A new study presented at this month’s American Orthopaedic Society for Sports Medicine conference suggests that low vitamin D levels may increase the likelihood of muscle injuries in athletes, specifically NFL players.
Vitamin D deficiency is rampant. Few foods contain this vitamin (fortified milk and other fortified products, fish – but you must eat the bones) and many of us aren’t getting the sunlight required to make vitamin D (not the best route anyway if you want to protect your skin). And, football players – even though they practice outside, are covered up in so much gear that little to no skin is exposed to UV rays from the sun.
In this study, 80% of the NFL football team studied had vitamin D insufficiency (they weren’t deficient per se, but their levels certainly weren’t optimal). Of the 89 NFL athletes on this team:
- 27 were vitamin D deficient (< 20 ng/ml)
- 45 had low levels (but not true deficiency; 20 – 31.9 ng/ml)
- 17 players had normal vitamin D levels (> 32 ng/ml)
- skeletal muscle has a receptor for vitamin D (which in the body acts like a steroid hormone)
- vitamin D deficiency has been tied to pain, specifically low back pain
- vitamin D deficiency is tied to fat infiltration in muscle tissue (fatty muscle = less effective functioning of muscle tissue)
- live in the Northern half of the country (above Atlanta, GA)
- play indoor sports or are covered in clothing outside
- have darker skin
- those who take in little to no vitamin D in their diet (fortified milk, fish with bones)
- muscle weakness or cramps
- joint pain, lower back pain
If you are an athlete and want to perform at your best, it makes sense to get tested. Go to your primary care physician, campus health center or a local testing facility (Lapcorp, Quest, directlabs.com). Ask for a 25(OH)D test and, get the results (don’t settle for them telling you that your levels are normal, low etc.). Ideally, for good health, your vitamin D should be 50 – 70 nmol/L or > 20 ng/ml (depending on the measure used).