Dear Doctor: When a medication says "take with food," what exactly does that mean? If you take it with a few crackers, does that count? I have a medication I take before going to bed, when I don't feel like eating anything big!

Dear Reader: When it comes to medications, how and when you take them can play a significant role on how effective they are. It also affects how they interact with your body. The direction to "take with food" means that you should not ingest that particular medication on an empty stomach.

There are multiple reasons for this. One is that the components of some medications can cause stomach upset, such as nausea or vomiting, if they are not taken along with food. Additionally, the presence of food can help to buffer the stomach and prevent potential irritation. Over the long term, medications like aspirin and other NSAIDs, corticosteroids like prednisone, as well as some oral contraceptives can cause inflammation or even ulcers when taken on an empty stomach.

The other thing that the presence of food does is to initiate digestion. When you eat, gastric acid is released into the stomach, which helps break down food -- and any medication -- into smaller components. For some medications, the bile and stomach acid produced during digestion boost the rate at which they break down and are absorbed. Conversely, other medications would be absorbed too quickly if taken on an empty stomach. The presence of food helps slow that process.

As to what "with food" actually means, it's not necessarily a full meal. If you happen to be timing your medication to breakfast, lunch and dinner, that's fine. But a few crackers at bedtime, as you said, can be adequate. Ditto for a piece of fruit or a glass of milk. It's probably a good idea to ask your pharmacist why your medication should be accompanied by food. That way, if it's to prevent inflammation or indigestion, you can monitor your response and increase or change the kind of food you're eating to maintain maximum comfort.

But -- and it's a very important one -- not all foods are created equal when it comes to medications. Grapefruit juice and some other fruit juices can change how drugs behave. They can increase the absorption rate of some drugs, including some statins. They can also change how the body metabolizes certain drugs, including antihistamines, birth control pills and blood pressure medications, among others. That means you can wind up with blood levels of a medication that are lower or higher than are optimal. Be sure to read the medication label. If you're uncertain what foods are OK, check with your pharmacist.

What about medications that require an empty stomach?

For these, take them either no less than one hour before a meal, or at least two hours after a meal. And if you're taking them after a meal, that means your medication will do its best work if you don't eat again for another two hours.

(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: Could you explain Guillain-Barre syndrome? My 57-year-old niece died of it, but it's still a mystery to me.

Dear Reader: First, please allow me to offer my condolences for the loss of your niece. There's no way to make the loss any easier, but I will try to explain a bit more about this terrible disease.

Guillain-Barre syndrome (GBS) is an acute inflammatory attack on the nerves by the immune system. The theory is that after certain viral or bacterial infections, the immune system, in its attempt to attack the virus or bacteria, also attacks the nerve cells because their proteins are similar to the viral or bacterial proteins. As the nerves fail to work, the patient develops progressive muscle weakness and nerve dysfunction throughout the body. Each year in the United States, the syndrome is diagnosed in one or two of every 100,000 people; the risk increases as we get older.

Infections with the intestinal bacteria Campylobacter jejuni have been known to increase the chances of GBS, with one study finding that three out of 1,000 patients infected with Campylobacter jejuni develop GBS. The bacterium is found in contaminated, undercooked poultry and meat, but also unpasteurized milk. Infection with HIV, influenza virus, Epstein Barr virus and cytomegalovirus also have been linked to a higher risk of GBS.

The influenza vaccine may slightly increase the chance of developing GBS. Specifically, about one out of a million people vaccinated against the flu develop the condition, although the rates are a bit higher with the H1N1 influenza vaccine -- about two in a million. Note that this is far lower than the number of people who die from the flu -- 1.4 per 100,000 -- and the number of people who develop GBS after the vaccine is actually lower than the number of unvaccinated people who develop it. The meningitis vaccine Menactra also has been linked to GBS in those ages 11 to 19, but the level of risk is still under investigation.

GBS manifests in many different ways, but symptoms generally begin with back pain and a feeling of tightness and tingling in the lower legs. One or two days later, weakness develops in the legs -- so much so that getting up from a chair or walking up the stairs can be difficult. Weakness then can develop in the mouth, throat and face, causing difficulty talking and eating. Weakness can also develop in the eyes, causing altered vision.

When the muscles used to breathe are involved, progressive shortness of breath develops, with 9.1 percent of patients hospitalized for GBS needing a respirator. In 70 percent of patients, GBS can also affect the nerves that go to the heart, blood vessels, bladder and the intestines, leading to abnormal heart, bowel and bladder function.

Without treatment, 67 percent of people with GBS will start to recover after four weeks. The recovery may be slow and incomplete depending on the severity of the illness. The use of plasmapheresis, which filters antibodies from the blood, can speed improvement, as can intravenous immunoglobulin. Even with these treatments, the death rate of those hospitalized with GBS is 2.58 percent.

Again, I'm sorry to hear about the passing of your niece. Better treatments are so obviously 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.)

Dear Doctor: We were shocked when our daughter, who is 26, was diagnosed with rheumatoid arthritis. I thought arthritis was something that elderly people got. What treatments are available, and what are our daughter's prospects for an active and healthy life?

Dear Reader: We're very sorry to hear about the medical challenge your family is facing and hope the information we offer will be of help.

When it comes to what is commonly referred to as "arthritis," we're actually talking about two different conditions. Osteoarthritis, which is the type of arthritis you're thinking of in regards to a more elderly population, is a degenerative disease. In osteoarthritis, the tissues of the joints deteriorate due to wear and tear. When the cartilage that cushions the joints begins to break down, it leads to swelling, stiffness and pain.

Rheumatoid arthritis, or RA, is an inflammatory autoimmune disease. Joint damage occurs because the immune system has gone haywire and begins to target the body's own tissues. Although RA most commonly affects the joints, it can also involve other parts of the body, including the lungs, digestive system, circulatory system, skin and eyes.

In the United States, about 1.5 million people (more women than men) are living with RA. It generally doesn't appear until the 40s, and becomes increasingly common as we hit our 50s and beyond, but cases in younger people are not rare.

The most common sites of inflammation in RA are the wrists and the finger joints closest to the palm. However, the knees, neck, ankles, feet, elbows and shoulders can also be involved. RA has a symmetrical pattern, so the joint on each side of the body is usually affected. In addition to that symmetry, symptoms of RA include tender and swollen joints, a feeling of warmth within the joints, fatigue and occasional fever. For many people, prolonged morning stiffness or difficulty moving again following a long period of inactivity can be some of the early signs of RA.

Treatment is tailored to each person's symptoms. Your daughter's rheumatologist will discuss lifestyle changes to address inflammation. This includes using special tools or aids to help with difficult tasks, pursuing the right kind of exercise -- hatha yoga has been found to be helpful -- and striking the optimal balance between activity and rest.

Eating a well-balanced anti-inflammatory diet can help manage RA symptoms. This treatment approach got a boost recently when a study found that RA patients who ate fish twice a week (baked, steamed, raw or broiled, but not fried) scored measurably lower on a standardized scale that measures disease activity.

Some medications for RA address pain and inflammation. Others take aim at the disease process itself. All have potential side effects, so urge your daughter to learn the risks and benefits of any proposed medication.

Looking to the future, advances in immunotherapy and the expanding study of the ever-surprising gut biome offer hope for RA sufferers. In the meantime, prompt treatment is crucial. Make sure your daughter finds a good rheumatologist she likes and begins her medical care.

(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.)