Category Archives: sunlight

Regular readers know that I am a nearly daily bike rider here in Chicago. As such I read some cycling blogs, too. One of my faves is Loving the Bike.

And, one of that blog’s regular contributors is Kelli Jennings, an Expert Sports Nutritionist who writes Ask the Sports Nutritionist.

Kelli is not only a world class athlete, but also a first rate nutritionist who writes clearly and accurately about her healthy and intelligent eating.

She recently wrote an item Adding Vitamin D for the Winter Months that I thought would interest you. Most importantly, you do not have to be a cyclist to benefit from Kelli’s information. I have written about Vitamin D as beneficial to every person. These ideas should benefit you, too, whether you ride a bike or not.
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If you are out on your bike most days, you likely believe you get plenty enough sunshine to make plenty enough Vitamin D.  I get it.  I’m lucky enough to live in a state that boosts more than 300 days a year of sunshine.  So, how come so many of us are Vitamin D deficient?

If you’ve never had your Vitamin D levels checked, you may be in for a surprise.  And, if you find your motivation and mood wavering and eventually diminishing each year in the cold-weather months, you may just find out why.

In fact, it’s not only an issue for athletes, but it’s estimated that at least 25-50% of adults in the United States are deficient in Vitamin D; which is a bit ironic, as it is the only vitamin that our bodies are able to produce (with adequate sunlight).  However, it may be this ability to produce it that gives us a false sense of optimism and a lack of urgency in eating Vitamin D food sources and supplementing.  There are many reasons why we become deficient, and even more reasons to make sure you’re not.

So, what are the implications for cyclists and how can you get enough?

It’s long been known that Vitamin D is important for the absorption of calcium, and therefore, for bone health.  In fact, it was historically thought that the main benefit of Vitamin D was to reduce risk of rickets.  In the last two decades, however, more and more research is finding that Vitamin D’s reach goes far beyond bones.  In fact, it has significant implications on overall health and wellness, respiratory infections, athletic performance, and mood.

Here’s what every cyclist needs to know:
Vitamin D for Athletic Performance:

Reduces Inflammation: After intense exercise, elevated levels of pro-inflammatory cytokines circulate throughout athletes’ bodies.  Vitamin D, along with omega-3 fats from fish oil, reduce the production of cytokines, while increasing the production of anti-inflammatory components.  This can improve recovery, reduce fatigue, and improve overall health.
Improves Immune Function: In studies, Vitamin D deficiency has been correlated with colds, influenza, and respiratory infections. On the other hand, adequate levels of Vitamin D trigger our immune system macrophage cells to release antibacterial peptides, which play a role in infection prevention.  If you want to stay well this Winter, get your Vitamin D.
Prevents Muscle Weakness and Fat Accumulation in Muscles:  Vitamin D deficiency is associated with elevated fat accumulation in muscles, which in turn reduces muscle strength and performance.  In at least one study, the deficiency and loss of muscle strength was demonstrated independent of muscle mass…muscle was actually displaced with fat AND weaker than it should be.  What’s more, there is evidence that supplementation of Vitamin D in deficient persons increases fast twitch muscle fibers in number and size, and reduces injuries (in athletes) and falls (in elderly).
Improves Overall Performance: Studies have shown a steady decline in performance in low-sunlight months, improved performance when athletes are exposed to UV rays (1950s), and peak performance when blood levels of 25 (OH) D are at or above 50 ng/mL.  What’s more, maximum oxygen uptake, or VO2 Max, drops in athletes in months when less UV rays reach the Earth, such as in late Fall months.
Vitamin D for Overall Wellness:
In addition to athletic performance, Vitamin D’s also important for:

Regulating Blood Pressure
Normalizing Blood Sugars and Insulin
Preventing Cancer, especially bladder cancer, breast cancer, colon cancer, ovarian cancer, prostate, and rectal cancer
Steady Moods and Prevention of Depression

Now that we know how important Vitamin D is, it’s no wonder that many experts believe the recommended amounts, and  “normal ranges” for lab values should be much higher than previously established.  But what other factors contribute to our seemingly inadequate intake and levels? Continue reading →