Conjugated Linoleic Acid Supplementation for Twelve Weeks Increases Lean Body Mass in Obese Humans

Abstract

Conjugated linoleic acid (CLA) alters body composition in animal models, but few studies have examined the effects of CLA supplementation on body composition and clinical safety measures in obese humans. In the present study, we performed a randomized, double-blind, placebo-controlled trial to examine the changes in body composition and clinical laboratory values following CLA (50:50 ratio of cis-9, trans-11 and trans-10, cis-12 isomers) supplementation for 12 wk in otherwise healthy obese humans. Forty-eight participants (13 males and 35 females) were randomized to receive placebo (8 g safflower oil/d), 3.2 g/d CLA, or 6.4 g/d CLA for 12 wk. Changes in body fat mass and lean body mass were determined by dual-energy X-ray absorptiometry. Resting energy expenditure was assessed by indirect calorimetry. Clinical laboratory values and adverse-event reporting were used to monitor safety. Lean body mass increased by 0.64 kg in the 6.4 g/d CLA group (P < 0.05) after 12 wk of intervention. Significant decreases in serum HDL-cholesterol and sodium, hemoglobin, and hematocrit, and significant increases in serum alkaline phosphatase, C-reactive protein, and IL-6, and white blood cells occurred in the 6.4 g/d CLA group, although all values remained within normal limits. The intervention was well tolerated and no severe adverse events were reported, although mild gastrointestinal adverse events were reported in all treatment groups. In conclusion, whereas CLA may increase lean body mass in obese humans, it may also increase markers of inflammation in the short term.

Ácido linoléico conjugado: efeitos no perfil lipídico e na composição corporal de camundongos exercitados

“…Mirand et al (2004), trabalharam com ratos suplementados com 1% de CLA, por seis semanas e submetidos a exercício aeróbio em esteira e, também, não observaram diminuição do ganho de peso corporal em relação aos não suplementados sedentários. Da mesma forma, Steck et al (2007), não encontraram diferenças significativas na perda de peso em humanos que ingeriram 3,4 g ou 6,4 g por dia de CLA por 12 semanas. Contudo, Hargrave et al (2004) observaram diminuição do ganho de peso em camundongos suplementados com 1% de CLA, por um período de 14 dias, assim como Yang et al (2003), em ratas ZDF suplementadas com 0,5% de CLA durante seis semanas.…”

“…É importante ressaltar ainda que alguns efeitos indesejáveis relacionados ao uso do ácido linoleico conjugado foram encontrados, tanto em estudos com humanos quanto em animais. Há relatos de aumento da resistência à insulina e aumento da glicose e insulina de jejum (SMEDMAN;, elevação da peroxidação lipídica (RISERUS et al, 2001) e redução do HDL em humanos obesos tratados com CLA (STECK et al, 2007).…”

Safflower Oil (Carthamus tinctorius L.) Intake Increases Total Cholesterol and LDL-cholesterol Levels in an Experimental Model of Metabolic Syndrome

“…4 In this context, the use of safflower oil (Carthamus tinctorius L.) is proposed to prevent or treat obesity. Safflower oil is extracted from saffron, a plant belonging to the Asteraceae family, 5,6 contains high content of polyunsaturated (75% linoleic acid) and monounsaturated fatty acids. 7 This composition stimulated further studies that demonstrated that dietary supplementation with safflower oil had a positive effect on lipid profile, with an antiatherogenic role.…”

Dietary modulation of body composition and insulin sensitivity during catch-up growth in rats: effects of oils rich inn-6 orn-3 PUFA

“…caffeine, green tea catechins and medium-chain TAG) or that shift nutrient partitioning in favour of lean tissue (e.g. conjugated LA) has been demonstrated at much lower doses in humans (albeit adults) than in laboratory rodents (27,46,47) .…”