Tagged Water

Milk and Other Surprising Ways to Stay Hydrated

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Credit Tony Cenicola/The New York Times

Most Americans have heard that they should drink eight glasses of water a day to stay hydrated, but there is surprisingly little data to support this advice.

But now, a new “beverage hydration index” provides evidence-based suggestions for how to most efficiently hydrate. The index was developed from a British study published in December that tracked how long 13 common beverages remain in the body after being consumed.

“In the last 25 years, we’ve done many studies on rehydration after exercise,” said Ronald J. Maughan, a hydration expert from Loughborough University, and lead author of the study. “We thought it was time to look at hydration in typical consumers who aren’t exercising.”

The hydration index is modeled after the well-known glycemic index, which measures how the body responds to the carbohydrate content of different foods. (The glycemic index is used to help individuals keep their glucose-insulin response under control.) The guiding principle behind the new hydration index is that some fluids last longer in your body than others, providing more hydration. After all, if you drink a cup of water and then immediately excrete half that amount in your urine, you haven’t added eight ounces to your water supply, but only four.

The British study determined the hydration index of 13 common beverages by having the participants, 72 males in their mid-20s, drink a liter of water as the standard beverage. The amount of water still remaining in subjects’ bodies two hours later — that is, not voided in urine — was assigned a score of 1.0. All other beverages were evaluated in a similar manner, and then scored in comparison to water. A score higher than 1.0 indicated that more of the beverage remained in the body as compared to water, while a score lower than 1.0 indicated a higher excretion rate than water.

The results showed that four beverages — oral rehydration solution, like Pedialyte; fat-free milk; whole milk and orange juice — had a significantly higher hydration index than water. The first three had hydration index scores around 1.5, with orange juice doing slightly better than water at 1.1. Oral rehydration solutions are specifically formulated to combat serious dehydration such as that resulting from chronic diarrhea.

“It’s a very clever, even brilliant study,” said Lawrence Armstrong, a hydration expert at the University of Connecticut and immediate past president of the American College of Sports Medicine. “It assumes that water is the optimal rehydration fluid, which is biologically correct, and then compares other fluids to water.”

Why is milk so efficient at rehydration? “Normally when you drink, it signals the kidneys to get rid of the extra water by producing more urine,” Dr. Maughan said. “However, when beverages contain nutrients and electrolytes like sodium and potassium, as milk does, the stomach empties more slowly with a less dramatic effect on the kidneys.”

Perhaps surprisingly, drinks containing moderate amounts of caffeine and alcohol or high levels of sugar had hydration indexes no different from water. In other words, coffee and beer are not dehydrating, despite common beliefs to the contrary, and regular soda can hydrate you just as well as water.

“It’s true that caffeine is a diuretic, but not at the concentration found in most coffee drinks,” Dr. Maughan said. “When we are thirsty, drinking normal tea, coffee or cola helps to rehydrate us. The exceptions are very strong coffee drinks or strong alcoholic drinks like distilled spirits.”

The hydration index could prove useful when making decisions about what beverages to consume and when. For example, if you’re going on a long drive and won’t have access to fluids (or to bathrooms), you’d be smarter to drink milk with its high hydration index rather than water or iced coffee. But don’t forget that milk has many more calories than water, so don’t overdo it, either.

While severe dehydration is rare except in heavy exercise, extreme environments and disease, studies have shown that heat and dehydration can contribute to increased mortality rates during hot weather. “Mortality increases sharply during heat waves, mostly because people don’t drink enough to compensate for their increased fluid losses,” Dr. Maughan said.

Dr. Armstrong noted that in hot weather, it’s important to monitor your hydration status throughout the day. He suggested paying attention to your thirst, and drinking when necessary. Also, if your urine color is a dark yellow, it’s time for a refreshing drink.

Dehydration: Risks and Myths

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Credit Paul Rogers

Truth to tell, sometimes I don’t follow my own advice, and when I suffer the consequences, I rediscover why I offer it. I’ve long recommended drinking plenty of water, perhaps a glass with every meal and another glass or two between meals. If not plain water, which is best, then coffee or tea without sugar (but not alcoholic or sugary drinks) will do.

