Written by Tom Powell, Performance Nutritionist
Tom Powell is a performance nutritionist who works with athletes ranging from amateur competitors to Olympians. As the founder of Silverback Performance, Tom and his team have helped secure over 500 podium finishes and are regularly featured in national teams.
For athletes striving for peak performance, the essential nutrients–protein, carbs, and hydration– are often at the top of their minds. But one crucial factor frequently slips through the cracks: vitamin D. Often referred to as the “sunshine vitamin,” vitamin D plays a pivotal role in athletic performance, muscle recovery, and overall health. Yet, despite its importance, it’s surprisingly easy to overlook. Athletes might unknowingly be missing out on the full potential of their performance because of this simple yet vital nutrient.
What is vitamin D?
Vitamin D is a fat-soluble vitamin that is crucial in calcium absorption, bone health, and immune function. It’s often called the “sunshine vitamin” because the body produces it when the skin is exposed to ultraviolet B (UVB) rays from sunlight. However, it behaves more like a hormone than a typical vitamin. After it’s synthesised in the skin or consumed in the diet, vitamin D transforms in the liver and kidneys to become its active form—calcitriol. This form regulates calcium and phosphate levels in the bloodstream, ensuring proper bone formation and muscle function.
Vitamin D3 (cholecalciferol) is the most effective form for maintaining these functions. It plays a crucial role in absorbing calcium, but without proper regulation, it may not reach where it most needs. This is where vitamin K2 comes into play. K2 ensures that calcium is deposited in bones and teeth, not soft tissues like arteries, which is vital for long-term health, especially for athletes who push their bodies to extremes.
In addition to its structural benefits, vitamin D interacts with over 200 genes in the body, influencing processes that impact immune function, inflammation, and even muscle repair. These roles are critical for athletes in maintaining physical health and supporting performance goals.
Why is vitamin D (and K2) important for athletes?
Athletes push their bodies to the limit, so they have specific nutritional needs beyond those of non- athletes. Vitamin D, particularly D3, is essential for athletes because of its impact on several key areas:
Bone health and strength
In high-impact sports, athletes are at risk of stress fractures and bone injuries. Vitamin D supports calcium absorption, crucial for maintaining strong bones and preventing fractures. However, without sufficient levels of vitamin K2, calcium may not be appropriately directed to bones, potentially leading to unwanted calcification in arteries. The D3-K2 combination ensures calcium strengthens bones and avoids soft tissues, reducing the risk of long- term damage.
Muscle function
Adequate vitamin D levels, especially D3, have been shown to enhance muscle strength, function, and coordination. Athletes with sufficient vitamin D levels tend to perform better in strength-based and endurance activities. Low levels can result in muscle weakness, reduced power, and a higher risk of injuries. Vitamin D3 helps athletes recover faster and build muscle more efficiently, and with K2 ensuring proper calcium regulation, the risk of muscle strain is reduced even further.
Immune support
Athletes often experience a weakened immune system due to the stress of intense training, making them more susceptible to infections. Vitamin D plays a vital role in modulating the immune response, which helps athletes stay healthy and fend off illnesses. Whether it’s a gruelling training session or the peak of the competition season, a robust immune system can make all the difference.
Performance enhancement
Emerging studies suggest that optimal vitamin D levels may contribute to improved athletic performance. This is particularly true for endurance athletes and those engaged in strength-based sports. While vitamin D alone won’t make you a superstar, it’s clear that maintaining adequate levels can lead to more efficient training, quicker recovery, and fewer injuries. K2 further supports this by ensuring the body uses the calcium appropriately for bone and muscle function, which could be a game-changer for athletes looking to push their limits safely.
Vitamin D deficiency in athletes
Despite its importance, many athletes are unknowingly deficient in vitamin D. Athletes who train indoors, live in regions with limited sunlight, or have darker skin (which requires more sunlight to produce vitamin D) are particularly at risk. Studies have found that anywhere from 30% to 50% of athletes, including elite-level professionals, are deficient in vitamin D.
Vitamin D deficiency can manifest in various ways. Still, for athletes, the consequences are often seen in slower recovery times, increased susceptibility to stress fractures, frequent colds or infections, and reduced muscle strength. Because the symptoms are subtle, many athletes may not realise they suffer from a deficiency until their performance or health declines.
How to ensure adequate vitamin D (and K2) levels
Luckily, ensuring adequate vitamin D levels doesn’t require a complicated plan. There are three primary ways athletes can maintain or boost their vitamin D levels, and it’s essential also to ensure adequate K2 intake to maximise the benefits of vitamin D:
1. Sunlight exposure
The most natural and effective way to boost vitamin D levels is through sunlight. Athletes should aim for about 10-30 minutes of midday sun exposure several times a week, depending on skin tone, location, and season. This may be challenging for those living in colder climates or training indoors, especially during winter. Apps like D-Minder can be helpful here as they help with timing sunlight exposure and monitoring time in the sun.
2. Dietary sources
While sunlight is the primary source, vitamin D can also be obtained through diet. Foods like fatty fish (such as salmon, mackerel, and sardines), fortified dairy products, egg yolks, and mushrooms exposed to UV light are excellent sources of vitamin D. Including foods rich in K2, such as fermented foods (like natto), hard cheeses, and egg yolks, is equally important. Combining D3 and K2 ensures calcium is absorbed and deposited correctly, enhancing bone and muscle health.
3. Supplements
Supplementation is often the most reliable solution for athletes with limited sun exposure or those at risk of deficiency. Vitamin D3 (cholecalciferol) is the preferred form, as it’s the most effective at raising blood levels of the vitamin. However, athletes should also take a K2 supplement to ensure calcium is utilised correctly for optimal results. Athletes should consult a healthcare provider before starting a supplement regimen, ideally following a blood test to determine their needs.
Conclusion
Adequate vitamin D levels, especially D3, are essential for athletes to maintain bone health and muscle function and optimise performance. Paired with vitamin K2, this combination enhances bone strength and recovery and prevents potential long-term issues like artery calcification.
Incorporating vitamin D and K2 into your health routine could be the missing link to unlocking your full athletic potential. Whether through sunlight, diet, or supplements, ensuring adequate levels of both nutrients is an easy yet effective way to take your game to the next level.
As the demands of sport and training push your body to its limits, paying attention to your vitamin D and K2 intake can be a game-changer, helping you perform better, recover faster, and stay healthier overall.
Read more from Tom Powell
Tom Powell, Performance Nutritionist
Tom Powell is a performance nutritionist sepecilsing in weight making sports like Olympic weightlifting and powerlifting as well as swimming, rugby, athletics and CrossFit. As a former high level athlete who's career was cut short due to I just, Tom transitioned into coaching and discovers hig passion for performance nutrition. Founder of Silverback Performacne he blends Science with experience to help athletes optimise their performance. Over his career he has helped athere's work towards the goals including, multiple, world, continental and national champions as well as medalists at the Commonwelath games Reaching over 500 podium finishes. His mission is to empower athletes to perform their best through nutrition.
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