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It has been theorized that vitamin D deficiency and inflammation may have a relationship, and there’s more evidence to confirm that theory. According to a recently released study, vitamin D deficiency has a “causative” role in the systemic inflammation that accompanies it. New research shows a link between reductions in elevated C-reactive protein (CRP) as vitamin D levels get closer to normal. In this most recent study, there wasn’t an apparent reversed effect, meaning changes in CRP levels didn’t seem to affect vitamin D levels.
According to the study’s author, it’s the first to show that the relationship between vitamin D status and CRP is at least partially driven by vitamin D itself. Serum CRP is a widely used marker for chronic inflammation.
Study researchers theorize that improving vitamin D status could help reduce chronic inflammation, but potentially only for people with a deficiency. Study results were published in the International Journal of Epidemiology.
An L-Shaped Association
There are several ways nutrition can affect systemic inflammation. There has, however, been a long-standing debate over the association between vitamin D and CRP. This debate especially surrounds serum 25(OH)D, an indicator of vitamin D status. Some reports of an observational association between the two are disputed in more comprehensive trials.
The authors of this study performed what’s known as a bidirectional Mendelian randomization analysis. They looked at nearly 295,000 unrelated participants, the largest cohort to date, with 25(OH)D measured concentrations. Overall, the concentration was 50,0 on average, with 11.7% of study participants having concentrations of less than 25 nmol/L, considered deficient.
The analysis in the study showed that serum 25(OH)D was associated with serum CRP in an L-shaped way. CRP levels and, therefore, inflammation significantly went down concerning vitamin D levels going up to normal levels.
The study’s authors summarized that improving vitamin D status in the deficiency range could reduce low-grade systemic inflammation, possibly reducing the risk or severity of inflammation-driven chronic illnesses.
The ongoing release of inflammatory molecules characterizes low-grade systemic inflammation. Vitamin D is already known to regulate calcium levels but may also modulate our body’s inflammatory response.
The Implications of Chronic Inflammation
Chronic inflammation is long-term, slow inflammation lasting for months to years. Chronic inflammatory diseases are the most significant death cause in the world. The prevalence of diseases associated with chronic inflammation is expected to continue going up over the next 30 years. Three out of five people worldwide die due to chronic inflammatory diseases each year. Especially prevalent diseases linked to chronic inflammation include:
- Diabetes, affecting 9.4% of the U.S. population
- Cardiovascular disease accounts for one in every three deaths in the U.S.
- Arthritis and joint diseases
- Chronic obstructive pulmonary disease (COPD)
Risk factors associated with chronic inflammation include:
- Older age
- Diets high in refined sugar and trans-fats
- Smoking cigarettes
- Low levels of sex hormones (testosterone and estrogen)
- Sleep disorders
Vitamin D Deficiency and Autoimmune Risk
One of the study’s authors, Dr. Elina Hypponen, told Medical News Today that in cell and animal studies, the hormonal vitamin D inhibits the production of inflammatory cytokines like interleukin-12 or IL-12. In this paper, researchers noted vitamin D could also promote the production of IL-10. IL-10 is an anti-inflammatory cytokine.
This could mean that vitamin D is a key immune regulator. Researchers conclude that improving vitamin D status among people in the deficiency range could reduce low-grade, systemic inflammation and the risk of inflammatory-related conditions, including autoimmune diseases.
Other Studies Looking at Vitamin D Deficiency and Inflammation
Above is an example of some of the newest research looking at the links between vitamin D deficiency and inflammation, but it’s not the only one. Studies have found a higher risk of unfavorable outcomes in acute infections associated with lower vitamin D status.
Chronic inflammatory diseases, including the ones below, tend to include people with lower vitamin D status.
- Atherosclerosis-related cardiovascular diseases
- Inflammatory bowel disease
- Chronic kidney disease
- Nonalcoholic fatty liver disease
Do You Have Vitamin D Deficiency?
An important distinction regarding the new research is that it shows a link between a true vitamin D deficiency and inflammation. That means if you aren’t deficient in vitamin D, there may be no benefit in raising your levels.
The recommended amount of vitamin D per day is 600 IU for adults. This goes up to 800 IU if you’re over 71. If you’re at particular risk of vitamin D deficiency, your doctor might tell you that you need more than this baseline.
Symptoms of vitamin D deficiency can manifest in a variety of ways. Some of the broad signs and symptoms of a deficiency of vitamin D can include:
- Frequently getting illnesses or infections
- Back and bone pain
- Slow healing of wounds
- Bone loss
- Hair loss
- Muscle pain
- Weight gain
Causes or risk factors for vitamin D deficiency include:
- Having dark skin
- Being older
- Being overweight or obese
- Not having a lot of fish or dairy in your diet
- Living far from the equator
- Spending most of your time indoors
- Working night shifts
- Having a liver disease or chronic kidney disease
- Conditions affecting absorption like Crohn’s or celiac disease
- Having had gastric bypass surgery
- Using medicines that affect the metabolism of vitamin D, including steroids and statins
Vitamin D deficiency is usually defined when someone has levels below 20 ng/mL. Levels from 21 to 29 ng/mL are considered insufficient.
Blood work can determine if you have a vitamin D deficiency. The vitamin exists in blood in two forms, 25(OH)D or calcidiol, or 1,25-dihydroxy vitamin D, also known as calcitriol. The 25(OH) test is most commonly used because this has higher concentrations, staying in your blood longer and making it easy to detect. You can ask a healthcare provider to test your vitamin D levels if you’re concerned, or you can do it using an at-home test.
You do have to be careful when supplementing with vitamin D because you can get too much. It can impact your calcium absorption and cause gastrointestinal symptoms.
Final Thoughts—Vitamin D Deficiency and Inflammation
There are potential links between vitamin D deficiency and inflammation. This is especially true of disease-promoting, chronic, low-level inflammation. If you’re worried about your vitamin D deficiency and inflammation, talk to your doctor.
Lennon, Annie. “Vitamin D supplements may help reduce chronic inflammation, study finds.” Medical News Today, August 15, 2022. Accessed August 22, 2022.
Yin Kai and Agrawal, Devendra K. “Vitamin D and inflammatory diseases.” Journal of Inflammation Research, May 29, 2014. Accessed August 22, 2022.
Melville, Nancy A. “Vitamin D Deficiency Clearly Linked to Inflammation.” MedScape, August 19, 2022. Accessed August 22, 2022.
Pahwa, Roma, Goyal Amandeep, and Jialal, Ishwarlal. “Chronic Inflammation.” NIH National Library of Medicine, June 19, 2022. Accessed August 22, 2022.