I dined out recently after an especially active day that included about five miles of walking, 40 minutes of lap swimming and a 90-minute museum visit. I drank only half a glass of water and no other beverage with my meal.

It did seem odd that I had no need to use the facilities afterward, not even after a long trip home. But I didn’t focus on why until the next day when, after a fitful night, I awoke exhausted, did another long walk and swim, and cycled to an appointment four miles away. I arrived parched, begging for water. After downing about 12 ounces, I was a new person. I no longer felt like a lead balloon.

It seems mild dehydration was my problem, and the experience prompted me to take a closer look at the body’s need for water under a variety of circumstances.

Although millions of Americans carry water bottles wherever they go and beverage companies like Coke and Pepsi would have you believe that every life can be improved by the drinks they sell, the truth is serious dehydration is not common among ordinary healthy people. But there are exceptions, and they include people like me in the Medicare generation, athletes who participate in particularly challenging events like marathons, and infants and small children with serious diarrhea.

Let’s start with some facts. Water is the single most important substance we consume. You can survive for about two months without food, but you would die in about seven days without water. Water makes up about 75 percent of an infant’s weight and 55 percent of an older person’s weight.

Human cells simply don’t function without water, and the body has evolved a finely tuned, complex system for making sure it has the water it needs under a wide range of conditions. In most cases, thirst is a reliable signal that more water is needed. A main job of the kidneys is to excrete just enough water to keep cells properly hydrated. However, contrary to myth, dark urine does not necessarily mean you’re dehydrated. Urine can be discolored by foods like asparagus, blackberries and beets.

Another popular myth: To moisturize skin, prevent wrinkles and produce a glowing complexion, you need to drink eight glasses of water a day. Drinking extra water doesn’t improve skin in people who are otherwise well hydrated. Better to use an emollient moisturizer to counter dry skin.

Good hydration definitely protects against kidney stones, and there is evidence that it counters constipation and exercise-induced asthma. It may also help protect against vascular diseases, like stroke, an elevated heart rate or sudden drop in blood pressure and is especially important for people with diabetes.

Despite the vital importance of water, there are relatively few good studies of how much is needed, by whom and under what circumstances, according to Barry M. Popkin, a professor of nutrition at the University of North Carolina at Chapel Hill. “We do not truly understand how hydration affects health and well-being, even the impact of water intakes on chronic diseases,” he and his colleagues wrote in Nutrition Reviews.

“Nearly all the funding of water research has been provided by industry,” Dr. Popkin said in an interview, referring to companies that sell all manner of beverages, including bottled water. “And most of the research on water has been organ-specific, done by people studying the kidneys or lungs. Whole body systems haven’t been well studied.”

There are no formal guidelines on how much water people need each day. The amount is affected by what people eat, their weight and activity level and even the environment in which they live.

The Institute of Medicine, which issues recommendations on the amounts of nutrients we need, states that an “adequate intake” of water ranges from 700 milliliters (about three cups) a day for newborns to 3.8 liters (16 cups) for lactating women. Still, the institute concluded that “individuals can be adequately hydrated at levels below as well as above the adequate intakes provided.”

Furthermore, the institute stated that all kinds of liquids can contribute to a person’s total water needs, including beverages like tea, coffee, juices, sodas and drinking water, as well as the moisture contained in foods like fruits, vegetables, soups and even meats. In fact, the institute estimates that the moisture in food accounts for about 20 percent of a typical person’s water intake.

Although the institute included juices and sodas as potential sources of hydration, these often sugar-laden beverages have become a serious nutritional problem in recent decades. The entire increase in fluid intake in the United States, from 79 ounces a day in 1989 to 100 ounces in 2002, came from caloric beverages, Dr. Popkin and colleagues reported. Studies have shown that people who drink these extra calories don’t compensate by consuming commensurately fewer calories from food, which has contributed mightily to the ballooning waistlines of Americans.

To be sure, it’s important for athletes to drink plenty of water, especially when high levels of activity, heat and humidity result in excessive sweating. But overdoing hydration has its own risks; marathon runners and other athletes have died after drinking more water than the kidneys are capable of processing in a timely manner, leading to swollen cells and dangerously low blood levels of sodium and other electrolytes.

