by Dr. Inez Kelleher
Lisa was surprised after her visit to the doctor. She had been tired for the past few months. Her 800 meter interval times confirmed that. They were about 5 to 10 seconds slower than they had been six months ago. And she hadn’t made any significant changes in her training.
She was surprised because her blood tests found she was very deficient in Vitamin D. She wouldn’t have thought of that deficiency as contributing to her fatigue.
But it did.
Three months later, after taking Vitamin D, her 800 meter times improved again.
Lisa’s story isn’t unusual. (Often when athletes think of a nutrient deficiency related to performance they think of iron or the B vitamins…. And sometimes they’re right.)
According to the Third National Health and Nutrition Study, more and more Americans have insufficient Vitamin D levels. About 77% of Americans have insufficient Vitamin D levels -- a significant increase over the last 30 years. Elite athletes are among them, according to recent studies.
If you’re an athlete who lives in a northern climate or if your sport is mainly indoors, you are at a higher risk of Vitamin D insufficiency. The sun is the most plentiful source of Vitamin D. Cholesterol is converted to Vitamin D at skin level by the UV light from the sun. Exposure to the sun without a sunblock lotion for a minimum of 20 minutes daily is required for your skin to make enough Vitamin D to support its functions.
But Vitamin D production may be comprised by various factors from the shade of your skin to your age. First, you can’t rely on making Vitamin D from the sun even if you live in a sunny climate. Scientists recently discovered Vitamin D deficiencies among those living in the Middle East, Australia, and Hawaii. Second, Vitamin D production may be compromised by your shade of skin. Dark skin absorbs less sunlight than light skin. Third, Vitamin D production has been found to be less efficient in those over 70.
What Athletes Should Know
As Sports Medicine and Nutrition studies show, restoring Vitamin D levels with supplementation correlates with improved muscle strength. Furthermore, research on athletes including soccer players, swimmers, and runners suggests improved performance, muscle strength and recovery, when vitamin D levels are restored and maintained at 40-50 ng/ml.
Restoring Vitamin D to normal levels (30ng/ml-100ng/ml) has also been associated with fewer stress fractures, decreased bone and muscle pain, decreased infections and,
among the elderly, a decreased number of falls. Insufficient (20-30 ng/ml) and deficient (<20 ng/ml) levels are associated with increased risk of stress fractures, and muscle injury, and infections.
This is not surprising given the multiple functions of Vitamin D. It helps absorb calcium – which, in turn, affects bone development and growth, and even muscle strength and mass, especially as we get older. Studies have also found that Vitamin D helps lower inflammation and boost the immune system.
How Much Vitamin Do You Need?
That depends, given that Vitamin D is stored in fat and that our bodies vary in terms of how they produce Vitamin D. Some people have problems absorbing Vitamin D in their digestive tract. Other people take medications such proton pump inhibitors and some cholesterol-lowering drugs that can limit Vitamin D absorption in the gut, so a higher dose may be required to maintain Vitamin D functions.
If you want to supplement Vitamin D intake for your needs, ask your physician to test your levels first, especially if you have suffered from stress fractures, bone and muscle pain, recent falls and frequent common infections, and injuries, or are taking medications that interfere with Vitamin D absorption.
Vitamin D Sources
Of course remember dietary sources with naturally occurring Vitamin D. These include fatty fish, salmon, egg yolks, and cheese. Fortified foods include cereals, milk, yogurt, soy milk, and orange juice.
Vitamin D supplements are available as Vitamin D3 or Vitamin D2. Vitamin D3, ergocalciferol, is obtained from fish., Vitamin D2, cholecalciferol, is obtained from yeast and mushrooms. D3 is more easily absorbed but if you are vegan you may want D2. The main point is to take Vitamin D as needed. The recommended daily doses differ amongst medical specialties. The National Institute of Medicine recommends a daily dose of 600 International Units (IU) for adults aged 19 to 70, while the Endocrine Society recommends 1500-2000 IU for the same age group.
