I read that creatine is a good supplement for ALS patients. Can you tell me if it really is useful? What is your opinion on Rilutek?

As nerve cells waste away or die, they no longer can send messages to muscles, which in turn leads to muscle weakening and eventually to the inability to move the arms, legs and body or to swallow. When chest muscles stop working, patients become unable to breathe on their own. ALS doesn't affect the senses or thinking ability and only rarely affects bladder or bowel function.

The cause of most cases of ALS is unknown, but about 10 percent are familial, associated with a genetic defect. Toxic injury to the brain may start the degenerative process in nonfamilial ALS.

Creatine, an important compound in muscle tissue, is the building block for ATP (adenosine triphosphate), the energy storing compound that fuels muscles during short, high-intensity exercise such as weight training.

I discussed your question about its use in ALS treatment with David Perlmutter, M.D., a neurologist in Florida (see www.perlhealth.com). He says that creatine, taken by itself, has been studied and found ineffective in the treatment of ALS. However, he tells me that a new study underway at the Massachusetts General Hospital is looking at creatine in combination two different doses of the breast cancer drug Tamoxifen to see if they are safe and effective for use in ALS patients. Dr. Perlmutter and his associates have been using Tamoxifen in their ALS patients for the past three years along with a ketogenic diet, which is very high in fat and very low in carbohydrates. The diet keeps the body in a constant state of "ketosis," in which it is forced to burn fats only. Dr. Perlmutter says the diet has been found to be exceptionally effective in the experimental animal model of ALS. ;

Tamoxifen emerged as a possible treatment for ALS more than 10 years ago when a neurology professor at the University of Wisconsin Hospital and Clinics in Madison saw that one of his ALS patients who was taking Tamoxifen for breast cancer seemed to be improving neurologically; the drug seemed to be slowing the progression of her ALS. Studies since then have shown that Tamoxifen prolongs survival in ALS patients with few side effects (primarily hot flashes). Since then preliminary evidence from animal studies of stroke and oxygen deprivation also suggests that Tamoxifen is neuroprotective.

As for Rilutek (riluzole), Dr. Perlmutter says that while this drug has been FDA approved for treatment of ALS, it has little effect on disease progression and is often associated with serious side effects.

Andrew Weil, M.D.

Are "Power Plate" vibration machines truly effective as a way to build/restore bone density? If so, what are the key points in choosing a machine?

A study from the University of Toronto published in the Nov. 15, 2011 issue of the Annals of Internal Medicine tested vibration machines for a year and found no differences in bone density in the 202 postmenopausal women who participated. At the outset, the women's bone mass was low but not low enough to require drug treatment. Their bone density was measured when the study began and a year later when it ended.

The researchers randomly divided the women into three groups; two groups were assigned to stand on a whole body vibration platform that moved at one of two speeds for 20 minutes a day. The third group served as controls. For the duration of the study all the women took calcium and vitamin D to see if the supplements plus vibration reduced the rate of bone loss.

Results showed no statistically significant difference in rate of bone loss over the year among the women in the vibration groups compared to the controls. The researchers concluded that whole body vibration should not be recommended to prevent bone loss.

The best way to avoid the age-related loss of bone mineral density that leads to osteopenia (bone mass that is low but not low enough to be classed as osteoporosis) and then to osteoporosis is to build up sufficient bone mass early in life. Maximum bone mass is reached around age 35. Once you reach midlife, your best strategy is strength training, also called resistance exercise.

Bone is constantly being re-formed by the action of opposing forces, some destructive, some constructive, in response to the stresses and demands placed on it. These changes are under precise cellular and hormonal control and can take place very quickly. Resistance exercise places demands on bone that cause the constructive influences to dominate, halting loss of mineral density and even adding to it. (Some aerobic activities such as walking, climbing stairs, and jogging help to maintain bone density, but others such as swimming and cycling do not.)

Bear in mind that a sedentary lifestyle promotes bone loss as well as muscle loss. Conversely, muscle use promotes the building of bone. Regular physical activity strengthens both muscles and bones, slows bone loss and decreases the risk of injury from falls. As the Toronto vibration study indicates, there is no substitute for the physical activity needed to keep your bones strong.

Andrew Weil, M.D.