At the same time, inadequate hydration can have debilitating effects. Studies by Lawrence B. Armstrong and colleagues at the University of Connecticut’s Human Performance Laboratory showed that dehydration can adversely affect vigilance, concentration, reaction time, learning, memory, mood and reasoning and can cause headaches, fatigue and anxiety.

Older people, especially the frail elderly, are among those at greatest risk of poor hydration, Dr. Popkin noted. The mechanism of thirst becomes less effective with age, and many older people cut back on how much they drink to limit how often they need to get to a bathroom.

“There’s a big problem with older people falling during the night and breaking bones when they get up to go to the bathroom,” Dr. Popkin said. “Many don’t drink because they’re afraid to fall, but instead they may die of the effects of dehydration.”

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Flint’s ‘Lead Water’ Poses Particular Threat to the Youngest

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FLINT, Mich. — Shanice Ollie is 18 weeks pregnant with her third child, so she’s not taking any chances. No matter what city health officials say, she will not drink, cook, do dishes or wash with “lead water,” which is how people here now refer to the tap water delivered to their homes.

“They’re saying it’s O.K. to shower in it, and it’s fine for dishwashing and clothes, but I don’t believe them,” said Mrs. Ollie, 31, motioning toward her cluttered kitchen, where cases of bottled water were stacked by the counter and three gargantuan garbage bags were overflowing with empty bottles for recycling. “They knew for a whole year and didn’t do anything about it. I can’t risk it.”

While the water crisis is a public health disaster for everyone in Flint, it presents an especially daunting challenge for pregnant women and parents of young children, who absorb more lead than adults and are especially vulnerable to the effects on their developing brains and nervous systems. Six months after families here first learned the water supply in this poverty-stricken community was heavily contaminated with lead, the crisis continues to exact an exhausting daily toll on family life.

Local fire stations stock the water, but residents have to pick it up and cart it home every day or every other day. Families go through prodigious amounts of bottled water: A family of four can easily use up a case of 40 half-liter (16.9-fluid-ounce) bottles in a 24-hour-period — just for drinking and cooking. While health officials say the water is safe for bathing, laundry and dishwashing, many families don’t trust the advice.

Mrs. Ollie has trained her sons, 6-year-old Kingston and 4-year-old Jase, to take sponge baths using microwaved bottled water — no more playing in the tub. They must also use bottled water to brush their teeth. After dinner, she uncaps and empties dozens of pint-size bottles of water into a large pot that she heats on the stove to wash dishes. On weekends, she and her husband drive the kids and all the laundry to Mrs. Ollie’s parents’ home in Lansing, Mich., to shower and wash up.

“It’s like living in a third-world country, right here in America,” Mrs. Ollie said. “I’m very angry. But what can you do? You have to keep living your life,” she added as she rinsed out the blender used to make smoothies for breakfast. “There goes three bottles of water right there.”

Even before the water was contaminated, raising healthy children and keeping them from harm was no easy task in a city where the median household income is less than $25,000 a year and the rate of violent crime is among the highest in the nation. Many families live on streets where every third or fourth house is boarded up, and in many strip malls, the only store open for business is the liquor store.

Children here start off at a disadvantage — one in seven babies is born prematurely, and lead can increase rates of preterm birth and low birth weight. High-school graduation rates in the city are low, and fewer than 12 percent of residents are college educated.

And then last fall, health department officials told residents to stop drinking the city tap water because it contained high levels of lead, a neurotoxin that can take a devastating toll on overall health and cognition.

Health officials are urging parents to test their children’s blood-lead levels and beef up their diet with foods rich in calcium, iron and vitamin C, which may blunt the body’s absorption of lead. But blood tests measure only lead exposure within the last 30 days, not the body burden of lead that has already settled in bones, soft tissue and the brain, said Dr. Carl R. Baum, a professor of pediatrics at Yale School of Medicine who is an expert on lead exposure.

Doctors have little advice about how to reduce the harm already done: There is no way to reverse the effects of lead, which affects every organ system. Children under the age of 6 are thought to be most vulnerable, Dr. Baum said.

