Water is by far the most important nutrient you consume each day. You can last a lot longer without calories, protein, and other nutrients. If you go just three to four days without water, your body will call it quits. While is it the most important nutrient, it is the one we tend to do without when we are busy. Millions of people are walking around mildly to moderately dehydrated without knowing it. And if you are immunocompromised, your sources of water need to be especially safe. Since water is so important, here are some key points to know about it.
To figure out how much water a body requires each day, multiply your weight in pounds by 15 for the amount in milliliters. If you prefer to think in liters (as water drinkers often do), you can multiply your weight in pounds by 0.015. That means if you weigh 150 pounds, you need at least 2,250 milliliters, or 2.25 liters (9.5 cups; eight cups is a half gallon), per day. If you are already dehydrated, you will need more to rehydrate your body. If you are chronically dehydrated, it will take a few weeks or more to fully rehydrate yourself. You will probably notice that you are urinating a lot while you get your body readjusted to a good water level.
The U.S. Environmental Protection Agency has standards set for contaminants that are possible health risks. You can contact your local water supplier to get an idea of what types of water and treatments are used in your area and if there are any special issues to be aware of for your health. If you get your water from an individual well, you can have a sample tested by your local water authority.
'Naturally pure water' does not exist. Drinking water comes from lakes, rivers, and reservoirs. People in rural areas and some city folk might drink groundwater from wells. Water suppliers might add coagulants to water to get the dirt and contaminants to form clumps that will settle to the bottom of tanks; it is then filtered to remove smaller contaminants like viruses and the protozoan giardia. From there, most water suppliers disinfect their water by adding chlorine or some other disinfectant to kill most bacteria and other contaminants. If your water comes from a well, it is naturally filtered through layers of earth into underground reservoirs and might need little to no treatment, depending on local conditions. In some cases water contaminated with organic chemicals may be treated with activated carbon.
The EPA and the Centers for Disease Control and Prevention recommend special care for drinking water if you are immunocompromised'specifically, if you have a CD4 count less than 200. In 2001 new standards for water safety were put into place for cryptosporidium and other difficult contaminants. While the standards are set, quality can vary from city to city, and the current information does not support a blanket recommendation to avoid tap water. However, for people with low CD4 counts, it may be worthwhile to take a few precautions.
' Boil water. If you live in an area with a high risk of cryptosporidium, this is the most effective way to kill the critter. You will need to boil water for a full minute.
' Have a point-of-use filter that cleanses water to one micrometer. These can include reverse-osmosis filters'those labeled as certified for cyst removal or as 'absolute' one-micron filters. Those labeled as 'nominal' may not remove cryptosporidium. Use filters according to instructions and change the filter components on a routine basis, as recommended by the manufacturer.
' Drink bottled water that has been filtered to one-micron specifications. Spring waters and well waters that are from protected sources are less likely to be contaminated than those from rivers and lakes. Distilled water and bottled water treated with reverse osmosis ensures cryptosporidium removal. Keep in mind that although bottled water may be filtered for cryptosporidium, this does not ensure the removal of all organisms that may cause problems in people with severely compromised immune systems.
Fields-Gardner is the director of services for The Cutting Edge, an HIV nutrition company in the Chicago area. She is a member of the International AIDS Society and the American Dietetic Association's Dietetic Practice Group on HIV and AIDS.
