Based on my talks at the Kiwanis Club of Longboat Key (November 7, 2010) and at Dr. C. Purser's wellness group (January 27, 2011).
Imagine driving along a busy road lined with red brick walled buildings. As you are driving along, without warning, a seemingly endless cascade of bricks falls out of nowhere and completely obstructs the road in front of you. This is what happens when one has a heart attack. The blood vessels, also called arteries are complex structures that transport red blood cells. During a heart attack, the blood vessels in the heart are suddenly blocked preventing red blood cells from reaching the heart muscle downstream. Red blood cells are important because they have hemoglobin, which transports oxygen. When the heart muscle is deprived of oxygen, this results in death of the cells of the heart and ultimately forms a scar tissue. Depending on how much heart muscle is involved and how long it is deprived of oxygen, the efficiency of the pumping mechanism of the heart is correspondingly reduced.
The rather sudden nature of a heart attack has its roots in our childhood. The central theme of all heart attacks is buildup of plaque or blockage in the blood vessels. This process of plaque formation starts very early in our lives. Diet plays a very important role in the formation of these blockages.
We are going to explore how blockages or plaques form in our blood vessels by tracing the pathways of food metabolism.
Key points
- Three major food groups: carbohydrates, proteins and fats.
- End product of food metabolism is carbon dioxide and water, regardless of the type of food.
- Excess carbohydrates and proteins are converted to fat for long-term storage.
- Cholesterol is important for integrity of all cells in the body, helps in the absorption and digestion of fats in the intestine, precursor of hormones such as testosterone and estrogen.
- Cholesterol and fats are insoluble in blood, are transported in the bloodstream attached to particles called lipoproteins. One such lipoprotein called LDL or bad cholesterol is responsible for the formation of blood vessel clogging plaques.
- Better the diet (lower calories: remember, carbohydrates, proteins and fats are interchangable, excess is ultimately stored as fat), less need for blood stream lipoprotein (LDL) transport of cholesterol and fat .
- Less circulating lipoproteins (LDL), less probability of plaque formation which leads to clogging of blood vessels.
- Mind influences diet to a large extent.
Major Food Groups
If we look at our daily diets, the three major food groups are proteins, carbohydrates and fats. No matter how the food is presented or how expensive the meal may be, the body looks at food and processes into these three primary building blocks. How we (our eyes, tongue, nose and mind) look at food and how the body mechanism looks at food is very different. Imagine being a five year old going to Disneyland. All that a five year old is interested in is the rides, the food and the excitement surrounding the trip. The parents of the child, on the other hand, are thinking about logistics such as how to get there, making arrangements for hotels etc. Both the child and the parents get to the same place, but both have different roles to play. When we take food, we are mostly concerned with the appearance, taste etc. and less concerned on the effects it has on our body. The body mechanism on the other hand is more focused on breaking food down into the 3 groups and using the energy derived from it. Most of the excess is sent out as waste, but some of it gets into our bloodstream and causes all our lifestyle related problems such as diabetes and heart disease.
Let’s take a prototypical meal consisting of steak (proteins, cholesterol), mashed potatoes (carbohydrates) and creme brulee (fats and sugars) to explain the link between what we eat and how it could potentially turn into a blood vessel clogging plaque. All three major food groups, that is, proteins, carbohydrates and fats are ultimately turned into carbon dioxide and water. Carbon dioxide is transported to the lungs and is sent out as part of the expired air. Water is lost through urine and sweat. Along the way, from the dinner table to carbon dioxide to water, energy is generated for bodily functions. Depending on what we eat and how much of it we eat, potentially harmful processes are also going on such as plaque buildup. Let’s follow the course of each of these three food groups after they enter our system.
Carbohydrates
We take in carbohydrates mainly in the form of table sugar (also called sucrose) and milk (also called lactose). These more complex sugars are broken down into simpler particles such as glucose. This breakdown starts in the mouth and is completed in the stomach and small intestine. Glucose crosses the wall of the intestine and enters tiny blood vessels on the other side of intestinal wall. It is then transported to the liver. The liver is the first point of contact for all food particles once it crosses the wall of the intestines. It is like the customs and immigration control when you enter another country. Glucose is rapidly processed through the liver just like a frequent flier with very little baggage. It then travels the blood stream and is utilized by the tissues of the body as an energy source. Once the body has had its fill of glucose, the remaining excess gets into mischief. In the liver excess glucose is turned into fat. The body sets no limit to fat storage as the body places a big premium on fat stores, since fat provides more energy per gram than either proteins or carbohydrates.
