2004-3-2
This is the VOA Special English Health Report.
Many people believe they are
supposed to drink eight glasses of water a day, or about two liters.
Why? Because that is what they have been told all their life. But a
new report offers some different advice. Experts say people should
obey their bodies; they should drink as much water as they feel like
drinking.
The report says most healthy people meet their daily needs for
liquid by letting thirst be their guide. The report is from the
Institute of Medicine, part of the National Academies. This
organization provides scientific and technical advice to the
government and the public.
The report contains some general suggestions. The experts say
women should get about two-point-seven liters of water daily. Men
should get about three-point-seven liters. But wait -- in each case,
that is more than eight glasses.
There is an important difference. The report does not tell people
how many glasses of water to drink. In fact, the experts say it may
be impossible to know how many glasses are needed to meet these
guidelines. This is because the daily water requirement can include
the water content in foods.
People do not get water only by forcing themselves to drink a set
number of glasses per day. People also drink fruit juices and sodas
and milk. They drink coffee and tea. These all contain water. Yet
some also contain caffeine. This causes the body to expel more
water. But the writers of the report say this does not mean the body
loses too much water.
As you might expect, the Institute of Medicine says people need
to drink more water when they are physically active. The same is
true of those who live in hot climates. Depending on heat and
activity, people could need two times as much water as others do.
All this, however, does not answer one question. No one seems
sure why people have the idea that good health requires eight
glasses of water daily.
It may have started with a misunderstanding. In
nineteen-forty-five, the National Academy of Sciences published some
guidelines. Its Food and Nutrition Board said a good amount of water
for most adults was two-point-five liters daily. This was based on
an average of one milliliter for each calorie of food eaten.
But that was only part of what the board said. It also said that
most of this amount is contained in prepared foods.This VOA Special
English Health Report was written by Jerilyn Watson.