Dr. Jeanne Conry, an obstetrician and gynecologist who is an expert on environmental exposures during pregnancy, said, “Our guidelines weren’t written for this level of exposure.” With so many unknowns, researchers are eager to study Flint, she added.

While some families hope to move away from Flint, most people here can’t afford to leave the cheap rentals and their support networks, and those who own homes know they aren’t likely to sell them. Many are also contending with other problems born of poverty, like disability, unemployment and substance abuse.

Christina and Adam Murphy, who have five children between them, including a newborn, learned their water was heavily contaminated with lead after one of their dogs got sick and another dog gave birth to a stillborn puppy.

Tests on the water in their home revealed lead levels of thousands of parts per billion, way over the allowable limit of 15 parts per billion, and now they are worried about the effects on everyone in the family. A son from Mr. Murphy’s previous marriage was recently diagnosed with fetal alcohol syndrome, and the couple’s 3-year-old daughter has been irritable lately. An older daughter has been having severe abdominal pain, which can also be caused by lead, while another son is having difficulties at school for the first time.

Mr. Murphy himself, a 36-year-old millwright, has been unable to work for over a month because of unexplained weakness and fatigue. He has lost several teeth and has been dropping things, and worries about his memory. Mr. Murphy is being evaluated to see if he has amyotrophic lateral sclerosis, or A.L.S., which has also been linked to lead exposure.

And Mrs. Murphy, like many parents in this area, spends an inordinate amount of time emptying bottles of water into pots and bowls, where it can be boiled or microwaved for bathing, washing dishes and cooking for five children under the age of 10. “It’s like living in the 1800s,” she said.

Last fall, Magen Baker and her husband moved away from Flint to a suburb on a different water system, but they remain worried about their children, including a 10-month-old who has been hospitalized twice with pneumonia and an older daughter who has been coming home with teachers’ notes about misbehavior and having trouble getting her homework done.

Mrs. Baker, 30, who manages a salon at a J.C. Penney, has been breast-feeding her baby, but she drank and cooked with Flint’s contaminated water while pregnant and now worries the baby may have been exposed to lead, which can cross the placenta and has been found in breast milk.

After Luke Waid, 29, a laid-off aerospace welder, found out his baby girl Sophia had tested high for lead, a public assistance case manager threatened to call Child Protective Services and have Sophia removed from their home because of the lead exposure. Last fall, of course, the family and case manager learned it was the water.

Now Mr. Waid is suing state and city officials, hoping to have his daughter’s medical bills covered at the very least. “I come from a poor family,” he said. “I paid my taxes, and paid an awful lot for water, and they poisoned my child through the water.”

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Staying Healthy While Traveling the Globe

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Credit Paul Rogers

On a recent trip to Tanzania with four grandsons, my most important task (beside protecting them from the jaws of a lion or leopard) was to keep them, and myself, in good health. It would not have been much fun to be stuck in a tent next to the commode or flattened on a cot while the rest of the gang viewed a dazzling array of wild animals from the safety of a Land Rover.

Although I came prepared for the worst, I did everything I could to make our trip the best. And I’m happy to report, no one got sick and we all had a great time.

When I described the steps I took to friends and physicians, they urged me to write about them. So here goes, along with a host of other helpful travel hints from well-informed professional sources.

No. 1: I reminded my grandsons daily, any water you drink or use to brush your teeth must come from a sealed bottle that you open. Ice wasn’t an issue in the bush, but that too should be prepared from bottled water. When you take a shower or swim in a pool, keep your mouth shut. (This warning was particularly pertinent for one grandson who always sings in the shower.)

No. 2: Before every meal, we each chewed one pink tablet of bismuth subsalicylate (sold as Pepto-Bismol and various store brands).

I have used this preventive since first reading about it in 1980 in The Journal of the American Medical Association in a study led by Dr. Herbert L. DuPont, an infectious disease and travel medicine specialist at the University of Texas, Houston. The study described how using these tablets greatly reduced the risk of traveler’s diarrhea among American students traveling to Mexico. In a subsequent study published in 1987, Dr. DuPont and colleagues reported that two tablets chewed four times a day reduced the risk of developing diarrhea by 65 percent. (Each tablet contained the standard dose, 262 milligrams of bismuth subsalicylate.)

