Q: What's this I hear about vitamins to protect against hearing loss? True?
A: Maybe so, but we won't know for sure until researchers confirm that what they've seen in animal studies holds up for humans.
Here's the story: Investigators at the University of Michigan found that giving high doses of vitamins A, C and E plus magnesium to guinea pigs one hour before exposing them to excessive noise was protective. The noise was loud enough to induce hearing loss, and the vitamin and mineral doses were repeated once a day for five days. Hearing loss is associated with prolonged exposure to loud noises - jets taking off, guns firing, even the amplified sounds of music at rock concerts or from your iPod.
The Michigan researchers explained that noise-induced trauma causes the energy-producing mitochondria in the nerve cells of the ear to churn out damaging free radicals. In turn, excessive free radical activity can damage the inner ear, leading to hearing loss. In their study, they compared the effects of three combinations of the vitamins with magnesium and a placebo in guinea pigs. One group got vitamins A, C and E; another got A, C and E plus magnesium; a third got magnesium alone; and a fourth received placebos.
All groups were then exposed to noise as loud as the sound of a jet taking off at close range. The researchers reported that the combination of vitamins A, C and E plus magnesium prevented the damage that leads to hearing loss and hypothesized that the doses taken after noise exposure seem to have "scavenged" the free radicals that continue to form even after noise exposure ends.
If this formula works as well in humans as it did in animals, the Michigan researchers said they envision combining the vitamins and magnesium into a nutrition bar to be given to soldiers for daily hearing protection in war zones.
They also suggested that the nutrition bar could benefit people whose hearing is at risk because they work in noisy environments or frequently attend noisy events, or habitually listen to loud music on their iPods. The Michigan study was published on Feb. 20, 2007, online in the journal Free Radical Biology and Medicine.
The lead researcher is confident enough that the findings will hold up in humans to have launched a startup company to develop the vitamin/magnesium combination.
Q: What are the health benefits of juicing?
A: Juicing can be part of a commitment to healthy living and a good way to increase your intake of fruits and vegetables, but I observe that people either love juicing or can't be bothered with it. If you enjoy juicing and juice products, I encourage you to prepare your own juice. It will taste better and give you more nutrients than store-bought brands.
One reason for the difference is that commercial juice is heat-treated to kill germs, making it safe for storage but altering its taste and lowering its nutritional value.
Home-squeezed citrus juice will retain more of the fruit's inherent health benefits, such as lower levels of inflammation and heart disease. And since it contains some of the pulp from the fruit, you also get some healthful dietary fiber. (On the other hand, juicing raw vegetables removes much of the fiber you need for intestinal health.)
You should be aware of some potential drawbacks of juicing. Home-squeezed juices tend to break down if they remain exposed to air, and pathogens can grow in them just as they can in commercial juices between extraction and consumption.
For that reason, it's important to drink fresh juice soon after you prepare it rather than making several days' supply at once. You should also be aware that if you drink mostly fruit juices, you might be getting more sugar and less fiber than you need. This can cause problems if you are diabetic or have weight issues. In general, I recommend against drinking fruit juice by itself. Instead, drink it along with something with extra fiber, healthy fat or lean protein. Any of these will reduce the glycemic load, moderating the impact on blood sugar. Also consider diluting fruit juices with some purified water.
Readers who wish to ask Dr. Weil a question may do so by visiting his Web site, www.drweil.com.