Well: Can Exercise Cause A.L.S.?

Phys Ed

Gretchen Reynolds on the science of fitness.

Photo Ever since the great Yankees first baseman Lou Gehrig -- pictured here scoring first run of the 1938 World Series -- died of A.L.S. in 1941, many Americans have vaguely connected A.L.S. with athletes and sports.Credit Associated Press

Amyotrophic lateral sclerosis has been all over the news lately because of the ubiquitous A.L.S. ice bucket challenge. That attention has also reinvigorated a long-simmering scientific debate about whether participating in contact sports or even vigorous exercise might somehow contribute to the development of the fatal neurodegenerative disease, an issue that two important new studies attempt to answer.

Ever since the great Yankees first baseman Lou Gehrig died of A.L.S. in 1941 at age 37, many Americans have vaguely connected A.L.S. with athletes and sports. In Europe, the possible linkage has been more overtly discussed. In the past decade, several widely publicized studies indicated that professional Italian soccer players were disproportionately prone to A.L.S., with about a sixfold higher incidence than would have been expected numerically. Players were often diagnosed while in their 30s; the normal onset is after 60.

These findings prompted some small, follow-up epidemiological studies of A.L.S. patients in Europe. To the surprise and likely consternation of the researchers, they found weak but measurable associations between playing contact sports and a heightened risk for A.L.S. The data even showed links between being physically active — meaning exercising regularly — and contracting the disease, raising concerns among scientists that exercise might somehow be inducing A.L.S. in susceptible people, perhaps by affecting brain neurons or increasing bodily stress.

But these studies were extremely small and had methodological problems. So to better determine what role sports and exercise might play in the risk for A.L.S., researchers from across Europe recently combined their efforts into two major new studies.

The more impressive of these, which was published in May in Annals of Neurology, involved almost two dozen researchers from five nations, who developed a deceptively simple but scientifically rigorous research approach. They asked 652 A.L.S. patients if they'd be willing to talk about their lives and activities and did the same with 1,166 people of matching ages, genders and nationalities. They conducted extensive in-person interviews with each volunteer, asking them how active they had been in professional or amateur sports, at their jobs and during leisure time. They also asked about past histories of injuries and accidents, including concussions and other head trauma but also other injuries.

They then compared answers from the people with A.L.S. to those of healthier people.

The results should reassure those of us who exercise. The numbers showed that physical activity — whether at work, in sports or during exercise — did not increase people's risk of developing A.L.S. Instead, exercise actually appeared to offer some protection against the disease. Even pro athletes showed no heightened risk, although they represented such a tiny subset of the patients with A.L.S. that firm conclusions cannot be drawn, the researchers say.

One aspect of people's lives did significantly increase their risk of developing A.L.S.: a history of multiple hits to the head. Men and women who had sustained at least two concussions or other serious head injuries were much more likely than other people, including never-concussed athletes, to develop A.L.S.

These results coincide closely with those of the other new study, a review article published in July in the European Journal of Epidemiology, which gathered data from 50 years' worth of epidemiological studies related to A.L.S. risk (including the other new study) and teased out the effects of physical activity. Most of the studies were limited in scope, but they amplified one another's validity when combined, the researchers thought.

And their main finding was that "in the general population, physical activity is not a risk factor for A.L.S.," said Dr. Benoit Marin, a neuroepidemiologist at the French Institute of Health and Medical Research in Paris who oversaw the new review.

But as Dr. Marin also pointed out, the studies involved were all associational, meaning that they cannot establish cause and effect. Exercise and a reduced risk for A.L.S. might be linked to other lifestyle factors, such as a healthy diet, and not to each other.

The new studies also cannot dispel the lingering and troubling questions about the effects of head injuries from contact sports.

"I would not consider this issue settled," said Ettore Beghi, a neuroscientist at the Mario Negri Institute for Pharmacological Research in Milan and senior author of the study published in May in Annals of Neurology.

In the United States, a few researchers have begun to look at football and A.L.S. risk, a plausible research concern, Dr. Beghi said, given evidence that head trauma sustained playing football might contribute to neurodegenerative diseases. But to date, the football data has been inconclusive.

For now, he and other scientists are continuing to study Italian soccer players, as well as athletes in other sports, including rugby, which, for some reason, confers no increased risk of A.L.S., although it involves considerable contact. Such research may ultimately "shed some light on the underlying mechanisms of the disease, which are still poorly understood," Dr. Beghi said.

The greatest obstacle to advancing the research, he added, is "the lack of funding," a situation that could be ameliorated, somewhat, with all of that ice dousing.

