PART 4: The negative changes induced by CLA include:

• Alteration of egg yolk and egg white pH, distribution of minerals in yolk and white, and decrease egg quality and hatchability of chicks;³¹
• At 2% of food, CLA accelerates the decomposition of storage lipids, resulting in lipid peroxidation and morphological change in the liver;³²
• In hens, 2.5% CLA reduced level of omega-6 and increased level of omega-3 fatty acids;³³
• At 1% of feed in mice, CLA increased TNFa (tumor necrosis factor alpha, an inflammatory factor) by 12 times, and uncoupling protein UCP-2 (a thermogenic factor) by 6 times; there was liver swelling, increased insulin resistance, and leptin depletion;³⁴
• Given 1g of CLA every second day, chicks showed altered fat metabolism;³⁵
• Given to rats at 3 to 5%, CLA changes the membrane lipids, increasing some and decreasing others, increases antioxidant enzymes in liver, and reduces both LDL and HDL cholesterol;³⁶
• At 6.6g/kg (0.66%) of food, CLA increased liver weight by increasing cell size (hypertrophy) but not fat levels in hamsters;³⁷
• In rats given 180mg/day of mixed isomers, CLA was found to compete for enzymes used to elongate and desaturate EFAs, thereby decreasing the production of EFA derivatives important to health;³⁸
• At 10g/kg (1%), CLA reduced rate of bone formation in rats, while EFAs enhanced bone growth;³⁹
• In mice fed an atherogenic diet containing 5g/kg (0.5%) of CLA, CLA increased the development of fatty streaks, one of the atherogenic markers;⁴⁰
• At 3% of food, CLA was ineffective in mice tumor multiplicity (TM), whereas SDA and EPA decreased TM by 50%;⁴¹

In summary, while CLA has shown promises of improving degenerative condition in animal studies, the promises come with contradictory findings and warnings of worsening of some conditions.