Obese people who are not prepared to do more exercise or eat more healthily should maybe start taking Ginkgo biloba. It might help keep their overweight from getting completely out of hand and reduce their chances of developing diabetes or other diseases. Brazilian nutritionists at the Universidade Federal de Sao Paulo come to this conclusion in an animal study that will soon be published in the Brazilian Journal of Medical and Biological Research.
Ginkgo and insulin
Ginkgo reduces blood sugar levels in rats with diabetes [Biomed Res Int. 2013;2013:162724.] and in human diabetics ginkgo improves insulin production. [J Clin Pharmacol. 2001 Jun;41(6):600-11.]
With this knowledge in mind the Brazilians came up with the theory that, because it improves insulin functioning, ginkgo might help muscles to absorb more glucose. As a result ginkgo might protect obese people, who eat so much that they are at risk of developing type-2 diabetes, against illness.
The researchers fattened a group of rats over a period of eight weeks with high-calorie food [HFD]. A control group was given standard food [NFD]. Half of the HFD group of rats were given 500 mg ginkgo extract per kg bodyweight [Gb] daily; the other half were given a liquid containing no active ingredients [V].
The rats in the HFD group put on more weight than those in the NFD group, but the ginkgo supplementation inhibited the growth of their fat reserves. That was partly due to the fact that the rats in that group ate less. Once you’ve noticed that the ginkgo supplementation also reduced the rats’ blood sugar level considerably, you’ll realise there’s more to the story.
The graph below shows what this is. The graphs show the functioning of the insulin receptor in muscle cells from the gastrocnemius muscle. Ginkgo supplementation with insulin [black bar] – but not without insulin [white bar] – boosted the activity of the anabolic signal molecule Akt, which is stimulated by insulin.
“Taking into consideration that most obese people resist adhering to a program of nutritional reeducation, Ginkgo biloba therapy might be very helpful for avoiding the development of comorbidities in those patients”, the researchers write. “These findings suggest that Ginkgo biloba might be an efficient therapy to prevent and/or treat obesity-induced insulin signaling impairment, and warrants additional studies to better understand the complex mechanisms involved in Ginkgo biloba’s hypoglycemic effects.”
Beneficial effects of Ginkgo biloba extract on insulin signaling cascade, dyslipidemia, and body adiposity of diet-induced obese rats.
Ginkgo biloba extract (GbE) has been indicated as an efficient medicine for the treatment of diabetes mellitus type 2. It remains unclear if its effects are due to an improvement of the insulin signaling cascade, especially in obese subjects. The aim of the present study was to evaluate the effect of GbE on insulin tolerance, food intake, body adiposity, lipid profile, fasting insulin, and muscle levels of insulin receptor substrate 1 (IRS-1), protein tyrosine phosphatase 1B (PTP-1B), and protein kinase B (Akt), as well as Akt phosphorylation, in diet-induced obese rats. Rats were fed with a high-fat diet (HFD) or a normal fat diet (NFD) for 8 weeks. After that, the HFD group was divided into two groups: rats gavaged with a saline vehicle (HFD+V), and rats gavaged with 500 mg/kg of GbE diluted in the saline vehicle (HFD+Gb). NFD rats were gavaged with the saline vehicle only. At the end of the treatment, the rats were anesthetized, insulin was injected into the portal vein, and after 90s, the gastrocnemius muscle was removed. The quantification of IRS-1, Akt, and Akt phosphorylation was performed using Western blotting. Serum levels of fasting insulin and glucose, triacylglycerols and total cholesterol, and LDL and HDL fractions were measured. An insulin tolerance test was also performed. Ingestion of a hyperlipidic diet promoted loss of insulin sensitivity and also resulted in a significant increase in body adiposity, plasma triacylglycerol, and glucose levels. In addition, GbE treatment significantly reduced food intake and body adiposity while it protected against hyperglycemia and dyslipidemia in diet-induced obesity rats. It also enhanced insulin sensitivity in comparison to HFD+V rats, while it restored insulin-induced Akt phosphorylation, increased IRS-1, and reduced PTP-1B levels in gastrocnemius muscle. The present findings suggest that G. biloba might be efficient in preventing and treating obesity-induced insulin signaling impairment.
PMID: 25075573 [PubMed – in process]