source: http://www.menshealth.com/mhlists/self_repairing_body/printer.php

Your Arteries
Your Bones
Your Liver
Your Guts
Your Brain
Your Lungs
If humans were like salamanders, that careless
carpenter down the street would have a full
set of fingers. But soon after our primordial
ancestors slithered out of the muck, limb
regenesis was chucked out of our genetic
portfolio like John Bobbitt's . . . well, you get
the picture. The good news: Our bodies still
retain some important repair mechanisms.
"Regeneration is actually a default state when
we're embryos," says David L. Stocum, Ph.D., a
regenesis researcher and dean of the school of
science at Indiana University-Purdue University
in Indianapolis. "We gradually lose that ability
as we develop—except in certain kinds of
tissues."
The holdouts? Your arteries, skin, liver, lungs,
and digestive tract, and certain parts of your
brain. They're all continually refreshed—if
you're healthy. "It's called maintenance
regeneration. It's kind of like working on your
car," says Stocum. "You've got something
going on—you're low on oil, you buy a quart. A
taillight goes out, you replace it. The clutch is
acting up, you fix it. It's the same thing with
your body."
(A few parts—including the liver and severed
bits of fingertips—can even grow back. Studies
suggest that adult stem cells in those areas
play a role.)
Make sure your body has all the tools and
parts it needs for a tune-up. Sometimes it's as
simple as revving your engine. Here's how to
mend broken bones, bypass clogged arteries,
sprout new brain cells, and more—by
optimizing your body's regenerative powers.

The damage:
Narrowing blood vessels.
The natural defense:
When your pipes start to clog like I-405 at
rush hour, a healthy body can handle the
traffic by enlarging existing arteries and even
growing new ones. It's a natural process called
angiogenesis, and here's how it works.
Links between blood vessels, called arterial
anastomoses, normally supply local tissues
with blood, like exit ramps shunting traffic
away from expressways. These exit ramps can
be pressed into service as full-fledged arteries.
"The cells in the vessel are able to detect when
stress is increased, and that prompts signals
that enlarge the anastomoses," explains Ronald
L. Terjung, Ph.D., associate chairman of the
University of Missouri's department of
biomedical sciences. "Blood can cross over (to
an unclogged vessel) and keep going."
What you can do:
First, clean your pipes. Cholesterol can hinder
the repair process. Researchers at Harvard
medical school compared tissues from two
groups of open-heart patients—one group with
clogged vessels and the other with clear ones—
and found that the clogged blood vessels
weren't able to respond to growth signals.
"Angiogenesis can't occur if the cells in the
blood vessel are damaged or blocked by
cholesterol," says author Roger J. Laham, M.D.,
director of the Angiogenesis Research Center at
Harvard medical school. So keep your
cholesterol low.
Make your own detours by running, swimming,
shooting hoops—whatever it takes to get your
blood pumping. A 2004 study published in the
journal BMC Physiology found that endostatin,
a factor involved in arterial growth, shot up by
an average of 73 percent in healthy volunteers
after about 10 minutes on a treadmill at an
average of 5 mph. Even better: The effects
lingered for up to 2 hours, and the harder the
subjects worked, the more endostatin was
released.
An injection may one day help. Scientists at the
University of Cincinnati injected three heart
patients with something called "growth factor
FGF1," the "on" switch for arterial growth.
After 3 months, all three were growing new
arteries and had increased bloodflow. "They're
very, very small branches of arteries that are
growing into an area just like a bush. They're
almost microscopic," says Lynne Wagoner,
M.D., the lead study author. "Some patients
are able to do this naturally on their own, but
in the patients we're studying, we're basically
doing that for them." The treatment is slated
for approval in 2006.

The damage:

A broken bone.
The natural defense:
"The healing response is generated by the
living parts of the bone, the cells that live
within the matrix," says Sherwin S.W. Ho,
M.D., an associate professor of orthopedic
surgery at the University of Chicago. No,
Keanu, healing faster isn't a matter of choosing
the red or blue pill. The matrix Dr. Ho is
talking about is the lightweight but durable
calcium carbonate structure that makes up
most of your bone. Inside little pockets in the
matrix are living cells, including bone-building
osteocytes. "When you break a bone, they're
released from the pockets," explains Dr. Ho.

What you can do:
Eat your greens. They'll give you loads of
vitamin K, a compound that helps lock bone
cells into place as they lay down new
scaffolding. One serving of spinach or broccoli
provides more than the recommended intake.
And break out the guacamole—avocados and
tomatoes are good sources of vitamin K, too.
Never heard of vitamin K? No surprise: Less
than 50 percent of all men ages 18 to 44 get
enough of it, researchers at Tufts University
found.

