Vitamin D is often referenced as the sunshine vitamin since the vitamin's primary source is attained through sun exposure. Yet, many people are vitamin D deficient.

Vitamin D is a fat-soluble hormone that plays a critical role in bone health, muscle function, adaptive immunity, and many human diseases like cancer, diabetes, and musculoskeletal health.²

Vitamin D Deficiency

In fact, vitamin D deficiency is a global public health issue.

About 1 billion people worldwide have vitamin D deficiency, while over 77% of the general population is insufficient.¹ So, what does that mean if you are an athlete who plays an indoor sport, trains indoors year-round, and rarely gets outside during the day?

What if you also live in the northern hemisphere? Odds are you are not getting enough vitamin D. Insufficient sun exposure can dramatically increase your risk of vitamin D deficiency. It can lead to a variety of negative health implications and hinder athletic performance.

Research has illustrated that vitamin D significantly affects muscle weakness, pain, balance, and fractures in the aging population.¹

Vitamin D plays a key role in:¹

Vitamin D deficiency occurs as blood levels drop to less than 20 ng/mL (< nmol/L), while vitamin D insufficiency for athletes is defined as blood levels reaching between 20-32 ng/mL (50-80 nmol/L).

Research has indicated that 40-50 ng/mL (100-125 nmol/L) seems ideal for optimizing athletic performance.¹

Who's at High Risk?

The people at high risk for vitamin D deficiency:^1,5

• Decreased dietary intake: Certain malabsorption syndromes like celiac disease, short bowel syndrome, gastric bypass, inflammatory bowel diseases
• Decreased sun exposure. Roughly 50% to 90% of vitamin D is absorbed through the skin. Twenty minutes of sunshine daily, with 40% of skin exposed, is required to prevent deficiency.
• Aging adults: The ability to synthesize vitamin D decreases by as much as 75% as we age.
• Overweight and obese individuals: Those who carry excess body fat can increase their risk of up to 55% due to vitamin D being trapped in adipose tissue and being unavailable in the bloodstream.

See the previous blog on factors that influence vitamin D levels.

Athletes Who Play Indoor Sports

Athletes who play indoor sports are at a greater risk of vitamin D deficiency.

Hockey players specifically spend a great deal of their time training, conditioning, and competing indoors, making it difficult to attain vitamin D through sun exposure. To add to the statistics, another study found that as much as 88% of the population receives less than the optimal amount of vitamin D.³

Several studies link vitamin D status to bone health and the overall prevention of bone injuries in the athletic population.

Research and Vitamin D Deficiency

Studies have illustrated that inadequate vitamin D levels are linked to a greater risk of stress fractures in young men and women published in the Journal of Foot & Ankle Surgery.⁴

A study published in the journal, Nutrients assessed vitamin D status among college men and women basketball players in the season. The players were either allocated a high-dose, low dose, or no vitamin D depending on their circulation 25-hydroxyvitamin D levels at the beginning of the study to identify the optimal dosage of vitamin D₃ supplementation optimal status.

The findings demonstrated that 13 of the 20 participants were vitamin D insufficient at baseline. Another finding was that of the athletes sampled, and the darker skin pigmentation increased the risk of vitamin D insufficiency at baseline.

Researchers found that most athletes who were vitamin D insufficient benefited from supplementation of 10,000 IU to improve their status.⁵

Another study concluded black professional football players have a higher vitamin D deficiency than white players.⁶

The study also suggests that professional football players deficient in vitamin D may also have a greater risk of bone fractures.⁷

Increasing power output is every athlete’s desire as it can translate into improved performance on the field. Your muscle tissues have several key receptor sites for vitamin D, and they will help support power production.¹

A study in soccer players found that increasing baseline vitamin D status over an 8-week period leads to increased vertical jump and 10-meter sprint times.⁹

Of course, we need further research in this area to identify the relationship between vitamin D levels and power output.

Still, the current literature is promising and that, at minimum, baseline vitamin D levels should be desired.

Sources of Vitamin D

The best vitamin D sources include egg yolks, mushrooms, fortified milk, yogurt, cheese, salmon, mackerel.⁸

Vitamin D rich food sources:

• 6 oz. fortified yogurt = 80 IU
• 3 oz. of salmon = 794 IU
• 1 cup of fortified cereal = 40 IU
• 1 cup of fortified milk = 120 IU
• 1 egg yolk = 41 IU
• 1 cup of fortified orange juice = 137 IU

Practical applications

Athletes who train indoors, consume little vitamin D rich sources and live > 35 degrees north or south may benefit from a vitamin supplement of 1,500 - 2,000 IU per day to keep vitamin D concentrations within a sufficient range.

Athletes who may have a history of stress fractures, frequent illness, pain or weakness, or overtraining signs should have their vitamin D status evaluated.

