Runner's World Essential Guides (2 page)

Fermented dairy products, such as yogurt, cultured milk, and kefir, contain live bacteria that bolster immune-system health. These bacteria, as well as a special fat in dairy called conjugated linoleic acid (CLA), can also help alleviate constipation, improve symptoms of certain intestinal ailments, such as inflammatory bowel disease, and reduce the occurrence of yeast infections in women. And people who are lactose intolerant may see an improvement in their symptoms when they regularly consume cultured dairy products.

Fish and other seafood provide a unique combination of nutrients important to runners. Most seafood is an excellent source of quality protein (you need about 50 percent more protein than your nonrunning friends) and also contains zinc, copper, and chromium—minerals that are often low in a runner’s diet. But the omega-3 fats found in fish, particularly those from cold waters, are what make seafood such an essential part of anyone’s diet.

Over the past decade, researchers have unfolded a fish story of grand proportions: People who eat fish and other seafood a few times per week have a lower risk of sudden heart attack, vascular disease, and stroke. Fish intake has also been linked to lower rates of depression. And recently, low intake of fish (and omega-3 fats) has been associated with certain behavioral conditions in children, such as attention deficit hyperactivity disorder. Anthropological scientists who study “caveman” nutrition theorize that our ancestors consumed much more omega-3 fats than we currently do and that many of our modern-day ailments, such as heart disease and Alzheimer’s, may stem from low omega-3 fat intake. Runners should also note that the omega-3s in fish have anti-inflammatory capabilities, giving them the potential to counter exercise-induced muscle soreness and help alleviate diseases such as psoriasis.

By eating lean meats, poultry, and eggs, along with dairy products, runners can easily meet their increased protein needs and take in crucial minerals that can be hard to get from nonanimal sources. In particular, meats are a great source of iron and zinc, which support healthy red blood cells and a strong immune system. And these two minerals are simply better absorbed by the body when they come from meat instead of nonmeat sources.

While a vegetarian lifestyle can be quite healthy, studies suggest that diets balanced with fruits, vegetables, whole grains, and lean cuts of meat, including beef and skinless poultry, help lower blood-cholesterol levels, blood pressure, and heart-disease risk. Sticking to lean meats, however, is key, so consider foods from animals raised in open pastures and that graze on grasses. Compared with their stockyard-raised, corn-fed counterparts, free-range, grass-fed animals may contain more omega-3 fats and less artery-clogging saturated fats due to their healthier diets and higher levels of activity.

Healthy eating means your running will improve, but you’ll notice other parts of your body benefitting, too.

David Grotto, R.D., encourages runners to get plenty of ACES—his acronym for vitamins A, C, E, and selenium—to help your body and protect your skin.

Vitamin A:
Red bell peppers, carrots, sweet potatoes, kale, spinach

Vitamin C:
Kiwi, grapefruit, broccoli, strawberries, potatoes

Vitamin E:
Almonds, sunflower seeds, olive oil, avocados, peanut butter

Selenium:
Brazil nuts, shellfish, salmon, tilapia, mushrooms

Deena Kastor went to the 2008 Beijing Olympics full of hope and expectations. But barely three miles into the race, the American marathon record holder fractured a bone in her foot. A blood test soon after revealed a surprising possible culprit: vitamin D deficiency. Although Kastor’s body had adequate amounts of bone-building calcium, she couldn’t fully absorb the mineral because her vitamin D levels were low. “I wasn’t aware of the serious consequences of low vitamin D,” she says now.

Sunlight is one of the most abundant sources of vitamin D (our bodies make the nutrient by absorbing UVB rays). Kastor, who’s battled skin cancer, suspects her vigilant use of sunscreen contributed to her deficiency. And hers is not an unusual case. According to a March 2009 study in the
Archives of Internal Medicine
, more than three-quarters of adults are vitamin D deficient. “Runners aren’t doing better than the average population,” says Todd Whitthorne, who oversaw a study at the Cooper Clinic in Dallas that found that 75 percent of those averaging 20 miles a week have low vitamin D levels.Researchers have long known vitamin D is important for bone health and that a deficiency can lead to serious (if rare) bone diseases such as rickets. But new research points to broader health benefits of getting adequate D, including lower risk of cancer, diabetes, and heart disease—as well as increased athletic performance. “With enough D,” says John J. Cannell, M.D., president of the Vitamin D Council, “you’ll run longer and faster, recover more quickly, and suffer fewer injuries.”