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Well: Of Little Help to Older Knees

Middle-aged and older patients are unlikely to benefit in the long term from surgery to repair tears in the meniscus, pads of cartilage in the knee, a new review of studies has found.

Researchers at McMaster University combined data from seven randomized, placebo-controlled trials involving more than 800 subjects treated for meniscal tears with surgery, sham surgery or nonoperative care. The subjects' average age was 56.

In six of the trials, the surgery provided a significant improvement in short-term functioning. But the pooled data showed no significant difference in long-term functioning among patients in the three groups. Nor did surgery provide either short- or long-term pain relief.

Dr. Moin Khan, a research fellow at the university and lead author of the study, published in the Canadian Medical Journal, said that its conclusion does not pertain to an acute meniscus tear in a young person. That requires surgery.

"But chronic pain from a small meniscus tear in a middle-aged person may not benefit from surgery," he said.

"Treatment with weight loss, anti-inflammatory medicine and physical therapy may be helpful for many patients."

A version of this article appears in print on 09/02/2014, on page D4 of the NewYork edition with the headline: Prognosis: Of Little Help to Older Knees.

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Well: Don’t Catch What Ails Your House

Photo Credit Tim Robinson

Personal Health

Jane Brody on health and aging.

In 1982, my husband and I bought a vacation home in the foothills of the Catskills. The inspector who checked out the property failed to note three critical facts: The house had three flat roofs (in snow country), no drainage from the muddy crawl space and no insulation under the floors.

In a few years, ours had become a "sick" house, with mini-lakes on sagging roofs, wet insulation underneath and a small pond in the crawl space. All of it contributed to rampant mold inside the house.

My husband was especially sensitive to mold, and he reacted with extreme fatigue whenever we visited. My sister-in-law, who lived in the house year round, complained of chronic headaches and sinus problems. I could smell the mustiness, and found mold growing on the wood cabinets and a leather love seat.

The moisture problem had to be fixed. Slanted roofs were constructed; wet insulation was replaced; downspouts were directed away from the house. We fitted the crawl space with a drain and a heavy plastic vapor barrier, and the floors above it were insulated.

Mold had to be removed from furniture and cupboards and their contents. Clothing was dry cleaned, or washed and heat-dried, to get rid of the odor.

Natural disasters like Hurricanes Katrina and Sandy left hundreds of thousands of people with flooded homes that quickly became infested with mold, unlivable and sometimes unfixable. Given moisture, mold will grow and reproduce behind wallboard, paneling, wallpaper and furniture, in ceiling tiles and insulation, on wood floors, around appliances like refrigerators and dishwashers, and under carpets and pads if not quickly dried.

But as my experience demonstrated, you don't need a flood to develop a mold problem. It can happen anywhere moisture is present — a hidden leak, for example, or condensation around windows or pipes. You may not even be aware of the problem, only the distress it causes.

Typical symptoms resemble those of an allergy like hay fever: a runny nose, sneezing, red or itchy eyes, throat irritation and coughing. Some people develop a skin rash; those with asthma may have an attack. According to research by the Mayo Clinic, an immunological response to mold may cause most cases of chronic sinusitis.

Mold can even infect the central nervous system, often fatally, as occurred in a 2012 outbreak of meningitis from epidural injections contaminated by Exserohilum rostratum. Of the 751 people infected across the country, 64 died.

The types of mold usually found in homes do not produce dangerous toxins. But they can bring misery and are best controlled by preventing their growth.

Molds are a type of fungus, and they grow by releasing spores into the air. The spores are not visible to the naked eye, but when they land on a moist surface (or when the surface they are on becomes moist), they begin to grow. Outdoors, molds play an important role in the decomposition of organic matter, like leaves and fallen trees.

Even the driest buildings contain mold spores, and those with indoor moisture may have thousands in every cubic foot of air. The spores are ubiquitous and can survive extreme dryness and cold, remaining dormant until moisture and oxygen provide a chance to grow.

These measures can reduce the buildup of indoor mold:

■ Fix leaks immediately, and thoroughly dry the affected area.

■ Regularly clear debris from roof gutters.

■ Keep air conditioner and refrigerator drip pans clean.

■ Insulate cold-water pipes.

■ Use an air conditioner or a dehumidifier, or both, and change the filters regularly to maintain a relative humidity below 60 percent. (The lower, the better.)

■ Vent appliances like clothes dryers that generate moisture to the outside.

■ Use an exhaust fan or open a window when washing dishes, cooking or showering.

■ Keep crawl space vents clear.

Do not use carpets in potentially moist areas like a laundry room, bathroom and basement. Replace sponges and dishcloths often, or wash and dry them with the regular laundry.

