Nourish, Protect, Thrive: Unlocking Musculoskeletal and Immune Health with Vitamins D, A & C

When it comes to building strong bones and joints and maintaining a balanced immune system, three vitamins stand out as key players—Vitamin D, Vitamin A, and Vitamin C. While each plays a distinct role, they are all important in supporting overall health and wellness. Let’s dive into the science behind these vitamins and explore how they contribute to musculoskeletal health and immune function.

Vitamin D

Vitamin D is the most common nutritional deficiency in the North American population (1). People living at northern latitudes (>55 degrees) are at particular risk – for reference, Ottawa is at 45 degrees and Edmonton is at 53 degrees; thus, many Canadians are vulnerable. Vitamin D3 from sunlight is absorbed through the skin. Vitamin D2 and D3 are also present in many foods, including milk products, eggs, and fatty fish such as salmon. Once absorbed into the body, Vitamin D3 must be converted by the liver and kidneys into its biologically active form known as 1,25 (OH)2D. However, it is typically 25(OH)D tested in the blood. Vitamin D is crucial for the absorption of calcium and phosphate, which are required for bone mineralization. Individuals with severe Vitamin D deficiency can develop nutritional rickets (impaired mineralization of growth plates in young children) and/or osteomalacia (impaired mineralization of bone tissue in children and adults), as well as a host of other health problems (e.g. seizures, heart problems, growth failure). There is also some evidence that low Vitamin D levels may be associated with increased rates of joint pain (2) and widespread musculoskeletal pain (3).

Interestingly, Vitamin D also interacts closely with our immune system. It suppresses the production of inflammatory proteins (cytokines) such as interleukin-2, interleukin-17 and interferon gamma. Vitamin D also regulates B-cell proliferation and antibody production (4). Vitamin D deficiency has been implicated as a risk factor for the development of various autoimmune diseases such as type 1 diabetes, multiple sclerosis, rheumatoid arthritis and inflammatory bowel disease. In a German cohort of patients with juvenile idiopathic arthritis (JIA) researchers found that patient with lower Vitamin D levels had higher disease activity scores, were more likely to progress from oligoarthritis (≤4 affected joints) to an extended disease course (>4 affected joints) and had a higher risk of developing JIA-associated uveitis in the first 3 years of disease (5). Similarly, in a cohort of patients with systemic lupus erythematosus (SLE), lower Vitamin D levels were associated with a higher incidence of kidney involvement (nephritis) and higher disease activity scores (6). Although Health Canada recommends supplementation with 400 international units (IU) of Vitamin D per day for children and teens, there is evidence that individuals with rheumatic disease require more than this, up to 2000 IU per day, especially if taking steroids (7). In addition, rheumatologists often counsel their patients to avoid sun exposure to prevent disease flares, further increasing the risk for Vitamin D deficiency. 

Vitamins A and C

Vitamin A must be ingested and found in liver, fish, eggs, dairy products, as well as green and orange vegetables. Vitamin A deficiency may occur in individuals with food insecurity or malabsorption problems. This vitamin plays an important role in ocular health as well as in the functioning of both the innate and adaptive immune system. Individuals with vitamin A deficiency may develop night blindness and progress to destruction of their cornea (outer layer of the eye), making vitamin A deficiency the leading cause of preventable childhood blindness. Vitamin A is also important in fighting infections such as measles and diarrheal illness.

Vitamin C is found in citrus fruit, berries, leafy greens and peppers. There is an increasing trend in Vitamin C deficiency (also called Scurvy) in the United States, particularly in males with neurodevelopmental disorders and selective eating habits (8). Vitamin C is required for collagen synthesis as well as proper immune function and iron absorption. Scurvy can therefore lead to easy bleeding, bone fragility and anemia. Bone x-rays of people with vitamin C deficiency can look like inflammatory arthritis, bone infection or inflammation. Skin bleeding can look like bruising or vascular rashes, which could mimic some rheumatic diseases.

In summary, Vitamins D, A, and C are essential for maintaining musculoskeletal health and supporting a balanced immune system. From strengthening bones to regulating immune responses, these nutrients play a crucial role in keeping us healthy. By making informed decisions about our dietary habits and supplementation needs, we can take proactive steps to nourish, protect, and thrive for long-term musculoskeletal and immune health.

References:

1. Health Canada, 2012 Cat. No.: H164-112/1-2012E-PDF. ISBN: 978-1-100-20028-6. Do Canadian Children Meet Their Nutrient Requirements Through Food Intake Alone? - Canada.ca

2. McNally JD, Matheson LA, Rosenberg AM. Epidemiologic considerations in unexplained pediatric arthralgia: the role of season, school, and stress. J Rheumatol. 36(2):427-33 (2009). 

3. Alonso-Pérez, J.L et al. Relationship Between Serum Vitamin D Levels and Chronic Musculoskeletal Pain in Adults: A Systematic Review. Nutrients. 16, 4061 (2024). 

4. Maruotti N, Cantatore FP. Vitamin D and the Immune System. J Rheumatol. 37 (3) 491-495 (2010).

5. Sengler, C., et al. Vitamin D deficiency is associated with higher disease activity and the risk for uveitis in juvenile idiopathic arthritis - data from a German inception cohort. Arthritis Res Ther 20, 276 (2018). 

6. Jiang L, et al. Serum 25(OH)D levels are associated with disease activity and renal involvement in initial-onset childhood systemic lupus erythematosus. Front Pediatr. 4;11:1252594 (2023). 

7. Vojinovic, J., Cimaz, R. Vitamin D—update for the pediatric rheumatologists. Pediatr Rheumatol 13, 18 (2015).

8. Reikersdorfer KN, et al. The Troubling Rise of Scurvy: A Review and National Analysis of Incidence, Associated Risk Factors, and Clinical Manifestations. J Am Acad Orthop Surg Glob Res Rev. 15;8(7):e24.00162 (2024).