Which form of potassium is best for augmenting food intake? At health food stores I find potassium in many forms - gluconate, chloride, aspartate, chelate, etc., but no one can tell me if one is better assimilated or useful than another.

Despite its importance to optimum health, I do not recommend that anyone take potassium supplements unless a doctor has prescribed them. We all can get adequate potassium from food sources, and for that reason supplements are needed only under specific medical circumstances. Potassium deficiency is rare, and when it occurs, it usually affects people with kidney disease, gastrointestinal disease and those who take diuretics.

Although bananas are probably the best known source of dietary potassium, other particularly good ones are baked potato with skin, prune juice, prunes, raisins, tomato juice and tomatoes, almonds, sunflower seeds, spinach and artichokes. Meat, fish and chicken are also good sources as are soy foods.

Taking potassium supplements on your own can lead to hyperkalemia, a higher than normal level of potassium in the blood that can be life-threatening and requires immediate medical treatment. The most common cause of hyperkalemia is acute or chronic kidney failure, but it also can be a side effect of certain medications, including angiotensin-converting enzyme (ACE) inhibitors (for lowering high blood pressure), non-steroidal anti-inflammatory drugs, and blood thinning agents such as heparin. Hyperkalemia can also stem from alcoholism or type-1 diabetes as well as excessive use of potassium supplements. Symptoms include muscle fatigue, weakness, paralysis, abnormal heart rhythms and nausea.

Symptoms of potassium deficiency, called hypokalemia, include irregular heartbeat, muscle weakness and cramps, and mood changes, as well as nausea and vomiting. A severe deficiency can lead to muscle paralysis and abnormal heart rhythms that can be fatal. Deficiencies usually stem from a loss of potassium due to prolonged vomiting, the use of some diuretics and some types of kidney disease. It is highly unlikely that a low dietary intake of potassium, by itself, would ever lead to a deficiency.

Andrew Weil, M.D.

I'm a woman in my 60s. I've always fought to keep my weight down, but as I get older, I've become concerned that being slim could be unhealthy. I recently heard that thin seniors are at higher risk of Alzheimer's disease and are more likely to die after surgery than overweight patients. How worried should I be?

The Alzheimer's data come from a study published in the November 22, 2011 issue of Neurology that looked for biological markers of the disease in 506 seniors, some with no memory problems, some with mild cognitive impairment or mild memory problems, and some who had been diagnosed with Alzheimer's disease (AD). Earlier research has shown that the biomarkers that signal AD can be present many years before the first symptoms appear. Using advanced brain imaging techniques and tests of cerebrospinal fluid, the investigators found the tell-tale biomarkers in 85 percent of the slimmest of their subjects, all of whom already had mild cognitive impairment. The biomarkers were found in only 48 percent of the overweight study participants.

In a statement that accompanied publication of the study, lead investigator Jeffrey Burns, M.D., associate director of the University of Kansas Alzheimer's Disease Center said that it is possible that in its earliest stages - long before memory problems appear - the disease may trigger changes in metabolism that lead to weight loss. Other experts have suggested that declines in mental function could affect the frequency with which affected individuals shop, cook and eat. Bear in mind that this study showed only an association between weight and Alzheimer's, not cause and effect.

As for the study on the weight-related risks of surgery, here researchers looked at data on nearly 190,000 patients who had various surgical procedures at 183 hospitals. They found that the risk of death was elevated in patients whose body mass index (BMI) was lowest, under 23.1. The researchers didn't have an explanation for their findings but said that it is possible that the thinnest patients weighed less because they were sicker.

Other evidence has suggested that being too thin as you get older can compromise your health. In 2010, findings from a widely publicized Australian study found that being a bit overweight in your 70s is associated with a longer life expectancy than being either obese or of normal weight. Researchers at the Western Australia Center for Health and Aging reviewed data on more than 9,000 men and women between the ages of 70 and 75 and found that those whose body mass index (BMI) classified them as overweight were the least likely to die over the study's 10-year follow up.

In my 2005 book Healthy Aging, I took issue with the notion that simply being overweight¸ as indicated by insurance company tables of ideal heights and weights or BMI measurements, makes people unhealthy and less likely to age gracefully. I also noted that being too lean may compromise health and longevity by limiting reserves of stored energy that may be needed to get through an injury or illness. Overall, my view is that it is better to be fit and fat than lean and not fit. If you're slim - and fit - and feeling good, I wouldn't worry that your weight is compromising your health - or that gaining a few pounds would be harmful.