Roof leaks can be especially challenging, leaving wet insulation and moisture behind walls. Roofing is best restored or replaced on a schedule before a leak occurs.

Keeping a house warm suppresses mold growth. Alas, my house still gets musty in winter; to save oil and money, I set the thermostat at 55 degrees when I'm not there.

Some people, especially those with severe allergies, chronic lung disease or suppressed immunity, are affected by outdoor mold in compost piles, cut grass and wooded areas. When cleaning the yard and raking or sweeping dead leaves, they should consider wearing a face mask or an N-95 respirator (a fancy dust mask that costs $12 to $25).

Cleaning up mold requires care. Limit your exposure by wearing goggles, a face mask and long rubber, neoprene or PVC gloves. You need not use chlorine bleach; soap and water, or a nontoxic commercial cleaner and a scrubbing sponge or brush, will work well on hard surfaces. Dry the area thoroughly after cleaning.

If you do use a bleach solution (no stronger than one cup of bleach to one gallon of water), never mix it with ammonia or a product that contains ammonia.

Do not paint over or caulk moldy surfaces. Clean away the mold first, and then use paint with a mold inhibitor.

Porous materials like ceiling tiles and carpets that have become moldy can be difficult to clean adequately and usually must be replaced.

You may need a professional contractor skilled in mold cleanup if the affected area is larger than 10 square feet. The Environmental Protection Agency recommends checking references and making sure the contractor consults its guide, Mold Remediation in Schools and Commercial Buildings, available at www.epa.gov/mold. The agency also provides a guide to cleaning contaminated heating and air conditioning systems.

 

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Well: Healing Teenage Cancer’s Scars

Personal Health

Jane Brody on health and aging.

Photo Credit Sarah Williamson

The teenage years can be tough enough under the best of circumstances. But when cancer invades an adolescent's life, the challenges grow exponentially.

When the prospects for treatment are uncertain, there's the fear of dying at so young an age. Even with an excellent chance of being cured, teenagers with cancer face myriad emotional, educational and social concerns, especially missing out on activities and losing friends who can't cope with cancer in a contemporary.

Added to that are the challenges of trying to keep up with schoolwork even as cancer treatment steals time and energy, and may cause long-lasting physical, cognitive or psychological side effects.

Sophie, who asked that her last name be withheld, was told at 15 that she had osteosarcoma, bone cancer. After a bout of how-can-this-be-happening-to-me, she forged ahead, determined to stay at her prestigious New York high school and graduate with her class.

Although most of her sophomore year was spent in the hospital having surgery and exhausting chemotherapy, she went to school on crutches whenever possible. She managed to stay on track, get good grades — and SAT scores high enough to get into Cornell University.

Now 20, Sophie is about to start her junior year and is majoring in biology and genetics with a minor in computer science. She plans to go to medical school, so this summer she has been studying for the MCATs and volunteering at a hospital.

Her main concern now is that people meet and get to know her as a whole, normal person, not someone who has had cancer, which is why she asked that I not identify her further.

"I'm pretty healthy, and I don't want people to think I'm weak and need special care," she said in an interview.

"Having cancer puts other issues into perspective," she added. "I feel like I have to do as much as I can. I've gotten involved in so much. I try to enjoy myself more. And I don't regret for a minute how I've been spending my time."

Sophie's determination to do the most she can and her desire for normalcy are hardly unusual, said Aura Kuperberg, who directs an extraordinary program for teenagers with cancer and their families at Children's Hospital Los Angeles. Dr. Kuperberg, who has a doctorate in social work, started the program, called Teen Impact, in 1988. It operates with the support of donations and grants and deserves to be replicated at hospitals elsewhere.

"The greatest challenge teens with cancer face is social isolation," she said in an interview. "Many of their peers are uncomfortable with illness, and many teens with cancer may withdraw from their friends because they feel they are so different and don't fit in."

In the popular young adult novel "The Fault in Our Stars," a teenager with advanced cancer says, "That was the worst part of having cancer, sometimes: The physical evidence of disease separates you from other people."

Within the family, too, teenagers can feel isolated, Dr. Kuperberg said. "Patients and parents want to protect one another. They keep up a facade that everything will be O.K., and feelings of depression and anxiety go unexpressed."

Teen Impact holds group therapy sessions for young patients, parents and siblings so they "don't feel alone and realize that their feelings are normal," Dr. Kuperberg said. The goal of the program, which also sponsors social activities, is to help young cancer patients — some still in treatment, others finished — live as normally as possible.

