Sun protection can have serious side effects
In the autumn of 2007, Julie Sands started to slow down.
At first Sands, a runner and triathlete from Winter Park, Fla., attributed it to overtraining, the stress of raising two 12-year-old twin girls, or simply the inevitable wear and 
tear of competing for nearly half of her 49 years. But as she tried to gear up for the Half Ironman world championships in nearby Clearwater, she realized there was something more seriously wrong.
"I could barely run 8-minute miles on my hard efforts, and that used to be my easy pace," she says. "I was tired all the time, and couldn't recover from my workouts. It felt like I was going in slow motion."
Sands went to see Dr. Ed Lee, an endocrinologist and occasional training partner and competitive rival, thinking she might be anemic. Lee ran a series of tests that came back with normal iron levels, eliminating the anemia hypothesis. But they showed something else: Sands was severely deficient in vitamin D. That seemed particularly ironic, that someone living in the Sunshine State should be deficient in what's known as the "Sunshine Vitamin," but Sands' levels were 19 ng/ml; an optimal level for active adults is considered to be 50 or higher.
She began taking supplements of 1,000 international units a day in December, and soon upped that dosage to 4,000. "By February I started to feel pretty good," she says.
Her results echoed that feeling; she began hitting 6-minute miles in her training, and at the Lake Placid Ironman in June had what she calls "the run of my life," passing 491 people on the final leg and going from 10th to third in her age group to qualify for the Ironman world championship in Kona, Hawaii. There she reprised her tactics from Lake Placid, going from 24th to 14th in her age group on the run and qualifying for Boston with her marathon split.
That was just a few months after Deena Kastor had seen her Olympic hopes dashed when a bone in her foot snapped like a twig just 5K into the marathon in Beijing. Subsequent tests revealed that while her calcium levels were normal, her body was unable to assimilate the bone-building mineral because she too was low in vitamin D, with levels near 15 ng/ml. In spite of living and training in near year-round sunshine, both Sands and Kastor, who lives in California, weren't getting the exposure to the sun that would produce vitamin D via absorption through the skin. "Since I was 25, I used sunscreen every day," says Sands. Kastor, who's had a long history of bouts of skin cancer, was even more cautious. "Here I thought I was making a healthy choice by wearing sunscreen and hats and clothes with high SPF values, when the truth of the matter is I was causing myself dangerously low levels of vitamin D," she says. The increased awareness of skin cancers, while a good thing in itself, has produced as a byproduct what Lee terms "an epidemic of vitamin D deficiency."
"I've seen it in pro golfers, in 21-year-old motocross riders," Lee continues. "Athletes, who produce so many free radicals and who sweat out a lot of nutrients, may be even more at risk than most." A recent study in the Archives of Internal Medicine claimed that 75 percent of Americans are deficient in the vitamin.
Besides exposure to the sun, there are two other sources of vitamin D— fish oil and foods that contain high levels of it, either naturally or through artificial fortification.
Vitamin D
Children growing up in the '30s and '40s may have had their taste buds scarred by daily doses of cod liver oil, but each tablespoon contained more than 1,000 units of vitamin D. Few parents today would dare force such yucky-tasting elixir on their kids, leaving diet as the final source of vitamin D. Unfortunately, there are a limited number of foods that contain significant quantities, leaving supplements as the last resort for most people.
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The commonly cited Recommended Dietary Allowance (RDA) for vitamin D is 400 IU per day, a figure Lee calls "ridiculously low." He explains, "It's the same for a 110-pound woman and a 200-pound man. That makes no sense." He feels that active adults should take at least 2,000 IU a day, and may require two to two-and-a-half times that amount. Also, as you age, your ability to absorb D through your skin diminishes, causing an increased dosage demand. To determine your blood levels, be sure to get a 25-hydroxyvitamin D test, also called a 25(OH)D. This measures the effective form of the vitamin that can interact with calcium to help bone health.
In addition to strong bones, vitamin D has recently been postulated as a preventive for certain cancers, particularly of the breast, colon, pancreas and prostate. But while those long-term benefits can't be dismissed, runners may be most interested in the faster times and quicker recoveries that someone like Sands experienced.
Kastor, who started running again in November and returned to racing with a win in the Bank of America Shamrock Shuffle 8K in Chicago on March 29, has felt numerous benefits since she's been taking vitamin D supplements.
"My skin feels better, I'm sleeping more soundly, my strength has increased, and I'm mentally alert and physically more charged up," she says. "Some of that might be due to the enforced three-month layoff I had after Beijing, but not all.
"It's amazing how essential vitamin D is to our well-being," she concludes. "It's too bad I had to learn it the hard way."
Every weight loss expert seems to have his or her own opinion about the best way to shed fat and get fit –– and one or two of them actually agree. Indeed, if you were to listen to them all, you'd eat more of everything and less of everything, and you'd eat it earlier, later, and not at all. Fat would save you and kill you, carbohydrates would make you skinny and fat, and protein would turn you into Adonis and put you on dialysis.
Moreover, when you apply that statement to a sport whose very motto is to "Live More" – you'll find motivation, even inspiration, everywhere.
