You may have heard that low vitamin D and sports injuries are closely related. Why is this?
Vitamin D is essential for properly absorbing and storing the calcium we obtain from calcium-rich foods, especially in bone. This is important for good bone health.
Vitamin D also acts as a prohormone in the immune system, at cellular level and in the musculoskeletal system.
This is why low vitamin D can be concerning. Let us explain!
Vitamin D Deficiency: Causes
We obtain vitamin D in two ways.
- Through food.
- Through our ability to produce vitamin D when sunlight reaches our skin, particularly the face and arms
Sunlight is the most important source for obtaining vitamin D. This does not mean dietary intake is unnecessary, as we explain below.
Why Is My Vitamin D Low?
Now you know how we obtain it, here are possible reasons for deficiency:
- Insufficient daily sun exposure (sunlight through a window does not count). If you work indoors in an office and train indoors too, your levels may be low. Weather and altitude also matter.
- A diet low in vitamin D-rich foods.
- Malabsorption with or without kidney or liver problems.
- Increased vitamin elimination due to medicines that alter its metabolism.
- Increased daily vitamin D requirements during pregnancy, breastfeeding and ageing. As you age, your ability to produce vitamin D from sunlight declines.
Perhaps learning to increase vitamin D without sunlight now seems more relevant!
What Are the Symptoms of Low Vitamin D?
Its main role is ensuring good bone health through calcium, so the most serious effects relate to this.
In children, it can impair growth and development and, in severe cases, soften and weaken bones, known as rickets. In adults, it increases the likelihood of bone fractures and reduced strength, with severe cases causing bone softening and deformity, known as osteomalacia.You may also experience muscle or bone pain and low bone density (osteoporosis or osteopenia).
Symptoms of Low Vitamin D in Women
Low levels are particularly concerning in postmenopausal women because bone regulation becomes less effective. Adequate calcium, and consequently vitamin D, is especially important.
What Vitamin D Level Is Concerning?
It seems that much of the population does not reach appropriate blood vitamin D levels. Is this true?
There is no single exact, indisputable target, but a reference range can be used.
An interesting study discusses whether proposed minimum values may be higher than necessary.
The key is avoiding deficient values, below 10 ng/mL of 25 (OH) D
Appropriate values would be around 20-40 ng/mL of 25 (OH) D
Values not to exceed would be above 70 ng/mL of 25 (OH) D
How Do You Interpret a Vitamin D Blood Test?
Be aware that routine blood tests do not usually include your vitamin D level. You need to request this explicitly.
Nor is it the only value to consider. As its main role is calcium regulation, calcium must also be considered, alongside phosphorus, alkaline phosphatase and another hormone regulating bone density: parathyroid hormone.
It may seem confusing. Here is the explanation.
With vitamin D deficiency, less calcium is absorbed. To compensate, parathyroid hormone draws calcium from bone to maintain blood levels. This increased effort can produce hyperparathyroidism, with blood calcium levels normal or slightly low. Meanwhile, phosphorus moves in the opposite direction: as calcium leaves bone for the blood, phosphorus moves from blood to bone. Blood phosphorus would therefore be low.
How Does Vitamin D Deficiency Affect Athletes?
If you are still young, low levels may prevent optimal growth and development, physically and muscularly. Over time, you may be more prone to fractures.
If you have finished growing, in terms of bones rather than achievements, you should look after your bone health to avoid rapid deterioration and reduced strength.
In either case, low vitamin D may increase susceptibility to illness. For a virus, it is like moving from a rocky, uneven track (your immune system) to a smooth, easily crossed path.
Vitamin D Deficiency and Injuries
Having low vitamin D levels does not mean you will immediately get injured, but higher levels could help prevent injuries.
How Can You Raise Low Vitamin D Levels?
The obvious answer would be more daytime sunlight , particularly mid-morning exposure of the face, hands and neck. However, during peak sunlight hours we are often working, travelling or busy indoors.
Days off may offer a chance for slightly more sun exposure.
You must also consider the weather and altitude where you live. Ask people in northern areas whether winter brings bright sunshine and short-sleeved weather!
For most people, especially during the working week, it will be necessary to increase vitamin D through food or specific supplementation.
How Long Does Vitamin D Take to Rise?
Serum levels can change quickly . A repeat blood test the following month should show a significant increase, provided you have started addressing the deficiency.
Vitamin D Supplements: Which Are Most Effective?
The nutrient vitamin D is fat-soluble, meaning it needs a fatty environment for absorption. Some supplements have oil-coated capsules to aid absorption. Check whether yours do, and consider taking them with a meal containing fat.
Magnesium also plays an important role in vitamin D metabolism, both regulation and use. Increasing our intake of magnesium therefore makes sense: more vitamin D without more magnesium means the same magnesium must process more vitamin D, potentially lowering magnesium levels.
Is Supplementation Essential If Vitamin D Is Low?
This depends on how low your vitamin D levels are.
The closer to 4 ng/mL , the more serious and the greater the need. The closer to 20-30 ng/mL , the lower the need. More sun exposure and foods rich in vitamin D and magnesium may be enough.
Can Too Much Vitamin D Be Harmful?
This is uncommon and generally results from excessive supplementation.
However, high vitamin D levels can be harmful, associated with vomiting, loss of appetite, weakness, constipation and even kidney damage.
As vitamin D also affects calcium , excess can raise blood calcium (hypercalcaemia), potentially causing kidney stones, heart rhythm problems and disorientation.
If you suspect high vitamin D levels from sun exposure, you can stop worrying about vitamin D excess, although excessive summer sunlight without adequate protection is still inadvisable. Your body can limit vitamin D production from light.
With excessive supplementation , it cannot control intake in the same way.
Foods Rich in Vitamin D
How can we improve low vitamin D levels through diet? Here are the richest sources:
- Liver, which transforms vitamin D in the body. Cod liver oil is particularly rich.
- Salmon
- Tuna
- Sardines
- Oysters
- Mackerel
- Prawns and shrimp
- Milk
- Cheese
- Egg (yolk)
- Fungi
- Mushrooms
Why Is Sun Exposure Recommended for Low Vitamin D?
As explained, sunlight allows us to produce the greatest amount of vitamin D , although this ability declines with age.
The exposure required is relatively short: 5 to 10 minutes of sunlight on the face, neck and arms would be more than enough.
Remember that sunlight through a window does not count, and bright, clear weather is not guaranteed daily. Diet therefore also matters.
Eating every day is more certain than sunshine every day.
If you have questions about ensuring your diet provides the vitamin D levels you need, work with one of our sports nutritionists. We can help with low vitamin D and injuries while improving sports performance. Explore our subscription options and let us get started!