"For many, cancer is a chronic illness, with echoes that last long after treatment ends," Dr. Kuperberg said. "There are emotional side effects — a sense of vulnerability, a fear of relapse and death, and an uncertainty about the future that can get in the way of pursuing their hopes and dreams. And there can be physical and cognitive side effects when treatment leaves behind physical limitations and learning difficulties."

But, she added, there is often "post-traumatic growth that motivates teens in a very positive way."

"There's a lot of altruism," she said, "a desire to give back, and empathy, a sensitivity to what others are going through and a desire to help them."

Sophie, for example, took notes for a classmate with hearing loss caused by chemotherapy. She recalled her gratitude for the friend "who was there for me the whole time I was in treatment, who would come over after school and sit on the couch and do puzzles while I slept."

One frequent side effect of cancer treatment now receiving more attention is the threat to a young patient's future reproductive potential.

In an opinion issued this month, The American College of Obstetricians and Gynecologists urged doctors to address the effects of cancer treatment on puberty, ovarian function, menstrual bleeding, sexuality, contraceptive choice, breast and cervical cancer screening, and fertility.

"With survival rates pretty high now for childhood cancers, we should do what we can to preserve future fertility," said Dr. Julie Strickland, the chairwoman of the college's committee on adolescent health care. "We're seeing more and more cooperation between oncologists and gynecologists to preplan for fertility preservation before starting cancer treatment."

The committee suggested that, when appropriate, young cancer patients be referred to a reproductive endocrinologist, who can explore the "full range of reproductive options," including the freezing of eggs and embryos.

For boys who have been through puberty, it has long been possible to freeze sperm before cancer treatment.

Although some female patients may be unwilling to delay treatment, even for a month, to facilitate fertility preservation, at the very least they should be offered the option, Dr. Strickland said in an interview.

She described experimental but promising possibilities, like freezing part or all of an ovary and then implanting it after cancer treatment ends. It is already possible to move ovaries out of harm's way for girls who need pelvic radiation.

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Well: Ask Well: Are Spray-On Sunscreens Safe?

A

The short answer is that for now, not even the Food and Drug Administration knows.

In 2011, with the number of sunscreen sprays "greatly increasing," the agency asked their makers to demonstrate their safety and efficacy. Little was known about sprays compared to rub-on sunscreen products like lotions. It was unclear, for instance, how much sunscreen spray consumers typically use, or what amounts effectively get on the skin.

The F.D.A. also proposed adding a warning to package labels to address the possibility that inhaling aerosolized particles could be unhealthy: "When using this product, keep away from face to avoid breathing it."

Manufacturers of sunscreen sprays provided the data, and the F.D.A. is still reviewing that information. So we still don't know how effective sprays are at filtering ultraviolet radiation, let alone if inhalation results in health problems.

The Environmental Working Group, an advocacy organization, recommends consumers avoid all spray-on sunscreens of any particle size, especially ones that use mineral ingredients like zinc oxide and titanium dioxide, which they say may pose problems if inhaled. Paul Pestano, a research analyst at the group, cited a 2006 report from the International Agency for Research on Cancer, part of the World Health Organization, that concluded that titanium dioxide is "possibly carcinogenic to humans." That conclusion was based on research involving rats inhaling high doses, but it's still worrisome, he said.

There's another reason to choose sunscreen wisely. In 2013, the F.D.A. warned about the risk of burns in those applying sunscreen sprays near open flames, such as outdoor barbecue grills or citronella candles. Many sunscreen sprays contain ingredients, like alcohol, that can catch fire.

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Well: Food and the Dying Patient

Photo Credit Getty Images

The patient had dementia and could no longer swallow. The intricate workings of the muscles of her throat were failing, and she was no longer able to move food or liquids reliably into her stomach. Instead, they too frequently ended up in her lungs, and she drowned a little more with every swallow. She was admitted to my intensive care service with pneumonia from aspirated food that had turned the bottom part of her left lung into a wet sponge. Her blood oxygen levels had dropped so low that we had to support her breathing by inserting a tube.

Now, after she was on powerful antibiotics and life support for three days, her oxygen level had improved and her fevers had abated. She was getting better, in a manner of speaking.

This pneumonia was her third, and easily her worst, in four months. This pattern is typical of end-stage dementia, when patients lose control of their swallowing mechanism and often die from the pneumonias that result from food lodging in the lung. Usually, these patients have gone in and out of the hospital through a sort of revolving door; as soon as one pneumonia is chased away by antibiotics, another emerges.

Our medical system deals well with organ dysfunction. When a kidney isn't working, we can clean blood with a dialysis machine. When a person can't breathe, we can push air into the lungs. And if there is trouble swallowing, we can bypass the throat with a feeding tube that goes through the abdominal wall directly into the stomach.

