More than half the U.S. population—including about 70 percent of the elderly and 90 percent of minorities—is vitamin-D deficient, according to Dr. James E. Dowd, author of “The Vitamin D Cure.” The nutrient helps maintain normal levels of calcium and phosphorus in the blood. It also helps the body absorb calcium and keeps bones strong. Vitamin D may also protect against osteoporosis, hypertension, cancer and other diseases, according to the Mayo Clinic.

Vitamin D is mostly produced in the skin after UV exposure from the sun, but it can also be derived from milk, fish, egg yolks and vitamin supplements. It’s harder for the obese and people with more melanin in their skin to absorb vitamin D. It doesn’t help that we’ve become a nation of sunscreen wearers who eat low-vitamin processed foods and work mostly indoors; that all leads to D deficiency, which can cause susceptibility to seasonal affective disorder, fatigue, headaches and a variety of immune-related diseases, according to Dowd.

  Illustration: Mark Matcho for Newsweek

 By Karen Springen

Like many couples, Brian Delaney, 35, and his wife, Daniela, 34, turned to in vitro fertilization after failing to conceive on their own. But after five attempts and an investment of $150,000, IVF failed them as well. Then Brian saw a male-infertility specialist, Columbia University’s Dr. Harry Fisch, who discovered that Brian’s low sperm production could be corrected through microsurgery. Three months later, Daniela was pregnant. Last November she delivered a baby boy, Harrison.

Long overlooked, male infertility has become a fruitful field of research. Doctors now know that, when a couple fails to conceive, the problem lies with the man as often as with the woman. And as the Delaneys learned, recent advances have dramatically improved experts’ understanding of how to diagnose, treat and prevent the condition. “Anything that makes the body unhealthy—a disease, toxins, excessive alcohol—will hurt fertility,” says UCSF urologist Paul Turek. “But most of these things that hurt fertility are reversible.” Some tips for men:

 
Illustration: Chris Gash for Newsweek

If your parents are unhappy, are you destined for unhappiness, too? Psychologists used to believe that genes played a determining role in our state of mind. But new research is finding that people can do more than previously thought to improve their outlook on life. “Things are more complex than simple genetic models suggest,” says Ed Diener, a professor of psychology at the University of Illinois who researches subjective well-being. “People are stuck with the genes they have … but we know that adult personality can change, and people probably have some control over this.”

How much control is still a matter of debate within the field. In a new book, “The How of Happiness” (Penguin Press. $24.95), Sonja Lyubomirsky, a psychology professor at the University of California, Riverside, proposes that a full 40 percent of our happiness is within our control. Using data from research on identical and fraternal twins, she concludes that an additional 50 percent is determined by genetics. The remaining 10 percent is dictated by circumstance—like a recent divorce or a financial windfall. “In the past, we’ve heard you can’t make people happy sustainably because happiness is genetic or because life’s circumstances won’t allow it,” says Lyubomirsky. “I argue that there are things we can actually change.”

Lyubomirsky, who has been studying happiness for nearly two decades, offers a dozen so-called happiness intervention strategies in her book, all backed by her own or others’ research. With help from a National Institute of Mental Health grant, she and colleague Ken Sheldon have conducted or reviewed dozens of studies with participants who, for example, wrote letters of gratitude, performed conscious acts of kindness or kept a “best possible selves” journal to outline future goals over six or more weeks. When compared with control groups, those who performed the activities regularly reported “significantly bigger” increases in their happiness levels, as compared with before the intervention. “Even nine months later, we still saw the effects: those who continued to practice these strategies had more sustained happiness,” she says. Here’s more advice from the book:

Don’t overthink it. When you catch yourself stewing over something, tell yourself, “Stop.” Or set aside 30 minutes late in the day to do nothing but ruminate. Chances are, when the appointed time comes, the issues that plagued your thoughts earlier will seem less consequential.

Learn good coping skills. Write down traumatic experiences and learn how to recognize, and argue with, overly pessimistic thoughts.

Savor life’s joys. Relish ordinary experiences, like a good meal or a hot shower; conjure up a favorite memory when you’re down.

Cultivate optimism. After studying Lyubomirsky’s strategies, photographer Kelly Radinsky, 45, set aside time each evening when she, her husband and two kids, ages 5 and 9, take turns sharing the favorite parts of their day.

Lyubomirsky recommends only trying strategies that match your personality and repeating them only as often as they fit into your schedule (otherwise, they could seem like obligations). She admits that some suggestions may sound “hokey” but stresses that they are based on controlled studies or correlational data showing they can significantly improve participants’ level of happiness compared with those who do not perform the exercises.

“This isn’t someone standing up and saying, ‘Just think positive thoughts.’ She’s doing rigorous research,” says Alan Kazdin, professor of psychology at Yale University and president of the American Psychological Association. “We’ve learned over the past few decades that there are strategies you can use that can actually change the brain, change behavior and then mood and understanding follow.”

Radinsky, who inherited “dark genes” from an abusive father and suicidal mother, says she sometimes has to work at making Lyubomirsky’s strategies a habit, but it’s worth it. “I think they can make the difference between a happy and an unhappy life,” she adds. That’s good news for the pessimists among us.

Photo Illustration by C.J. Burton for Newsweek

Ed Goldston used to sprinkle salt on almost everything he ate—from soups and salads to steak. That changed about 15 years ago when his doctor diagnosed him with hypertension and told him to go on a low-sodium diet. The Pittsburgh real-estate investor agreed to stop adding salt to his meals, but that wasn’t enough. “I found out there was so much salt added to food before I even picked up a shaker.”

