Nutrition is a vital aspect of performance optimization for athletes. When it comes to recovery from intense exercise, there are a number of things to consider, as our nutrition guide for runners explains in more detail.
But what role do vitamin supplements play here? Recently, studies have demonstrated the importance of Vitamin D for runners in enhancing their performance and recovery.
In this article we are going to explore the ins and outs of Vitamin D for runners and delve into:
- What exactly Vitamin D is
- Why Vitamin D is important for runners
- What the risks of Vitamin D deficiency are for runners
- Vitamin D supplements- do they work, and how much and how should you take them
Ready to boost your running game?
Let’s get into it!
What is Vitamin D?
Vitamin D is a nutrient that is gaining increased attention from those interested in sports nutrition. It is crucial for helping our bodies absorb and maintain adequate levels of calcium and phosphate, which are needed to keep our bones, teeth and muscles healthy and strong.
Certain studies have revealed that a high proportion of athletes have Vitamin D deficiency.
Often, this is caused by a lack of awareness that sun exposure is the main source of Vitamin D.
Anything that limits the amount or quality of sun exposure can compromise Vitamin D levels. Therefore, athletes that primarily train indoors are particularly at risk here, as are athletes who train at higher latitudes.Dietary factors are also important. Very few food sources naturally contain the vitamin, and the exceptions are often foods that athletes tend to avoid, such as fatty fish and red meat.
Many athletes are also prone to under-fueling, which can increase the risk of Vitamin D deficiency.
Why is vitamin d important for runners?
Vitamin D is critical for keeping runners’ bones, teeth, and muscles healthy and strong.
Having adequate Vitamin D levels in runners reduces their risk of injury, improves muscle strength, and aids recovery.
Improving your Vitamin D status gives your body a better chance of adapting skeletal muscle functions following strenuous exercise.
Muscle power and force in marathon runners are also linked closely to vitamin D levels. Therefore, Vitamin D supplementation can provide an important boost during recovery from endurance running.
What are the Risks of Vitamin D Deficiency for Runners?
Deficiencies in this area can affect endurance and strength, as well as increase injury risk. In the National Football League (NFL), for example, players with low vitamin D levels were found to be at greater risk of bone fractures.
Deficiency in Vitamin D can also increase the risk of muscle myopathy, muscle weakness, and fatigue.
And it turns out that long-distance runners are particularly at risk.
A report led by Brittany Ammerman found that 76.5% of patients with ligament and cartilage injuries and 54.6% of patients with muscle/tendon injuries had low Vitamin D levels, a finding indicative of the increased injury risk caused by lack of nutrition in this area.
Vitamin D Supplementation For Athletes
Being able to get all of your Vitamin D from the sun and your food is ideal.
But if that’s not possible, or if you are hitting high mileages each week and want to cover your bases, one alternative option for boosting Vitamin D levels is supplementation.
Taking Vitamin D supplements can increase strength, improve physical performance and reduce the risk of injury, especially for those with particularly low levels of the vitamin.
Does Vitamin D Supplementation Work?
A recent study conducted by the Journal of the International Society of Sports Nutrition looked into the effects of Vitamin D supplementation on the skeletal muscles of endurance runners (all of whom were ultramarathon competitors).
The study monitored how runners’ bodies responded to supplementation over a 3-week period.
It was found that 3 weeks of Vitamin D supplementation had a positive effect on serum 25(OH)D levels in endurance-trained runners (this is how Vitamin D levels are measured). Using Vitamin supplements also caused a marked decrease in levels of post-exercise biomarkers like troponin, myoglobin, creatine kinase, and lactic dehydrogenase.
Essentially, Vitamin D supplementation works. The study concluded that supplementation could play an important role in the prevention of skeletal muscle injuries following exercise with eccentric muscle contraction in athletes.
Which Type of Vitamin D Supplement Should I Take?
Seeing as we’ve now been through the potential benefits of Vitamin D supplementation, you may be wondering how to integrate this practice into your recovery routine.
The most commonly recommended type of Vitamin D supplement is Vitamin D3, or cholecalciferol. This is the natural form of Vitamin D that your body produces from sunlight. Supplements are made from the fat of lamb’s wool.
