25 August 2007

Insulin Resistance - Are You At Risk?

Insulin is the hormone responsible for the control of blood sugar (glucose) and is manufactured by the pancreas. People who have type 1 diabetes produce very little (or even none) of this hormone. As a result, they must take regular injections of insulin in order to function normally. Type 2 diabetes on the other hand is where the body produces insulin normally but the insulin doesn’t work as it should so greater amounts of insulin are required. The body is said to be ‘resistant’ to insulin. Over time, the pancreas begins to fail and then type 2 diabetes develops. Insulin resistance (IR) is characterised by an inability of the body cells to bind insulin and allow nutrients to flow into the cells. This results in elevated levels of glucose in the bloodstream, leading to many serious health issues. Over time, it may result in blindness, peripheral neuropathy (damaged blood vessels and nerves in fingers and toes that may require amputation) and coronary heart disease to name a few. IR is a symptom of several diseases including type 2 diabetes, poly-cystic ovarian syndrome and obesity. It also appears to occur in people who use certain medications like antidepressants.

The mechanism of IR is simple. When you consume a food containing carbohydrate, your blood sugar (blood glucose) increases. Depending on the amount eaten, the type of carbohydrate eaten and what has been eaten with it, insulin will be secreted from the pancreas. Insulin then binds with receptors on cell membranes and allows glucose (and other nutrients) to flow into the cells. Over many years, the insulin receptors get bombarded with insulin and become de-sensitised to it’s action. Just like a regular coffee drinker becomes de-sensitised to caffeine and requires greater amounts to get the same ‘hit’, someone with insulin resistance requires more and more insulin to drive the nutrients into the cells. It is interesting to note that in the past type 2 diabetes was also called adult-onset diabetes because it took many years for the cells to become de-sensitized to insulin. Unfortunately though, IR and type 2 diabetes is now becoming prevalent in children so the term adult-onset is no longer used.

The causes of Insulin Resistance

High intake of high-density or refined carbohydrates. Concentrated sources of carbohydrates like sugars, bread, pasta, cereals, rice, pastries, etc. all cause a dramatic rise in blood sugar leading to insulin secretion and over time, IR. High intakes of saturated and trans-fatty acids. All of your body cells have membranes made of phospholipids, part of which comes from the fats we consume. A high intake of saturated and trans-fatty acids results in the cell membranes becoming less permeable, which makes the passage of nutrients across the cell membrane more difficult.

Nutrient deficiencies

The body has a requirement for a whole range of nutrients: minerals, vitamins, amino acids and fatty acids. These nutrients have numerous functions in the body. Several minerals are involved in the transport of nutrients across cell membranes. These include chromium, selenium and vanadium. A deficiency of any of these minerals impairs this function, resulting in IR. Lack of exercise. Any type of exercise involves muscular contraction, which means fuel is required by the muscle cells of the body. Furthermore, the transport of fuel into the cells means that the permeability of the cell membranes must improve for this to occur. A lack of exercise results in cell permeability staying the same or, over time, decreasing. This leads to IR.

Preventing insulin resistance

Overcoming IR requires incorporating lifestyle habits that are the exact opposite of the causes. This means following a diet that is low in high-density and refined carbohydrates and high in natural (low-to-medium density) carbohydrates. These include foods like fruits and vegetables. Replacing your existing fat/oil intake with unsaturated (‘healthy’) fats can make your cell membranes more permeable, which means nutrients can flow into the cells easier and wastes can flow out of the cells easier.

Good sources of ‘healthy’ fats include olive oil, fish oil, flax seed oil, avocadoes, nuts and seeds. Selecting foods that are high in the minerals (chromium, selenium and vanadium) involved in nutrient transport through cell membranes is beneficial. These include foods like oysters, whole-grain cereals, fish and shellfish, raw onion, potatoes, egg yolk, beef, broccoli, nuts/seeds, parsley and garlic. Supplementing your diet with the previously mentioned minerals can also be beneficial in improving insulin sensitivity. There are also other nutrients that nutritional science has discovered that can dramatically improve insulin sensitivity. These include alpha lipoic acid (ALA), 4-hydroxyisoleucine (an extract from fenugreek seed), corosolic acid (from Banaba Leaf) and extracts from cinnamon.

Finally, incorporating exercise into your lifestyle can reverse IR by increasing cell permeability. Find the type or types of exercise you enjoy doing and can see yourself doing long term. Make a commitment to perform it on a regular basis and get moving! Most disease common in civilised societies are reversible through lifestyle choices. You are now at a cross-road with two possible paths to follow. One path will lead you to a life of fun, energy, passion and health. The other to a rapid physical decline, lethargy, reduced quality of life and an early death… The choice is yours.

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