Q: Does cranberry juice really help prevent bladder infections?

A: Cranberries contain two compounds that seem to prevent bacteria from sticking to cells in the kidney, bladder, and other parts of the urinary tract. Effects on urinary acidity may also reduce the rate of infections. Studies to test the effectiveness of cranberry products in preventing urinary tract infections are hard to compare, because they’ve used different products (cranberry juice concentrate, cocktail, or capsules) and different doses. We need more studies to provide clear answers, but most experts say that one or more forms of cranberry juice may help prevent recurrent urinary tract infections in women who are prone to them. Women who rarely get these infections may not derive any special benefit. Research does not currently support a role for cranberries in the treatment of urinary tract infections that already exist.

Q: Do water-soluble vitamins build up in your body and become toxic?

A: Health experts used to think that extra amounts of water-soluble vitamins would be excreted in the urine, but we now know that in some cases, an excessive intake of vitamins can cause problems. For instance, folic acid from supplements and fortified foods that amounts to 1,000 micrograms (mcg) or more per day can delay the diagnosis of a vitamin B-12 deficiency, increasing the development of the nerve damage caused by this deficiency. Second, an intake of vitamin B-6 that equals 100 milligrams (mg) or more each day from food and supplements can lead to nerve damage. This damage is reversible after the excessive B-6 is stopped. Third, a daily niacin (vitamin B-3) intake from supplements and fortified foods that totals 35 mg or more can lead to tingling, burning flushing reactions. Although extremely large doses (3,000 mg) of niacin may be used to treat high blood cholesterol, reactions can range from liver toxicity to blurred vision and high blood sugar. A niacin treatment should only be used under a doctor’s supervision. Lastly, a consumption of vitamin C totaling 2,000 mg or more per day can lead to diarrhea and digestive disturbances.

Q: Does a Mediterranean diet require eating only Italian or Greek dishes?

A: Italian and Greek dishes can be wonderful examples of nutritious and delicious food. But you can have a healthy Mediterranean-style diet without eating any of these ethnic dishes. The key nutrition principles to follow in creating your own Mediterranean-style eating plan are: Limit portions of meat and poultry; choose fish at least three times a week; make fruits and vegetables an abundant part of your meals; use olive oil as your fat (for example, in salad dressing or on vegetables); and serve legumes, such as lentils, garbanzo beans, and kidney beans, at least a few times a week if not daily. In Mediterranean cuisine, garlic, onion, and a variety of herbs make these foods delicious and add more health benefits. You, too, can flavor your food selections to suit your palate, but stick to healthful herbs and spices, and avoid deep-frying and high-fat flavorings. Above all, remember that a Mediterranean diet is a mostly plant-based diet.

Q: Are scones lower in sugar and calories than muffins?

A: While recipes vary, scones usually are lower in sugar than muffins. But they are often higher in calories due to greater fat content. Scones available at popular bakery and coffeehouse chains today generally contain anywhere from 410 to 560 calories each (without spreading any added butter or jam on them). Their sugar content of three to seven teaspoons of sugar is lower than that of many muffins, but fat content of 14 to 29 grams is a substantial load. Check nutrition information of restaurants or recipes you use, since different flavors (even from the same source) can vary substantially.

Q: Is it true that alcohol can affect blood pressure?

A: Yes, all major recommendations about how to avoid or control high blood pressure include the advice to avoid drinking too much alcohol. Health experts recommend a limit of no more than one standard drink a day for women and no more than two standard drinks a day for men. Incidentally, you should also follow these same recommendations to lower your risk of cancer. A standard drink is 12 ounces of beer, five ounces of wine, or 1.5 ounces of 80-proof liquor. However, the most important lifestyle influences on keeping a healthy blood pressure are weight control, regular exercise, limiting sodium consumption, and getting enough potassium. Yet, in addition to these major influences, blood pressure is affected by many other factors as well. For instance, heart-healthy omega-3 fats (found in certain fish like salmon and albacore tuna), calcium, and magnesium might help reduce blood pressure, while excess alcohol or caffeine could raise it. Although drinking alcohol within the recommended limits should not disrupt your pressure, individual circumstances may vary and should be discussed with one’s physician.

Q: Are meatless meals a good way to cut calories?

A: They can be, but don’t assume that absence of meat automatically means lower calorie content. A meatless meal that contains a lot of fat from foods that are deep-fried or cooked in a lot of butter or oil will not be low-calorie. Likewise, large amounts of high-fat cheese or concentrated sweets like syrup or sugar add significant calories regardless of whether a meal contains meat. To reduce calorie content, make low-calorie foods such as vegetables a major focus of the meal. The effect of meat and poultry on calories varies dramatically from high-fat choices like sausage, regular ground beef, and chicken wings to low-fat choices like pork loin, beef sirloin, and skinless turkey or chicken breast meat. Finally, one of the strongest influences of all on a meal’s calorie content is how much you eat. Overeating can turn any meal into a source of too many calories.