Dear Doctor: I've been seeing advertisements for glutathione, saying the supplement enhances the body's cells. The ads also say the claims haven't been evaluated by the Food and Drug Administration. What can you tell me about it?

Dear Reader: Glutathione is an antioxidant produced in the body through enzymatic reactions, using the amino acids cysteine, L-glutamic acid and glycine. It helps repair cells damaged by pollution, stress and other harmful influences, and it is undeniably important.

Mice unable to form glutathione will die before birth. Mice that have been genetically altered to not produce glutathione in the liver will die after one month. People with mutations in the enzymes that form glutathione are more susceptible to oxidative stress. The deficiency in the production of glutathione leads to the breakdown of red blood cells, enlargement of the spleen, gall stones, and after many years can lead to mental deterioration. Also, these patients are more prone to severe anemia when exposed to certain chemicals or drugs.

Less is known about glutathione's use as a general supplement, although it has been evaluated by the FDA for AIDS-related weight loss. People with AIDS have reduced production of glutathione in the intestine, and supplementation with glutathione could help in the ability to digest food.

Glutathione has also been studied in cystic fibrosis patients. Decreased glutathione in their intestines can lead to inflammation of the intestine, pain, decreased absorption of food, weight loss and growth failure. A 2015 study published in the Journal of Pediatric Gastroenterology and Nutrition found that supplementation with glutathione three times per day with meals has been shown to decrease intestinal inflammation and improve growth in children with cystic fibrosis.

Other research assessed glutathione's effect on people with vascular disease of the arteries that go to the legs. Decreased blood flow can lead to calf pain when walking, but the study found that glutathione given intravenously twice a day helped ease patient symptoms.

Because you're presumably healthy, you're unlikely to have any deficiency in the production of glutathione. If you're interested in improving your body's ability to recover from exercise by enhancing your muscles' ability to heal, that's a different question. People who exercise vigorously create oxidative free radicals, which can lead to muscle fatigue and decrease muscle performance -- suggesting that an antioxidant may be helpful.

However, people who exercise regularly naturally produce more antioxidants in the muscles to prevent damage, possibly in response to the regular formation of oxidative free radicals. Regardless, the body takes care of itself without the need of a supplement.

As of yet, there is no good study of the use of glutathione in healthy people. Some nutritionists recommend increasing the intake of the amino acids cysteine and glutamate, which make glutathione, but this hasn't been studied either.

In short, the supplement has shown benefit among cystic fibrosis and AIDS patients who have decreased glutathione in the intestine, and it may show benefit in inflammatory conditions of the intestine, such as ulcerative colitis and Crohn's disease, but this needs to be studied as well.

At this point, I would not recommend taking glutathione. If you're healthy, your body should produce an adequate amount of this important antioxidant.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I understand that Alzheimer's disease causes memory loss and leads to dementia. But when someone has Alzheimer's, what is the actual cause of death?

Dear Reader: Alzheimer's disease is a progressive disease of the brain in which dementia is the most noticeable of numerous symptoms. Changes within the tissues of the brain slowly destroy vital connections between different regions of the brain, and between the brain and the body. The result is that Alzheimer's disease is the fifth-leading cause of death among adults over 65, and is the sixth-leading cause of death for all adults nationwide.

The disease was first identified in 1906 by Dr. Alois Alzheimer, who connected a patient's dementia to certain physical abnormalities he found when he examined her brain after her death. But the human brain is so intricate and Alzheimer's itself is so complex that more than a century later, scientists are still working to discover both the cause of, and a cure for, the disease.

Although each case of Alzheimer's is different, researchers have identified three general stages of the disease. In the first stage, symptoms of cognitive impairment, such as memory loss or confusion, have either not yet appeared or are quite mild. However, significant changes are taking place within the brain, including nerve death, tissue loss and the buildup of abnormal clumps and tangles of protein.

These changes lead to the second stage of the disease, during which symptoms become more pronounced. Patients begin to experience significant memory loss, confusion, impaired reasoning, poor spatial skills and a loss of language. By the final stage of Alzheimer's, the brain has shrunk dramatically. Patients can no longer communicate, are unable to recognize faces, even of family members and loved ones, and are unable to care for themselves.

Patients with advanced-stage Alzheimer's need 24-hour supervision and help with personal hygiene, dressing and eating. Changes in brain function make it increasingly difficult for them to move about, sit up and even swallow. This leads to complications such as bedsores, skin infections, blood clots and sepsis. Injuries from falls are common. Difficulty in swallowing makes eating and drinking an ongoing challenge, and can lead to weight loss, malnutrition and dehydration.

The most common cause of death among Alzheimer's patients is aspiration pneumonia. This happens when, due to difficulty in swallowing caused by the disease, an individual inadvertently inhales food particles, liquid or even gastric fluids. Because our mouths and throats contain numerous bacteria, these are carried deep into the lungs. There they multiply and grow, which leads to pneumonia. Due to the impaired immune systems of Alzheimer's patients, pneumonia is often fatal.

It's important to remember that Alzheimer's patients are often elderly and thus may have a range of medical conditions associated with advancing age. These include stroke, cancer, heart disease, diabetes, hypertension and stroke, any of which can cause death, whether or not Alzheimer's is present.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: Sometimes when I awake from a good sleep, one of my hands is asleep, and I have to shake or massage it back to normalcy. It's usually my thumb and the two fingers next to it. Is this normal?

Dear Reader: No, this is not normal. Your symptoms are typical of carpal tunnel syndrome, which occurs because of a compression of the median nerve at the wrist. The median nerve provides sensation to the thumb, index and middle fingers. It also supplies the muscles that control the thumb and the smaller muscles that control the index and middle fingers.

The median nerve is in real cramped quarters as it makes its way through the wrist. As you look at the palm surface of your hand and move your eyes toward your wrist you can see multiple tendons. The median nerve has to share room with nine of these tendons that are within the carpal tunnel. When there is inflammation in the wrist, or the tendons become inflamed, the median nerve gets compressed.

The first symptoms are often noted during sleep, when we have a tendency to flex the wrists, so that our hands curl. This flexion of the wrists causes greater compression of the median nerve, which leads to the sensation of tingling in the thumb and the index and middle fingers, as if your hands are falling asleep.

Carpal tunnel syndrome is very common and can be caused by repetitive work involving recurrent compression on the median nerve. Studies have been mixed as to the type of work that can cause this. One study showed that recurrent use of a computer mouse was associated with carpal tunnel syndrome, but there has been no consistent association with recurrent keyboard use.

Women are more likely to have carpal tunnel syndrome than are men. The rate is 5 percent in the general population, but women have rates ranging from 7 percent to 18 percent. One study, published in Environmental Research, for example, found a greater rate of carpal tunnel syndrome in female butchers and meat cutters.

Diabetes, rheumatoid arthritis and hypothyroidism are diseases that are associated with an increased risk of carpal tunnel syndrome.

As for a diagnosis, that can be done through a physical exam or through a nerve conduction study.

For starters, I would consult your doctor. If he or she diagnoses carpal tunnel syndrome, wearing a wrist brace at night would be the likely recommendation. Whether rigid or of a softer variety, wrist braces help because they don't allow the wrist to curl when you're sleeping. In addition, a physical therapist can teach stretches and range of motion exercises that can ease symptoms.

Finally, pay attention to signs of weakness in the hand. This would be noticed mostly in the use of the thumb, such as if you start dropping keys or begin having difficulty holding a cup. These signs suggest additional treatment, such as surgery, may be needed.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)