Posts Tagged ‘best foods for diabetes’

Omega 3 fish oil may help activate anti-diabetic genes

Tuesday, March 8th, 2011

Fish oils may help to activate anti-diabetic genes

Polyunsaturated fatty acid fish oils may activate genes that regulate fat cell differentiation and glucose homeostasis, according to new research on mice.

The new study published in Journal of Nutritional Biochemistry suggests supplementation with omega3 fish oil activates the transcription factor PPARγ, increasing regulation of adipocytes and helps to maintain glucose homeostasis.

“We demonstrated that adipogenic genes and glucose metabolism genes were elevated in PPARγ transgenic mice when fed fish oil. This transgenic mouse model provided direct evidence to demonstrate omega 3 , especially EPA  regulate glucose homeostasis through interaction with PPARγ,” wrote the researchers, led by Dr Yu-Hsiang Yu from the National Taiwan University

Vital roles

Peroxisome-proliferator-activated receptor γ (PPARγ) is considered an important transcription factor in regulating fat cell (adipocyte) differentiation, and is also known to play a vital role in maintaining glucose homeostasis. The transcription factor is a target for many anti-diabetic drugs as activation promotes glucose dispersal.

Activation of PPARγ occurs through the binding of specific ligand molecules; however, polyunsaturated fatty acids such as arachidonic acid, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are also known to have a high binding affinity for PPARγ.

Previous studies suggest that polyunsaturated fatty acids (PUFA) and their metabolites are able to regulate PPARγ activity, demonstrating that DHA treatment increases PPARγ-responsive gene expression in a cell model.

However, most research demonstrating PPARγ activity uses in vitro cell models and there is currently no direct evidence available to demonstrate that polyunsaturated fatty acids are able to activate PPARγ in vivo.

The authors said the current experiment was designed to determine the potential for PUFA, particularly EPA and DHA, to activate the function of PPARγ in vivo.

Wild-type and transgenic mice – with over expressed PPARγ –were supplemented with either fish oil or PPARγ ligands (rosiglitazone) for four months to investigate whether fish oils have similar effects to true PPARγ ligands in vivo.

Results

Dietary rosiglitazone fed mice had a significantly lower feed intake, but had no significant effect on body weight or fat pad weigh, whereas fish oil supplementation did not significantly decrease feed intake, but significantly decreased body and fat pad weight, found the researchers.

Dr. Yu and colleagues reported that adipogenic genes (LPL, FAT, SREBP-1c and FAS) were markedly up-regulated by rosiglitazone supplementation. Fish oil supplementation increased LPL and FAT, but not SREBP-1c or FAS; however, stained muscle sections indicated no lipid accumulation in skeletal muscle.

Researchers noted that transgenic mice fed a fish oil supplementation had increased expression of adipogenic and glucose uptake genes, leading to reduced plasma glucose concentration.

Natural regulator

The authors suggested that polyunsaturated fatty acids, particularly EPA and DHA, may serve as a natural regulator of glucose uptake in vivo, stating that such effects are mainly mediated through PPARγ activation.

“Our data demonstrated that the PPARγ-regulated glucose metabolism genes, GLUT-4 and ADN were dramatically increased in skeletal muscle of PPARγ transgenic mice when fed rosiglitazone or fish oil, suggesting activation … by either ligand,” concluded the authors.

Source: Journal of Nutritional Biochemistry

“The function of porcine PPARγ and dietary fish oil effect on the expression of lipid and glucose metabolism related genes”

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

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