Saturday, October 20, 2012

Insulin Story

  In the classic movie, Dances with Wolves, Kevin Costner befriends few Sioux Indians and serves them coffee. The coffee is bitter, so he gives them a small sack of sugar and tells one of the Sioux Indians to put a handful of sugar in his mouth, the Sioux Indian complies and the next scene is priceless.... a big smile appears on the Sioux man's face after tasting refined sugar for the first time in his life. Somehow, sugar makes us happy. There is no better picker-upper than a good chocolate bar in the late afternoon. You can walk down to the vending areas of most office buildings and will observe folks going in and out selecting their favorite snacks in the late afternoon. While we are stuffing our faces with sugars and elevating our blood glucose to almost toxic levels, the poor insulin is doing its best in keeping our glucose levels down and sadly losing this battle. Insulin is one of the most important hormones in our bodies responsible for managing the blood sugar or levels of glucose. Although, glucose is absolutely necessary for the cells as fuel, but having too much glucose present in the blood is toxic. This is where the insulin story begins and it is best told in the paleo context. In this blog post, using the KIS principle (keep-it-simple), I will attempt to describe many of the functions of this important hormone.

   Insulin is a protein made by the beta cells in the pancreas. Insulin is released in small quantities all day but its activities increase especially around meal times. A meal rich in carbohydrates elevates the blood glucose levels. To lower the glucose levels, insulin is released. Below are few insulin interactions when a meal is consumed:
  • A meal high in carbohydrates is digested quickly and absorbed in the blood stream via small intestine. The blood glucose levels goes up.
  • The cells begin to use glucose as a source of energy right away. The brain cells and the red blood  cells use glucose exclusively.
  • Pancreas begins to release insulin.
  • The excess glucose is sent up to liver to be converted to glycogen. Glycogen is no more than few glucose molecules stringed together. This is one of many ways nature stores energy. Some of the glycogen is stored by the liver and some is stored in the muscle cells for a flight or fight types of response. Glycogen is the first reserve of energy that body can tap into in an emergency situation. Unfortunately, the glycogen stores are small and can not store an unlimited supply. Once the glycogen stores are full, then liver begins to create fatty acids from the glycogen. These fatty acids are eventually assembled as triglycerides and end up in the blood stream.
  • Insulin activates a special receptor on the fat cells called LPL (lipoprotein lipase). Once activated LPLs actively begin to gather passing by triglycerides in the blood stream and store them in the fat cells. Since there is ample glucose available for fuel, the purpose of this is to take triglycerides out of circulation as a possible source of energy for the cells to use.
  • The remaining glucose gets used by the cells, as the glucose levels fall, the low glucose blood level stimulates the pancreas to release glucagon. Glucagon is a hormone, not to be confused with glycogen, which is a stored form of glucose. Glucagon, promotes the release of glycogen from the liver and the muscles to be released back into the blood stream as glucose for energy. This raises the blood glucose levels again and causes pancreas to release more insulin and the cycle continues until all the available glucose from the meal is fully used up. 
  • The above process may take up to four hours. Then body begins to feel hungry again until more  food is introduced. If you are in a fasting state, say at night sleeping, the low blood glucose levels activate another hormone inside the fat cells called HSL (hormone-sensitive lipase). HSL releases the triglycerides stored in the fat cells to the blood stream for the body to use as energy. This helps us get through a long night without a meal. The fat reserves are only tapped once the glucose from the meal and the stored glycogen in the muscles and the liver is depleted.
   Insulin and glucagon are complimentary hormones, insulin promotes the storage of fat while glucagon promotes the release of glycogen from the liver and the muscles. These two hormones keep the glucose levels constant and provide a steady supply of energy for the cells who are constantly working...in other words keeping us alive. So what happens when these processes are not regulated? What happens when pancreas does not release insulin after a meal and the blood glucose levels remain high? Or what happens when the insulin is ineffective and is not able to bring down the elevated glucose blood levels? This is a toxic situation. High blood levels of glucose do not play nice with proteins and form AGEs (advanced glycation end products). The AGEs end up damaging proteins, enzymes, and DNA in the body. A human body is a nice warm vat of fluid with constant temperature. When a confectioner caramelizes sugar to make candy, the end product is a gooey and chewy material that can be used as the base for many candies. In a crude analogy the excessive glucose in the blood stream acts like a caramelized sugar in a warm confectioner vat.  Basically not a good situation. Let's look in detail the situations in which insulin is not properly regulated.
  • Type 1 diabetes is the condition in which pancreas fails to make insulin. In this situation, the patient must inject a dose of insulin several times per day to keep the blood glucose levels down. This situation is less common and basically attributed to factors like genetics, toxins, or a virus. Not much can be done, before modern medicine, the patients usually died, but these days patients can prolong life by injecting insulin into their bodies daily.
  • Type 2 diabetes, is more common and is attributed to diet and life style. This is where the paleo context becomes relevant. The onset of type 2 diabetes is accelerated by the foods we eat, especially simple carbs and refined grains. The refined grains and simple carbs like sugars in soft drinks and juices deliver an overdose of glucose to our blood stream. Below are the steps that lead to type 2 diabetes:
    • Simple carbs are quickly digested and enter our blood circulation. Insulin is released in response to high levels of blood glucose.
    • Insulin stimulates the removal of fats from the blood stream and also promotes glycogen to be stored in the liver and the muscle cells. The liver and the muscles can only store a finite amount of glycogen. Once full they refuse to accept additional storage of glycogen.
    • Blood glucose levels remain elevated, pancreas responds by releasing more insulin, the muscles still resist and refuse to accept additional glycogen. 
    • This prolonged condition eventually leads to cells becoming insensitive to insulin. This condition is called insulin insensitivity. At this point the person experiences an onset of type 2 diabetes. It may take several years for this condition to develop to a full blown type 2 diabetes. It all depends on the body weight and the individual lifestyle. One thing for sure, refined grains and simple carbs play a major role in developing insulin insensitivity. 
   In a type 2 diabetes, the insulin becomes ineffective in lowering the blood glucose levels after a meal. The person requires assistance in the form of a pill to lower his or her blood sugar or eat measured portioned controlled meals to sustain life. As you can imagine, this situation is not normal and eventually leads to many other chronic diseases. So how to avoid this fate? The answer of course, is paleo way of eating. The fats, proteins, vegetables, nuts and seeds, staple of paleo diet do not raise the blood glucose levels to a point of no return, but provide all the necessary nourishment for the body. Our paleo ancestors did not have refined grains nor large gulps of fountain sodas available to them. They walked several miles per day in search for their food. They ate fatty meats when available. Our paleo ancestors lived as hunter gatherers traveling in small bands for over 2 million years. The Sioux Indians alluded to in the beginning of this post were also hunter gatherers moving around in a large mass of land, they followed the buffalos (tatanka) for their livelihood. They killed only what was needed for the sustance of the tribe and ended up using every part of the buffalo. Nothing went to waste. Within few decades of the arrival of European settlers the Sioux Indians were subjugated and abandoned their hunter gatherer way of life. The sugar eating scene in the movie Dances with Wolves pretty much tells the whole story. I will leave you with few funny advertisements sent by my friend Cal. Judge for yourself..







   

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