Let it Flow

The panel, led by Barry M. Popkin, a nutrition professor at the University of North Carolina, US, was distressed by the burgeoning waistlines and the contribution that popular beverages make to weight problems. But the experts also reviewed 146 published reports to find the best evidence for the effects of various beverages on all of the above health problems. I looked into a few others, and what follows is a summary of what we all found. At the head of the list of preferred drinks is — you guessed it — water. No calories, no hazards, only benefits.

Liquid Calories

About 21 per cent of calories consumed come from beverages, predominantly soft drinks and fruit drinks with added sugars. There has been a huge increase in sugar-sweetened drinks in recent decades, primarily at the expense of milk which has clear nutritional benefits. The calories from these drinks account for half the rise in caloric intake since the late 1970s. Add the current passion for smoothies and sweetened coffee drinks (there are 240 calories in a 16-ounce Caffe Mocha without the whipped cream), and you can see why people are drinking themselves into XXXL sizes.

But calories from sweet drinks are not the only problem.

The other matter cited by the panel, in its report in The American Journal of Clinical Nutrition, is that beverages have “weak satiety properties” — they do little or nothing to curb your appetite — and people do not compensate for the calories they drink by eating less. Furthermore, some soft drinks contribute to other health problems. The American Academy of General Dentistry says that non-cola carbonated beverages and canned (sweetened) iced tea harm tooth enamel, especially when consumed apart from meals. And a study of 2,500 adults in Massachusetts, linked cola consumption to the thinning of hip bones in women.

If you must drink something sweet, the panel suggested a no-calorie beverage like diet soda prepared with an approved sweetener, though the experts recognized a lack of long-term safety data and the possibility that these drinks “condition” people to prefer sweetness.

Fruit juices are also a sweet alternative, although not nearly as good as whole fruits, which are better at satisfying hunger.

Coffee, Tea and Caffeine

Here the news is better. Several good studies have linked regular coffee to a reduced risk of developing Type 2 diabetes, colorectal cancer and Parkinson’s disease.

Most studies have not linked a high intake of either coffee or caffeine to heart disease, even though caffeinated coffee raises blood pressure somewhat and boiled unfiltered coffee raises LDL and cholesterol levels.

Caffeine itself is not thought to be a problem for health or water balance in the body, up to 400 milligrams a day. But pregnant women should limit their intake because more than 300 mgs a day might increase the risk of miscarriage and low birth weight.

A study of more than 600 men suggested that drinking three cups of coffee a day protects against age-related memory and thinking deficits. For tea, the evidence on health benefits is mixed and sometimes conflicting. Tea lowers cancer risk in animals, but the effects in people are unknown. It may benefit bone density and help prevent kidney stones and tooth decay. And five cups of black tea daily helps arteries expand and thus may improve blood flow to the heart.

Alcohol

Alcohol is a classic case of “a little may be better than none but a lot is worse than a little.” Moderate consumption — one drink a day for women and two for men — has been linked in many large, long-term studies to lower mortality rates, especially from heart attacks and strokes and may also lower the risk of Type 2 diabetes and gallstones. The panel found no convincing evidence that one form of alcohol, including red wine, was better than another. But alcohol even at moderate intakes raises the risk of birth defects and breast cancer. And heavy alcohol consumption is associated with several cancers, cirrhosis of the liver, hemorrhagic stroke, hypertension, dementia and some forms of heart disease.

Dairy and Soy Drinks

Here my reading of the evidence differs slightly from that of the panel, which rated low-fat and skim milk third, below water and coffee and tea, as a preferred drink and said dairy drinks were not essential to a healthy diet. The panel acknowledged the benefits of milk for bone density, but unless people continue to drink it, the benefit of the calcium and vitamin D is not maintained. Other essential nutrients in milk include magnesium, potassium, zinc, iron, vitamin A, riboflavin, folate and protein — about eight grams in an eight-ounce glass. The lactose intolerant can try soy milk. A 10-year study of overweight individuals found that milk drinkers were less likely to develop coronary risk factors like hypertension and low levels of protective HDLs. To me, this says you may never outgrow your need for milk. And

–JANE E. BRODY