That last option had been offered to this patient's family when she was admitted to the emergency room. "If she makes it through this, she could get a feeding tube so that this doesn't happen again," they were told. And so now that she was improving, her family was asking for the tube.

But contrary to popular belief, a feeding tube does not prolong life in a patient with dementia. It actually increases suffering. A stomach full of mechanically pumped artificial calories puts pressure on an already fragile digestive system, increasing the chance of pushing stomach contents up into the lungs. And surgically implanted tubes are a setup for complications: dislodgments, bleeding and infections that can result in pain, hospital admissions and the use of arm restraints in already confused patients. But maybe most important, the medicalization of food deprives the dying of some of the last remnants of the human experience: taste, smell, touch and connection to loved ones.

So why do so many demented patients die with feeding tubes?

Food is how we know best to care for one another, from breast to deathbed. And thus it runs contrary to every impulse we have as humans to stop feedings. As a dying person becomes unable to process food on her own, our tendency is to plug life into her with a tube pumping artificial nutrition.

Since the beginning of time, humans have fed their dying by hand.  Spooned slowly so as not to overwhelm, a trickle of broth or a favorite food ground up to taste may be the last small pleasures for a dying body.

But hand feeding has increasingly become a quaint piece of human history.  We fed until they would take no more, and knew that we had done everything we could. But with the feeding tube, we can, and feel we must, keep going.  Patients frequently die with plastic tubes weaving mysteriously under their gowns, entering bodies at unnatural angles, rendering them a little more alien to us.  Those who are most needed sit a little further away from the bed, afraid to dislodge tubes that are supposedly keeping their loved one alive.   And the patient's mouth will usually remain dry and empty until the end.

My last conversation about the patient's feeding took place on my way to my car Friday afternoon. The patient's sister was walking in as I was walking out. She thanked me for the care I'd provided and told me they had decided to go with the tube. "I couldn't not feed her," she said. "I can't leave her starving."

The next day, my patient was wheeled down to the operating room for her feeding tube, then a few hours later wheeled back to intensive care. Over the next couple of weeks, her sister sat on a chair beside her most days, wearing the requisite paper gown and gloves for guests of patients with resistant bacteria from prolonged hospital stays. She sat off to the side, separated from her sister by tubes, bedrails and the bustle of activity around them.

But the patient never went home to her sister and their beloved soap operas.  She died two weeks later in the intensive care unit, a different pneumonia in her lungs.

In the face of death, food and hope are highly seductive. But once again, I was left wondering: Does our need to feed our dying loved ones blind us to what's really best for them?

Jessica Nutik Zitter is an attending physician at Highland Hospital in Oakland, Calif. She is board certified in critical care and palliative care medicine.

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Well: What Is So Special About Iyengar Yoga?

Slide Show

This week, the international yoga community said goodbye to a beloved teacher, B.K.S. Iyengar, who died at the age of 95. He is credited with bringing yoga to the Western world and making it accessible to every age and walk of life. To learn more about what makes Iyengar yoga so special to those who practice it, I spoke with Carrie Owerko, a teacher at the Iyengar Yoga Institute of Greater New York. She was also a student of B.K.S. Iyengar, and studied with him in India in February. Here's an edited version of our conversation.

Q. Why was B.K.S. Iyengar such an important teacher?

B.K.S. Iyengar was really a pioneer. He was one of the people who brought yoga to the West and really made it popular because he made it approachable for anyone. He felt that yoga was for everybody. No matter what the challenges — physical challenges, mental challenges or age — he didn't see any limitation.

I think one of his main contributions was making yoga accessible, but also the degree of attention he gave to the practices of asana, or postural yoga, and to pranayama, the breathing exercises, was immense. He was also an amazing communicator. He was constantly finding new ways to help his students increase their capacity to be aware of what was going on in their bodies and minds.

Iyengar is a lot of the yoga people experience in the United States. The teacher may not be teaching Iyengar, but that teacher has been influenced by Iyengar yoga in some way.

What is unique about Iyengar yoga?

What distinguishes Iyengar yoga is the very high degree of attention paid to alignment. Props may be used to increase awareness and to make the poses accessible. Sometimes we hold the poses longer than students might be used to in a flow-style class. There is an emphasis on movement, but then learning how to calmly abide in the body.

The diversity of practice is another distinguishing element. We don't do one sequence every day. That is the case in other popular types of yoga where there might be a consistent sequence repeated day to day. Even though we do repeat some of the same poses, there is a lot of diversity in the sequencing. In my experience that helps prevent injury and overuse. His approach is therapeutic in nature. That is a huge aspect to the practice.

