CLA And Insulin Sensitivity |
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 | The topic of CLA and its effects on insulin sensitivity is controversial because there are two areas of possible concern. First, although animal studies show that CLA helps insulin work more effectively; other studies suggest insulin resistance and blood sugar control may be worsened. This does not necessarily mean that one or the other is true, but rather that more human studies need to be done in addition to the previous animal studies. Generally speaking, when research data that is related to health yields conflicting information, it means that more studies need to be done (especially more human studies). The problem is that human studies are difficult to conduct due to a variety of legal and practical issues. Once more solid information becomes available, Rejuvanex will update you on the latest CLA related information.
The question that is up for debate is whether or not CLA can improve insulin sensitivity (good) or decrease it (bad). Decreased insulin sensitivity is the same thing as increased insulin resistance, and neither is good. Being obese or overweight affects the way insulin works in your body. Extra fat tissue can make your body resistant to the action of insulin, but exercise helps insulin work well. If you have insulin resistance, your muscle, fat, and liver cells do not use insulin properly. The pancreas tries to keep up with the demand for insulin by producing more. Eventually, the pancreas cannot keep up with the body's need for insulin, and excess glucose builds up in the bloodstream. Many people with insulin | |
| resistance have high levels of blood glucose and high levels of insulin circulating in their blood at the same time. |
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| On the other hand, if CLA does indeed improve insulin sensitivity, it could mean a real breakthrough in the diabetic community. Insulin treatment is based on improving glucose control and preventing complications, especially cardiovascular disease. Diet is a mainstay of treatment along with exercise and weight loss. Since the information Rejuvanex can provide is contradictory, we strongly advise all diabetics and borderline diabetics to consult their physicians before beginning to take CLA. |
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| The following scientific study showed that CLA improved insulin sensitivity and decreased insulin resistance (good). |
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| “The purpose of this project was to investigate molecular mechanisms for the effects of dietary CLA on insulin resistance and atherogenesis (development of atherosclerosis). It is important to investigate atherogenesis in the insulin-resistant state because people with Type 2 diabetes have a significantly elevated risk of cardiovascular disease and vascular complications. These are very significant health problems given the increasing incidence of obesity and Type 2 diabetes, and the huge costs associated with obesity- and diabetes-related complications, in particular, cardiovascular disease. |
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| It has been proposed that CLA function is mediated via modulation of transcription factors known a peroxisome proliferator-activated receptors (PPARs). It is known that PPARs are activated in vitro by long chain fatty acids, and that PPAR-binding sites are present in the regulatory region for several proteins in lipid metabolism. Of direct interest to the present project, insulin sensitizing drugs such as the thiazolidinediones are ligands for PPARγ which are abundant in adipocytes and involved in adipocyte differentiation and fat storage. In contrast, hypolipidemic drugs such as clofibrate activate PPARα which is abundant in liver and involved in the regulation of fatty acid oxidation. Furthermore, it has been demonstrated that activation of PPARγ is involved in the uptake of oxidized low-density lipoprotein (LDL) into foam cells during formation of atherosclerotic plaques. Thus, we hypothesized that the mechanism for improved insulin sensitivity, hypolipidemia, reduced adiposity and reduced atherogenesis by CLA involves the modulation of PPARs (ligand-activated transcription factors) resulting in altered lipid metabolism (e.g. more fat oxidation, less fat storage and less oxidized LDL uptake by machrophages). Understanding molecular mechanisms associated with CLA consumption is important to the dairy industry because of future potential for functional food/nutraceutical claims that need to be based on sound scientific evidence. | | |
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| The objective of this project was to determine whether dietary CLA can reduce insulin resistance and ameliorate early markers for atherogenesis (atherosclerosis) and cardiovascular disease in young Zucker rats as a model for the early states (insulin resistance and obesity) of Type 2 diabetes. |
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Conclusions:
Fa/fa Zucker rats are a model for obesity and insulin resistance. CLA-fed fa/fa Zucker rats had greater insulin sensitivity based on improved oral glucose tolerance and reduced circulating leptin concentrations. These changes were independent on body weight. CLA-fed rats had elevated circulating adiponectin and reduced serum cholesterol which are associated with reduced cardiovascular disease risk. Future studies need to determine which CLA isomer (or combination of isomers) is responsible for improved insulin sensitivity and reduced cardiovascular risk.” |
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| The following scientific study showed that CLA decreased insulin sensitivity and increased insulin resistance (bad). |
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Conjugated Linoleic Acid (CLA) Supplementation Worsens Insulin Sensitivity And Fibrinogen Concentrations
Posted October 06, 2004 |
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 | Researchers at the Department of Clinical Medicine, Trinity Centre for Health Sciences, and the Metabolic Research Unit, St James’s Hospital, both in Dublin, investigated the effect of CLA supplementation on markers of glucose and insulin metabolism, lipoprotein metabolism, and inflammatory markers of CVD in subjects with type 2 diabetes.
Thirty-two subjects with stable, diet-controlled type 2 diabetes received CLA in a randomized, double-blind, placebo-controlled trial. A 3-h 75-g oral-glucose-tolerance test was performed, and fasting plasma lipid concentrations and inflammatory markers were measured before and after the intervention.
Much to the researchers surprise the CLA supplementation significantly increased fasting glucose concentrations (6.3%) and reduced insulin sensitivity. Total HDL-cholesterol concentrations increased by | |
| 8%, The ratio of LDL to HDL cholesterol was significantly reduced. CLA supplementation reduced fibrinogen concentrations, but had no effect on the inflammatory markers of CVD (C-reactive protein and interleukin 6). Based on this small study it would be hard to recommend a nutrient with potentially adverse effects on type 2 diabetes patients. |
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| Source: Diabetes In Control.com: American Journal of Clinical Nutrition, Vol. 80, No. 4, 887-895, October 2004 |