Proteins
Proteins are the basic building blocks of the body, just like bricks are to a building. Dietary proteins is broken down into basic building blocks called amino acids. These amino acids are transported across the wall of the intestines and these protein building blocks are transported to various cells in the body. Amino acids are essential for hemoglobin, neurotransmitters and other key bodily functions. They can also be converted to glucose and fat for storage.
Fats
Fats are the major fuel source for humans. Absorption of fat is a little more complicated. The basic unit of fat is called triacylglycerol- 3 fatty acids attached to a backbone of glycerol. Most fat is absorbed in the small intestine. Since it is not soluble in water or blood, it needs to be modified into a form that would be suitable for absorption across the wall of the intestine. Cholesterol that is produced by the liver form what are called as bile salts which are in turn released from the gall bladder in response to a high fat meal. Fat does not readily dissolve in blood unlike glucose. A cup containing a sugary drink can be easily washed with water alone. A greasy plate needs a detergent to get the grease off. Just as you would use a detergent to clean off a greasy plate, bile salts derived from cholesterol act as a detergent to help absorb fat. A tiny package consisting of dietary fat and the bile salts then arrives at the wall of the intestine. Here the bile salts drop the fat off at a tiny door that opens to the other side of the intestinal wall. The bile salts stay back and go to work and pick up other particles of fat and help transport them across the intestinal wall.
Once the particles of fat have crossed the wall of the intestine, they need help again since they cannot dissolve in blood. Luckily, the body sends help in the form of a courier particle called lipoprotein. These lipoproteins are like trucks transporting goods on the freeway. Lipoproteins help in transport of fats and cholesterol in the bloodstream. Fat is taken up cells and organs of the body for energy and the remainder is stored as fatty deposits in areas such as the abdomen resulting in obesity.
In summary, the body has three silos, one each for carbohydrates, proteins and fats. Everything that we eat is broken down into basic building blocks for transport across the wall of the intestine to the blood stream. Proteins, fats and carbohydrates are essential for health and well being when taken in the right amounts.
Cholesterol
Where does cholesterol fit in? Cholesterol is important for maintaining the integrity of cell membranes, it is precursor of bile salts (these have a detergent action that helps in the absorption and storage of fat), hormones (such as estrogen and testosterone) and vitamin D.
Cholesterol is supplied by food and the liver has the ability to manufacture cholesterol. Some of the cholesterol produced by the liver is turned into bile salts which help in the absorption of fats and dietary cholesterol. Cholesterol is also transported in the blood stream to various parts of of the body, and cells take up this cholesterol to maintain the integrity of their walls and for other functions. As mentioned previously, cholesterol like fat is not soluble in blood. The liver is like a factory producing goods for consumer use. It has limited capacity for storing inventory as the liver factory is mainly involved with production (works in 3 shifts- breakfast, lunch and dinner) and not storage.
The liver factory also make trucks that transport cholesterol and fat. These trucks are called the lipoproteins. The liver packages cholesterol and fat into these trucks. The ensuing lipoprotein is called VLDL or very low density lipoprotein. These contain fats and cholesterol that are useful for cells of the body. Once the VLDL particles are depleted of fat, some of these are converted to LDL or low density lipoprotein or what is commonly referred to as “bad cholesterol”. These LDL particles are cholesterol rich. Some cells of the body need this cholesterol for their needs. The rest of the LDL is either recirculated by the liver or is left traveling along the blood stream if the liver’s capacity to process it is saturated.
Blood Vessel Blockage or Plaque Formation
This free circulating LDL or bad cholesterol is the precursor of blood vessel blockages. LDL by itself does not cause blockages. It needs help. Just like the fire triangle which consists of heat, oxygen and fuel, LDL in concert with a damaged blood vessel wall and an oxidation process (enhanced by free radicals produced in the body) causes the process that ultimately results in blood vessel blockages.
