Heartburn

The scourge of teenaged life acne may result from the very diet that feeds it, suggests a new study that flies in the face of three decades worth of conventional thinking on the cause of facial blemishes.

Editor’s Note: Food Pyramid Replaced

In June 2011, the USDA replaced the food pyramid with a new plate icon.

© 2011 WebMD, LLC. All rights reserved.

And this time, it’s not just isolated items such as chocolate or pizza being implicated. It’s the entire typical western diet, a gamut of highly refined starchy and sugary foods that not only includes those “junk” foods but also the very breads, cereals, and carbohydrates that are the cornerstone of the USDA Food Pyramid.

The theory, reported in the December issue of Archives of Dermatology: Most staples in the American diet are high-glycemic foods those that tend to spike blood sugar levels and have already been implicated in increasing risk of diabetes, obesity, cholesterol, and other health conditions.

But they also cause acne, says Loren Cordain, PhD, a Colorado State University health and exercise scientist and lead researcher of the study. He says these foods cause acne by triggering a “hormonal cascade”: By raising levels of insulin and insulin-like growth factor (IGF-1), more male hormone testosterone is produced, which leads to overproduction of more sebum the greasy gunk that blocks pores and triggers acne. Researchers have long known that elevated testosterone levels does trigger acne.

“If you eat grains, drink milk, or have any processed foods, you essentially have a high-glycemic load diet,” Cordain tells WebMD. “About 85% of the grains in the western diet are refined and highly glycemic. Half of the total per capita calorie intake in this country is high glycemic load foods. It’s a universal manifestation of western foods.”

But why are teens most likely to wear the battle scars of a national diet consumed by those of all ages? “Because the teenaged years are a time of natural insulin resistance,” Cordain explains. “The teens are growth years; for tissues to grow, they become insulin resistant.”

In the U.S., acne plagues up to 95% of teens and about half of adults under age 40. Yet some primitive populations eating all-natural foods are virtually pimple-free, says Cordain. His international team of researchers studied 1,200 people (including 300 teens) in New Guinea and 115 (with 15 teens) in remote Paraguay and couldn’t detect a single zit in two years of study. These people only eat what they hunt, gather, or grow themselves fruit, vegetables, seafood, and lean meats and no refined foods.

“We then looked at other studies that examined incidents of acne in similar populations South Americans and New Guineans now living in westernized settings,” he tells WebMD. “We found that when they become more westernized and start eating like Americans, they do develop acne,” he notes. “So it’s not genetics.”

Doctors have long known that many functions
of human vision decline with age, but the reasons for this are not so clear. A
study published in the April edition of Nature Neuroscience indicates
that age-related changes in the visual cortex, the part of the brain where
visual information is processed, may bear part of the blame.

“Amazingly, no one before has looked at single cells in the aged
higher-order primates to see if the visual cortex also deteriorates with
age,” study author Matthew T. Schmolesky tells WebMD. “We have found
evidence of changes in the primary visual center of the brain that we think
may, in part, underlie decreased speed and accuracy in recognizing the shape
and motion of an object,” says Schmolesky, a doctoral candidate in the
department of neuroscience at the University of Utah.

A large majority of the cells in the visual cortex of young monkeys are
known to respond to the orientation of an object. In older monkeys, the study
found, the percentage of cells that are sensitive to orientation is less than
half that in younger animals. This means that these monkeys might be less
capable of recognizing shapes.

In human terms, that could mean you don’t recognize something as quickly or
might mistake it for something else. In activities such as driving, where a lot
of information is coming at once, you might make more mistakes or take longer
to recognize a problem.

The researchers studied neurons, or nerve cells, in four young monkeys and
four older ones. The monkeys were given an anesthetic, and probes were placed
in their brains to measure how often the neurons in the area that controls
vision fired when presented with a certain type of stimulation. The cells’
ability to respond selectively to the way a line or bar was aligned (the
“orientation bias”) or to the direction of its movement (“direction
bias”) was determined. In older monkeys, about 42% of the neurons showed
significant orientation bias, compared to 90% for the younger ones.

