Dr. Arthur C. Guyton died in an automobile accident on April 3, 2003. He was 83. Among his many accomplishments, two stand out. He was the father of ten Harvard educated doctors, and he proved that the kidneys are the long-term controllers of blood pressure. It is the second of these that is relevant to the subject of this article. His discovery of the kidneys' role in high blood pressure has been confirmed by kidney transplant experiments. When kidneys from rats with high blood pressure are transplanted into rats with normal blood pressure, the rats receiving the transplanted kidneys also develop high blood pressure. On the other hand, when kidneys from rats with normal blood pressure are transplanted into hypertensive rats, the hypertensive rats develop normal blood pressure. The same effect has been observed in humans. When a good kidney is transplanted into a person with severe kidney disease and high blood pressure, the blood pressure often returns to normal.
There are two types of fatty liver: alcoholic fatty liver and non-alcoholic fatty liver. Alcoholic fatty liver is the first of three stages of alcoholic liver disease - alcoholic fatty liver, alcoholic hepatitis, and al coholic cirrhosis. Fatty liver is simply the accumulation of large amounts of fat in liver cells. Alcoholic hepatitis is the inflammation of the liver due to the toxic effects of alcohol. Alcoholic cirrhosis is irreversible scarring and loss of liver tissue due to alcohol. The medical term for fatty liver is steatosis. When inflammation occurs with fatty liver, the condition is called steato-hepatitis. The association between fat accumulation in the liver and alcohol has been recognized for centuries. However, it was not until 1980 that the term nonalcoholic steatohepatitis, or NASH, was coined to describe a condition of fatty liver inflammation occurring in people who drink little or no alcohol. The risk or causative factors for NASH are obesity, diabetes, elevated levels of triglycerides and cholesterol, rapid weight loss, starvation, steroids, estrogen, certain drugs, and weight-reduction surgery. Symptoms of fatty liver are usually nonspecific, such as fatigue and weakness and sometimes upper abdominal pain or discomfort over the area of the liver and a feeling of fullness or bloating in that area. This may be due to the stretching of the liver with fat.
The Effect of the Liver on the Kidneys
Damage to the largest filtering organ of the body, the liver, puts a great deal of stress on the body's other major filtering organs, the kidneys. Many kidney disorders have been associated with cirrhosis. The most serious of these is known as hepatorenal syndrome. Hepatorenal syndrome i s kidney failure in people with severe end-stage cirrhosis of the liver, but with no other known cause of kidney failure. In fact, the kidneys themselves are inherently normal. This is dramatically evident when the same kidneys are transplanted into a normal body. They then function well. It is the diseased liver that causes the kidneys to fail. This is again dramatically confirmed by a transplant operation. If a person with hepatorenal syndrome receives a liver transplant, his kidney function will often return to normal.
The Liver and High Blood Pressure
In hepatorenal syndrome, severe liver disease causes severe kidney dysfunction. It is plausible, therefore, that liver disease of whatever degree could impact on kidney function to the same degree. Since the kidneys control blood pressure, whatever affects the kidneys will also affect blood pressure. If the liver affects the kidneys, then damage to the liver can cause damage to the kidneys and, therefore, raise blood pressure. This connection might explain why alcohol, obesity, diabetes, high cholesterol and sugar are risk factors for high blood pressure. They are all also risk factors for fatty liver, the first stage of liver disease.
Fatty liver is revesible. If someone has high blood pressure, and fatty liver is the cause, then life style changes that reverse fatty liver should lower blood pressure. These life style changes would involve reduction or elimination of alcohol, reduction or elimination of refined suga r, weight loss, control of type 2 diabetes and lowering of cholesterol levels through changes in habits of eating and exercise. Initiating such changes can increase your chances of living to a ripe old age like Dr. Guyton and perhaps even longer. However, it will probably not increase your chances of fathering 10 Harvard-educated doctors.
Mary Lou Williams, M. Ed., is a lecturer and writer in the field of nutrition. She welcomes inquiries. She can be reached at (239) 267-64880.