Sunday, March 29, 2009

Understanding Antioxidants


Antioxidants are named for their ability to prevent a chemical reaction called oxidation, which enables molecular fragments called free radicals to join together, forming potentially carcinogenic (cancer-causing) compounds in your body.
Antioxidants also slow the normal wear-and-tear on body cells, so some researchers noted that a diet rich in plant foods (fruits, vegetables, grains, and beans) seems likely to reduce the risk of heart disease and maybe reduce the risk of some kinds of cancer. For example, consuming lots of lycopene (the red carotenoid in tomatoes) has been linked to a lower risk of prostate cancer — as long as the tomatoes are mixed with a dab of oil, which makes the lycopene easy to absorb.
However (you knew this was coming, right?), recent studies show that although a diet rich in fruits and veggies is healthful as all get-out, stuffing yourself with the antioxidant vitamins A and C has ab-so-lute-ly no effect on the risk of heart disease.

Phytochemicals Are Everywhere


Did you take French literature in high school or college? If your answer is no, you may as well skip to the third sentence in the paragraph that follows. But if your answer’s yes, then you’re probably familiar with Molière’s The Bourgeois Gentleman. The bourgeois gentleman is a lovable but pompous character who’s surprised to discover he’s been speaking prose all his life without knowing it.
Your relationship with phytochemicals is probably something like that. You’ve been eating them all your life without knowing it. The following are all phytochemicals:
  • Carotenoids, the pigments that make fruits and vegetables orange, red, and yellow (dark green vegetables and fruits like kiwi contain these pigments, too, but green chlorophyll masks the carotenoids’ colors)
  • Thiocyanates, the smelly sulfur compounds that make you turn up your nose at the aroma of boiling cabbage
  • Daidzein and genistein, hormonelike compounds in many fruits and vegetables
  • Dietary fiber
These and other phytochemicals, such as vitamins (yes, vitamins), perform beneficial housekeeping chores in your body. They
  • Keep your cells healthy
  • Help prevent the formation of carcinogens (cancer-producing substances)
  • Reduce cholesterol levels
  • Help move food through your intestinal tract
The undeniable value of phytochemicals is one reason the U.S. Department of Agriculture/Health and Human Services Dietary Guidelines for Americans urges you to have at least five servings of fruits and vegetables and several servings of grains every day.
Did you notice that no minerals appear in the list of phytochemicals? The omission is deliberate. Plants don’t manufacture minerals; they absorb them from the soil. Therefore, minerals aren’t phytochemicals.

Wow — You think that was a hot flash?


Then you need extra calcium. Both men and women produce the sex hormones testosterone and estrogen, although men make proportionately more testosterone and women, more estrogen. Testosterone builds bone; estrogen preserves it.
At menopause, a woman’s production of estrogen drops precipitously, and her bones rapidly become less dense. As men age and their testosterone levels drop, they’re also at risk of losing bone tissue, but the loss is less rapid and dramatic than a woman’s.
For both men and woman, severe loss of bone density can lead to osteoporosis and an increased risk of bone fractures, a condition more common among women of Caucasian and Asian ancestry. Estrogen supplements can help a woman maintain bone tissue, but taking the hormone may have serious side effects, including an increased risk of breast cancer. Twenty years ago, nutritionists thought it impossible to stop age-related loss of bone density — that your body ceased to absorb calcium when you passed your mid-20s. Today, medications such as alendronate (Fosamax) protect an aging woman’s bones without estrogen’s potentially harmful effects. Increasing your consumption of calcium plus vitamin D may also be helpful, regardless of your gender. But the most recent studies says the value of extra calcium may not be as high as once believed. What can I say? Stay tuned for more on this one.