I have relied on these tablets, albeit in a lesser dose because I’m a lot smaller than average, during trips to Vietnam, Thailand, Peru, Indonesia, India and Nepal, and never got sick despite eating salads and peeled fruit, which one is warned to avoid. In fact, in India and Nepal, my traveling companion, who also took the tablets, and I were the only ones who stayed healthy even though the others in our group assiduously avoided those no-no foods and we did not.

So for the five of us going to Tanzania, I packed 15 tablets for each day of our trip — and no one experienced the slightest gastrointestinal upset. That wasn’t the case, though, for most of the others on our itinerary. However, if you choose to try this preventive, I suggest you check first with your doctor and perhaps consider using Dr. DuPont’s larger dosage.

Without a preventive, which is no guarantee against food-borne illness, stick to “safe food” that is cooked and served hot, and fruits and vegetables you have washed in bottled water and peeled yourself. Never eat undercooked foods — eggs, meat, fish or poultry — or any food sold by street vendors.

Reduce your exposure to germs by washing your hands often, and always before eating. A hand sanitizer with at least 60 percent alcohol can be used if soap and water are unavailable.

I took no chances, especially since I was responsible for four children. I had an emergency supply of Lomotil (for digestive problems) and azithromycin (Zithromax Z-pak, for infections) just in case.

No. 3 (really No. 1 chronologically): I made sure we were all up-to-date on routine vaccines — measles-mumps-rubella, varicella (chickenpox), diphtheria-tetanus-pertussis, polio and an annual flu shot — and added two (for hepatitis A and typhoid) that the Centers for Disease Control and Prevention recommends for travelers to Tanzania. You can review recommendations for other destinations on the C.D.C. website at cdc.gov/travel. We also each filled prescriptions for generic Malarone (atovaquone proguanil) to prevent malaria, and I checked daily to be sure the boys remembered to take it.

I also packed an ample supply of sunscreen, insect repellent with 20 percent or more of DEET, and a first-aid kit of hydrocortisone cream, antibiotic ointment and a variety of bandages, though happily the latter two were never needed. For one grandson prone to motion sickness, I took some meclizine as well.

As the oldest traveler in the group (and the shortest now that my youngest grandson, at age 11, has passed me), I am acutely aware of the risk of blood clots when flying long distances. I always book an aisle seat so I can get up every hour or so and walk around for a minute. It also helps to move your legs and flex your ankles frequently. You might also wear graduated compression stockings on very long trips. Similar precautions apply to long car or train trips.

Although the risk of clots is generally very small, they can be life-threatening. At greatest risk are people over 40, those who are obese or pregnant or have limited mobility (for example, because of a leg cast) or who have a personal or family history of clots. Estrogen-containing medications also raise the risk; I usually take one of those, raloxifene, prescribed to protect my bones. But it can increase the risk of a clot, so I stop taking three days before a plane trip of four or more hours. For more information, check the C.D.C. advisory on blood clots and travel, and talk to your doctor.

Even when traveling alone, I always purchase travel health and medical evacuation insurance because, well, you never know. People on my various trips have broken bones or become seriously ill and had to return home mid-trip. Two men died while snorkeling on separate trips of mine.

Consider carrying a card that lists your blood type, any chronic illnesses or serious allergies and the generic names of prescription medicines you take. Bring some extra doses in case of travel delays.

Other worthy precautions: To avoid nasty parasitic diseases like schistosomiasis, do not swim or wade in fresh water in developing countries or wherever the sanitation is poor. Pools should be chlorinated. However adorable an animal (domestic or wild) may be, keep your distance. Do not touch or feed any animal you don’t know. Some carry rabies. Should you get bitten or scratched by an animal, wash the wound immediately with soap and clean water and, if at all possible, get to a doctor quickly.

If you expect to be at a high altitude (8,000 feet or higher), consult your doctor about medicine to prevent altitude sickness, which can take more than the starch out of a person. I was glad I did when traveling to Cusco, Peru (11,154 feet) and climbing in the Sacred Valley of the Incas (9,000 feet). The recommended preventive is acetazolamide (generic version of Diamox).

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