Wednesday, May 27, 2009

New Model Of Cancer Development: Low Vitamin D Levels May Have Role

New Model Of Cancer Development: Low Vitamin D Levels May Have Role: .

"In studying the preventive effects of vitamin D, researchers at the Moores Cancer Center at the University of California, San Diego, have proposed a new model of cancer development that hinges on a loss of cancer cells' ability to stick together. The model, dubbed DINOMIT, differs substantially from the current model of cancer development, which suggests genetic mutations as the earliest driving forces behind cancer."

"The first event in cancer is loss of communication among cells due to, among other things, low vitamin D and calcium levels," said epidemiologist Cedric Garland, DrPH, professor of family and preventive medicine at the UC San Diego School of Medicine, who led the work. "In this new model, we propose that this loss may play a key role in cancer by disrupting the communication between cells that is essential to healthy cell turnover, allowing more aggressive cancer cells to take over."

Reporting online May 22, 2009 in the Annals of Epidemiology, Garland suggests that such cellular disruption could account for the earliest stages of many cancers. He said that previous theories linking vitamin D to certain cancers have been tested and confirmed in more than 200 epidemiological studies, and understanding of its physiological basis stems from more than 2,500 laboratory studies.

Wednesday, May 06, 2009

Study demonstrates that key role insulin plays in obesity | Dr Briffa's Blog

Study demonstrates that key role insulin plays in obesity | Dr Briffa's Blog:

The idea that obesity is a disorder of fatty accumulation (and not just down to the calorie principle) is explored in Gary Taubes’ book The Diet Delusion (titled Good Calories, Bad Calories in the USA). In this book, Taubes’ exposes the fallaciousness of the calorie principle, and instead goes after what might cause fatty accumulation in the body.

Now, fat is stored in fat cells as substances called triglycerides. Triglyceride is made from substances known as free fatty acids. It takes 3 fatty acids and one molecule of a substance known as glycerol to make triglyceride. The free fatty acids are absorbed from the bloodstream into the fat cells. They can flow out again too. What ‘fixes’ them in the fat cells is their conversion to triglycerides.

The conversion of free fatty acids to triglyceride is dependent on the supply of a substance called alpha glycerol phosphate. This is produced when glucose is metabolised in the cell. In other words, the more glucose that gets into the fat cells, the more fat will tend to get fixed there.

For most people glucose comes from sugars and starches (carbohydrates) in the diet. But to get into the cells it requires the action of the hormone insulin. So, dietary carbohydrate supplies the glucose necessary for the manufacture of triglycerides, and also stimulate the secretion of insulin which gets the sugar into the cells. Insulin also stimulates triglyceride formation through its action on other hormones (lipoprotein lipase, glycerol phosphate acyltransferase and hormone sensitive lipase).

In short, what this means is that carbohydrate and insulin will tend to cause the accumulation of fat in the cells.

Friday, May 01, 2009

Dopamine and Insulin Resistance - Full Text View -

Dopamine and Insulin Resistance - Full Text View -

"Obese individuals have fewer striatal dopamine type 2 receptors (DRD2) than normal weight individuals. Lower DRD2 levels are associated with addiction and a decreased sense of pleasure. Obesity is also associated with insulin resistance (poor insulin action); however approximately 10% of obese adults are metabolically healthy and do not have insulin resistance. We propose that insulin resistance contributes to low dopamine type 2 receptors and, using PET imaging, aim to determine if DRD2 binding in the brain and insulin resistance correlate."