Friday, April 22, 2011

Sugar and Refined Carbohydrates in Your Diet

Since the 1940s, North Americans have suffered an incredible increase in disease. Today, 70 percent are overweight, 35 percent become diabetic, 40 percent die of heart attacks, and we have very high rates of certain cancers. Major culprits appear to be refined carbohydrates and lack of exercise.

In the late 1940s, Ancel Keys noted the increasing heart attack rate in North America and blamed dietary saturated fats and cholesterol in animal products. John Yudkin in England blamed sugar. At that time, Ancel Keys won the debate and Fred Staire, the chairman of Nutrition at Harvard School of Public Health and a personal friend of mine, wrote that sugar is safe. John Yudkin died discredited in 1997, but today it appears that he was a prophet.

Due to the acceptance of Ancel Keys' views, scientists developed drugs to lower cholesterol and told people to avoid saturated fats. The rate of heart attacks has gone down, primarily because of drugs and a better understanding of what causes them. Yet the incidence of diabetes and obesity keep rising. The culprits appear to be refined carbohydrates, particularly all sugars.

High blood sugar damages every cell in your body. After a person eats refined carbohydrates, particularly any sugared drinks, blood sugar can rise too high. This causes sugar to stick to the outside surface of cell membranes where it is converted by a succession of chemical reactions to sorbitol which destroy the cell to damage every cell in your body to cause blindness, deafness, heart attacks, strokes and all the side effects of diabetes.

Being fat causes high blood sugar levels. Before insulin can do its job of driving sugar into cells, it must first attach on special hooks on cells called insulin receptors. Fat inside cells blocks insulin receptors. Muscle cells full of fat cannot respond to insulin and the sugar remains in the bloodstream. Full fat cells send out hormones that block insulin receptors to prevent insulin from clearing sugar from the bloodstream.

High rises in blood sugar make you fat and cause diabetes.
When blood sugar levels rise too high, the pancreas releases large amounts of insulin. Insulin converts sugar to triglycerides. If you do not burn these triglycerides for energy, they fill fat cells with fat and you gain weight. Full fat cells block insulin receptors so blood sugar rises and you become diabetic.

Exercise helps to prevent diabetes.
Sugar cannot enter resting muscles unless insulin is there to drive the sugar into muscles. However actively contacting muscles can draw sugar from the bloodstream without needing insulin. So during exercise, muscles can remove sugar from the bloodstream to prevent the extra sugar from damaging cells and being converted to fat. It also helps make insulin receptors on cells respond to insulin and push sugar into cells.

You need to exercise every day.
Muscles draw sugar from the bloodstream without insulin only when they are actively contracting or lack oxygen and they can continue drawing sugar without insulin maximally for up to an hour after you finish exercising. They lose all ability to remove sugar without insulin 17 hours after you finish exercising. Since the sugar-lowering benefit of exercise lasts in muscles no more than 17 hours, you must exercise every day to retain this benefit.

The highest rises in blood sugar come from sugar in drinks.
All sugared drinks cause very high rises in blood sugar levels. Orange juice will cause the same high rise in blood sugar as sugared soft drinks. When food enters your stomach, the pyloric sphincter at the end of the stomach closes. Then solid food is converted to a liquid soup that is pumped into the intestines by stomach muscle contractions. An orange can stay in your stomach up to five hours, while orange juice passes immediately into your intestines where it is absorbed, causing a rapid rise in blood sugar.

Foods made from flour also cause high rises in blood sugar.
Grains are seeds of grasses. They have a thick capsule that is so tough that you have to cook them for at least an hour just to make them palatable. Blood sugar barely rises after you eat WHOLE grains. However when you grind whole grains into a powder, the flour that is formed can enter the bloodstream immediately to cause a high rise in blood sugar. So pastas and breads can cause high rises in blood sugar, even if they are made from whole grains.

Diabetics should eat fruits and whole grains, and so should you.

Fruits are full of sugar. However, diabetics who do not eat fruits do very poorly. Everyone should eat fruits and whole grains, even those who are overweight, diabetic, or have high cholesterol levels. Everyone should restrict sugared drinks and flour, particularly if they are overweight, diabetic or have heart problems.

Where does meat fit into this picture?
The saturated fat in red meat has been shown to block insulin receptors and raise blood sugar levels. The monounsaturated fats in fruits, whole grains and vegetables have been shown to unblock insulin receptor.

What's the best way to lower high cholesterol?

The best way to lower cholesterol is to restrict calories. It is far more effective than restricting dietary fat and dietary cholesterol. If you ate nothing but fatty meat and reduced your calories by a third, your cholesterol would drop significantly. The cholesterol that you eat in meat, fish and chicken goes to your liver where it is broken down into 2-carbon units. If you do not have enough calories, these 2-carbon units are burned for energy. On the other hand, if you have lots of extra calories, the 2-carbon units are converted to cholesterol to raise your blood cholesterol level.

