Can a 'fertility diet' get you pregnant?

Can a 'fertility diet' get you pregnant?

Can changing your diet improve your chances of getting pregnant? "The Fertility Diet," a new book by some prominent Harvard Medical School researchers, suggests that it can — that among other things, eating ice cream and cutting back on meat may help raise your fertility.

The problem is that much of the research behind the book doesn't live up to its hype. "The Fertility Diet" isn't the first to promote nutritional changes as a way to increase the odds of pregnancy; an online search will turn up any number of titles like "The Infertility Diet," "Fertility Foods" and so on.

Essentially, their recommendations are alike: a heart-healthy diet with more fruit and vegetables, less meat and bad carbs, more healthy fats and few or no trans fats.

While the messages are similar, a big difference is that the newest book comes from Harvard. As a result, it's had an enviable amount of buzz. Newsweek even devoted its Dec. 10 cover to an excerpt.

The notion that something as simple as better eating might improve fertility is certain to raise the hopes of tens of thousands of couples. But unfortunately, the findings in this book don't apply to a vast majority of people with infertility problems. Instead, they are based on women with ovulatory infertility, a condition caused by irregular ovulation that affects fewer than a third of infertile women.

And while it's never a bad idea to improve your nutrition, there is no definitive evidence that many of the diet changes outlined in the book will increase a woman's odds of getting pregnant.

"It's marketing," said Dr. Jamie Grifo, a respected fertility researcher who is director of the New York University Fertility Center. "There's a limit to what conclusions you can draw from the way they conducted the study."

The findings on fertility in the Nurses' Health Study come from more than 18,000 women who were trying to get pregnant over an eight-year period. But while that sounds like a lot, only about 400 of the women were given diagnoses of infertility related to irregular ovulation. So many of the associations between nutrition and fertility outlined in the book are based on a relatively small number of women.

It's important to note that while the study showed strong associations between certain habits and fertility, it did not prove that the women's diet was what made the difference. Furthermore, it was the women themselves who reported their eating habits, and only every few years. Critics note that most people can't remember what they ate last night, let alone over the course of a few years.

Two recommendations in "The Fertility Diet" are backed by relatively solid science. For a woman with irregular ovulation, attaining a healthy weight and taking a multivitamin with folic acid can improve her odds of getting pregnant. Being overweight or underweight has been shown to suppress ovulation, because both conditions throw off a woman's natural hormone levels.

In a major study of vitamins and folic acid to reduce the incidence of neural-tube defects in babies, the researchers noted a trend they hadn't expected. The women taking the vitamins were not only more likely to conceive, but also more likely to have twins.

The heart-healthy diet recommendations behind "The Fertility Diet" might influence ovulation because they affect insulin levels. Insulin levels, in turn, can affect sex-hormone-binding globulin, which can affect the amount of free androgen in a woman's body. Too much can suppress ovulation.

Importantly, the nurses' study found associations between fertility and certain eating behaviors, but it didn't test whether adopting new eating habits would make a difference. Dr. Walter Willett, the Harvard nutrition researcher who is a co-author of the book, acknowledges the limits of the data, but adds that he believes it is "highly likely" that the diet will help some women, given what is known about dietary influence on other body functions like blood pressure.

"The underlying principles are compatible with good health and prevention of some of the complications of pregnancy," he said. "This is a good eating strategy anyway. It's going to be clearly a safer, more modest approach to fertility than just jumping right into heavy medication."

The weakest recommendation in "The Fertility Diet" is the notion that ice cream and whole-fat dairy products will increase fertility. Even the study authors note in the book that it would be an "overstatement" to say there are even "a handful" of studies on the subject.

To their credit, the book's authors acknowledge early on that the research has limitations and that their diet doesn't guarantee a pregnancy. Dr. Jorge Chavarro, the lead author, said it had been a challenge to balance the limitations of scientific research with the commercial demands of book publishing. Even the simple title of the book, he added, belies the complexity of the findings.

"I would describe it as an apparently fertility-enhancing dietary pattern, but that doesn't go with the flow of your reading," he said. "This is not a cure for infertility. We have been very careful in explaining what we think these dietary changes can do and what they cannot do ."

Regaining Lost Luster

Regaining Lost Luster

New developments and clinical trials breathe life back into gene therapy

The past 15 years have been a roller coaster for gene therapy. After being touted in the early 1990s as “the medicine of the future,” gene therapy left an 18-year-old dead and three others with leukemia; in July it was tied to the death of a 36-year-old Illinois woman undergoing treatment for rheumatoid arthritis, although further investigation cleared her therapy of the blame. Gene therapy scientists, however, believe they can put the bad news behind them, thanks to a handful of recent developments and others just over the horizon.