French fries were an obvious source, but he didn’t realize that ketchup was packed with sodium, too. He stopped topping his pizza with anchovies, then realized that even a slice of plain cheese can have more than 750 milligrams of sodium, about a third of the recommended daily allowance. Goldston, now 72, started avoiding pizza altogether. Soon he’d added packaged lunchmeats, snack foods and canned soup to his blacklist. “I was really amazed at how much salt I was consuming without even realizing it,” he says.

Stories like Goldston’s have doctors concerned. The U.S. Department of Health and Human Services recommends no more than 2,300 milligrams of sodium a day, or about a teaspoon of salt. Those with, or at risk for, high blood pressure should limit their intake to 1,500 milligrams. But most Americans consume triple that amount—about three quarters of it from processed foods.

If the body’s kidneys can’t eliminate enough sodium, it starts to accumulate in the blood. That increases blood volume, which makes the heart work harder and puts more pressure on the arteries. Studies have linked high-sodium diets with an increased risk of stroke, heart disease and high blood pressure. “It’s a major health problem,” says Dr. Daniel Jones, president of the American Heart Association.

Last month the Food and Drug Administration called a hearing to review its policies on salt in food. The Center for Science in the Public Interest has asked the agency to add health warnings to salt packets a half ounce or larger and to impose stricter limits on salt in processed foods, a move the American Medical Association supports. Richard Bonnette, a consumer-safety officer at the FDA, says implementing such regulations would be “challenging” and could take several years.

What to do in the meantime? Madelyn Fernstrom, founder and director of the University of Pittsburgh Medical Center’s Weight Management Center (where Goldston is a patient), urges her clients to read nutrition labels and avoid high-sodium processed foods like canned vegetables, rice and noodle mixes and microwavable meals. She recommends buying sodium-free foods or products marked “low sodium,” which must contain 140 milligrams or less per serving. And though only about 10 percent of the salt Americans consume comes from the shaker (some is also found naturally in foods), Fernstrom suggests using other seasonings instead. Ultimately, says Dr. Christine Gerbstadt, a physician and spokesperson for the American Dietetic Association, “If you leave it to chance, you’re going to eat too much salt. You have to be conscious about it.”

That strategy has worked for Goldston, who lowered his blood pressure from 172 over 82 to 120 over 70 with the added help of a hypertension drug. “I still try to stay under 1,500 milligrams of sodium each day, and that’s hard,” he says. “But it’s worth it. I feel great.” Doctors hope that with more publicity about the benefits of a low-sodium diet, millions of other Americans will feel better, too.

Photo illustration by Viktor Koen for Newsweek

Jeanne Dulaney is a time-crunched software consultant who often eats out on the company expense account. But the 51-year-old from Montgomery, Ala., paid the price for her frequent restaurant dining: 40 extra pounds on her 5-foot 5-inch frame. With little time to commit to a real-world weight-loss program, Dulaney became a mouse-clicking dieting maven after seeing an ad for ediets.com. “I’m on my computer all the time, so I figured I’d give it a try,” she says.

Three years later, Dulaney is nearly 50 pounds lighter. She’s even started to run half-marathons with some new- found friends, other members of ediets.com. “Everyone who is trying to lose weight needs help,” she says. “I got mine from my computer.”

No one actually knows how many people like Dulaney have found weight-loss success with Internet-based commercial programs. But what is clear is that Web-based diets are becoming a booming part of the $30 billion U.S. weight-loss industry. The choices are endless. Internet-only weight-loss programs like ediets.com, diet.com and WebMD, and diet icons like Weight Watchers and South Beach are all competing for your weight-loss bucks. Even fitness franchise Curves opened a new online dieting site last week.

Although research into the effectiveness of online dieting is in its infancy, science is showing that it probably won’t hurt you. And, depending on the program’s components, these online purveyors may help you drop some pounds. With 24/7 access and anonymity, the sites may be helpful for folks who are too busy, or too shy, to attend a more structured program.

The Experiment: We cleaned apples and pears four different ways: rinsing under cold running tap water, scrubbing with a brush, washing with a vinegar solution and scrubbing with antibacterial soap. We took surface samples from the produce and grew the bacteria in petri dishes.

Interested? Any old ski poles will do in a pinch, but specially designed models work best. They have rubber tips that grab pavement and wrist straps that secure the poles to your arms so you can maintain a loose, comfortable grip on the handle. The Instructor has an adjustable-length, lightweight carbon and aluminum shaft, and each pair comes with an instructional DVD ($149.95; leki.com). Trekking poles are heavier and sturdier than Nordic walking poles and are made for mountain hikes over rocks and roots. The Trail by Black Diamond features a durable metal tip, and the shaft telescopes down for easy storage when not in use ($79.95; bdel.com).

NEWSWEEK: What herbs and spices have the strongest scientific data to back their health benefits?
LEE: Traditionally, there have not been many scientific studies done on spices. But garlic has some data behind it, and so does cayenne pepper and cinnamon.

How can garlic improve your health?
There is some data that shows garlic may lower LDL, or bad cholesterol, if taken orally. But the studies were done with raw garlic and in very high doses—you wouldn’t have many friends if you were taking that much garlic. The active ingredient in garlic is allicin, the same chemical that gives garlic its pungent odor. No one has really shown that freeze-dried garlic has the same effect.