Sugar : A tale of two cities

The City of Sun : Lets first look at the brighter side of sugar, we see that it is a carbohydrate, naturally present in fruits and vegetables. It is present in fruits and vegetables because plants use the sun’s energy and carbon dioxide to produce sugar and water, as a food source for growth. And what is the name of this incredibly important reaction, Photosynthesis. Not surprisingly, judging by their names, the two plants that are outstanding in their field at producing and storing sugar are Sugar beet and Sugar cane. These two are harvested to give us table sugar, called sucrose, which is made up of 50% glucose and 50% fructose.

What is Glucose you ask?

Glucose, the stuff used by our bodies as energy for our cells, is extracted from the carbohydrates that we eat and is constantly being transported to the brain because our brains are choosy when it comes to food, they only want glucose and they want it all the time. The reason for this constant calling is because the brain cells cannot store glucose, unlike the rest of the bodies cells. This is why our blood always contains sugar, because our brain never stops. No one can doubt the importance of our brain to us, and so follows the importance of sugar to us also.

Effect of sugar in our diet
Photo from istockphoto

The City of Sin : When in the wrong hands, sugar can be deadly. Who here reading this has experienced feelings of fatigue, feeling spaced out and unable to think straight after cheap pizza and chips with coke or an over-indulgence of jelly beans. To then crave more sugar in order to lift you back up from the daze. My sister told me a funny story about her 2 year old daughter who got her hands on too much sugar one day, resulting in a crazy run-around baby closely followed by a mute, just wanting to lie down baby. This is a good time to try and explain what is going on in these cases.

There is a time and a place for eating lots of sugar, and willy-nilly throughout the day is not one of them. Directly following exercise is, and we will explain this in a bit.

Lets look at the the level of glucose in the blood and go from there. The body wants to keep this level at 4mmol per litre of blood (equal to 1 gram of sugar per litre or a teaspoon of sugar in circulation throughout the entire bloodstream) to keep it running smoothly. In order to do this, the body employs a whole host of door to door salesmen and women in the form of insulin. The insulin sales team are ready and waiting at their company headquaters, aka the pancreas which is located behind stomach street. Once the digestive system releases glucose from food into the bloodstream, the alarm raises and the sales team get to work. They visit the bodies cells, especially the liver and muscle cells, and sell glucose to the cell owner. This is turing into a bit of a tongue-twister! The act of selling glucose is performed by insulin binding to the insulin receptors on the cell, which then open the cell’s door to glucose, thereby removing it from the blood. This act of glucose storage in cells is vital, as it is from these stores that the body can release glucose to feed the brain if blood sugar becomes low.

The sales-team works at its best when there is a manageable influx of glucose after eating, simply because the pancreas does not need to release extra insulin to manage the job successfully. For example, on eating an apple where the sugar is in its natural form alongside plenty of fiber, the digestive system breaks this down and releases glucose gradually due to the fiber slowing down the digestive process. The same can be said for a balanced meal, with carbohydrate, protein and fat. The fat and protein slow down the release of glucose into the blood and so the insulin team can cope with the demand and not require all their staff and effort at once.

What happens after drinking a bottle of coke, or eating a packet of skittles or anything loaded with sugar and not much else? Alarm bells ring louder in the pancreas as the brain detects a huge wave of glucose entering the blood at a speedy rate. The sales team recruit the entire office to get out and shift the glucose into the cells. This results in a much higher then usual insulin level in the blood and even when the glucose has been stored away, the insulin levels remain high, because the liver may be unable to remove the circulating insulin fast enough. The sales-team are working overtime, which results in a blood sugar dip below the bodies ideal level. This has a knock on effect, since it interferes with the usual steady supply of glucose to the brain, and can result in fatigue, poor decision making or in my niece’s case, not wishing to engage in conversation or activity!

And how do most of us react to this drop in blood sugar level, by eating more sugar. Thus causing a repeat of the above and subsequent poor blood sugar control throughout the day.

I mentioned earlier about a licence to eat sugary foods after exercise. This is because exercise uses up the glucose stores in our muscles and therefore the muscles crave glucose following a bout of activity. On eating within one hour after exercising, the muscles replenish their glucose levels without having a negative effect on the blood glucose levels and brain function. Some may say, eating after exercising is undoing all the good. But exercise offers so much more then just calorie expenditure. We will discuss all this in up and coming blog entries.

Click here to read my next blog which will explain how to keep your blood sugar levels steady by avoiding refined carbohydrates eaten on their own, e.g. a plate of chips or toast and jam with tea for breakfast. This is why beans belong to toast so that the glucose is released at a steadier rate due to the protein content of the meal. We will look at ways of controlling your blood sugar levels and will go into more detail on food choices and nutritional advice to keep energy levels from fluctuating.