A number of new studies show vitamin D’s vital effect on athletic performance. One study, published in February 2009 in the
Journal of Clinical Endocrinology & Metabolism
, concludes that adolescents with higher levels of vitamin D can jump higher, quicker, and with greater power than those with lower vitamin D levels. A review in
Molecular Aspects of Medicine
in December 2008 shows that vitamin D increases the size of fast-twitch muscles and improves muscular strength. Some research shows low levels of vitamin D may increase risk for sports injuries, including stress fractures such as Kastor’s, because the nutrient is so vital for bone health.

Dr. Cannell recently published a literature review in
Medicine & Science in Sports & Exercise
examining the relationship between vitamin D, UVB exposure, and athletics. He looked at studies from the 1940s and 1950s on German and Russian athletes who received UVB radiation. Those studies suggest that exposure to UVB may boost performance. Other studies Dr. Cannell reviewed suggest physical performance peaks in the summer and then declines in early fall; one possible explanation for this link is that UVB is strongest in the summer season, contributing to better athletic performance at that time of year.

There are almost no symptoms of vitamin D deficiency, so one of the only ways to know you’re getting an adequate amount is with an expensive blood test. Runners who live in the northern half of the United States and all of Canada and Europe (where winter sun isn’t strong enough to make vitamin D) are more at risk than others. People who use sunblock, spend a lot of time indoors, or have dark skin (more pigment works as a natural sunscreen) are also at risk of a deficiency.

Current government guidelines call for adults 50 and younger to get 200 International Units (IU) of vitamin D daily (a cup of vitamin D-fortified milk provides about 100 IU); those between 51 and 70 need 400 IU. But many experts believe that’s not nearly enough. “The guidelines need to be overhauled,” says Michael F. Holick, M.D., Ph.D., professor of medicine, physiology, and biophysics at the Boston University School of Medicine and author of the upcoming book
The Vitamin D Solution
. “Until then, people need to be proactive about their vitamin D intake and follow vitamin D-friendly habits.”

Dr. Holick recommends getting between 200 and 400 IU of vitamin D every day through food. While there aren’t a huge number of naturally high vitamin D sources, many foods—from mushrooms to cereal—are fortified with it (see “Eat Your Vitamins,” below). Because even the richest food sources contain only a few hundred IU, he says that runners should consider taking a daily vitamin D supplement that contains 2,000 IU.

Dr. Holick suggests getting moderate sun exposure, aiming for 10 to 15 minutes of sun two or three times weekly from May to October between late morning and mid afternoon, when the sun is strongest. (He also advises protecting your hands and face with SPF, though, since they’ve likely sustained the most UVB damage.) During this time, you’ll take 1,000 to 3,000 IU of vitamin D, which will stay in your body longer than D from food or supplements. “There’s little evidence that moderate sun exposure increases skin-cancer risk,” say Dr. Holick and other experts. Still, the American Academy of Dermatology, which recently acknowledged that sun protection can cause vitamin D deficiency, doesn’t condone sun exposure as a way to boost the mineral. It recommends getting vitamin D from food and supplements.

That’s the route Kastor has chosen, making sure she gets an adequate amount of vitamin D by eating foods rich in the nutrient and taking a supplement. “Hopefully, others will learn from my experience,” she says, “and not have to discover their deficiencies the same way I did.”

Together, calcium and vitamin D protect your bones. To get 1,200 to 1,500 milligrams of calcium a day, eat plenty of dairy, dark greens, and canned fish. Cod liver oil packs 450 IU of vitamin D per teaspoon—but tastes like, well, cod liver. Try getting your D from these tastier sources instead.