However, many medical professionals have suggested that Vitamin D2 works just as well as D3.
D2 is also referred to as calciferol, and it’s derived from irradiated fungus. While certain studies have found that Vitamin D2 supplementation has lower stability, bioavailability, and absorption than D3, and its effects on muscle strength are limited, it is still used by many.
Nutritionists and doctors are likely to advise different forms of Vitamin D supplement depending on the individual. For this reason, it’s important to seek guidance from professionals.
How much Vitamin D Should I Take?
According to WebMD, taking 400-1000 IU of Vitamin D daily is a relatively risk-free way to reduce your chances of suffering from Vitamin D deficiency. However, this is a figure that is recommended to the general population. For athletes, higher portions may be required.
Generally, 2000-6000 IU of daily Vitamin D is the amount recommended for athletes.
As an endurance sport, long-distance runners are likely to require something towards the top end of that spectrum when recovering from intense sessions. However, Vitamin D deficiency can hit different people in different ways; therefore, it’s important to discuss your intake with a professional.
Are there any side effects of Vitamin D Supplementation?
Well-managed, moderate Vitamin D supplementation is generally pretty low-risk. However, it’s important to be aware of some of the potential problems that may arise. Let’s summarise the key issues.
Vitamin D Toxicity
Using an excessive amount of supplements can result in Vitamin D toxicity, which causes hypercalcemia (a buildup of calcium in the blood). This can lead to nausea, vomiting, anorexia, frequent urination, and in severe cases, altered mental status or kidney failure.
Vitamin D toxicity can sometimes arise due to improperly manufactured supplements, but usually, it’s a result of unintentional consumption of extremely high doses. It’s crucial that supplementation is carried out by professionals with knowledge on the subject and awareness of the risk of intoxication.
Pregnancy and Breast-Feeding
Vitamin D supplementation is generally safe during pregnancy and breastfeeding when used in daily amounts below 4000 IU, although when used in higher doses there is a chance it could cause harm to the infant. Therefore, it’s important to liaise with your healthcare provider and ensure safe dosages are used.
Children and Infants
As you might expect, Vitamin D supplementation is slightly riskier for young children.
Infants from 6-12 months should not take more than 1500 IU daily, while children aged 1-3 should not take more than 2500 IU daily. This number rises gradually with age — for more guidance on this, check out the NHS website.
Other Potential Risks
Certain health conditions can be worsened by Vitamin D supplementation.
While this shouldn’t worry most people, it’s important to bear in mind any potential risks. For example, atherosclerosis (hardening of the arteries) can be worsened by taking extra Vitamin D.
Those who suffer from histoplasmosis (a type of fungal infection) should also exercise caution, as Vitamin D supplementation could increase calcium levels, therefore leading to kidney stones and other problems.
More on the potential side effects of Vitamin D supplementation can be found on the WebMD site.
It’s important to recognise that generally, the best way to maintain healthy levels of Vitamin D is simply to ensure you eat protein-rich food and spend 15-30 minutes in the sun each day. However, this isn’t always enough for some people.
Endurance athletes can be particularly at risk of suffering from Vitamin D deficiency, due to factors like dietary choices, training conditions, and under-fueling. If you fall into this category, refer to this list when considering taking Vitamin D for recovery:
- Maintaining adequate Vitamin D levels reduces the risk of injury, improves muscle strength and aids recovery
- Ensure you are absorbing 30+ minutes of sunlight each day and eating protein-rich food before resorting to supplementation
- Refer to a medical professional when making any decision regarding supplements
- Make sure you take a suitable level of supplementation depending on the intensity of your training and your level of Vitamin D (2000-6000 IU daily is often the amount recommended to athletes)
- Beware of Vitamin D toxicity and other potential health risks
If you take these factors into account and exercise caution when using Vitamin D supplementation, you may find that this practice can boost your ability to recover quickly and perform better.
Maintaining strong Vitamin D levels is crucial for maintaining bone strength, improving physical performance and reducing the risk of bone or muscle injury. Follow our advice, and utilise this nutritional knowledge to your advantage.
For more on how nutrition can impact your training, check out our article on the 10 Rules of Marathon Training Nutrition.