Forget sunshine just being for fun. Science suggests that vitamin D which your body makes from sun exposure, is a muscle superhero! We all know that vitamin D is vital for strong bones and preventing osteoporosis, but recent research suggests it plays a starring role in muscle health too.
According to scientific research, the vitamin D your body produces from sun exposure has remarkable benefits for your muscles. We know that vitamin D is crucial for maintaining strong bones and lowering the risk of osteoporosis, partially due to its effects on calcium absorption. However, according to research, it also plays a powerful role in promoting muscle health. Could vitamin D help your muscles repair and recover after a workout? Could it also help you get stronger? Let’s take a closer look.
Why Vitamin D Is an Essential Nutrient
Vitamin D is a fat-soluble vitamin, meaning it dissolves in fatty solvents rather than watery ones. You can synthesize vitamin D from sunlight exposure or obtain it through dietary sources. Unfortunately, there’s a scarcity of foods that contain vitamin D in their natural state. Exceptions include mushrooms exposed to sunlight, fatty fish, and egg yolks.
You can also get vitamin D from vitamin D-fortified foods, like milk, breakfast cereals, and yogurt. Vitamin D helps regulate calcium and phosphorus. But scientists are interested in what other roles vitamin D plays in the human body. One area they focused on was muscle tissue.
Why are they looking at muscle? They observed that skeletal muscle has vitamin D receptors (VDRs) and wanted to know why the receptors were there. They wondered what role these receptors play in muscle function. It’s not a silly question to ask. In fact, research links vitamin D deficiency with poor muscle strength and performance. Some of the most common symptoms of vitamin D deficiency involve the muscles. These include proximal muscle weakness, diffuse muscle pain, and gait impairments.
But how does vitamin D influence skeletal muscle repair and regeneration? Lab and animal studies show that vitamin D regulates the growth of myoblasts. These are precursor cells that connect with each other to form mature muscle fibers as your muscles repair and regenerate. There’s also evidence that lack of sufficient vitamin D makes it harder for skeletal muscle to regenerate after injury or damage.
But, as with most things, it’s not as clear cut as we’d like. If you’re deficient in vitamin D, it interferes with muscle repair, but high doses of vitamin D can also make it harder for skeletal muscles to repair and regenerate. It’s an example of the “sweet spot” phenomenon.
Research also shows vitamin D helps support healthy muscle mitochondria, the powerhouses of cells. They’re responsible for producing the energy muscle cells need for muscle contraction and repair. Vitamin D deficiency makes muscle cells function less efficiently. Plus, another study found that supplementing with vitamin D boosts mitochondrial function in adults who are deficient.
The Anti-Inflammatory Benefits of Vitamin D
When you work your muscles against resistance, the force of muscle contraction creates microscopic tears in the fabric of the muscle. Your immune system responds to this damage by launching an inflammatory response. Unfortunately, when the inflammatory response gets out of control, it hinders muscle repair and regeneration. Research suggests that vitamin D helps reign in the inflammatory response you get after a workout. It reduces inflammatory markers that play a role in muscle damage.
Still, we need to learn more about how vitamin D affects exercise performance. It would also be helpful to know whether supplementing with vitamin D in people who are deficient or borderline deficient improves muscle function and exercise performance. Older adults and people with excess body fat are at higher risk of vitamin D deficiency. Research suggests that as much as 40% of the population has levels that are too low for optimal health. Older adults and people with excess body fat are at higher risk of vitamin D deficiency. Unfortunately, most healthcare providers don’t routinely screen for vitamin D deficiency.
As of now, some studies show the benefits of supplementing with vitamin D on exercise performance while others don’t. Why the discrepancies? They may be due to differences in study populations, vitamin D dosages, and outcome measures. Hopefully, future research will clarify this issue.
Conclusion
There are still unanswered questions about how vitamin D affects muscle function. You require a specific amount of vitamin D to keep your muscles and bones healthy and to avoid deficiency. But we still don’t know what dosage is best for maximizing muscle repair and performance. One thing is obvious though. Commonly occurring, vitamin D insufficiency can impair immunological, bone, neurological, and muscular function, and health. So, make sure you have an adequate amount of vitamin D to unlock the full potential of your muscles and help them recover after exercise. If you’re at elevated risk of vitamin D deficiency, based on these risk factors, ask your doctor to check your vitamin D level.
- Inadequate sun exposure (due to staying indoors, covering clothes, or living at higher latitudes)
- Dark skin pigmentation
- Malnutrition or low dietary intake of vitamin D
- Obesity
- Lack of college education
- Lack of daily milk consumption
- Older age (over 65)
- Smoking
- Kidney or liver failure, which prevents the body from adequately processing vitamin D.
- Certain medications that interfere with vitamin D metabolism
- Malabsorption syndromes such as Crohn’s disease, celiac disease, and cystic fibrosis
- Exclusive breastfeeding in infants, especially if the mother is vitamin D deficient.
- Prematurity in infants
- Certain medical conditions like lymphoma, pancreatic insufficiency, and hyperparathyroidism
- Having undergone gastric bypass surgery or small intestine resection
Embrace the power of the “sunshine vitamin” and give our muscles the support they need to thrive.
References:
- Książek A, Zagrodna A, Słowińska-Lisowska M. Vitamin D, Skeletal Muscle Function and Athletic Performance in Athletes-A Narrative Review. Nutrients. 2019 Aug 4;11(8):1800. doi: 10.3390/nu11081800. PMID: 31382666; PMCID: PMC6722905.
- Latham CM, Brightwell CR, Keeble AR, Munson BD, Thomas NT, Zagzoog AM, Fry CS, Fry JL. Vitamin D Promotes Skeletal Muscle Regeneration and Mitochondrial Health. Front Physiol. 2021 Apr 14;12:660498. doi: 10.3389/fphys.2021.660498. PMID: 33935807; PMCID: PMC8079814.
- Montenegro KR, Cruzat V, Carlessi R, Newsholme P. Mechanisms of vitamin D action in skeletal muscle. Nutr Res Rev. 2019 Dec;32(2):192-204. doi: 10.1017/S0954422419000064. Epub 2019 Jun 17. PMID: 31203824.
- “Vitamin D Deficiency: Symptoms, Treatments, and Causes – Healthline.” 19 Jan. 2024, https://www.healthline.com/nutrition/vitamin-d-deficiency-symptoms.
- Curr Opin Clin Nutr Metab Care. 2009 Nov; 12(6): 628–633.doi: 10.1097/MCO.0b013e328331c707
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