Resistance Not Futile
Our body uses sugar as fuel, and insulin is the hormone that brings sugar and fat from the blood into the cells, or the smallest units of function, in our body. If our body is a car, and sugar and fat are like petrol, insulin is like the fuel injection part of the engine. It injects the fuel into the engine so the car can run. Normally, after we have eaten, sugar is absorbed into our blood. That causes insulin to be made by the pancreas and that causes the sugar from the blood to enter the muscles, brain, heart and other organs to be used and liver and fat tissues to be stored. Likewise fat from the blood is either used or stored.
This is simply resistance of the body to insulin. Linked to obesity, when too much nutrients have been stored in our body, the body refuses to let more nutrients go into its cells by becoming resistant to insulin.
So what if I have insulin resistance?
The pancreas has to work extra hard to make more insulin to overcome it. If it succeeds, the person just becomes fat and insulin resistant but not diabetic. However, when the body cannot make enough insulin to overcome the resistance, the sugar in the blood cannot go inside the liver and fat tissues to be stored, and there is excess sugar in the blood. Thus the person develops pre-diabetes (impaired fasting glucose and/or impaired glucose tolerance) or even frank diabetes mellitus. The fat in the blood cannot go inside the fat tissues, but get deposited in the wrong places like the liver, around the gut, in the muscles and in the heart. That causes dysfunction of all the organs involved. Unfortunately, Asians seem to have less ability for the pancreas to compensate for insulin resistance. So that partially explains our high rates of diabetes at 11.3% in Singapore as compared to 8.3% in the United States, even though we are not as fat.
Insulin resistance further lowers the good cholesterol (HDL-cholesterol) levels, makes the bad cholesterol smaller (easier to get deposited into blood vessels), causes blood vessels to malfunction thereby increasing blood pressure risk, makes the blood more prone to clotting and inflammation to go up. All these increase the chance of a heart attack, stroke and premature death.
In addition, insulin resistance can make the liver become fatty and inflamed, which may progress to hardening (cirrhosis of the liver). Sleep apnoea and polycystic ovary disease have also been linked to insulin resistance.
What increases Insulin Resistance?
Genes and advancing age are two drivers of insulin resistance which cannot be changed. As mentioned earlier, obesity is the main correctable driver. Unfortunately, Singapore’s obesity rates have jumped sharply from 6.9% in 2004 to 10.8% in 2010. More worryingly, young men from age 18 to 39 have the highest rate of obesity. The other correctable driver of insulin resistance is physical inactivity. Unfortunately, only one in five Singaporeans engage in regular physical activity, and half do not exercise at all.
How can we tackle insulin resistance?
First of all, one should lose some weight if overweight or obese. A healthy diet and exercise will help most people lose some weight. Take lots of fibres from fresh fruits and vegetables, oats, cereals and wholemeal bread and brown rice. Exercise by playing sports, jogging, swimming, brisk walking, and even just slow walking for people who are unfit. Thirdly, avoid simple sugars and starch but take complex starch. Studies have shown that adopting this diet can reduce insulin resistance and pre-diabetes symptoms can be reversed!