Why did B.K.S. Iyengar use props in his teaching?

Take the yoga block. Everybody knows a yoga block. It's something you can get at Bed Bath & Beyond. The prototype of the yoga block was actually a rock or cinder block from B.K.S. Iyengar's garden. When he was teaching students, he would sometimes place students over his knee for a supported back arch if they couldn't support themselves. The story goes that he asked his daughter to go in the yard and bring this cinder block to help. That was the beginning of the yoga block. He would use whatever was in the environment — tables, chairs, ropes. The more common props — belts, straps, blocks and chairs, this is the type of equipment that was not really used in the practice of yoga. Now everybody is using them. There are never enough props to go around.

Is there a distinguishing pose or style of pose that is unique to Iyengar?

I don't know of a pose that we do exclusively in Iyengar that is not done in other styles. But the headstand and shoulder stand are really important poses in our practice. They are not always taught in other styles of yoga. We have alternatives for people who are not able to do them. If someone comes to an Iyengar class, they know there will be some inverted pose that is taught. We don't require people to do them but we try to make them accessible and safe. We insist on a yoga blanket to prevent overstretching of the neck area. Iyengar yoga is very cautious and mindful.

When did you last practice with B.K.S. Iyengar?

In February of this year I was in India and B.K.S. Iyengar was in the practice. Even though his daughter and son and now his granddaughter are teaching the majority of the classes now, he would be in the practice hall every single day correcting people and engaging people. Even at 95 years old, he couldn't help himself. He had to teach. It was his calling.

Do you have any special memories of him?

There were several different times where we had exchanges and encounters. He notices everything. One memory that stands out — I hadn't been to India for a few years. He saw me and said, "Oh, a little bit thin." I had only lost like three pounds and thought, "How could he possibly notice that?" We were laughing. My mother doesn't even do that.

Another time when he was in the United States for his book tour, we had done a demonstration of poses at the City Center in New York to celebrate his book tour. He loved the theatrical, and we did this demonstration and he was very enthusiastic.

I remember when we were at the institute he looked me in the eye and said, "You have to maintain.'' To someone who doesn't practice yoga, that might not mean anything, but we had worked so hard. It pushes you to break into new territory and challenge yourself, and after doing that you might back off. But that thing about maintaining the practice, that really stuck. Excellence is what he wanted of us. It's hard to put into words what you feel for someone who has changed your life.

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Well: Is Breakfast Overrated?

Photo Credit Illustration by Ben Wiseman

For years, we've heard that breakfast is the most important meal of the day. But scientific support for that idea has been surprisingly meager, and a spate of new research at several different universities — published in multiple articles in the August issue of The American Journal of Clinical Nutrition — could change the way we think about early-hours eating.

The largest and most provocative of the studies focused on whether breakfast plays a role in weight loss. Researchers at the University of Alabama at Birmingham and other institutions recruited nearly 300 volunteers who were trying to lose weight. They randomly assigned subjects to either skip breakfast, always eat the meal or continue with their current dietary habits. (Each group contained people who habitually ate or skipped breakfast at the start, so some changed habits, and others did not.)

Sixteen weeks later, the volunteers returned to the lab to be weighed. No one had lost much, only a pound or so per person, with weight in all groups unaffected by whether someone ate breakfast or skipped it.

In another new study — this one of lean volunteers — researchers at the University of Bath determined the resting metabolic rates, cholesterol levels and blood-sugar profiles of 33 participants and randomly assigned them to eat or skip breakfast. Volunteers were then provided with activity monitors.

After six weeks, their body weights, resting metabolic rates, cholesterol and most measures of blood sugar were about the same as they had been at the start, whether people ate breakfast or not. The one difference was that the breakfast eaters seemed to move around more during the morning; their activity monitors showed that volunteers in this group burned almost 500 calories more in light-intensity movement. But by eating breakfast, they also consumed an additional 500 calories each day. Contrary to popular belief, skipping breakfast had not driven volunteers to wolf down enormous lunches and dinners — but it had made them somewhat more sluggish first thing in the morning.

Together, the new research suggests that in terms of weight loss, "breakfast may be just another meal," said Emily Dhurandhar, the assistant professor at the University of Alabama who led the study there. Skipping breakfast in these studies, she said, did not fatten people.

Each study was fairly short-term, however, and involved a limited range of volunteers. More randomized experiments are needed before we can fully understand the impact of breakfast, said James Betts, the professor who led the study of lean people. It's not yet clear, for instance, whether heavy people's bodies respond differently to morning meals than lean people's, or if the timing and makeup of breakfast matters.