Don't take it lying down. A busted bone isn't a
6-month excuse to sit on your butt. "At some
point, you have to introduce a modicum of
stress on the bone to stimulate those
osteocytes to lay down more bone," says Dr.
Ho. Most breaks are ready for light stress at 6
weeks. Initially, Dr. Ho gives his patients
squeeze balls and a regimen of light curls for
arm breaks, and crutches for leg breaks.
"Once you're ready for heavier exercise, you
should do a couple of sets of 15 to 20
repetitions per day at the highest resistance
you can complete without pain," says Dr. Ho.
Go ultra. If you're a competitive ice-skater,
power forward, or stripper and need to get
back on the floor immediately, consider an
ultrasound bone-healing system like the
Exogen, which has been shown to help bones
heal as much as 38 percent faster. Some
insurance plans will cover sessions.

The damage:
Years of drinking. Or just a binge.
The natural defense:
Your liver is one of the only organs that can
spring back after part of its tissue dies (the
process is called compensatory hypertrophy).
But that's only if you don't booze it to the
point of cirrhosis, a chronic liver disease in
which normal liver tissue is replaced with
scarred, nonfunctional tissue. "People who are
at risk consume more than 14 drinks a week or
regularly have more than five at a time," says
Mark Mailliard, M.D., director of the hepatitis
C program at the University of Nebraska.

What you can do:
Balance your liver. It's really just a sponge full
of chemicals, and a compound called
glutathione (GSH) helps keep everything in
check. Not only does GSH detoxify things like
Tylenol (which is why alcoholics should never
pop one while drinking—the by-product is
toxic), but it's also essential for liver
regeneration. Rats unable to create GSH are
also unable to grow back liver tissue, a
University of Southern California study found.
"We're not sure how it works. That's the black
box," says Shelly Lu, M.D., the lead author of
the study. "We know it helps with cell growth,
and we know it's involved in cell death, too."
Dr. Lu also knows that popping SAM-e—a
supplement that converts to glutathione in the
liver—can bring your GSH levels back to
normal. In Europe, where SAM-e is actually
prescribed for liver disease, the standard
dosage is 1.2 grams (g), or about three tablets,
per day. "If you're a drinking man, you should
also be taking folic acid and a B-vitamin
complex, because they're essential in the
formation of SAM-e and glutathione," adds Dr.
Lu.

The damage:
Intestinal distress—there's a five-alarm fire
down below.

The natural defense:
Torch your gut with booze, barbecue, or both,
and the lining of the intestine will simply
slough it off. Cells there have one of the
fastest cellular turnover rates in the body—
each one clocks out after only a couple of
days of (very, very dirty) work, making room
for a new one.

What you can do:
Rough it and you'll speed up the changing of
the intestinal guard. "Having some roughage in
your diet helps knock off a few of the older
cells, almost like pruning a tree," says Kenneth
Koch, M.D., a professor of internal medicine
and chief of gastroenterology at Wake Forest
University school of medicine. Aim for 25 to
30 g fiber a day, starting with a whole-grain
breakfast cereal, followed by whole-grain
bread at lunch and lots of fruits and vegetables
all day long. Dr. Koch recommends foods
containing bran because they produce the
most "stool bulk." Delicious!

The damage:
You scorched your gray matter in ways you
can't even remember.
The natural defense:
For years, it was thought that we stopped
making fresh neurons in puberty, meaning that
sometime in high school a long die-off of brain
cells commenced. Turns out it only seems that
way. "The brain is just another organ," says
Fred H. Gage, Ph.D., a professor in the
laboratory of genetics at the Salk Institute and
the first researcher to demonstrate new
neuronal growth in mammals. "The brain is
attempting to fix itself, just as skin tries to heal
itself after a nick or cut."

What you can do:
Work your body. Animal studies have shown
that exercise can induce neurogenesis (the
formation of new neurons) in two key areas of
the brain: the hypothalamus, which helps form
new memories and learning; and the olfactory
bulb, where your sense of smell is located. The
studies were done on rats, but what's good for
a rodent should be good for your brain: Try to
get at least 30 minutes of exercise 2 or 3 days
a week.

The damage:
Bad air, from smoke or smog, has clogged
your air-exchange system.
The natural defense:
The lungs come equipped with a self-cleaning
cycle, but overloading them with smoke or
smog will gunk up the works. The cilia, or
hairlike structures in your lungs, flagellate
(that's move) upward, coaxing the bad stuff
out of the alveoli (little air sacs) and into the
trachea, where the gunk grows into a
frightening reminder of why you should have
been better to your lungs to begin with. "It's
like a mucus escalator," says Norman Edelman,
M.D., a scientific advisor to the American Lung
Association. "That's a major form of defense.
Within a few days to a week (after quitting
smoking], you start feeling better, and you
start coughing up all that bad mucus you have
down there."
What you can do:
Exercise will help loosen the large chunks after
you first come clean. But you should be
exercising already. Retinoic acid, or vitamin A,
could actually help your lungs rebuild. Rats
and mice with emphysema (they smoked tiny
little cigarettes) given the compound were able
to restore alveoli, which swap carbon dioxide
for fresh oxygen to pre-emphysema levels,
according to a recent study published in the
European Respiration Journal. You'll get several
times the recommended daily allowance (900
micrograms) in only one serving of carrots,
sweet potatoes, or mango.