Nutritionists are placing more emphasis on what we drink and its impact on our health. Here's what you need to know about the health implications of the major beverage categories.
In the world of nutrition science, what people drink has long been an afterthought. Today, however, there is a growing understanding that what—and how much—you drink can have a substantial impact on health and disease.
During a million or so years of human evolution, we’ve relied almost exclusively on one beverage: water. Milk, juices, soft drinks and other beverages are comparatively recent additions. Water doesn’t entirely satisfy us today. Americans spend more than $200 billion a year on beverages. Some of this is for bottled water. The lion’s share, though, is for sugar-sweetened soda and coffee.
We drink mainly to replenish fluid lost when we breathe, sweat and urinate. The beverages you choose to top off your tank can have an impact on health far beyond any physiological function.
Water is, and should be, the most commonly consumed beverage on the planet.
It offers 100 percent of what we need with no calories and at little cost.
Health benefits of water
- In one survey of almost 6,000 Chinese adults, the more water an individual drank the lower his or her chances of being overweight.
- An even larger study, this one of 20,000 Seventh Day Adventists living in California, found that the group of individuals who drank five or more cups of water a day were 50 percent less likely to have had fatal heart attacks than those who drank two or fewer cups. Comparing high versus low intakes of fluids other than water showed increases in risk of fatal heart attack.
Adverse effects of water
- Virtually none.
Although we can’t say for certain exactly when humans began eating or brewing coffee beans, there is good evidence that coffee trees were being cultivated almost 1,000 years ago. According to the National Coffee Association, Americans drink about 400 million cups of coffee a day.
A cup of coffee delivers mostly water. Taken black without sugar, it’s almost calorie free. In addition to
some vitamins and minerals, it contains polyphenols, chlorogenic acid, caffeine
and smaller amounts of hundreds of other substances.
Health benefits of coffee
- Among 120,000 initially healthy men and women, individuals who drank six or more cups of coffee a day were one-half to one-third less likely to have developed diabetes over the 12 to 18 years of follow-up than those who didn’t drink coffee.
- The onset of Parkinson’s disease was 80 percent lower among men who drank three or more cups of coffee a day in a study that followed 8,000 Japanese-American men for 30 years.
Other potential health benefits of drinking coffee:
- Lower risk of gallbladder disease.
- Protection against colon cancer.
- Improved memory and thinking skills.
- Decreased risk of suicide in women.
- Lower chance of developing type 2 diabetes.
Adverse effects of coffee
In general, drinking coffee is safe. However, caffeine is mildly addictive, and many coffee drinkers must get their daily “fix” or face headaches or grogginess. Drinking unfiltered coffee such as espresso can increase levels of total and LDL (bad) cholesterol, while filtered coffee does not appear to influence cholesterol levels. One report suggests the possibility that people with epilepsy who drink a lot of coffee may put themselves at risk for seizures and that cutting down on coffee or eliminating it altogether may help prevent seizures.
After water, tea is the world’s second most commonly consumed beverage. It is made from the leaves of a bushy evergreen plant named Camellia sinensis. The leaves are prepared in different ways to yield three basic types of tea: green, black and oolong. A cup of tea contains mostly water with a smattering of poly-
phenols, catechins, chlorogenic acid, caffeine, methylxanthines, theobromine and hundreds of other substances in even smaller amounts.
Health benefits of tea
- In a survey of 1,210 adults, those who reported drinking tea daily for 10 years or more had 20 percent less body fat compared to non-tea drinkers.
- A 10-year study of 1,500 initially healthy Taiwanese men and women showed that those who drank 1/2 to 2 1/2 cups a day were 46 percent less likely to have developed hypertension during the study period when compared to those who didn’t drink tea. The decrease in risk was even greater, 65 percent, for those who drank more than 2 1/2 cups a day.
- In a careful trial that included 15 volunteers with high cholesterol, drinking five servings a day of black tea reduced
- LDL (bad) cholesterol by 11 percent and lipoprotein by 16.4 percent compared to a caffeine-free placebo.