Similarly, the percentage of cells that were strongly biased for direction
was lower in the aged monkeys. The older animals’ cells appeared to respond to
all stimuli, which means that they were working randomly. This led the authors
to suggest that the cells’ decreased selectivity may be due to age-related
changes in control of these cells in the brain.

“There are literally thousands of articles about what goes on in the
aging eye, but we have spent very little time looking at the brain,” says
Schmolesky. “We also think that many of these same degenerative processes
occur in other [brain] areas, including those responsible for hearing and touch
perception.” If researchers continue to study the aging central nervous
system, he says, they may find the reasons for these study results and can then
start targeting the declining processes for intervention.

“We have ample evidence that not all visual deficits are related to
optics of the eye, such as cataracts blurring the lens,” says James N. Ver
Hoeve, PhD, who reviewed the study for WebMD. Ver Hoeve is senior scientist and
director, electrodiagnostic service, in the department of ophthalmology and
visual sciences at the University of Wisconsin-Madison. But “this is the
first article that suggests it is the cells of the visual cortex that are
affected by aging and not just the optics,” he says.

There have been many studies of the relationship between intake of antioxidant vitamins, thought to reduce damage in the body from everyday living and unhealthy habits, and the risk for cataracts. Some have produced conflicting findings. A new study in the March edition of the journal Ophthalmology suggests that certain vitamins may reduce the risk for some types of cataracts. Intake of polyunsaturated fat, protein, or spinach may also be helpful.

A cataract is a cloudy or opaque area on the normally clear lens of the eye. The three kinds of cataracts are usually described by their location on the lens. The most common type, usually associated with aging, is the nuclear cataract that occurs in the center of the lens. The cortical cataract, most often seen in people with diabetes, begins as wedge-shaped spokes at the outer edges of the lens and progresses as the spokes move toward the center. The subcapsular kind develops slowly from a small opaque area, usually at the back of the lens.

“The Blue Mountains Eye Study was set up in 1992 to study the causes of the common eye diseases that affect older people: cataract, macular degeneration, and glaucoma,” says lead author Robert G. Cumming, PhD, in an interview with WebMD. “We studied the three main types of cataract: cortical cataract (which affected 24% of people in our study), nuclear cataract (19%), and posterior subcapsular cataract (6%). Some people had more than one type.” Cumming is associate professor in the department of public health and community medicine at the University of Sydney in Australia.

The researchers enrolled almost 3,000 people in the study, which will look at the development of cataracts over time. This initial report deals with the cataracts that are already present at the beginning of the study, and looks at the impact that past dietary habits may have had. Investigators also are looking at other factors that may have an influence on cataract development.

They found that higher intakes of protein, vitamin A, niacin, thiamin, and riboflavin were associated with lower levels of nuclear cataract. Intake of polyunsaturated fats, found in vegetable oils, fish, and fish oils, was associated with reduced levels of cortical cataract. No nutrients were associated with posterior subcapsular cataracts.

“These findings support other research suggesting that antioxidant vitamins reduce the risk of cataract”, says Cumming. “Several B group vitamins riboflavin, niacin and thiamine were also associated with reduced risk of nuclear cataract.” The only food associated with cataract prevention was spinach – perhaps due to its high content of a nutrient called lutein.

Cristina Leske, MD, MPH, is distinguished professor of preventive medicine and ophthalmology at the SUNY Stony Brook Campus. She tells WebMD that the study is well done and confirms what others have found in earlier research. Leske was not involved in the study.

“The problem with an observational study like this one, is that it looks at associations between diet and cataracts, but not in a way that allows us to say cataracts are caused by lack of these nutrients,” she says. “Until we have hard evidence, we really can’t make any recommendations to consumers.”

Everyone’s doing it. Getting laser eye surgery,
that is.

Laser eye surgery is all the rage today, and as many as 800,000 Americans
will throw away their eyeglasses and contacts lenses after they undergo laser
eye surgery this year.

But at least one leading eye surgeon says that for certain people with low
levels of nearsightedness, or myopia, a newer procedure involving Intacs may be
the way to go.