Andrew Weil, M.D.

• oily, cold water fish, such as salmon, mackerel, herring, and sardines
• walnuts
• freshly ground flaxseeds and hemp seeds - and the oils extracted from them
• unprocessed soy and canola oils
• specially fortified eggs

Eating these can also help treat depression, bipolar disorder, autism, and attention deficit hyperactivity disorder.

In addition to getting too few omega-3s, most North Americans and Europeans consume omega-6 fatty acids in excess. Omega 6s are common in the mainstream North American diet; they are found in seeds and nuts, and the processed oils extracted from them. Refined vegetable oils, such as hydrogenated cotton and soy oils, are used in most snack foods, cookies, crackers, and sweets as well as in fast food. Many nutrition experts believe that before we relied so heavily on processed foods, humans consumed omega-3 and omega-6 fatty acids in roughly equal amounts, and we would be healthier if we hewed more closely to this distribution. Now most people get much more of the latter.

If you're eating three ounces of fish two to three times a week, as I recommend, snacking on walnuts and adding freshly ground flaxseeds to cereals and salads you're probably getting enough omega-3s. A three-ounce serving of Alaskan salmon or herring contains about two grams of omega-3 fatty acids, while three ounces of sardines gives you about 1.3 grams. You can substitute one ounce of walnuts for a serving of fish, or add a tablespoon or two of freshly ground flaxseeds or hemp oil to your diet. (These plant sources provide you with alpha linolenic acid, which the body converts inefficiently to the omega-3s it needs.)

Along with these dietary additions, ;I recommend that everyone take two to three grams daily of a fish oil supplement. Look for one derived from molecularly distilled fish oils, which are free of mercury, PCB, and other contaminants.

To answer your question, the short answer is no, you cannot take too much omega-3s. There is, however, one exception, for individuals who take anti-coagulant drugs or have blood coagulation problems. They probably should avoid fish oil supplements since omega-3s can affect blood clotting. Very high intakes of fish oil/omega-3 fatty acids (termed "Eskimo amounts" by the National Institutes of Health, in reference to diets that consist almost exclusively of fish) may increase the risk of hemorrhagic stroke and have been associated with nosebleed and blood in the urine.

Andrew Weil, M.D.

My cousin was just diagnosed with lung cancer and never smoked a day in his life. What could have caused his lung cancer?

The main causes of lung cancer among non-smokers are exposure to secondhand smoke, radon gas, carcinogens at work, and air pollution.

The U.S. Environmental Protection Agency (EPA) lists radon exposure as the leading cause of lung cancer in non-smokers, accounting for about 20,000 deaths every year. Radon is an odorless, colorless gas produced by the breakdown of uranium that seeps out of the earth, more commonly in some places on the planet than others. It sometimes enters basements through concrete cracks and becomes trapped there, concentrated in the air. The risk of lung cancer is higher in people who have lived for many years in a house contaminated by radon.

Exposure to other carcinogens such as asbestos and diesel exhaust increases the risk of lung cancer. This tends to occur in the workplace in jobs traditionally held by men. The ACS reports that exposure rates have declined in recent years due to measures taken to protect workers, but they are still a concern.

Both indoor and outdoor air pollution increase the risk of lung cancer. A study published online on October 6, 2011 in the American Journal of Respiratory and Critical Care Medicine found that in China where many homes have coal burning stoves and poor ventilation, lung cancer rates are high among non-smoking women.

Unfortunately, there aren't currently any risk-free tests to find lung cancer early and routine screening isn't recommended for non-smokers. Lung cancer doesn't produce symptoms in its early stages. By the time it causes ;shortness of breath, coughing that doesn't go away, wheezing, coughing up blood, chest pain, and, sometimes, repeated bouts of pneumonia, it is usually inoperable and often has spread beyond its site of origin.

The best way to protect yourself from lung cancer is to avoid tobacco - quit if you smoke, and if you don't, stay away from smokers and smoky surroundings. Eat plenty of fruits and vegetables, and test your home for radon.