- A study that compared a variety of dietary and lifestyle factors between 340 heart-attack survivors and 340 similarly aged men and women found that those who drank at least one cup of tea a day had a 44 percent lower risk of heart attack.
Other potential health benefits of drinking tea:
- Better control of blood sugar.
- Improved blood flow through the arteries that nourish the heart.
- Lowered risk of prostate cancer.
- Decreased inflammation.
Adverse effects of tea
- The plant from which tea is made, Camellia sinensis, can concentrate minerals such as fluoride and aluminum. Drinking a large amount of tea over time can lead to a mottling of the teeth known as dental fluorosis and theoretically can cause aluminum toxicity.
Just less than one-half of all fruit in the United States is consumed as juice. Orange juice accounts for two-thirds of all juice consumed. About one-quarter of four-month-old infants and one-half of eight-month-old infants drink juice regularly. One cup of fresh-squeezed orange juice delivers 112 calories, 26 grams of carbohydrate, almost two grams of protein, a half-gram of fat and almost double the daily recommended intake of vitamin C.
Health benefits of fruit juice
- About the best that can be said for juice as a beverage is that it supplies some vitamin C and a variety of antioxidants. True fruit juices also deliver some fiber. Fruit-flavored juices deliver little more than sugar water enriched with a few vitamins. There is little data to support health benefits for juices.
Adverse effects of juice
- Some (but not all) studies show an increased risk of short stature and obesity in children who drink a lot of juice.
- Excess juice consumption has been identified as a possible cause of failure to thrive in children.
- Drinking juice has also been linked with an increase in cavities.
Archeological excavations in Britain suggest that humans have been drinking milk from non-human mammals for at least 6,000 years. In different parts of the world, milk is obtained from cows, sheep, goats, camels, horses, donkeys and buffalo. Milk is a dietary staple in some parts of the world and uncommon in others. Per capita milk consumption ranges from a high of 43 gallons a year in Ireland to half a gallon per year in China. The United States is somewhere in the middle, with a per capita consumption of 25 gallons per year.
A cup of whole milk is a significant source of calories, fat and other nutrients. It delivers 156 calories, eight grams of protein, 11 grams of sugar and nine grams of fat (5.5 of them saturated fat), along with 290 milligrams of calcium, 227 milligrams of phosphorous, some vitamin B 12, riboflavin, beta carotene and other micronutrients.
Health benefits of milk
- In a 10-year study of 3,000 initially healthy young adults, each daily serving of milk decreased the risk of obesity by 17 percent and the risk of insulin resistance syndrome by 25 percent.
- A national study that included 3,300 white women showed that those who drank at least one cup of milk a day during childhood and adolescence had higher bone mineral density than those who drank less milk. Higher levels of milk intake during adolescence were also associated with 50 percent lower risk of breaking a hip, spine or forearm.
- Decreased colorectal cancer is another possible benefit of consuming dairy products.
Adverse effects of milk
Consumption of dairy products has been linked to a number of health problems. These include:
- Possible increase in testicular cancer.
- Possible increase in prostate cancer.
- Possible effects on reproduction and development during puberty.
- Possible increase in ovarian cancer.
Approximately half of all Americans have at least one soft drink a day. Over 80 percent of these are sugar-sweetened, not diet. Soft drinks make up the major source of added sugar in children’s diets.
These are generally empty calories—calories without healthful nutrients. A 12-ounce can of cola, for example, gives you about 110 calories (most of them from sugar), no protein, no fat, no vitamins or minerals and 34 milligrams of caffeine.
Health benefits of soft drinks
- There really aren’t any. About the most that can be said for soft drinks is that they provide a “way to prevent dehydration.” That’s from the American Dietetic Association, which receives financial support from the soft drink industry.
Adverse effects of soft drinks
- Children who have at least one soft drink a day take in about 200 calories more each day than those who don’t have soft drinks.
- In middle-school children, every additional serving of soft drinks a day increased the risk of obesity by 60 percent.
- Women who drink at least one soft drink a day have an 83 percent increased risk of developing diabetes.