The inner lining of all blood vessels is a very thin membrane that is easily damaged by harmful substances in cigarette smoke, shear stresses from hypertension and from prolonged exposure to high blood sugars as in diabetics. When this lining is damaged, spaces open up between cells. LDL particles that are damaged by free radicals move into the spaces created by the damaged blood vessel lining. Cells deeper inside the blood vessel then call for help. Help arrives in the form of a certain type of white blood cell. White blood cells are like the police force of the body. They help in fighting infections. They also happen to take up LDL particles that are modified by free radicals resulting in free oxidized LDL. Once this happens inside the wall of the blood vessel, foam cells are formed. Foam cells are the white blood cells that have swallowed oxidised LDL (damaged by free radicals) particles. As these foam cells accumulate, the smooth lining of the blood vessel is deformed and further spaces are created by the separation of the cells lining the inside of the blood vessels. There are other particles floating around the blood stream called platelets that try to repair this damage. These platelets are “sticky” particles that are involved in blood clotting. In the process of repairing the damage, these “sticky” particles actually accentuate the process by attracting other platelet friends that propagate the process and ultimately resulting in a blood clot. Most blood clots heal and as they heal, the blockage worsens. Some blood clots happen suddenly and fill the whole of the blood vessel and this is what happens in a heart attack.
This process occurs over and over again over several years, ultimately forming blockages which may result in strokes and heart attacks. The same process that forms blockages can also weaken the outer wall of the blood vessel, which result in the outward bulging of blood vessels. This is referred to as aneurysm formation.
Summary
As we can see here, a simple dinner meal can fuel the process that results in blood vessel blockages. Occasional intake of excess calories does not cause harm. It is repeated actions that overwhelm the body’s capacity to process these calories causes this. Carbohydrates, proteins and fats are interchangeable i.e., the excess is stored as fat. If excess fat is taken in, excess cholesterol is also likely taken in. During the transport of this excess fat and cholesterol, LDL or “bad cholesterol is left behind which ultimately initiates the process that results in blocked blood vessels.
Where does mind play a role? When people are stressed, blood pressure goes up. This high blood pressure or a fluctuating blood pressure creates shear forces on the blood vessels. It is like taking a thin piece of paper and pulling it apart in different directions hoping it won’t tear. When one is stressed out or depressed, one tends to overeat the wrong kinds of food, calling it “comfort food”. What is “comfortable” for the mind, could potentially be poisonous for the body. Repeated thoughts lead to actions, repeated actions lead to habits. In similar fashion, we allow our minds to latch onto certain thoughts, which may create a stressful inner environment. This stress leads to change in lifestyle and this may ultimately lead to disease.
In life we all have good and bad experiences. One cannot have a good experience without a bad one. It is like walking out in the sun and hoping not to cast a shadow. We should not attach much importance to these good and bad experiences. However, we need what these experiences teach us to move ahead in life. Consider this example. If you are trying to reach a destination that is 200 miles away, you will likely chose to drive on an expressway, not a country road. An expressway has a smooth surface that enables you to drive fast. This smooth surface is built on a foundation of rough rock. The smooth surface is like our good experiences and the rough rock is like our bad experiences. If you dwell only on the bad experiences and feel bad, it is like driving on a road made of rough rock. You will get to your destination very slowly. If you dwell only on your good experiences, it is like driving on a very smooth surface that is not built on a solid foundation. Your ride will be smooth for a short distance, but you won’t get far before the road gives out. These good and bad experiences are like birds flying in the sky. Just as we don’t attach much importance to birds flying overhead, we should not gt attached to these good and bad experiences. If not, the birds of good and bad experience will create nests in our subconscious minds. These birds will then lay eggs and these will hatch into thoughts that lead us to seek these experiences over and over again. These thoughts are stored in the subconscious mind for our future consumption. We then start the process of craving for the good experiences while trying to avoid the bad ones, without realizing that they are two sides of the same coin. Repetition of the process of craving for these experiences leads to attachments and disappointments. This then leads to mental disequilibrium, stress and ultimately disease.