The first FDA-approved option for correcting mild nearsightedness without a
laser, Intacs are two tiny half rings that are placed within each eye to gently
reshape the cornea, which is the transparent tissue covering the front of the
eye. In the nearsighted eye, the cornea is too steep, but the Intacs remedy
this problem.

“[Putting in] Intacs is almost a cosmetic procedure for people who can
see OK without glasses, but want extra crispness to their vision,” says
Brian S. Boxer Wachler, MD, director of the UCLA Refractive Center at the Jules
Stein Eye Institute in Los Angeles.

While LASIK eye surgery (laser in situ keratomileusis) also corrects mild
nearsightedness, “the big difference between Intacs and LASIK is that
Intacs are removable and easily adjustable in the future,” he tells
WebMD.

Because it is a newer procedure, Intacs are not as widely available as the
laser surgery and may be more expensive, he adds.

During LASIK surgery, the cornea is cut with a blade in a circular pattern
so it can be lifted and held back to show the tissue underneath. Then some
corneal tissue is removed using a laser.

LASIK surgery, however, is not without its risks namely decreased night
vision and dry eyes. “People with low degrees of nearsightedness are often
afraid of having a risky, drastic procedure like LASIK on their eyes,”
Boxer Wachler tells WebMD.

But some people, including Jessica Mulrain, 30, still opt for LASIK surgery.
“I had LASIK in August 1999 to correct mild nearsightedness,” she tells
WebMD. “The results were immediate and fantastic. My friends don’t even
recognize me without my glasses.”

While Intacs were not offered to Mulrain, she says she would still undergo
LASIK because she is so happy with the results. “I didn’t have any of the
side effects that I was warned about either,” she says.

“It’s really a decision based on whether people want to stay with LASIK,
a procedure that has been around longer and that they know people who have
undergone, or try a newer technology that has the potential for removability or
adjustability down the road,” says Daniel Durrie, MD, director of
refractory surgery for the Hunckler Eye Center in Kansas City, Mo. “Some
people may choose Intacs because it provides them with the ability to change
for a better technology if one is developed in 10 years or so,” he tells
WebMD.

People with high blood pressure especially
those who are being treated with potent drugs to control the condition may
be at higher risk of an age-related eye disease that can lead to blindness, a
new study says.

The study, published in the March issue of Archives of Ophthalmology,
says people with high diastolic blood pressure (the bottom number of a blood
pressure reading) should be checked regularly for age-related macular
degeneration (AMD).

The macula is an area of the retina, the nerve layer in the back of the eye.
Its job is to distinguish details at the center of the field of vision. With
age, the macula deteriorates, and the ability to focus clearly decreases.
Macular degeneration is the leading cause of blindness in older people. It
occurs gradually, and symptoms include difficulty reading and performing other
activities that require sharp vision.

There are two forms, one that involves bleeding under the retina and one in
which there is damage to the retina without bleeding. The type with bleeding,
called neovascular macular degeneration (NV-AMD), is more damaging. Roughly 80%
of patients with AMD have the less serious form, although it can lead to the
neovascular type.

For this study, Leslie Hyman, PhD, and members of a study group used
photographs to classify the eyes of 644 participants and group them according
to which form of AMD they had neovascular (NV) or non-neovascular (non-NV)
or into a control group that did not have the disease.

They found that people with the more serious type of AMD were more than four
times as likely to have high diastolic blood pressures (greater than 95 mmHg)
as those with the less serious type of the disease. The patients with
neovascular AMD were more likely to be taking blood pressure medications than
those with the less serious type. In addition, neovascular AMD was associated
with higher dietary cholesterol intake and increased levels of HDL cholesterol
(the so-called “good” cholesterol).

What this means, Hyman says, is that people with moderate to severe high
blood pressure should be carefully monitored, whether or not they already have
AMD.

“These findings emphasize the importance of careful follow-up in two
important, chronic conditions, one that causes [death], the other that causes
severe visual loss,” says Hyman, an associate professor in the department
of preventive medicine at University Medical Center in Stony Brook, N.Y.

“Since some patients with NV-AMD are potentially treatable and vision
loss can be delayed; the identification of any high-risk groups is helpful for
early detection and treatment,” she says.

