One of the most controversial aspects of metabolic syndrome - and type 2 Diabetes - is the role of hyperinsulinaemia, or high levels of insulin in the blood, as a factor in causing cardiovascular problems. As insulin resistance increases, the pancreas loses its ability to respond adequately to ingestion of carbohydrates. The post meal glucose levels therefore start to rise higher than normal - a condition known as "impaired glucose tolerance"

The difference between having metabolic syndrome and developing Diabetes Type 2 is how much insulin your pancreas is able to produce. Some people have diabetic genes that will simply not allow their pancreas to keep producing sufficient insulin to overcome insulin resistance. Their blood glucose levels will therefore continue to rise until they are diagnosed with diabetes. Others are fortunate enough to have a strong and efficient pancreas, which is able to keep producing more and more insulin. They may, however, become quite obese as they tolerate the intake of more and more sugary and high carbohydrate foods.

Another factor is that insulin resistance vastly reduces the number of insulin receptor sites on the wall of your cells. The average healthy person ha some 20,000 receptor sites per cell, while the average overweight individual can have a few as 5,000. If you have too few receptor sites, glucose bounces off the cell wall instead of passing through the receptor site to be burned as energy. When this happens, glucose remains in the blood stream, causing elevated levels of blood sugar, which are first of all sent to the liver to be turned into glycogen - the "reserve tank" for energy. After saturation point, the remaining blood sugar is stored as far. Insulin is essentially a fat storage hormone. As such it was invaluable in the days when food was less plentiful and often involved large amounts of energy to find it. It converts a portion of any excess glucose into glycogen, a storage form of sugar in the muscles and liver. Once the glycogen storage areas are filled, any further glucose in the blood that is surplus to requirements by the body and the brain, will be converted by insulin to fat, thereby fuelling to-day's obesity epidemic.

Having insulin resistance without going on to develop Type 2 diabetes can lead to heart attack and strokes, without the early warning sign of high blood glucose levels. A diagnosis of diabetes might, therefore, be a blessing in disguise, as it warns of the need to modify your diet and lifestyle before it's too late. It is also thought that post-prandial (after meal) blood glucose levels may be more important than fasting levels, and some recent studies have suggested that fluctuating blood glucose levels - going very high after meals and then coming down again, may be an even greater risk than sustained high levels. Fortunately, insulin resistance can be estimated with a test known as a "C-peptide" test.

After the continual onslaught of a refined carbohydrate diet, the body's cells become overwhelmed by so much insulin and simply become resistant to it. This forces the body to work harder to produce enough insulin to maintain blood glucose at close to normal ranges (3.8-5.5) - a bit like taking a drug so much that more is required to maintain its effectiveness, or the diminishing effect of coffee as you drink more and more (try giving up for a couple of weeks and then having a double espresso!). The combination of insulin resistance and high insulin levels can go on for years without a person realizing it, because blood glucose levels may be normal, or near normal. However, the excess insulin that the pancreas is continually pumping out starts doing damage to the body, altering blood-fat ratios, raising blood pressure, and storing high levels of fat - especially around the middle of the body. This can lead to a more advanced form of insulin resistance, in which high triglycerides and LDL cholesterol levels and low amounts of HDL cholesterol are present, combining to form metabolic syndrome (or Syndrome X).

Some people will go on to develop Type 2 Diabetes, but others will not. In those who don't, their bodies keep pumping out high levels of insulin, and they are more at risk of developing cardiovascular disease, or any of a number of other diseases associated with high insulin levels. A typical road to diabetes might run as follows:

As insulin resistance increases, the pancreas loses its ability to respond adequately to ingestion of carbohydrates. The post-meal glucose levels therefore start to rise higher than normal - a condition known as impaired glucose tolerance. Further insulin resistance, which starves the cells of their fuel, forces the liver to respond by raising glucose production, which in turn makes the fasting blood glucose levels rise. Both fasting and post prandial blood glucose levels that are higher than normal, but not high enough to be classified as diabetes - are considered to be forms of pre-diabetes. Type 2 diabetes is typically diagnosed when glucose levels go even higher (above 5.8).

