Posts Tagged ‘insulin resistance’

Omega-3-rich supplements may improve blood lipid levels of people with metabolic syndrome

Tuesday, March 8th, 2011

Omega-3-rich supplements may improve blood lipid levels of people with metabolic syndrome, reducing the risks of developing serious health problems, says a new study.

The research, published in The Journal of Nutrition, suggests that the effects of metabolic syndrome– a major risk factor for insulin resistance and diabetes – can be reduced through the addition of omega 3 fatty acids in low-fat, high-complex carbohydrate diets.

“Fish oil supplements correct many metabolic alterations associated with insulin resistance, including reduced postprandial plasma triglyceride concentration” stated the researchers, led by Jose Lopez-Miranda from the University of Cordoba, Spain.

Risk factors

Metabolic syndrome is the name given to a group of risk factors that frequently include obesity, hypertension, high levels of blood lipids, and high blood sugars.

The condition is a common precursor to type II diabetes, and is also strongly associated with increased risk of major health problems such as heart disease and stroke.

The causes of metabolic syndrome are unknown, although they are thought to involve both genetic and environmental factors – including poor diet.

One way to increase the overall health – and reduce the risks – of people with metabolic syndrome, has been to eat a diet low in saturated fat and high in complex carbohydrates. However, previous research has suggested that this diet does not help to reduce high levels of blood lipids – with some studies observing such a diet could even be raising blood lipid levels.

Positive effects

The new study looked into the effects of four different diet combinations on blood lipid metabolism, in 117 patients with metabolic syndrome.

In accordance with previous suggestions, the researchers found that a low-fat, high-complex carbohydrate diet had “several detrimental effects”, including significantly increasing total triglyceride levels, and triglyceride rich lipoprotein cholesterol levels.

In contrast, intake of the same diet supplemented with omega-3 was found to have no effects on blood lipid levels, with researchers observing that a diet rich in monounsaturated fats, or a low-fat diet rich in complex carbohydrates and omega-3 fatty acids, resulted in lower circulating blood lipid levels than a diet rich in high saturated fats or a diet low in fats and high in complex carbohydrates.

The data from the study suggest a place for higher omega-3 intake in people with metabolic syndrome, and supports previous research that suggests monounsaturated fatty acids can have a positive effect on blood lipid levels.

“The long-term effect of the low-fat, high-complex carbohydrate diet, pre vs. post intervention phases, showed several beneficial effects of long chain omega-3 PUFA supplementation,” stated the researchers.

“Our data suggest that long-term intake of an isocaloric, low-fat, high-carbohydrate diet supplemented with long chain omega-3 … have beneficial effects on postprandial lipoprotein response in patients with metabolic syndrome,”

Source: The Journal of Nutrition
Published online ahead of print, doi:10.3945/jn.109.120816
“A Low-Fat, High-Complex Carbohydrate Diet Supplemented with Long-Chain (n-3) Fatty Acids Alters the Postprandial Lipoprotein Profile in Patients with Metabolic Syndrome”
Authors: Y. Jimenez-Gomez, C. Marin, P. Perez-Martinez, et al

Omega 3 stronger than any other anti inflammatory

Wednesday, December 15th, 2010

GPR120 Is an Omega-3 Fatty Acid Receptor Mediating Potent Anti-inflammatory and Insulin-Sensitizing Effects”

Omega-3s may reduce inflammation by acting on a receptor found in fat tissue and on inflammatory immune cells called macrophages, according to research.

The new research published in the journal Cell, suggests the mechanisms behind omega-3’s actions as an anti-inflammatory are due to its action on G-protein-coupled receptor 120 (GPR120) working as an omega-3  FA receptor/sensor.

“Omega-3s are very potent activators of GPR120 on macrophages – more potent than any other anti-inflammatory we’ve ever seen,” said lead researcher Dr Jerrold Olefsky of the University of California, San Diego.

Anti-inflammatory

Omega-3 fatty acids have been long associated with anti-inflammatory effects; however the mechanisms behind such effects have been poorly understood.

GPR120 is a G protein-coupled receptor (GPCRs) – part of a group involved in many important cell functions, and is the target of many drugs.

Previous research has suggested that five GPCRs – including GPR120 included – respond well respond to free fatty acids.

Since chronic tissue inflammation is linked to insulin resistance in obesity, the researchers used GPR120 knock-out mice to investigate if omega-3 leads to GPR120-mediated anti-inflammatory and insulin sensitizing effects in vivo.

Robust effect

Researchers found that GPR120 functions as an omega-3 receptor in pro-inflammatory macrophages and mature adipocytes.

When knock-out mice were fed a high-fat diet and treated with omega-3 fatty acids, they showed all the signs of inflammation and the insulin resistance that leads to diabetes with omega-3 having no effect.

Normal mice on a high-fat diet still gained weight, however, omega-3s “had a really robust effect in preventing inflammation,” Olefsky said.

The study also observed that by signalling through GPR120, omega-3 fatty acids mediate potent anti-inflammatory effects to inhibit certain key inflammatory signaling pathways.

The study reports that omega-3 treatment was as effective – or in some cases more effective – than the popular insulin-sensitizing drug Rosiglitazone.

The researchers noted that activation of GPR120 by omega-3s blocks not one, but all inflammatory pathways.

Interpretation

Olefsky said his team focused on GPR120 from the beginning because of where it is found – in fat tissue and on macrophages. Olefsky noted that if your goal is to fight inflammation then “that’s just where you’d want them to be expressed.”

How these findings can be interpreted for humans is not yet clear, but with a growing trend in omega-3 supplementation and increased dietary intakes of omega-3 a goal for many consumers.

Olefski says it is too early to make any formal reccomendations at the moment, but highlights that he does not see any problem with people taking omega-3 supplementations “as long as it isn’t in enormous doses.”

Olefski said that further research needs to be conducted into several – currently unknown – omega-3 mechanisms. For one, omega-3s seems to block the migration of macrophage cells into tissues – “It’s a remarkable effect, and we don’t know its action,” he added.

Source: Cell

Vol 142(5) pp. 687 – 698, doi: 10.1016/j.cell.2010.07.041

“GPR120 Is an Omega-3 Fatty Acid Receptor Mediating Potent Anti-inflammatory and Insulin-Sensitizing Effects”


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