Vital Information:

People with high diastolic blood pressure may be more likely to suffer from
age-related macular degeneration (AMD), the No. 1 cause of blindness among the
elderly.
Those with moderate to severe high blood pressure, who are more likely to
be taking medications, should be checked regularly for AMD.
AMD occurs gradually, as the area of the retina responsible for the center
of the field of vision begins to deteriorate.

If you’re one of the millions of people who
have dry-eye disease, take note: Eye drops containing the drug cyclosporine
significantly improve the symptoms of dry-eye disease and could be a huge
breakthrough in the treatment of this stubborn and irritating condition, say
the authors of a study in the journal Ophthalmology.

In dry-eye disease, the immune cells in your eye increase the concentration
of substances that inflame the eye, leading to tissue destruction and causing
more substances that inflame the eye to be released in the tears. This sets up
a vicious cycle in which the inflammation attracts and activates more immune
cells, which in turn release more inflammatory substances that irritate the
eye. Symptoms include blurred vision, extreme sensitivity to light, and an
itching or a “gritty” feeling in the eye. In extreme cases, it can
cause blindness.

“Cyclosporine prevents activation of the [immune] cells and also seems
to help certain cells in the tear glands live longer because there is no more
inflammatory response,” says co-author Thomas K. Mundorf, MD, an
ophthalmologist in private practice in Charlotte, N.C. “Then you get
improved function of the tear gland, which secretes a more normal
tear.”

Until now, the only treatments ophthalmologists had for dry-eye disease were
artificial tears or plugs in the tear ducts, both of which were ineffective in
many patients. Steroid drops offered a bit more relief but had serious side
effects.

Mundorf tells WebMD that plugs blocked the tears, preventing drainage, but
that may have kept the inflammatory substances in the eye. “The exciting
thing to me is [that] what we have with cyclosporine is a way to intervene.
It’s been kind of remarkable in some of these patients. You feel like you’re
doing something for them,” he says.

Mundorf estimates that 12 million to 20 million people in the U.S. suffer
from dry-eye disease, compared to 3 million to 6 million people with glaucoma.
Seen most often in women who have been through menopause, dry-eye disease also
is associated with certain forms of eye trauma, injury, and an abnormality of
the tear duct glands or eyelids. Diseases such as rheumatoid arthritis, and
some drugs such as beta-blockers, commonly prescribed to treat high blood
pressure, also can cause dry-eye disease.

Doctors also are seeing more and more cases among patients who have
undergone corneal laser surgery to correct nearsightedness.

In the study, the investigators, led by Kenneth Sall, MD, looked at nearly
670 patients who completed the six-month trial. They tested cyclosporine in two
concentrations: 0.05% and 0.1%, each administered as one eye drop twice a
day.

A third group received dummy drops that contained no drug twice a day.
Patients were allowed to use artificial tears as needed up to month four, but
could not administer them 30 minutes before or after taking the study
medication to prevent dilution of the medication.

The FDA is considering approval of a new breed
of extended-wear contact lenses, which users would be able to wear for up to a
month with less discomfort and less risk of infection than with the
first-generation lenses from the early 1980s.

But will the convenience of the new 30-day lenses justify their risks?
That’s the point debated in a pair of “Point-Counterpoint” articles in
the March issue of Review of Ophthalmology.

In her “point” article, Penny A. Asbell, MD, argues that it does. In
the accompanying “counterpoint,” William Ehlers, MD, says that although
the risks of extended-wear lenses are small, simple convenience does not
justify their use.

In 1981, the FDA approved lenses that could be worn for up to 30 days
without removal. Studies, however, showed that some people who wore them had
more eye infections, and the recommended wearing time was decreased to seven
days. The cornea, the clear part of the eye on which the contact lens is
placed, did not get enough oxygen when people wore these lenses overnight. That
made the eye more susceptible to infections, which include everything from a
simple type called conjunctivitis to more serious infections that could cause
blindness.

The newer extended-wear lenses are made of very different materials, which
allow more oxygen to reach the cornea. One such lens is the PureVision lens
from Bausch & Lomb, which is approved for seven-day use and is under study
for 30-day use, says William T. Reindel, MD, director of global professional
marketing for vision care at Bausch & Lomb.

