The gut includes the stomach, small intestine, large intestine, rectum, and anus. It is also called the gastrointestinal or GI tract.

The gut plays an important role in keeping you healthy. It is where food is broken down, digested, and the nutrients absorbed into the system. It is also one of the body's first immune defenses. The lining of the gut contains over half of the body’s lymphocytes (immune cells).

The gut protects you from infection by helping to get rid of dangerous germs and chemicals. Nausea, vomiting, and diarrhea are three ways in which the gut responds to anything that comes into your body that might be harmful.

HIV, HIV medications, and HIV-related conditions can all cause problems in the gut.

HIV
The gut is the site of hidden reservoirs (pockets) of HIV, even if you take HIV drugs. HIV causes damage to the lining of the intestines as it infects the many immune cells present there. Research is going on to understand how HIV behaves in the gut and how to develop drugs to target HIV there.

HIV medications
When you start a new drug, you may experience GI symptoms at first such as:

• Diarrhea
• Nausea, vomiting, loss of appetite
• Pains
• Gas
  

When these symptoms occur as side effects of HIV treatment, they are usually mild, and tend to go away after the a few days or weeks as your gut gets used to the medicine.

HIV-related conditions
If GI problems occur without a recent change in medication, it’s probably not a drug side effect. If they continue or get worse, it may be a sign that you have an infection, especially if you also have a fever. Some AIDS-related opportunistic infections (OIs) affecting the gut include:

• Cryptosporidiosis
• Microsporidiosis
• Cytomegalovirus (CMV)
• Mycobacterium avium complex (MAC)
  

Severe or long-lasting GI problems can lead to serious health problems and can prevent HIV drugs from entering the system and fighting HIV. It's best to report these symptoms to your health care provider to determine if they are a side effect of treatment or a symptom of something more serious.

Diarrhea is one of the most common side effects of HIV, intestinal infections, and HIV drugs. Left untreated, it can cause dehydration (loss of water and nutrients) and wasting (unintentional weight loss).

You have diarrhea if you have watery stools or if you have three or more bowel movements each day. If your diarrhea lasts for more than a few days, contains blood, or if you have a high fever or stomach pain you should contact your health care provider.

Your health care provider should:

• Test your stool to see if you have a parasite, protozoa (microscopic organism), virus, or bacteria
• Check your blood for HIV-related infections, proteins, vitamins, and other nutrients
• Use a special tool to look inside your gut (colonoscopy or endoscopy)

It can be difficult to diagnose the cause of diarrhea, but it is important to try since many infections will require treatment to be resolved.

If HIV drugs are causing your diarrhea you may be able to switch therapy. But that option is not for everyone and you should discuss it with your health care provider before you stop or change any HIV drugs.

There are some medications and supplements that can help manage diarrhea. These include:

• Over-the-counter remedies such as Imodium, Kaopectate, and Metamucil
• Prescription medicine such as Lomotil for harder-to-treat symptoms
• Calcium, fiber, and glutamine (an amino acid) supplements

Diarrhea can cause you to lose a lot of your body’s water and vital nutrients (electrolytes). If the water is not replaced you will become dehydrated. Symptoms of dehydration include:

• Thirst, anxiety, weakness, confusion, lightheadedness, fainting
• Smaller amounts of urine
• Dry and pale skin
• Increased heart rate
• Decreased blood pressure

Try to drink before you feel dehydrated. Clear juices, such as apple, peach, or pear are less harsh on the gut than other types of juices that are high in acid (such as orange or grapefruit). Peppermint, ginger, and nutmeg are believed to help with gut problems. Try peppermint or ginger tea or ginger ale. Nutmeg can be added to your food or drinks. Sports drinks can also help to replenish electrolytes. You should seek medical attention if you are dehydrated.

Some foods cause diarrhea or make it worse including:

• Coffee and other beverages with caffeine (cola, some other soft drinks, tea, etc.)
• Alcohol
• Chocolate
• Fried, fatty, and spicy foods
• Hard to digest (insoluble) fiber such as raw vegetables, potato peels, beans, and brown rice
• Dairy products (milk and cheese)

Some foods can help to relieve diarrhea, such as the BRATT diet:

• Bananas
• White rice
• Apple juice or apple sauce
• Toast
• Herbal Tea

Nausea, vomiting, and anorexia (loss of appetite) often occur as side effects of starting or switching HIV drugs. For many people, nausea goes away by itself after a few weeks on the drugs. Other people require help from drugs called antiemetics (anti-nausea drugs). Some antiemetics interact with HIV drugs, so be sure to speak to your health care provider about all the medications you are taking (including over-the-counter, prescription, street drugs, and herbs), even if you only use them occasionally.

Megace (a hormone) and Marinol (a synthetic version of marijuana) may increase appetite. Marijuana may be effective for nausea and appetite loss but is not legal or available everywhere.

Nausea, vomiting, and anorexia can be particularly problematic for pregnant women who may be experiencing morning sickness because of their pregnancy.

Ways to cope with nausea include:

• Eating dry crackers
• Eating small meals more often
• Sticking to bland foods that are easier to digest
• Relaxing before meals and chewing slowly
• Sipping ginger tea or ginger ale

Gas (farting) and bloating can usually be managed by not eating foods such as beans, broccoli, and vegetable skins. Over the counter or prescription drugs may also be used to relieve gas.

Heartburn (acid reflux) causes a burning sensation in your chest. It has nothing to do with your heart! It can happen when your stomach acid backs up into your esophagus. Try to stop eating certain foods to avoid heartburn:

• Spicy or fatty foods
• Alcohol
• Caffeine
• Citrus juices (orange, grapefruit, lemon, and tomato)

If symptoms do not go away you should see your health care provider.

HIV, other infections, and HIV drugs can cause many side effects that involve the gut. When GI problems are drug side effects, they usually go away after a few days or weeks. But for some HIV+ people, these side effects can last longer and have a serious impact on quality of life.

It's best to report GI symptoms to your health care provider to determine if they are a side effect of treatment or a symptom of something more serious. You can also use the following tips to manage symptoms and keep your gut as healthy as possible:

• Keep your bowel movements regular: you can try over-the-counter products such as Citrucel or Metamucil
• Probiotics or "good" bacteria like lactobacillus (found in yogurt and acidophilus capsules) may help improve your intestinal environment
• Drink lots of water
• Eat high-fiber foods (whole grain rice, bread, oats, vegetables and fresh fruits)
• Cut down on caffeine, fried foods, sugar, and animal fat
• See your health care provider on a regular basis