Vitamin D is best absorbed when taken with a meal that contains fat.

It is important to follow up with a physician to assess vitamin D levels further and meet with a registered dietitian to discuss nutrition intervention further.

Discover supplements that benefit your specific needs with Supplement Advisor

The supplement industry sometimes seems like the wild wild west, where you’re left feeling like there are more questions than answers:

Should I take fish oil? Isn’t it good for reducing inflammation and heart health? What’s better? Pill form or liquid?

Or:

I have recently started the Ketogenic diet. Is it true I should be taking multivitamins and a folic acid supplement because I’m no longer getting folic acid from grains?

Or:

I’m a menstruating woman who doesn’t eat red meat. Should I be taking an iron supplement? And doesn’t Vitamin B12 play a role in red blood cell health, too, helping fend against becoming anemic? Should I take that, too? Do I need a B12 supplement too?

Enter Supplement Advisor’s free assessment test.

Supplement Advisor is a web-based company designed to empower health-conscious people to improve their cognitive function, as well as emotional and physical potential through simple and personalized supplement guidance designed by their advanced AI, ultimately helping you navigate through the wild wild west of the supplement industry easily and quickly.

One way they do this is through their assessment tool, a tool that lets you to either take a full assessment, or select a particular area to see if you might benefit from taking a supplement. The areas include:

• Memory
• Motivation
• Focus
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• Energy
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• Sleep.

How it works:

Let’s say you’re curious if you might benefit from taking a magnesium supplement to help regulate your blood sugar levels and stop you from having energy crashes in the middle of the day. And if so, what products might be best for you.

Giving you these answers is exactly what Supplement Advisor’s tool is designed to do.

All you do is select energy, hit submit and answer a few questions, such as:

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After answering the questions, the AI engine—which will continue to get smarter and smarter as more people take the assessment and the database grows—quickly analyzes your responses and offers various recommendations in terms of what products might be best for your specific needs.

Sleep

Because fifty to seventy million people in the United States suffer from some kind of sleep disorder—from having trouble falling asleep, to insomnia to sleep apnea—one of the most common reasons to take a supplement is for sleep.

On top of the natural products, nine million Americans take prescription drugs to help them sleep.Prescription drugs, however, can come with some side effects, including gastrointestinal problems, prolonged drowsiness during the day, daytime memory and cognitive performance challenges or various allergic reactions.

A better option for many is a melatonin supplement.

Why is it better?

Melatonin is a hormone the body produces naturally. It’s responsible for regulating your body’s internal clock by responding to lightness and darkness.

When it gets dark out, melatonin increases in your body and lets you know it's bedtime by attaching to receptors in the brain that help you relax and feel tired. During the day, on the other hand, your body makes dopamine, which signals you to release less melatonin, thus helping keep you awake.

When you select sleep on Supplement Advisor’s assessment tool, it once again, puts you through a series of questions, including:

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• Do you have trouble falling into a deep sleep?
• Do you experience restless sleep?
• Lucid dreaming in the REM stage has shown to be helpful with reducing stress and dealing with trauma. Would you be interested in lucid dreaming more often?

From there, you’re given a list of options of various products that might help your particular sleep concern or deficiency.

Giving it a try

As a writer, my focus needs to be one point to handle long days staring at a computer. I tend to be really focused and motivated in the morning, but fade after 2 p.m. before I have completed all my work for the day.

I decided to give the tool a try to see if there was something I could take to improve my focus.

The tool asked me:

• Do you experience attention disruption when your brain is stressed and overworked?
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• Are you able to attend to more than one task simultaneously?
• Are you able to shift attention from one task to another without losing focus?
• Do you feel able to focus intently enough to create goals and monitor your progress?

I answered no to the first question, as usually being stressed out and overworked lights a fire under my bum. Similarly, I find it easy to ignore distractions and can remain focused on one task for a long time, so I also answered no on the second and third questions, as well. The final question was also a no.

Where I struggle is with focusing on more than one task at a time and definitely with shifting attention from one task to another without losing focus, hence I answered yes on the fourth and fifth questions.

What the tool recommended as the top product: A probiotic-fermented Vitamin B complex for energy, brain and mood support (it also recommended various other Vitamin B complex options).

(Funny enough, my naturopath also recommended I take a B Vitamin supplement. I’ll call that a win).

I decided to take it a step further and also selected the motivation assessment, as sometimes it’s not that I lose focus so much as I lose motivation in the final couple hours of my work day. I was then asked:

• Do you feel like you want to crawl in bed and watch Netflix all day?
• Is your sleep and nutrition regular and adequate?
• Are you a stressful person? If so, does it influence your decisions?
• Is your blood sugar high?

Supplement Advisor’s recommendation: Mane Brain’s brain-boosting power, a supplement is designed to help you feel more energized, alert, focused, and less forgetful.

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