What is a healthful diet?
You can eat all the fruits, vegetables, whole grains, beans, seeds and nuts you want. You should restrict all refined carbohydrates made from flour and avoid sugared drinks, except when you are exercising. I believe that you should also avoid red meat; AND you should exercise every day.

Sunday, April 17, 2011

Deep Muscle Soreness after Prolonged, Intense Exercise

You should stop exercising for several days when you feel deep muscle soreness after very long exhaustive exercise such as running a marathon (26 miles), cycling a century (100 miles), going on a very long hike or lifting heavy weights repeatedly for a long time. Prolonged deep muscle soreness after running a long distance very fast is characterized by severe damage to the muscle fibers themselves. The muscle fibers are torn, the cell membranes are ruptured and the internal content of cells leak outside into the surrounding tissue (J Neuro Sci 1983;59:185-203). Of course, you do not need to stop exercising for the mild muscle soreness that you feel after a normal hard workout.

The deep muscle soreness that follows hard running is far less likely to occur in cyclists, swimmers or athletes in other sports because running causes eccentric contractions, while swimming and cycling usually do not. Muscles move your body by pulling on bones when they shorten. However if your sport forces muscles to lengthen when they contract, the severe force on the muscles caused by eccentric contractions (stretching during contraction) tears the fibers and ruptures the membranes. When you run fast, particularly down hills, your thigh muscles try to keep the knee and hip from bending excessively when your heel hits the ground, and they are stretched and torn.

The severe soreness from muscle damage is virtually always reversible, will almost always heal completely without treatment, and is part of the training process. Mild casual exercise does not help you to heal faster, so you might just as well curtail your running for a few days until the soreness lessens. You should not resume intense exercise until the soreness disappears completely.

Highly trained, competitive athletes will recover faster by eating a diet rich in protein and carbohydrates. However, less-conditioned people with muscle soreness will only gain weight if they increase food consumption.

Although many athletes believe that massage, stretching, or cross training help to relieve deep muscle soreness, scientific research has failed to prove that they actually hasten the recovery process.

Tuesday, April 05, 2011

HPV and Cancer

How do you get HPV? You acquire Human Papilloma Virus (HPV) through direct skin to skin contact with an infected person, through vaginal, penile, oral, or anal sexual contact, even if a person has no warts. The more sexual partners you have, the more likely you are to be infected and develop cancers from it. These viruses cause virtually all cases of cervical cancer and many cancers of the skin, vagina, penis, anus, mouth, nose, head and neck. Using condoms helps reduce your chances of becoming infected, but does not offer complete protection. Six million North Americans are newly infected each year, Twenty million are infected now with HPV, and more than 80 percent of sexually-active men and women have been infected.

Types of HPV: More than 150 different HPV viruses have been found, and the ones most likely to cause cancers are types 16, 18, 52 and 59. They are also the ones that persist the longest, and are most likely to cause cancers and abnormal PAP smears.

Can I ever get rid of HPV? Doctors cannot cure HPV, they can only destroy the warts caused by these viruses with chemicals or remove them with surgery. Most infections appear to clear themselves without any treatment (Am J of Ob and Gyn, 2000;183(3): 561-567). DNA tests of HPV show that 70 percent of women clear HPV infections within one year, and only nine percent continue to be infected after two years (NEJM, 1998;338(7):423-428). A summary of several studies shows that 90 percent of HPV tests become negative in about two years. The current theory is that you become infected with HPV through sexual contact and it can disappear without treatment, as cultures fail to find it. We do not know if the virus really goes away, but we often cannot find it. However some people never clear the high-risk HPV types and it is the persistent infections that can lead to cancers (Trends in Microbiology, 2011(Jan);19(1):33-39). Each additional sexual exposure increases your chances of acquiring additional HPV viruses and the specific viruses that cause cancer. You can have several different HPV virus types at the same time. Infected people who continue to have the most sexual contacts are the ones most likely to continue to be infected with HPV, as each new exposure carries risk for a new infection.

How long does it take for the virus to become undetectable? The average time for a person who has acquired HPV to have the virus unavailable for culture is six months. However, those with high risk HPV 16 and 18 took an average of almost eight months for the virus to become non-detectable. Again, we do not know if it really goes away.

Does having the virus cause abnormal pap smears? Most women who are infected with HPV will not develop a positive PAP test.

Immunization: Immunization protects you from infection with the viruses in that vaccine. It does not protect you from the many viruses not in the vaccine. High risk HPV subtypes are associated with almost all cervical cancers. Available HPV vaccines contain high risk HPVs 16 and 18.