“It’s time to rethink extended-wear lenses,” Asbell tells WebMD.
“Clearly this is a new era and it requires a new approach to contact lens
use. For the first time, we have a soft lens that is high in oxygen
permeability and therefore should provide more natural wear, while maintaining
comfort and good-quality vision for the patient.” Asbell is professor of
ophthalmology and director of cornea services at the Mount Sinai School of
Medicine in New York.

Studies of these newer lenses show that infections are uncommon, and that
the real issue is some slight drying of the eyes. Asbell argues that in light
of this, the new 30-day lenses offer people a good alternative to refractive
surgery to correct their vision.

Ehlers, who is in private practice in Torrington, Conn., argues that wearing
these lenses overnight deprives the eyes of oxygen, which can cause the eyes to
swell. Dryness, as well as infections that cause ulcers of the cornea which
have been reported to be four to 20 times greater in people using extended-wear
lenses far outweighs any benefits, he says.

Ehlers also argues that people who seek the convenience of extended-wear
lenses probably won’t be happy about the more frequent visits to an eye-care
specialist that these lenses require. “I believe that any wearer of 30-day
lenses should visit the ophthalmologist more frequently an idea that
probably won’t appeal to patients who think themselves too busy to remove
lenses daily. Refractive surgery might be a better option,” he writes.

Throw away your bungee cords and use
ropes instead to tie down your gear when you’re loading the top of the car for
the family vacation or the trip back from the hardware store, say eye doctors
who treat people with eye injuries.

Over a five-year period, eye trauma specialists at the Wills Eye Hospital in
Philadelphia treated 67 patients with moderate-to-severe injuries to the eye
from bungee cords elastic tie-down straps with J-shaped or S-shaped metal
hooks at either end. These are the cords that parents always struggle with as
they’re trying to pack up the gear and head out of town.

The patients sustained injuries when the hooks either straightened out and
lost their grip under heavier-than-normal loads, broke apart from the strap, or
came loose when the load was being tied down. The hooks snapped back at the
user, struck the eye, and, in some cases, inflicted injuries severe enough to
cause them to lose all sight in the affected eye or even to lose the eye
itself.

“We’re proposing that these hooks be redesigned with a gated clip that
would prevent the hook from becoming disengaged from the object it’s secured
to,” says lead researcher Anthony J. Aldave, MD, senior ophthalmology
resident at Wills Eye Hospital of Thomas Jefferson University in Philadelphia,
in an interview with WebMD. “People have proposed this before, and, yes, it
would cost a little more for the manufacturers to redesign these hooks. But the
fact is that a simple modification could probably have prevented the vast
majority of these injuries.”

“I agree in general that a redesign would help, but what I advise my
patients is: Just don’t use a bungee cord, period. Just use a rope,” Eugene
S. Lit, MD, tells WebMD. Lit, the director of the eye trauma service at the
Massachusetts Eye and Ear Infirmary in Boston, was not involved in the
Philadelphia study, which was reported here Tuesday at an eye research
meeting.

In the study, more than half of the patients who came into the emergency
room for a bungee cord-sustained eye injury required hospitalization for
treatment of the injuries, which included bleeding within the eye, lacerations
to the eye, traumatic cataracts (clouding of the lens of the eye as a result of
the blow), and tearing or detachment of the retina from the back of the eye.
The retina is the tissue lining the inside of the eye that acts as a screen on
which images are captured and transmitted to the brain. Most of the damaged
eyes had a mild-to-serious loss of vision, 15% had no useful vision, and three
patients had injuries that were so severe that the eyes had to be surgically
removed.

Mice that glow green may sound like something out of The Wizard of Oz, but little rodents that shine like the Emerald City (under ultraviolet light) could hold the key to a treatment that could one day help to repair eyes damaged by common blinding diseases.

A team of Boston researchers has shown that stem cells primitive “master” cells that can grow into any type of cell in the body can, in animal models, start a new population of apparently normal vision cells known as photoreceptors. Diseases such as age-related macular degeneration and diabetic retinopathy can cause gradual deterioration of the photoreceptors, accompanied by a usually irreversible loss of sight in the central field of vision.

