Early exercise may lower cancer risk


January 18, 1994|By Dr. Gabe Mirkin | Dr. Gabe Mirkin,Contributing Writer United Features Syndicate

Recent research shows that starting an exercise program at a young age may help to prevent breast cancer in women. In 1840, the average woman started to menstruate at age 16.5. Now, 150 years later, she starts to menstruate at age 12.9. That's a decrease of more than 3 months per decade over the last century and a half.

This earlier start of menstruation is probably caused by the extra calories women take in and do not burn. After all, over the last 150 years, modern conveniences and mass production of food have helped women exercise less and eat more. The extra calories are associated with an increased risk of developing breast cancer. With one in every eight women having a chance of developing breast cancer during her life, anything that will help protect women from that dread disease will be welcome.

Studies at the University of Warwick in England show that over the last 10 years, the trend has reversed and young women are starting to menstruate at an older age again.

A report in the British journal Lancet speculated that later onset of menstruation may be caused by the current mass participation of young women insports. Girls who participate in vigorous exercise in their early years start to menstruate much later than those who do not exercise. Each year of physical training before puberty delays the onset of menstruation by five months. Perhaps, this increased interest in sports participation at a young age also will help to reverse the marked increase in the incidence of breast cancer over the last 150 years.


Q: My body-building friends all take "glandulars." Do these pills really build larger muscles?

A: You're right to be skeptical. Many health food stores sell glandulars, which are made from animal tissue. They are supposed to replace the same type of tissue in your body. For example, eating the muscle tissue of animals is supposed to replace muscle damaged by hard exercise so an athlete can recover faster from a workout. This is nonsense. Anything you eat will be absorbed into your body only after it is broken down into its basic structural material. The meat you eat is muscle made up of protein, which must be broken down into its building blocks -- amino acids -- before it can get into your bloodstream. Then your body assembles the amino acids to make protein for its own use.

The amino acids in muscle are the same as those in brain, kidney, or any other tissue. The amino acid, lysine, is the same whether it comes from an animal's muscle, brain, red blood cell or kidney. Your body can't tell whether lysine came from a cow, corn, beans, worms or fish.

Q: My doctor says my homocysteine level is high. Should I be concerned? If so, what should I do?

A: One established risk factor for suffering a heart attack is having high blood levels of homocysteine. The vitamins folic acid, pyridoxine and B-12 help to clear homocysteine from your blood. When you don't meet your needs for even one of these vitamins, homocysteine levels rise, increasing blood cholesterol levels which can cause heart attacks.

Eating fruits, vegetables and whole grain cereals provides ample amounts of folic acid and pyridoxine. Fish, meat, chicken, eggs and dairy products provide vitamin B-12.

Older people are far more likely than younger people to have low blood levels of pyridoxine, folic acid and B-12 and to have high blood levels of homocysteine. As you age, you gradually lose your sense of taste and smell, enjoy eating less and actually do eat less.

Older people eat fewer fruits and vegetables and have a decreased capacity to absorb vitamin B-12 from their intestines. Everyone should eat lots of fruits, vegetables and whole grains, and older people need them even more than younger people do. You may want to take vitamin supplements as well, but vitamins are not a substitute for a healthy diet.

Dr. Mirkin is a practicing physician in Silver Spring specializing in sports medicine and nutrition.

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