Change 4 life - relevant 4 U?

Our bodies are fuelled by the food we eat, and one of the basic fuels all the cells in the body need is glucose. The body's cells need glucose for everything we do and in every part of the body - moving, thinking, feeling - everything.

Glucose is made in the liver, after food containing carbohydrate (starch and sugar) has been through the digestive system. Once the glucose is made by the liver, the hormone insulin takes it around the body to the cells which need it at the time. Extra glucose is stored in muscles or fat. Glucose is always stored away as quickly as possible because free unused glucose travelling around in the blood can damage our organs and fur up our arteries. Our bodies are programmed to reduce the levels of glucose in the bloodstream as fast as possible.

If the glucose produced by food is released slowly into the bloodstream by the liver, then the body has time to deal with it by releasing the right amount of insulin. Problems occur if glucose is released too rapidly, or in large quantities. The body then responds to these high level of glucose by releasing high levels of insulin which quickly transfer the excess glucose to fat stores where it is no longer harmful and can be used later. If this happens too often, and too much fat is stored, the result is weight gain.

But weight gain is not the only problem. If insulin levels are raised too often and for too long, the body can become resistant to insulin and glucose can remain in the bloodstream where (a) it damages organs and arteries, and (b) the cells which need the glucose do not get enough. When this happens, the body triggers more and more insulin to try and rectify things. A high level of insulin in the bloodstream can make you very hungry. This makes you eat more and so on in a vicious circle. You may eventually develop diabetes because there is too much free glucose in the blood for too long. The medical term for this situation is the "Metabolic Syndrome".  

The Metabolic Syndrome is extremely common and becoming more and more of a problem - thought to affect 20 to 30% of the adult population in westernised countries - a "hidden epidemic". Typically, the Metabolic Syndrome leads to obesity, raised blood pressure, raised fatty acids in the blood such as cholesterol and triglycerides, and raised levels of glucose in the blood. There is a greatly raised risk of heart disease and diabetes.

But here is the bit the most relevant for Rethink  - Metabolic Syndrome is also closely associated with mental illness.

A recent study from Finland showed people with high levels of psychological distress at the start of the study were more than twice as likely to have developed Metabolic Syndrome when studied again in 7 years later, after adjusting for other relevant factors.

Other authors have shown much the same thing - depressive symptoms and depressive episodes are closely associated with the Metabolic Syndrome. We do not understand why, and we do not understand which is "chicken" and which is "egg" - but the research is ongoing.

Just as in depression, there is an association of Metabolic Syndrome with schizophrenia, but here the picture is more complex because antipsychotic drugs, particularly the newer atypicals (including clozapine) and some mood stabilising agents such as sodium valproate can also raise the risk of the Metabolic Syndrome developing - a double whammy. 

• http://www.biomedcentral.com/content/pdf/1471-244x-11-173.pdf
• http://onlinelibrary.wiley.com/doi/10.1111/j.1751-7893.2011.00321.x/abstract

So, what can we do about it? Keep the thinking caps on - here comes the diet bit...

Certain foods are particularly bad for triggering high glucose production, and certain foods are very good, steadying blood glucose and reducing appetite. The "glycaemic index" is a way of measuring how quickly, and by how much, a person's blood glucose concentration increases after eating certain foods. You can modify your diet to include mostly food with a low GI index - in which case you will tend to lose weight without being hungry.

You can "cure" the Metabolic Syndrome - whether or not you have depression or schizophrenia, by changing your diet and losing weight. For example a pilot study showed that patients with severe mental illness prescribed clozapine who were put on a five-week low GI diet lost some weight even after such a short time.

Of course, changing your diet is much easier said than done, particularly if you are suffering from a mental illness. Low mood makes some people crave comfort foods such as doughnuts, chips or sweets, and, if you have not got the energy to cook, it is easier to buy ready meals. But small changes can make a big difference - go for baked beans on whole wheat toast, for example.

There is a lot written about low GI diets. The Royal College of Psychiatrists has issued a useful leaflet about diet which is helpful although it does not address the Glycaemic Index directly. There are also a number of cookbooks. Personally I have found books such as "Easy GI Diet" by Helen Foster to be very useful. There are tables available on the Net showing the GI index of foods. Basically, unrefined cereals, beans, vegetables and fruit are low GI, and cakes, biscuits, chips, fizzy drinks and confectionery bars are high GI and should be avoided.

Take it from me - the low GI diet works and is well worth a try. Make it your New Year's resolution. I'll even send you some of my favourite recipes.

• Download the Rethink  Mental Illness Physical health and nutrition factsheet.

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