% to 12% feed intake in the mice consuming CLA may be responsible for part of the apoptosis, although authors cite other studies where apoptosis was not observed after restricting feed intake by 60%. No change in body weight was observed (Miner et al, 2001).
b. Conjugated linoleic acid (CLA) significantly altered body composition in developing rats compared to control. Female Sprague-Dawley rats were fed either a control diet or control diet plus 0.05% CLA from the time of gestation to weaning. At weaning, the pups were assigned to the control or CLA diet until 11 weeks of age. No differences were reported for the dams in body weight, number of pups, weight of litters, or feed intake. CLA-fed female pups were significantly heavier than those of dams fed the control diet at weaning at 21 days. The male progeny had significantly increased gastrocnemius muscle mass (p less than 0.001) and increased tail length (p less than 0.001) compared to controls by the end of the study. Males exposed to CLA during gestation and post-weaning were the largest, fastest growing, and most feed- efficient of all groups. The opposite held true for those males never exposed to CLA. At weaning, CLA-fed females had a significant reduction in fat pad mass and decreased adipose cell size, but not number of cells (Poulos et al, 2001).
c. Conjugated linoleic acid (CLA) improved insulin-stimulated glucose transport and glycogen synthase activity in skeletal muscle, reduced adiposity, improved glucose tolerance, upregulated uncouple protein-2 (UCP-2) in muscle and adipose tissue, and downregulated peroxisome proliferator-activated receptor (PPAR)- gamma mRNA in the liver in rats. Rats were fed a control diet, a CLA-supplemented diet (1.5% CLA), or 50% control diet and 50% CLA diet. The CLA diet contained 47% cis-9, trans-11-CLA, 47.9% cis- 10, trans-12-CLA or 91% cis-9, trans-11-CLA. The 50:50 diet was most effective in reducing adiposity, improving insulin-stimulated glucose transport and glycogen synthase activity in skeletal muscle, and improving glucose tolerance. Both the 50:50 and 91% cis-9,trans-11-CLA diets upregulated uncoupling protein 2 in muscle and adipose tissue, and downregulated PPAR-gamma mRNA in liver compared to control (Ryder et al, 2001).
d. Conjugated linoleic acid (CLA) reduced cell size of adipocytes but did not change cell numbers. Sprague-Dawley rats were fed 0.25 grams/100 grams or 0.5 grams/100 grams of purified CLA (97% CLA), or 0.5% of feed- grade CLA (55% CLA) for five weeks. Fat pad weight was reduced by 13%, 25%, and 32% in rats fed 0.25% (pure), 0.5% (pure) and 0.5% (feed-grade) CLA, respectively (p less than 0.05), as compared to controls. Compared to controls, CLA-fed mice had a mean adipose cell volume of 15%, 28%, and 29% lower in the rats fed 0.25 (pure), 0.5% (pure) and 0.5% (feed-grade) CLA, respectively (p less than 0.01) (Azain et al, 2000).
e. Conjugated linoleic acid (CLA) reduced fatty acid composition of perirenal white adipose tissue (PWAT) and serum leptin levels in Sprague-Dawley rats fed a diet containing 2% CLA for 1, 3, 6, and 12 weeks. Reduced leptin levels are associated with inhibition of food intake and acceleration of energy expenditure. CLA may act as a peroxisome proliferator activated receptor (PPAR) activator. Activating PPARs has reduced serum leptin levels (Yamasaki et al, 2000).
f. ICR female and male mice fed a diet containing 0.5% CLA had lower body fat and increased lean body mass as compared to controls. Slight differences in the male and female emerged. Body fat was reduced by 60% in female mice and 57% in males. Lean body mass increased by 14% in males and 5% in females compared to controls (p less than 0.05) (Park et al, 1997).
Linear Mode