Gene therapy describes any treatment in which doctors insert new or modified genes into a person’s cells to treat or prevent disease. Researchers initially planned to treat hereditary disorders such as cystic fibrosis, in which normal gene products are deficient, by delivering functional copies of missing genes to cells that need them. Since then, scientists have expanded gene therapy’s possible applications to include “training” immune cells to hunt down cancer, building new blood vessels and making the immune system resistant to infection.

“We really don’t know the full dimension of what it can do,” says Arthur Nienhuis, a hematologist at St. Jude Children’s Research Hospital in Memphis and president of the American Society of Gene Therapy (ASGT). In addition to 12 cancer treatments and a heart treatment currently in large phase III clinical trials, there have been a handful of early-stage developments: in June doctors at New York–Presbyterian Hospital announced promising results from a phase I trial for Parkinson’s disease; a therapy that has restored sight to 70 congenitally blind dogs is being tested in humans at the University of Pennsylvania; and eight research groups are gearing up to test new HIV treatments. Although no gene therapies have yet been approved by the U.S. Food and Drug Administration, more than 800 trials are ongoing; China has approved two cancer treatments, but their efficacy remains unclear.

What makes gene therapy so promising also makes it extremely challenging. It can target only those tissues that need it,  “which is a major contrast with traditional pharmacotherapy, where you take a pill or receive an injection, and a very, very small portion of the injected or ingested drug actually arrives at the [correct] site,” says David Dichek, a cardiologist at the University of Washington. But ensuring that the gene reaches its target is no small feat. Trials can skirt this problem when targeted cells can be injected directly or easily removed—with the latter method, doctors can manipulate isolated cells in the lab and replace them in the patient later. But getting genes to inaccessible targets has been one of the field’s biggest hurdles.

Most scientists use modified viruses as  “vectors” to deliver gene therapy. Viruses are good at delivering genetic payloads to cells; after all, that is what they do. If scientists strip viruses of their genetic material and replace it with therapeutic genes, viruses will deliver this payload to the cells instead. Different viruses do different things—some attack the liver, others nerves; some insert their DNA into the host genome, others do not—so physicians can choose those that best suit their purposes and further engineer them if need be. “There’s been a lot of effort to steer viruses to go specific places,” says Donald Kohn, an immunologist at the Keck School of Medicine of the University of Southern California and Childrens Hospital Los Angeles.

But viruses come with a catch:  “Our immune system developed to reject them,” Kohn explains. What killed 18-year-old Jesse Gelsinger in 1999 was a powerful immune response to his therapy, not the therapy itself. So even if a vector reaches its target, scientists must ensure that the body does not attack the “infected” cells. Recently scientists have identified a number of ways of achieving this, by using lower therapy doses, pretreating patients with immunosuppressive drugs and masking vectors so immune cells do not notice them. Some scientists also use vectorless “naked” DNA and genes packaged in other ways.

Even if gene therapy conquers these challenges, will it ever overcome its negative reputation? Some scientists maintain that it has never been that unsafe, relatively speaking. “If you compare the safety profile of gene drugs in development versus the traditional small-molecule pharmaceutical drugs, there’s no evidence that gene therapy is any more dangerous,” says Savio Woo, an oncologist at Mount Sinai Hospital in New York City. Thousands of patients have been treated, and only a few adverse events have been reported, he states; the leukemia that developed in three “bubble boy” patients may have been a side effect specific to the therapeutic gene, which stimulates immune cell growth. “Any time a few cells divide a lot, you always worry about secondary genetic changes, which is how cancers form,” notes Mark Kay, a geneticist at Stanford University.

As the field continues to evolve and improve, scientists hope that the public’s perceptions of it will, too.

 “We clearly have had clinical successes, and now we’re on the threshold of achieving many more,” says ASGT president Nienhuis. “I think we’re going to hear a lot about them in the next several years.”

A New Way to Help Networks Handle Ever-Heavier Data Loads

A New Way to Help Networks Handle Ever-Heavier Data Loads

Researchers discover a way to briefly store data acoustically to alleviate traffic bottlenecks 

 
SEEING THE LIGHT: Researchers successfully transferred encoded information from a laser beam to sound waves and back to light waves, a breakthrough that could speed development of faster optical communication networks.

As demand for streaming video over the Web, voice over Internet protocol (VoIP) calling services and other forms of Internet-based multimedia communication skyrockets, content creators and consumers are counting on fiber-optic networks to handle these increasing loads quickly and efficiently. One way to ensure this happens is to enhance the ability of such networks, which transmit data over glass or plastic threads, to capture and retain data even for very brief intervals.