For now, the slightly unsatisfying takeaway from the new science would seem to be that if you like breakfast, fine; but if not, don't sweat it. "I almost never have breakfast," Dr. Betts said. "That was part of my motivation for conducting this research, as everybody was always telling me off and saying I should know better." Based on the results of these studies, he said his habits won't change.

Neither will those of Dr. Dhurandhar, who enjoys a morning meal. But, she said, "I guess I won't nag my husband to eat breakfast anymore."

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Well: Feeding Your Canine Athlete

Photo Dogs are endowed with more endurance-related muscle fibers than cats, making them better running companions.Credit IStock

Phys Ed

Gretchen Reynolds on the science of fitness.

Many people who run or walk with their dogs treat them like human running partners, offering them sips of Gatorade or half of a sports bar during a workout. But the latest science about performance nutrition for canines underscores that dogs are not people. They have more fur and cellular mitochondria, the small structures in cells that generate energy; lower body weights; and fewer fecal-related inhibitions than their human companions, each of which affects their nutritional needs.

To learn more about sports nutrition for dogs, I spoke recently with Dr. Joseph Wakshlag, a professor of clinical nutrition and sports medicine at Cornell University College of Veterinary Medicine in Ithaca, N.Y., and the author of a comprehensive new review about nutrition for active dogs, published this month in Veterinary Clinics of North America: Small Animal Practice. Among its many tidbits of knowledge, the article notes that dogs are endowed with more endurance-related muscle fibers than cats, making them better running companions; competing in a Frisbee or agility competition is, for a dog, glorious fun but relatively little exercise, requiring only about 25 percent more calories than lying on a rug; and consuming sports drinks tends to cause dogs to empty their intestines soon afterward, often with little warning.

This is all useful information, as were Dr. Wakshlag's replies to my questions. What follows are excerpts from our conversation.

How much exercise qualifies a dog as an athlete, and do canine athletes have special dietary needs?

It's similar to human athletes. There are sprinters, acrobats, marathon runners, all with different nutritional considerations. On the one hand, you have earthdogs — the dachshunds and such — designed for fast, short sprints, and then there are sled dogs that run 50 miles or more. Your typical running companion would be somewhere in between. In general, I'd say that if a dog is running continuously for more than 30 minutes, you should probably take a look at its diet, in terms of performance.

Does that mean feed it like a human runner?

No. Humans and dogs fuel exercise very differently. When we run, we start out burning mostly glycogen, which is stored carbohydrates. Dogs don't, partly because they have more mitochondria in their muscles than we do. Dogs burn fat as their primary endurance fuel, and carbohydrates are not very important for them.

So there's no reason to give a dog a sports bar, which is full of carbohydrates, during a run?

No. Same for those gel packets. I see people sharing them with their dogs. The dog may like it, but its not helping its running. Fat is the fuel for performance dogs.

So should an athletic dog's diet contain lots of fat?

That's a good question. For dogs jogging along with you for 20 minutes a few times a week, a normal commercial dog food containing about 15 or 16 percent fat should be fine. But if you and your dog run five or 10 miles a day, that dog likely needs a slightly higher-fat diet.

There are special high-performance dog foods now that contain as much as 20 percent fat. Or you can just add a teaspoon of olive oil to your dog's kibble. That increases fat intake by 1 or 2 percent, which can be plenty. On the other hand, fat is somewhat indigestible and can lead to greater fecal mass. So if you increase your dog's fat intake, be prepared to carry an extra plastic bag or two when you go running.

What about protein? How important is it?

Vital. Athletic dogs need protein to build and maintain muscle. In general, their diet should consist of at least 25 percent protein, preferably from meat. In one study, dogs fed plant-based soy protein experienced far more musculoskeletal injuries than dogs consuming meat protein.

And treats? Are they a good idea?

It depends on what else your dog is eating. The biggest health problem for most dogs is overweight. If you took your dog for a two-mile walk and reward him with a Milk-Bone, you've just given him more calories than he burned. A pat on the head would be healthier.

Do you recommend raw-food diets, which have become popular for dogs?

The raw-food diets available at pet stores are fine, if expensive. I do not recommend that people create their own raw-food diets at home. It's difficult to include all of the necessary nutrients, and there can be food-borne illnesses.

Any advice on hydration for exercising dogs?

Dogs don't sweat like we do. They pant to cool themselves. But they do lose fluids during activity. On the other hand, they are much better than most people at rehydrating. We did a study with search-and-rescue dogs working in 90-degree heat. They replaced their fluid losses almost drop for drop.

My advice would be to make sure that water is available if you'll be running with your dog for more than 30 minutes. But don't share your Gatorade. Dogs don't need carbohydrates or electrolytes, and the only study I know of that tested sports drinks in dogs found that the main outcome was gastrointestinal distress.

