Tuesday, May 27, 2008

Fewer Omega-6's May Reduce Cancer Risk

Researchers at UCLA show that reducing intake of corn oils helps to prevent prostate cancer in mice (Cancer Research, April 15, 2008). Corn oil and other vegetable oils are extremely rich sources of omega-6 fatty acids.

Fats are classified by their chemical structure into omega-3s, omega-6s, and omega-9s. Omega-6s cause your body to produce prostaglandins that turn on your immunity to cause inflammation, while omega-3s turn down your immunity to reduce inflammation.

Your immunity is supposed to be good for you. When a germ enters your body, your immunity produces white blood cells and proteins called antibodies that attack and kill the germ. After that germ is gone, your immunity is supposed to stop making so many immune cells and proteins. If it remains active, your immunity attacks your own body to damage tissue and increase risk for heart attacks, certain cancers, and diabetes; it can also worsen existing diseases such as some types of dementia, asthma or psoriasis.

For more than 2 million years, humans have eaten diets that have a ratio of omega-6s to omega-3s of about two to one. However, over the last 100 years, humans have added extracted vegetable oils to other foods that they eat and increased the ratio to 12 to one and perhaps as high as 20 to one. This increase in the ratio of omega-6s to omega-3s is a cause of inflammation. The increase in omega-6's has come primarily from vegetable oils that are added to baked, fried and other prepared foods. Omega-3s oils are relatively unstable so they are not found in most prepared foods.

Good food sources of omega-3's include seafood and beans, whole grains, nuts and other seeds. We do not know if changing the ratio of omega-6s to omega-3s will help to prevent cancers in humans, but several studies show that they appear to both prevent and slow cancers in animals.
More on omega-3s and omega-6s

Thursday, May 22, 2008

Breast Cancer Risk Lower with Exercise

A recent study from Washington University School of Medicine in St. Louis shows that exercise starting during adolescence can protect girls from breast cancer (Journal of the National Cancer Institute, May 2008). Researchers tracked 65,000 nurses who answered questionnaires about exercise. Within six years, 550 were diagnosed with breast cancer before menopause. Those who exercised regularly as teens were 23 percent less likely to develop premenopausal breast cancer than their sedentary peers. Ages 12 to 22 appear to be the most important time to use exercise to help prevent breast cancer.

Higher estrogen levels increase risk of breast cancer. Exercise lowers estrogen by reducing body fat. Fat cells make estrogen, and after the menopause fat cells are the principal source of estrogen. Other factors that increase breast cancer risk are also related to higher estrogen levels: starting to menstruate at an early age, late onset of menopause, taking estrogen after menopause, and being overweight.

Wednesday, May 21, 2008

Kidney function improved by exercise

We already know that exercise helps to prevent heart attacks, strokes, diabetes, obesity and certain cancers, and may extend life span. Now a report from Italy shows that exercise may also help to prevent kidney damage that occurs with aging (Clinical Journal of Sport Medicine, May 2008).

Doctors measure kidney function by calculating the ability of the kidneys to rid the body of a breakdown product of metabolism called creatinine. Regular exercisers have lower blood creatinine levels and also have kidneys that are better able to clear creatinine from the bloodstream as measured by a test called Glomerular Filtration Rate (GFR).

According to this study, professional bicycle racers have better kidney function than both sedentary people and recreational cyclists. This is very interesting because professional cyclists dehydrate themselves with almost every workout, in spite of the huge amount of fluid they consume. The researchers found that frequent dehydration accompanied by drinking large amounts of water did not cause kidney damage. This repeated stress on the kidneys may even explain why the professional cyclists had better kidney function than the less-active participants.
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Sunday, May 18, 2008

Ibuprofen reduces risk of Alzheimer's

Researchers at Boston University School of Medicine followed 250,000 veterans over the age of 55 years and showed that taking ibuprofen for five years was associated with a 40 percent reduction in the development of Alzheimer's disease (Neurology, May 2008).

Alzheimer's disease is associated with the deposition of tangled webs of protein in the brain. Several previous studies show that ibuprofen reduces these protein deposits in the brains of animals. A leading theory on the cause of Alzheimer's disease is that a person's immunity attacks the brain to cause dementia. Ibuprofin reduces inflammation, the body's response to an overactive immunity. Another study in the same issue of Neurology showed people that with shorter arms and legs may be at a higher risk for developing dementia later in life. More on preventing dementia

Thursday, May 15, 2008

Smoking Bans DO Reduce Teen Smoking

Teenagers who live in cities or towns with strict smoking bans are 40 percent less likely to become regular smokers, according to a study published in the Archives of Pediatrics & Adolescent Medicine (May 2008). The study also reported that youths with smoking parents or friends are at high risk for smoking themselves, but strong smoking bans in restaurants reduce the chance that they will become smokers.

Massachusetts passed a workplace smoking ban that included restaurants in 2004. Since then, high school smoking rates in Massachusetts have dropped from 21percent of students in 2005 to 18 percent in 2007. At least 23 states, the District of Columbia and Puerto Rico now require most public places and workplaces, including restaurants and bars, to be smoke free.
Fitness and health newsletter

Wednesday, May 14, 2008

Progesterone helps to prevent uterine cancer

They're supposed to prevent pregnancy, and they do, but intrauterine devices (IUDs) also reduce uterine cancer risk by more than 40 percent (Meeting of the American College of Obstetricians and Gynecologists, May 6, 2008).

