High Dose of A Conjugated Linoleic Acid Mixture Increases Insulin Resistance in Rats Fed Either A Low Fat or A High Fat Diet

Abstract

Obesity and related diseases are becoming more prevalent. Conjugated linoleic acid (CLA) might be a useful coadjutant treatment helping to decrease fat mass. However, the precise impact of CLA is unclear because the decreased body fat mass is followed by an increase in insulin resistance. This study aimed to evaluate some of the consequences of a high dose of CLA in rats fed a normal low fat or a high fat diet for 30 days. Male Wistar rats were separated into 4 groups (each n = 10): Control group receiving 7% fat (soybean oil); CLA group receiving 4% soybean oil and 3% CLA mixture; animal fat (AF) group, receiving 45% fat (lard); and animal fat plus CLA (AF+CLA) group, receiving 42% lard and 3% CLA mixture. The CLA mixture contained 39.32 mole% c9,t11-CLA and 40.50 mole% t10,c12-CLA. After 30 days, both CLA groups (CLA and AF+CLA groups) developed insulin resistance, with an increase in glucose in the fasting state and in an insulin tolerance test. The CLA group had increased liver weight and percentage of saturated fatty acids in liver and adipose tissue. Feeding the high fat diet resulted in increased hepatic triacylglycerol accumulation and this was exacerbated by dietary CLA. It is concluded that a high dose of CLA mixture increases insulin resistance and exacerbates hepatic steatosis when combined with a high fat diet.

Microbial Production of Conjugated Linoleic Acid and Conjugated Linolenic Acid Relies on a Multienzymatic System

“…On the other hand, commercial mixtures of RA and C 18:2 t10, c12 (i.e., CLAcontaining oils) were found to exert negative effects, such as impairment of both medium-and long-term spatial learning and memory in rats with brain lesions (12) or increased insulin resistance in male Wistar rats fed either high-or low-fat diets (13). The latter effect has also been observed in humans but, in general, seems to be associated with C 18:2 t10, c12 (14,15).…”

“…When assaying the quantitative and qualitative transfer of 13 C to CFA, a mixed microbial population from the rumen of a dairy cow was tested in batch cultures in the presence of [ 13 C]LNA (25). During the incubation time (48 h), both nonconjugated and conjugated 18:2 and 18:3 isomers were enriched with 13 C. Interestingly, for C 18:2 , six unknown isomers were reported, while for C 18:3 , there were 10 plus 2 conjugated forms listed. Formation of RA and isomers C 18:2 t10, c12 plus t9, t11; t9, c11; c9, c11; t11, t13; t8, t10; and c10, c12 was also observed.…”

An high dose of a conjugated linoleic acid increases fatty liver and insulin resistance in lactating mice

“…Feeding lactating mice with CLA can result in diminished mammary gland lipogenesis and reduced growth rate [18,19], but the exact metabolic and physiological changes involved remain unclear. More recently, Bezan (2018) demonstrated that feeding a high dose (3%) of CLA increases insulin resistance and exacerbates hepatic steatosis in male Wistar rats [20]. The intake of trans-fatty acids during lactation was also found to increase maternal lipids in the liver (Assumpção, 2004) and liver weight [21].…”

“…CLAs used in supplements originate from the processing of vegetable oils such as Safflower oil, and always include an equimolar mixture of c9,t11-CLA and t10,c-12-CLA. Most studies of CLAs have used a mixture of isomers, with c9,t11-CLA and t10,c-12-CLA the most abundant [20,22]. To explore this further, two experiments were performed in which mice were fed with a CLA mixture.…”

Restrição dietética de magnésio associada à dieta hiperlipídica: implicações sobre a homeostase do mineral e sensibilidade à insulina

“…Ao contrário do que algumas pesquisas apontam (JACOB et al, 2013;SANTANA et al, 2014;LU et al, 2016;BUSSEROLLES et al, 2003), a dieta hiperlipídica e a restrição dietética de Mg não promoveram modificações no perfil lipídico e na concentração de citocinas inflamatórias no tecido adiposo. Porém, alguns estudos crônicos desenvolvidos com ratos Wistar alimentados com dietas hiperlipídicas relatam a ausência de inflamação e de alterações nos níveis de lipídios circulantes assim como o presente estudo (GZIELO et al, 2017;BEZAN et al, 2018). As diferenças nesses resultados podem decorrer das variações no teor de lipídios e no perfil de ácidos graxos da dieta, peso e idade dos animais utilizados e do tempo de estudo.…”