Andrew Weil, M.D.

According to the American Cancer Society (ACS) symptoms of chemo brain can include memory lapses, trouble concentrating, problems multi-tasking, difficulty remembering common words when speaking, thinking more slowly, and being generally disorganized. The ACS reports that most of the time chemo brain symptoms occur soon after cancer treatment and last only a short time, but also notes that some patients experience long-term mental changes, some of which are subtle.

One of the problems in understanding chemo brain and determining how widespread it is, is that most patients' baseline cognitive skills aren't tested before treatment, so researchers have no way of knowing for sure whether any patient really is worse afterwards.

In a study published in the November (2011) issue of the Archives of Neurology, researchers from the Stanford Cancer Center looked at 25 breast cancer patients who had undergone chemotherapy, 19 breast cancer patients who did not have chemo, and 18 healthy women. The study was conducted about five years after the cancer patients were treated. The women were asked to report on their own sense of changes in thinking and problem solving. They were also asked to perform a card sorting chore designed to measure problem-solving skills. All of them had functional MRI (fMRI) studies to assess brain changes.

The researchers found that the breast cancer patients who did not have chemotherapy showed some brain changes on their fMRIs but no impairment on the cognitive tests. However, the women who had received chemotherapy had brain changes that reflected their cognitive test performances, which were slower than that of the other women; they also made more mistakes on the cognitive challenge. The fMRI changes were consistent with how the women who had had chemo described their altered mental abilities.

The Stanford researchers suggested that other components of cancer treatment could play a role in chemo brain, including radiation therapy, which most of the women went through. Other considerations were whether they took the estrogen-blocking drug tamoxifen after treatment - the drug has been associated with cognitive impairment; and possibly even the anesthesia used for surgery. The disease itself might be to blame, too, perhaps due to the effects on the brain of inflammation associated with cancer.

While there's no sure cure for chemo brain, the problem is more common in patients who are the least active, mentally and physically. Consequently, exercise - mental and physical - may help.

Andrew Weil, M.D.

Does edible red desert clay help build strong bones? Is it a heavy metal detoxifier? I'm wondering if it does what its supporters say it does.

Ingesting clay if it has properly sourced and packaged is probably harmless, but I doubt if it helps with detoxification. My own view is that the body does a good job of cleaning and purifying itself if you stop putting toxins in and focus on getting good nutrition, regular exercise, and develop other healthy habits. In fact, none of the many supplements and herbal products purported to detoxify the system and purify the blood are necessary to good health.

You can help the body rid itself of unwanted materials by drinking more pure water to increase urinary output, taking baths or saunas, which can help eliminate toxins through sweating, eating plenty of fiber-rich fruit, vegetables and whole grains to ensure regular eliminations, and getting enough aerobic activity to stimulate breathing.

I wouldn't depend on red clay to help build strong bones either. To prevent bone loss, take 2,000 IU of vitamin D daily. ; Eat calcium-rich foods: high quality, organic dairy products such as yogurt and milk, sardines (with bones), dark green vegetables like collard greens, bok choy and broccoli, whole soy-based products like tofu, and calcium-fortified soymilk and orange juice. Women can take supplemental calcium - 500 to 700 mg a day in two divided doses taken with meals, and no more than 1,500 mg a day from all sources; calcium citrate is best. (Men should not take calcium supplements.) Take half the amount of magnesium as you do of calcium to offset the constipating effects of calcium.
Here are my other recommendations for keeping bones strong:

• Eat plenty of vegetables and fruit. Potassium, magnesium, vitamin C and beta carotene (found in fruits and vegetables) have been associated with higher total bone mass. A diet rich in vegetables and fruit and moderate in animal protein and grains may minimize the acid-ash residue of the diet.
• Make sure you're getting vitamin K in your diet. Vitamin K regulates calcium in the body, keeping it in the bones and out of the arteries. The best sources are green leafy vegetables (see the calcium-rich greens listed above), but most vegetables are good sources. If you are taking a blood-thinning medication, talk with your doctor about vitamin K.
• Avoid salty processed foods and fast food. Don't salt your food before tasting it. Some studies suggest that high dietary sodium is bad for bones.
• Limit caffeine intake. It can contribute to bone loss.
• Avoid alcohol or drink only in moderation. Alcohol can decrease absorption of calcium from the intestines and lead to deficiencies in vitamin D and magnesium.
• Try to do at least 30 minutes of weight-bearing activities, such as walking, weight training and calisthenics most days of the week. Getting regular physical activity is the most important thing you can do to avoid osteoporosis.

