Science Update

Recent Trial Investigates Potential Link Between Vitamin D, PUFAs, and Autoimmunity

Autoimmunity refers to an abnormal response from the immune system that may lead to the destruction of certain tissues or organs. There are more than 80 conditions that are categorized as autoimmune diseases, and epidemiologic evidence suggests that some may be increasing in prevalence. Recent research indicates that certain micronutrients may support health in the presence of an autoimmune response. 

Polyunsaturated fatty acids (PUFAs) are a group of molecules that include ω-3 and ω-6 fatty acids. While ω-3 PUFAs such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been shown in research to help support a healthy inflammatory response and immune health, ω-6 fatty acids may exhibit certain pro-inflammatory qualities. Overall, the typical Western diet contains more ω-6 fatty acids, which may create an imbalance in the overall ratio between ω-6 and ω-3. This imbalance may potentially increase the risk of developing certain autoimmune conditions

Deficiencies in vitamin D have also been linked to a potentially increased risk of certain autoimmune diseases. Vitamin D receptors (VDRs) are present throughout the body including some immune cells, such as lymphocytes and monocytes. Calcitriol, or 1,25[OH]2D, is a form of vitamin D that has been shown to help modulate T-cell differentiation, the secretion of interleukin-10, and the production of certain pro-inflammatory cytokines in monocytes and macrophages through VDR signaling.

Infante and colleagues recently published a commentary on a randomized controlled trial exploring the potential efficacy of supplementation with vitamin D and ω-3 PUFAs on parameters related to autoimmune diseases. This 5-year placebo-controlled study, of vitamin D and ω-3 PUFA co-supplementation (VITAL), involved daily supplementation of more than 25,000 participants with 2,000 IU (50 mcg) or 1 g of ω-3 PUFAs, or a combination of these. Vitamin D supplementation was found to help reduce the incidence of autoimmune disease by 22%; ω-3 PUFAs helped reduce the rate of incidence by 15%, and both treatment arms were more efficacious than a placebo. The authors conclude that co-supplementation with vitamin D and ω-3 PUFAs may help support health in the presence and prevention of certain immune-mediated conditions. 

Infante and colleagues attribute these conclusions to the potential bidirectional interplay between the metabolism of vitamin D and PUFAs. In a clinical trial in individuals with hypovitaminosis D, the administration of cholecalciferol plus ω-3 PUFAs for 12 weeks was shown to help increase the ratio of 1,25[OH]2D to 25[OH]D at a greater rate when compared with a treatment arm receiving cholecalciferol plus olive oil. More research is needed before an understanding of biochemical mechanisms or clinical conclusions can be determined. 

Micronutrients, such as vitamin D and ω-3 PUFAs, may support an inflammatory response. Research also indicates that these micronutrients may also support many aspects of immune health.

By Colleen Ambrose, ND, MAT