But, as Michael J. Young, PhD, and colleagues from Schepens Eye Research Institute in Boston reported this week at a major eye research meeting here, it may be possible to one day replace defective photoreceptors with a new, homegrown population.

As you may remember from high school biology class, the eye has cells known as rods and cones both are types of photoreceptors that allow us to see motion, shapes, and colors. The photoreceptors live in the central portion of retina, the delicate tissue covering the inside of the eyeball that serves as a screen for receiving and transmitting images to the brain.

Young and his fellow researchers have found in experiments that it may be possible to help damaged retinas heal themselves by injecting a special type of stem cell called a retinal progenitor cell into the eye. The cells would then, ideally, undergo a metamorphosis and take on the characteristics of rods and cones; cell scientists call this type of transformation “differentiation.”

But, choosing the right type of stem cell is of critical importance. “In stem cell research, there is the question of ‘When do you start?’ Some people start right at the beginning with embryonic stem cells that have no fate, and then try to control their differentiation,” Young tells WebMD. “With repair, I think the most important thing is to start at the right point. There are all these branch points, and you want to know, ‘What’s my target, and how do I get there?’ We have no idea how to take an embryonic stem cell and turn it into a photoreceptor; we know a lot about how to take a retinal progenitor cell and turn it into a photoreceptor.”

And that’s where the shiny verdant mice come in. The researchers used a strain of laboratory mice that have been bred to have virtually every cell in their body contain a chemical that will glow green under ultraviolet light. The researchers then teased retinal progenitor cells out of the retinas of these mice and implanted the cells into tissues in the laboratory and into the eyes of other mice. Using ultraviolet light, they were then able to trace where the transplanted cells went and what happened to them.

Tired of uncomfortable contact lenses? Annoyed by the
slip-sliding of glasses? You would consider laser eye surgery to correct your
vision, but you’ve heard there can be distracting side effects, like seeing
halos and starbursts around lights. How common are they, and which type of
surgery will give you the best results with the lowest risk of side effects? A
new study, in the May issue of the journal Ophthalmology, may help open
your eyes.

“The side effect that the study specifically focused on were these
optical symptoms that are not captured with conventional, 20/20 vision
testing,” study co-author Roger Steinert, MD, tells WebMD. “When you go
on the Internet, you see lots of comments on halos and glare and [double
vision]. … Those kind of visual complaints, we know they occur, and we hear
about them from patients. What this study looked at is whether or not there was
a difference between LASIK and PRK [two popular types of laser surgery] in the
frequency of these complaints.” Steinert is a consultant for Summit
Technology Inc., which manufactures lasers for eye surgery.

Steinert and colleagues asked 220 patients with moderate to severe
nearsightedness to fill out a questionnaire about certain side effects they
experienced before and six months after undergoing one of two procedures: the
older PRK or the more recently approved LASIK.

In both procedures, the surgeon uses a laser, which produces a beam of
ultraviolet light in pulses that last only a few billionths of a second, to
remove a microscopic amount of tissue from part of the eye called the cornea.
“Basically, you are using the … laser to reshape the cornea,” Michael
Gordon, MD, tells WebMD. “They are both effective, but there is more
scarring and discomfort and greater delay in visual recovery associated with
PRK.”

In PRK, Gordon says, the doctor removes the top layer of cells, called the
epithelium. “Then you do the lasering and remodeling right on the surface
of the cornea. The reason you get a delay in visual recovery and some pain is
that removing the epithelial layer is like having a large scratch on the
surface of your cornea that has to heal over.

“With LASIK, the surface of the cornea is essentially untouched because
you make a little flap in the very upper layer of the cornea, then you do the
lasering and reshaping of the cornea underneath the flap,” he says.
“The flap folds back and conforms to that new shape, so you don’t have that
scratch that has to heal on the surface of the cornea.” Gordon, who is in
private practice at the Vision Surgery and Laser Center in San Diego, was one
of the surgeons involved in the study.