Andrew Weil, M.D.

Do transonic pest repellants have any adverse effects on humans? We are considering purchasing one of these to keep mice out of our home. It seems like a good alternative to pesticides, but I would like to make sure it is safe for my family.

House mice usually move indoors in the fall when it gets colder outdoors, particularly at night. Getting rid of them isn't easy.

Transonic pest repellants may seem like a good way to discourage mice from settling into your house. These devices emit regularly repeated sounds above the range of human hearing that, in theory, will drive mice away. The trouble is, evidence indicates they are ineffective. Because the sounds are directional, they don't penetrate behind objects and they lose intensity with distance. According to a report from the University of California at Davis, there is little evidence that sound, magnetic, or vibration devices of any kind will drive established mice (or rats) from buildings or prevent them from taking up residence. I don't know that they cause any adverse effects in humans, other than the hit your wallet will take as a result of investing in a device that doesn't work.

Assigning the job of mice control to a cat isn't the solution either. While some cats (and dogs) will catch and kill mice, cats are unlikely to eliminate existing mice populations. Mice usually can find hiding places where they can raise their young out of the reach of even the most enterprising cat. And, of course, mice will eat the cat's food (or the dog's) if it is left out.

Your best bet is to use traps. The advantages are that they don't require use of rodenticides that could be harmful to humans and pets and you can see whether you've caught a mouse and then dispose of it. The best bait to use is peanut butter. ;

Instead of traps, you could consider glue boards - the mouse gets stuck walking across the adhesive, but these aren't considered humane since the mouse isn't killed quickly and may struggle to escape. If you find a live mouse on a glue board, you'll have to kill it yourself. Flushing isn't humane and releasing the mouse outdoors just adds to the population that will try to move into your house.

The best way to deal with mice is prevention - sealing or screening all openings that may give mice entry into your house and not leaving any food around to attract them. Be sure to store foods (and garbage) in metal or heavy duty plastic containers with tight fitting lids.

Andrew Weil, M.D.

My husband's family grew up making homemade sassafras tea from the tree bark and root. We just started brewing our own, and now I am concerned with health side effects after reading some articles online. Is there a reason to be concerned? Should we stop drinking it?

Sassafras (Sassafras albidum) grows throughout the eastern United States and as far west as Texas. Extracts of the root and root bark were used by Native Americans and the early European explorers of North America, who believed them to be a miracle cure. The essential oil from the root bark and twigs were widely used to flavor root beer and candy and to scent soap and perfume as well as for making tea.

However, the volatile oils found in the bark of the root of the sassafras plant are 80 percent safrole, a compound that turns out to be carcinogenic in laboratory animals. Studies have shown that rats and mice injected with large amounts of safrole have trouble walking and show signs of nervousness and confusion as well as difficulty with body temperature regulation. Long-term exposure to safrole can cause liver cancer in laboratory rats. For these reasons, in 1960 the FDA banned food additives containing safrole. Health authorities in Canada followed suit.

Perhaps the biggest effect of this ban has been to eliminate the use of sassafras root in the making of root beer. Today, sassafras can be used as an ingredient in root beer only if the safrole has been removed through a laboratory extraction process. Small amounts of safrole also occur naturally in black pepper, star anise, nutmeg, witch hazel, and basil, all of which are safe in the amounts usually consumed. Another culinary use of sassafras is for making the Creole spice filé (dried sassafras leaves ground to a fine powder) which thickens gumbo, when okra is not in season.

;Consuming moderate amounts of safrole in plant products (such as sassafras tea) is not comparable to injecting large amounts of the pure chemical into the abdomens of rats. A search of the medical literature for sassafras tea shows only one report of an adverse effect: excessive sweating in a man who began drinking it.

If you're living around the trees and want to drink the tea for a few weeks in the early spring, I see no reason not to try it, but I'm also unaware of any documented health benefits of sassafras tea.

Andrew Weil, M.D.