An IUD is a small, T-shaped plastic device inserted into the uterus. Only two percent of women who use contraception in the United States choose an IUD, despite the proven safety and effectiveness of this long-term method. Worldwide, however, IUDs are the most widely used reversible contraceptive. Most IUD's prevent pregnancy by releasing small amounts of the hormone progesterone into the uterus. This is also why they help to prevent uterine cancer.

The ovaries of healthy women are supposed to produce two hormones: estrogen and progesterone. Many women lack progesterone and they are the women who are at increased risk for uterine cancer. Estrogen stimulates the uterus to grow, and progesterone stops the stimulation. If a woman has estrogen and no progesterone, her uterus is stimulated all the time, which can lead to uncontrolled growth which is cancer.

The woman most likely to get uterine cancer has high blood levels of insulin. Insulin acts directly on the ovaries to stop them from releasing eggs. Women who do not release eggs have no progesterone and therefore are at high risk for uterine cancer. A woman can find out if she has high insulin levels just by getting a blood test, called C peptide, that measures insulin production by the body. If it is above 3, her body makes too much insulin.

However, you can usually tell if a woman has too much insulin just by looking at her. Insulin causes a person to lay down fat primarily in the belly. Women with big bellies and small hips usually have high insulin levels and are also at high risk for diabetes. Most people who will develop diabetes usually stop responding to insulin. This causes the pancreas to release increasing amounts of insulin, until the pancreas eventually dies and then the person must take insulin.

If you are a woman who stores fat primarily in your belly, you should get blood tests called C peptideand HBA1C to see if you are already diabetic. You can also tell if you are pre-diabetic if your good HDL cholesterol is low, your triglycerides are high, or your liver shows excessive amounts of fat. Start a supervised exercise program, lose weight, and restrict refined carbohydrates. You may also want to see if your doctor advises using an IUD to help prevent uterine cancer.
More on Polycystic Ovary Syndrome (PCOS)

Monday, May 12, 2008

How Vitamin Pills May Affect Lifespan

The issue of vitamin supplements is far from settled. Most doctors take multivitamins themselves and recommend them to their patients. However, I continue to believe that it is better to get vitamins in whole foods than in pills.

Most vitamins are parts of enzymes that start chemical reactions in your body. Each chemical reaction produces end products that are changed by further chemical reactions from other vitamins to other products that benefit your body. When you take a vitamin that has been isolated from the hundreds of other substances found in foods, that enzyme causes a chemical reaction that accumulates a disproportionate amount of its end products. If the substance that acts as an enzyme for the next chain of chemical reactions is not available, you can accumulate end products that may be harmful.

For example, people who take niacin to lower cholesterol show a marked elevation of homocysteine, a major risk factor for heart attacks. Homocysteine levels are raised by a deficiency of B12, folic acid and pyridoxine. When you eat your niacin in whole grains, all of those components are present, along with many others whose functions we may not yet understand.

The study I mentioned in the previous post is in Cochrane Database of Systematic Reviews More

Friday, May 09, 2008

Prevent Injuries: Background Before Peaking

Injuries often occur when people start a new exercise program, change to a different sport, or return to exercise after a long break. In the enthusiasm to get started, it is easy to overstress muscles that have not been used before. That's why "background before peaking" is one of the most important principles of training. It takes several weeks or even months to build up strength and endurance for any new sport.

Competitive athletes in all sports use this principle. First they spend many months in background training, working out for long hours, mostly at low intensity, followed by a shorter period of peak training in which they do far less work, but at a much greater intensity. A few months before an important race, they reduce their workload but go as fast and hard as possible two or three times a week.

Start your new exercise program at very low intensity and low volume. Gradually increase your workload for several months before you try to run fast, lift heavy or exercise intensely. If you are just beginning to exercise, go at a relaxed pace until your muscles feel heavy and then stop. For the first several days or weeks you may be able to exercise only for a few minutes at a time. If your muscles feel sore the next day, take the day off. Increase the amount of time gradually until you can exercise 30 minutes a day at a relaxed pace and not feel sore. You may progress rapidly to the 30-minute goal, or it may take you two, four, six weeks or more. No matter how long it takes, don't get discouraged. Exercising too much or too hard, too soon will set you up for injuries. More

Thursday, May 01, 2008

Weight Lifting Past Fatigue Does Not Strengthen Muscles More

When you want to become very strong, you try to lift very heavy weights. Weight lifters have known for a long time that you don't pick up the heaviest weight you can move, raise it once and then quit for the day. They do their weightlifting in sets. For example, they lift and lower a weight in three sets of ten or one set of six.

If you exhaust your muscles by bench pressing a weight for three sets of ten, is there any benefit to try to do another set? Researchers from Australia showed that you gain nothing if you force extra lifts after your muscles are exhausted (Journal of Strength and Conditioning Research, August 2007). This study should serve as a warning particularly to young lifters. Plan your workouts. When your muscles are tired or sore, don't try to keep on lifting through the soreness. After a hard workout, go easy for as many days as it takes for your muscles to feel fresh again. More