Most people with Type 2 diabetes start out by producing plenty of insulin - sometimes even 2-3 times the amount that people without diabetes produce, although it simply doesn't work efficiently. In the later stages, however, the pancreas becomes so exhausted that it stops producing adequate amounts.

By the time a person has met the post-meal (2 hours after eating) blood glucose criteria for pre-diabetes, his or her risk or cardiovascular disease is greatly increased, and by the time they have met the criteria for diabetes, serious health complications may therefore already have developed. It is therefore of paramount importance to catch the diabetes process much earlier than currently happens, in order to prevent so much damage taking place in the body. Tests which help to do this are fasting and post-meal blood insulin tests; a fasting C-peptide test (which gives an index of the amount of insulin the body is producing), an oral glucose tolerance test (in which blood sugar levels are monitored after drinking a glucose solution) and HbA1C test, which gives an estimate of average blood glucose levels over the past 3-4 months.

Signs and symptoms of insulin resistance and/or metabolic syndrome include:

Excess weight around the middle
High blood pressure
High levels of LDL cholesterol and triglycerides
Low levels of HDL cholesterol
Excessive fatigue
Tiredness after meals
Difficulty concentrating
Frequent cravings for sweets and high carbohydrate foods
Feeling "high" after eating sweet foods or drinking coffee, followed by feeling Low for a while later.
Having difficulty losing weight
Irritability if going too long without food.

As with hypoglycaemia, insulin resistance responds best to a diet which contains carbohydrates that are broken down slowly. The longer it takes for them to be digested and absorbed, the more slowly glucose is released into the blood stream, causing a slow blood sugar response. The glycaemic index was developed in Canada in 1981, when David Jenkins and Tom Wolever discovered a means of measuring how long a food containing carbohydrate takes to raise blood glucose levels in the body. In addition to reducing the need for insulin, low Glycaemic Index foods will satiate hunger for longer, thereby reducing overall food intake and the need for sugary snacks. They tend to have higher a content of fibre, which slows down digestion. Protein and fat also take longer to digest. Lean meats, fish, eggs (not fried!), poultry without skin, seeds, beans and other pulses, whole grains and fresh fruits and vegetables are all excellent. www.glycemicindex.com is an excellent site containing full details of the glycaemic index of different foods.

It is also important to include olive oil in the diet as this improves the sensitivity of insulin receptors. A study reported in the Journal of the American Medical Association found that women who ate 5 servings of nuts a week were 27% less likely to develop diabetes than those who rarely ate them. Omega 3 fatty acids such as are found in fish oils, pumpkin and flax seeds (and oils); salmon, mackerel, sardines and tuna keep insulin receptors responsive to insulin, whereas fried foods and highly processed cooking oils and hydrogenated fats should be avoided.

Chromium is a mineral that is a vital component of what is known as the Glucose Tolerance Factor. It works closely with insulin to facilitate the uptake of glucose into cells. Without chromium, blood sugar levels stay elevated because the action of insulin is blocked so that glucose is not transported into the cells. Chromium increases insulin sensitivity and also has the effect of lowering LDL cholesterol and triglycerides levels. Researchers feel that we need at least 200 micrograms per day of chromium and no studies have shown any toxic side effects at that level. The best food sources are whole grain products, pulses and spices - particularly cinnamon. Highly processed foods are usually low in chromium and also enhance chromium losses, thereby reinforcing the deficiency. Chromium deficiency can be detected through hair mineral analysis, but is otherwise difficult to detect.

Insulin resistance can also arise when the body secretes a lot of adrenaline as adrenaline increases blood glucose levels. It does this by stimulating the liver to release more glucagon (stored glucose) and export it into the bloodstream to send to the muscles in preparation for "fight or flight". To-day, however, most forms of stress involve neither fleeing nor flying, and the resulting extra glucose just puts an extra call on insulin. As does the production of cortisol, the "anti-stress" hormone.

As with hypoglycaemia and Type 2 diabetes, insulin resistance can be viewed as a progression of the same illness - a malady caused by the Western diet. The body was simply not designed to handle the amount of sugar, salt, saturated fat and highly refined foods that are eaten to-day, nor for the types of stress we encounter. Maybe it's time to re-evaluate your diet and lifestyle, particularly if there is a family history of Type 2 diabetes.