Toward that end, a team of researchers from Duke University and University of Rochester's Institute of Optics recently reported in Science that it successfully transferred encoded information from a laser beam to sound waves and back to light waves, a breakthrough that could speed development of faster optical communication networks. Swapping data between optics and acoustics allows it to be stored in pockets of acoustic vibration created when laser beams interact along a short strand of optical fiber.

The research is significant, because it addresses how memory can be created for optical pulses. "The primary thrust is investigating slow light via stimulated Brillouin scattering, where we slow down a pulse as it propagates through an optical fiber," says study co-author Daniel Gauthier, chairman of Duke's department of physics. Brillouin scattering occurs when light traveling through a medium, such as glass, changes its path as it encounters varying densities.

The main goal of the research is to pave the way for better fiber-optic communication systems, which today consist of fiber placed underground and linked by routers. The typical way to send data over an optical network is to break it up into chunks called packets. When a packet comes into a router, its address information is read. The problem with routers is that they each contain a single switch that can only process one packet at a time. As a result, some packets are dropped unless others coming in are buffered (saved) or can wait until it is their turn to be routed. "If you drop the packet, you reduce the throughput of the entire network," Gauthier says. "If you buffer, then the packets are processed one after the other."

As greater demands are placed on telecommunication infrastructures, "it's important to start to investigate parallel technologies," he adds.

Gauthier and his colleagues discovered that when two laser beams of slightly different frequencies are pointed at one another along a piece of glass fiber, they create acoustic vibrations called phonons. When co-author Zhaoming Zhu, Gauthier's postdoctoral research associate, encoded information onto one of these beams, the data could be imprinted on these newly created phonons and retained for 12 billionths of a second, long enough to be transferred back to light again by shining a third laser through the fiber.

"When thinking about how to store light in optical fibers," Zhu says, "we realized that we can convert optical information to acoustic vibration, something that hasn't been done before."

The researchers are seeking ways to create longer storage times and reduce the peak power of the laser beam needed for retaining and reading out the information, a process that will take years before a commercial version of the technology is available.

"There is still a great need for developing new strategies for optimizing the flow of information over the Internet," says Robert Boyd, a professor of optics and physics at the Institute of Optics and a research co-author. "If two data packets arrive at a switch at the same time, you need to store one until the other packet clears the switch, maybe 100 nanoseconds later. Our technique is aimed at … building buffers for high-speed telecommunications."

During the first phase of the project—which is part of the Defense Advanced Research Projects Agency's (DARPA) Defense Sciences Office slow-light program—Zhu says he learned that pulses could be stored and read out at a later time. The second phase was the actual experiment in which data pulses were stored (as acoustic waves in an optical fiber) and retrieved after a certain period of time.

"We really want to demonstrate that methods for storing optical information are much broader than people thought," Gauthier says. "In the current telecommunication systems, you turn the optical signal into an electronic signal and store it in RAM. The optical data pulses are then regenerated by using the electrical signals to turn on and off an auxiliary laser source. But this process generates heat. The faster this is done, the more heat is generated."

For this to work in the real world, the scientists say the communication fibers must be made of a material that provides an acoustic time frame long enough to allow the information to move from optical to sound, then return to optical. One option, Gauthier says, is to work with a new type of glass made from a chalcogenide, which has good semiconductor properties and contains one or more elements from the periodic table's chalcogenide group, also known as the "oxygen family," which includes oxygen, sulfur, selenium and tellurium.

Another option that researchers are exploring is to run the laser beams through a hollow optical fiber filled with gas (such as xenon), which would allow them to use a less powerful laser to induce longer lasting sound waves in the gas. This could potentially create a sound wave 50 times longer and allow the lasers used to be 100 times less powerful—and less energy intensive—thereby delivering more data more quickly at a lower cost.

Martian Meteorite Harbors Life's Building Blocks

Martian Meteorite Harbors Life's Building Blocks

Organic molecules inside space rock were probably the result of plain old chemistry

 
THE STUFF OF LIFE: Carbon-rich minerals (brown and white globules) found in rock from the Sverrefjell volcano on the Norwegian island of Svalbard show a similar pattern to minerals in Martian meteorite ALH84001, suggesting that both formed from known chemical reactions—and not in living cells, as was once proposed for ALH84001.

Chemicals in a Martian meteorite that were once held up as possible evidence of life on ancient Mars were more likely the product of heat, water and chemistry, according to a new study. Researchers from the Carnegie Institution of Washington and the University of Oslo in Norway reached that conclusion after comparing the four-pound (two-kilogram) extraterrestrial rock, ALH84001, with samples of earthly volcanic material—and discovering a matching pattern of minerals consistent with a chemical process that yields carbon compounds after rapid heating and cooling.

Although the study does not support the existence of life on Mars, researchers say it shows that some of the chemical precursors of life—at least as we know it—were kicking around on the Red Planet some 4.5 billion years ago.