Lisa was surprised after her visit to the doctor. She had been tired for the past few months. Her 800 meter interval times confirmed that. They were about 5 to 10 seconds slower than they had been six months ago. And she hadn’t made any significant changes in her training.
She was surprised because her blood tests found she was very deficient in Vitamin D. She wouldn’t have thought of that deficiency as contributing to her fatigue.
But it did.
Three months later, after taking Vitamin D, her 800 meter times improved again.
Lisa’s story isn’t unusual. (Often when athletes think of a nutrient deficiency related to performance they think of iron or the B vitamins…. And sometimes they’re right.)
According to the Third National Health and Nutrition Study, more and more Americans have insufficient Vitamin D levels. About 77% of Americans have insufficient Vitamin D levels -- a significant increase over the last 30 years. Elite athletes are among them, according to recent studies.
If you’re an athlete who lives in a northern climate or if your sport is mainly indoors, you are at a higher risk of Vitamin D insufficiency. The sun is the most plentiful source of Vitamin D. Cholesterol is converted to Vitamin D at skin level by the UV light from the sun. Exposure to the sun without a sunblock lotion for a minimum of 20 minutes daily is required for your skin to make enough Vitamin D to support its functions.
But Vitamin D production may be comprised by various factors from the shade of your skin to your age. First, you can’t rely on making Vitamin D from the sun even if you live in a sunny climate. Scientists recently discovered Vitamin D deficiencies among those living in the Middle East, Australia, and Hawaii. Second, Vitamin D production may be compromised by your shade of skin. Dark skin absorbs less sunlight than light skin. Third, Vitamin D production has been found to be less efficient in those over 70.
What Athletes Should Know
As Sports Medicine and Nutrition studies show, restoring Vitamin D levels with supplementation correlates with improved muscle strength. Furthermore, research on athletes including soccer players, swimmers, and runners suggests improved performance, muscle strength and recovery, when vitamin D levels are restored and maintained at 40-50 ng/ml.
Restoring Vitamin D to normal levels (30ng/ml-100ng/ml) has also been associated with fewer stress fractures, decreased bone and muscle pain, decreased infections and,
among the elderly, a decreased number of falls. Insufficient (20-30 ng/ml) and deficient (<20 ng/ml) levels are associated with increased risk of stress fractures, and muscle injury, and infections.
This is not surprising given the multiple functions of Vitamin D. It helps absorb calcium – which, in turn, affects bone development and growth, and even muscle strength and mass, especially as we get older. Studies have also found that Vitamin D helps lower inflammation and boost the immune system.
How Much Vitamin Do You Need?
That depends, given that Vitamin D is stored in fat and that our bodies vary in terms of how they produce Vitamin D. Some people have problems absorbing Vitamin D in their digestive tract. Other people take medications such proton pump inhibitors and some cholesterol-lowering drugs that can limit Vitamin D absorption in the gut, so a higher dose may be required to maintain Vitamin D functions.
If you want to supplement Vitamin D intake for your needs, ask your physician to test your levels first, especially if you have suffered from stress fractures, bone and muscle pain, recent falls and frequent common infections, and injuries, or are taking medications that interfere with Vitamin D absorption.
Vitamin D Sources
Of course remember dietary sources with naturally occurring Vitamin D. These include fatty fish, salmon, egg yolks, and cheese. Fortified foods include cereals, milk, yogurt, soy milk, and orange juice.
Vitamin D supplements are available as Vitamin D3 or Vitamin D2. Vitamin D3, ergocalciferol, is obtained from fish., Vitamin D2, cholecalciferol, is obtained from yeast and mushrooms. D3 is more easily absorbed but if you are vegan you may want D2. The main point is to take Vitamin D as needed. The recommended daily doses differ amongst medical specialties. The National Institute of Medicine recommends a daily dose of 600 International Units (IU) for adults aged 19 to 70, while the Endocrine Society recommends 1500-2000 IU for the same age group.