Why does overweight lead to diabetes?

and can antioxidants prevent it?

Overweight often leads to type-2 diabetes and the early stage of the condition known as insulin resistance. A new scientific study suggests that oxidative damage, also known as oxidative stress, sets the stage for these disturbances in the body's sugar and lipid metabolism. The doctors behind this study therefore theorize that it is possible to prevent type-2 diabetes with antioxidants that are known to counteract oxidative stress.

Overweight is a growing threat to public health, especially because it increases the risk for type-2 diabetes, cardiovascular disease, hypertension, and premature death. Inflammation, unhealthy fats, and oxidative stress are known to have a role in the development of type-2 diabetes. The big question, however, is which of these factors trigger type-2 diabetes in overweight individuals. In order to answer that question, a group of healthy men were asked to volunteer to gain massive weight by means of an intensive diet. The diet showed surprising results in a matter of no time.

Rapid fattening led to early-stage type-2 diabetes

Guenther Boden and his team of researchers from Temple University School of Medicine in Philadelphia, USA, provided the six male volunteers with 6,000 calories daily, which is more than twice the amount of calories in a normal diet. The men were not allowed to exercise and they were monitored closely. After one week, the volunteers had gained 3.5 kilos on average. This, needless to say, was expected. However, on the second day of the study the researchers observed that the men had elevated insulin levels in their blood and signs of insulin resistance, which is when the cells are no longer able to absorb sufficient amounts of glucose (blood in the sugar). As insulin resistance is an early stage of type-2 diabetes, a disease that may take several years to develop, it was highly relevant for the scientists to investigate how and why insulin resistance could occur that soon in the body.

Oxidative stress triggers insulin resistance

The researchers took blood samples, urine samples, and fat biopsies to determine how the massive calorie exposure affected the blood and cells. The only thing they were able to see at this early stage was that it was oxidative stress that led to insulin resistance, not the other potential threats such as inflammation and unhealthy fats. The oxidative stress was simply a side effect of the body's insufficient conversion of fat and glucose.
  The fewer nutrients the cells were able to convert, the more free radicals were generated as a by-product. Free radicals are highly aggressive oxygen compounds that damage the cell membrane and nucleus, causing widespread havoc unless they are effectively neutralized.

Destruction of molecules that transport glucose

The study samples revealed that the special molecules (GLUT4) that transport glucose showed signs of damage caused by free radicals and oxidative stress. The destruction of these molecules that are important for transporting glucose may explain the early signs of insulin resistance, a problem which is characterized by inability of the cells to take up glucose.
  A free radical impact is also seen with infections, poisonings, and other stress factors that should be taken into account in real life.

Sufficient antioxidant levels protect against oxidative stress

The only protection we humans have against free radicals is the presence of so-called antioxidants. However, if the free radicals outnumber the antioxidants it leads to a state called oxidative stress. The only way to defend oneself against this is by making sure to consume sufficiently large quantities of the particularly potent antioxidants.
Our diets provide antioxidants like vitamins A, E, and C, plus selenium, zinc, and coenzyme Q10 that are all essential nutrients. Also, we get numerous plant compounds from our diet. However, even a healthy and balanced diet is unable to provide sufficient levels of all the needed nutrients such as selenium and coenzyme Q10.

No antioxidant can replace selenium

When it comes to protection of cells and tissue there are some selenoproteins called GPX that are particularly powerful. No other antioxidants are able to replace these selenoproteins so it is vital that we have sufficient levels of GPX in the body. Selenoproteins need selenium in order to function.
  The average daily selenium intake in Europe is below the RDA level of around 55 micrograms. In contrast, the daily selenium intake in countries like the United States and Japan is often around 100-200 micrograms. The agricultural soil in large parts of Europe contains very little selenium, and altered diets with less fish and hardly any organ meat contribute to the declining selenium intake in this part of the world. This, however, is something we can compensate for with a special type of selenium yeast that contains over 30 different organic selenium species and emulates the variety of selenium compounds in a selenium-rich diet.

Q10's double function - throughout life

Q10 is a coenzyme that is an integral part of the cellular energy metabolism, but it also has an important function as an antioxidant. We humans synthesize most of the Q10 that is needed, but our endogenous production of the substance declines with age. This impairs the energy turnover in cells and increases the risk of oxidative stress caused by overeating or any other factor that generates massive amounts of free radicals in the body. Therefore it is vital that we have sufficient amounts of Q10 in the body - throughout life. Q10 supplements may be a good idea, but as Q10 is not easily absorbed in the body it is advisable to stick with products that can document their bio-availability.

Food for thought in the future

The researchers behind the above mentioned study assume that it may be possible to prevent insulin resistance and type-2 diabetes with antioxidants. Of course, more research is needed in order to clarify this but the paradox that some overweight individuals never develop diabetes may be explained by the fact that they have a greater intake of antioxidants. At least the study gives food for thought, simply because it revealed how fast the body showed signs of damage caused by massive overeating.

Referencer:

Boden G et al. Excessive caloric intake acutely causes oxidative stress, GLUT4 carbonylation, and insulin resistance in healthy men.

Science Translational Medicine 2015

Judy, William V. et al: Coenzyme Q10 Facts or Fabrications. Natural Products Insider 2007

Hertz Niels: Hjertesund senior. Ny Videnskab 2012

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