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Well: Legal Marijuana for Parents, but Not Their Kids

Photo Credit Stuart Bradford

The Well Column

Tara Parker-Pope on living well.

When the antidrug educator Tim Ryan talks to students, he often asks them what they know about marijuana. "It's a plant," is a common response.

But more recently, the answer has changed. Now they reply, "It's legal in Colorado."

These are confusing times for middle and high school students, who for most of their young lives have been lectured about the perils of substance abuse, particularly marijuana. Now it seems that the adults in their lives have done an about-face.

Recreational marijuana is legal in Colorado and in Washington, and many other states have approved it for medical use. Lawmakers, the news media and even parents are debating the merits of full-scale legalization.

"They are growing up in a generation where marijuana used to be bad, and maybe now it's not bad," said Mr. Ryan, a senior prevention specialist with FCD Educational Services, an antidrug group that works with students in the classroom.

"Their parents are telling them not to do it, but they may be supporting legalization of it at the same time."

Antidrug advocates say efforts to legalize marijuana have created new challenges as they work to educate teenagers and their parents about the unique risks that alcohol, marijuana and other drugs pose to the developing teenage brain.

These educators say their goal is not to vilify marijuana or take a stand on legalization; instead, they say their role is to convince young people and their parents that the use of drugs is not just a moral or legal issue, but a significant health issue.

"The health risks are real," said Steve Pasierb, the chief executive of the Partnership for Drug-Free Kids. "Every passing year, science unearths more health risks about why any form of substance use is unhealthy for young people."

Already nearly half of teenagers — 44 percent — have tried marijuana at least once, according to data from the partnership. Regular use is less common. One in four teenagers report using marijuana in the past month, and 7 percent report frequent use — at least 20 times in the past month.

Even in the states where marijuana is legal, it remains, like alcohol, off-limits to anyone younger than 21. But the reality is that once a product becomes legal, it becomes much easier for underage users to obtain it.

This summer, the Partnership for Drug-Free Kids released its annual tracking study, in which young people were asked what stopped them from trying drugs. Getting into trouble with the law and disappointing their parents were cited as the two most common reason young people did not use marijuana. The concern now is that legalization will remove an important mental barrier that keeps adolescents from trying marijuana at a young age.

"Making it legal makes it much more accessible, more available," said Dr. Nora Volkow, the director of the National Institute on Drug Abuse. "This is the reality, so what we need to do is to prevent the damage or at least minimize it as much as possible."

Drug prevention experts say the "Just Say No" approach of the 1980s does not work. The goal of parents should not be to prevent their kids from ever trying marijuana.

Instead, the focus should be on practical reasons to delay use of any mind-altering substance, including alcohol, until they are older.

The reason is that young brains continue to develop until the early 20s, and young people who start using alcohol or marijuana in their teens are far more vulnerable to long-term substance-abuse problems.

The brain is still wiring itself during adolescence, and marijuana — or any drug use — during this period essentially trains the reward system to embrace a mind-altering chemical.

"We know that 90 percent of adults who are addicted began use in teenage years," Mr. Pasierb said. "They programmed the reward and drive center of their teenage brain that this is one of those things that rewards and drives me like food does, like sex does."

Studies in New Zealand and Canada have found that marijuana use in the teenage years can result in lost I.Q. points. Mr. Pasierb says the current generation of young people are high achievers and are interested in the scientific evidence about how substance use can affect intelligence.

"You have to focus on brain maturation," he said. "This generation of kids wants good brains; they want to get into better schools. Talk to a junior or senior about whether marijuana use shaves a couple points off their SATs, and they will listen to you."

Because early exposure to marijuana can change the trajectory of brain development, even a few years of delaying use in the teen years is better. Research shows that young adults who smoked pot regularly before the age of 16 performed significantly worse on cognitive function tests than those who started smoking in their later teenage years.

Drug educators say that one benefit of the legalization talk is that it may lead to more research on the health effects of marijuana on young people and more funding for antidrug campaigns.

The Partnership for Drug-Free Kids plans to continue its "Above the Influence" marketing campaign, which studies show has been an effective way of reaching teenagers about the risks of drug use. The campaign does not target a specific drug, but it teaches parents and teens about the health effects of early drug use and tries to empower teens to make good choices.

"Legalization is going to make the work we do even more relevant," Mr. Pasierb said. "It's part of the changing drug landscape."

A version of this article appears in print on 08/19/2014, on page D1 of the NewYork edition with the headline: In Drug Fight, Erratic Cues For Teenagers .

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