400 IU Mushroom enriched with vitamin D, 3 oz

360 IU Salmon 3.5 oz

345 IU Mackerel 3.5 oz

250 IU Sardines Canned in oil, 1.75 oz

200 IU Tuna Canned in oil, 3 oz

98 IU Milk Vitamin D-fortified, 1 cup

60 IU Margarine Fortified with D 1, tablespoon

40-50 IU Cereal Fortified with 10 percent of vitamin D Daily Value, 3/4 cup

20 IU Whole Egg

12 IU Swiss Cheese 1 oz

As a runner you strive for a balanced diet, but even the most conscientious eaters can miss out on key nutrients. If your meal plan doesn’t contain a perfect balance of every performance-enhancing vitamin—and, really, whose does? You may benefit from popping a pill or two. “It’s always best to eat whole foods, since they supply nutrients in combinations pills can’t replicate,” says sports dietitian Molly Morgan, R.D. “But taking certain supplements can help ensure runners get everything active people need.” Here’s how to decide whether your diet needs a boost from some of the most common pills runners pop.

“Calcium reduces stress-fracture risk by strengthening bones,” says Morgan, “and plays a key role in muscle and nerve function.” A study in the
American Journal of Clinical Nutrition
found people with high calcium intake have a lower risk of developing type-2 diabetes. If you eat at least three daily servings of dairy, you probably have enough calcium in your diet. But if you regularly fall short, supplementing is a good idea, says Morgan.

How to Pop It:
Take 1,000 milligrams of calcium citrate or calcium carbonate daily, says Morgan (women 51 or older need 1,200 milligrams). To boost absorption, take it in two doses at meals a few hours apart.

Studies show EPA and DHA, the omega-3 fatty acids in fish oil, help reduce exercise-induced asthma and muscle soreness and increase lean body mass. Both are in fatty fish, like salmon and sablefish. “If you eat two or three servings of fatty fish a week, you get plenty of omegas,” says Cassandra Forsythe, R.D., Ph.D. But if you’re among the 65 percent of runners who rarely or never eat seafood, according to a runnersworld.com poll, supplements are a good choice.

How to Pop It:
A supplement with 1,000 milligrams of fish oil may actually contain little DHA and EPA. “Read the label,” says Forsythe, “and find one that contains at least 500 milligrams of DHA and EPA combined.”

“Iron is vital for producing hemoglobin, a compound that carries oxygen to muscles,” says Diane DellaValle, R.D., who’s studied the mineral’s role in exercise. “Low iron causes energy to sag and affects performance.” Men rarely have low iron, but research shows premenopausal female runners are at risk. Women who feel tired and weak may need a supplement, but since high doses of iron can damage organs, DellaValle stresses runners should consult a doctor before supplementing.

How to Pop It:
If a blood test reveals you have low iron, take ferrous sulfate. “It’s well absorbed and tolerated by most people,” says DellaValle. Pair it with foods rich in vitamin C to boost absorption.

A 2007 study in the
American Journal of Clinical Nutrition
found 35 percent of adults swallow multivitamins. Another recent study reported long-term takers are less likely to have heart attacks. So should you pop? “If you’re healthy and eat a variety of whole foods, you probably won’t benefit from a multi,” says Morgan. “If you struggle to eat all the food groups, it can fill nutritional gaps.” Morgan adds a multi may also help during hard training, when some nutrient needs increase.

How to Pop It:
Pick one with 100 percent of the DV for most vitamins and minerals, but avoid excesses. High doses of some nutrients can be dangerous. Humidity affects potency, so keep pills out of the kitchen and bathroom.

The body needs vitamin D to absorb calcium, making it vital for bone health. That’s why the Institute of Medicine recently raised its recommended daily intake from 200 international units (IU) to 600 IU for most age groups. Newer research has also linked vitamin D to lower risk for heart disease, breast cancer, and diabetes. But getting enough is difficult since it’s in few foods and our bodies only make it when exposed to UV rays. “Generally, most runners could benefit from a vitamin D supplement,” says Forsythe.

How to Pop It:
Forsythe recommends getting your vitamin D level tested. “If you fall below 30 ng/ml, take at least 1,000 IU of vitamin D3 daily.” Pair it with your largest meal to increase absorption.