Discovered in 1984 in Allan Hills, Antarctica, researchers believe that meteorite ALH84001 struck Earth some 3.5 to four billion years ago after being kicked up from the Martian surface and into space by the impact of another meteorite. NASA researchers triggered international headlines in 1996 when they discovered, among other possible indicators of life, traces of polycyclic aromatic hydrocarbons (multiringed carbon molecules found in living cells) along surface fractures in ALH84001.

Initial excitement that such compounds might represent traces of Martian microbes faded within a year or two as researchers came up with other possible explanations for the meteorite's unique features.

"What was missing was whether Mars could actually undertake organic chemistry itself," says Carnegie geophysicist Andrew Steele, who led the new study. To find out, he and his colleagues examined the chemical makeup of 0.1-millimeter carbon globules from samples taken at several depths from ALH84001. They identified rings of magnetite (iron oxide) arranged around the sooty spheres in the same pattern as in frocks from a volcano on the island of Svalbard, Norway.

The researchers, whose results appear in the September 2007 issue of Meteoritics & Planetary Science, attribute the pattern to known chemical reactions in which strong heating followed by rapid cooling causes carbon dioxide to rearrange itself into more complex molecules in water, with iron oxide serving as a catalyst. Additional carbon molecules could have been cooked up when ALH84001 was ejected from Mars, they note.

"This process may be making a lot of the stuff of life, without any help from things that are alive," says John Rummel, senior scientist for astrobiology for NASA's Planetary Science Division, who was not involved in the study. And that, he adds, means there could still be life there waiting to be discovered.

Steele says the results lay the groundwork for interpreting future chemical studies of the Martian surface, such as experiments to be carried out by the Mars Science Laboratory rover mission, scheduled to launch in fall 2009. "If you find complex organic species on Mars, it's not necessarily life."

Caught on tape: Death star galaxy

Caught on tape: Death star galaxy
 

This composite photo provided by NASA shows A powerful jet from a supermassive black hole is blasting a nearby galaxy in the system known as 3C321, according to new results from NASA. This galactic violence, never seen before, could have a profound effect on any planets in the path of the jet and trigger a burst of star formation in the wake of its destruction.

The latest act of senseless violence caught on tape is cosmic in scope: A black hole in a "death star galaxy" blasting a neighboring galaxy with a deadly jet of radiation and energy.

A fleet of space and ground telescopes have captured images of this cosmic violence, which people have never witnessed before, according to a new study released Monday by NASA.

"It's like a bully, a black-hole bully punching the nose of a passing galaxy," said astrophysicist Neil deGrasse Tyson, director of the Hayden Planetarium in New York, who wasn't involved in the research.

But ultimately, this could be a deadly punch.

The telescope images show the bully galaxy shooting a stream of deadly radiation particles into the lower section of the other galaxy, which is about one-tenth its size. Both are about 8.2 billion trillion miles from here, orbiting around each other.

The larger galaxy has a multi-digit name but is called the "death star galaxy" by one of the researchers who discovered the galactic bullying, Daniel Evans of the Harvard-Smithsonian Center for Astrophysics.

Tens of millions of stars, including those with orbiting planets, are likely in the path of the deadly jet, said study co-author Martin Hardcastle of the University of Hertfordshire in the United Kingdom.

If Earth were in the way — and it's not — the high-energy particles and radiation of the jet would in a matter of months strip away the planet's protective ozone layer and compress the protective magnetosphere, said Evans. That would then allow the sun and the jet itself to bombard the planet with high-energy particles.

And what would that do life on the planet?

"Decompose it," Tyson said.

"Sterilize it," Evans piped in.

The jet attack is relatively new, in deep space time. Hardcastle estimates it's no more than 1 million years old and can stretch on for another 10 to 100 million years.

"A truly extraordinary act of violence," Evans said. "The jet violently slams into that lower half of the neighboring galaxy after which the jet dramatically twists and bends."

The good news is that eventually an area of hot gas that gets hit and compressed by this mysterious jet — astronomers are still baffled by what's in it and how it works — over millions and billions of years can form stars, Tyson said.

NASA, the National Radio Astronomy Observatory in United States and the University of Manchester in the United Kingdom used ground optical and radio telescopes, the Hubble Space Telescope, the Chandra X-ray Observatory, and the infrared Spitzer Space Telescope to get an image of the violence on various wavelengths, including invisible ones. The results will be published in The Astrophysical Journal next year.

The two galaxies are only 24,000 light-years apart and are in a slow merging process. The jet has already traveled 1 million light-years. A light-year is about 5.88 trillion miles.

Tyson said there are two main lessons to be learned from what the telescopes have found:

"This is a reminder that you are not alone in the universe. You are not isolated. You are not an island."

And "avoid black holes when you can."