12 Signs of Vitamin D Deficiency You Need to Recognize
Vitamin D deficiency is often associated with a variety of diseases, from depression to cancer. Below is the key scientific evidence supporting the link between deficiency of this “sunny” vitamin and vitamins and various health problems.
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Scientists continue to actively research vitamin D, studying its effects on diseases such as diabetes, hypertension, cancer, and autoimmune disorders, including multiple sclerosis.
Overweight
A 2015 meta-analysis published in Obesity Reviews demonstrated that obese people—regardless of age and gender—are 35% more likely to have vitamin D deficiency than those with a normal body mass index. A 2019 study from the Cochrane database found that fat cells tend to retain vitamin D, hindering its absorption into the bloodstream and reducing overall levels. Thus, excess body weight may be a factor exacerbating vitamin D deficiency.
Furthermore, decreased vitamin D levels in excess weight are associated with decreased bioavailability of the vitamin and decreased synthesis in the skin under the influence of ultraviolet rays. Vitamin D plays a key role in regulating metabolism, immune function, and bone health, so its deficiency in obese individuals may exacerbate inflammatory processes and metabolic disorders, such as insulin resistance and an increased risk of developing type 2 diabetes. It is recommended to monitor vitamin D levels and, if necessary, correct deficiency through medical supervision and appropriate vitamin D supplementation, especially in overweight patients.
Diabetes
A study conducted in Spain and published in the Journal of Clinical Endocrinology & Metabolism in 2015 found that people with diabetes or prediabetes had significantly lower vitamin D levels than those with normal blood glucose levels. This pattern was observed across all BMI categories, including both lean and overweight individuals. The authors emphasize that vitamin D deficiency and obesity are mutually reinforcing, increasing the likelihood of developing diabetes and other metabolic problems.
Cardiovascular_Pathologies
Heart disease and low vitamin D levels are known to often go hand in hand. A recent study published in the European Heart Journal confirmed that vitamin D deficiency can provoke high blood pressure and increase the risk of cardiovascular disease.
However, an inverse correlation has not been proven: scientists have not found a direct link between improved vitamin D levels and a reduction in cardiovascular risk. A 2019 meta-analysis in JAMA Cardiology, which included more than 83,000 patients, found that taking vitamin supplements did not reduce the incidence of serious cardiac events such as heart attack or stroke.
Nevertheless, maintaining adequate vitamin D levels remains important for overall health, as this vitamin is involved in regulating calcium metabolism and influences immune system function. Furthermore, some studies suggest a potential role for vitamin D in reducing inflammation, which can contribute to the development of atherosclerosis.
Maintaining a healthy lifestyle, including a balanced diet, regular physical activity, and controlling risk factors (such as hypertension, high cholesterol, and smoking), is key to preventing cardiovascular disease. Vitamin D can be obtained not only from supplements but also through adequate sun exposure and foods rich in this vitamin, such as fatty fish, eggs, and fortified dairy products.
Multiple Sclerosis
In 2013, an international team of researchers analyzed the condition of 465 patients in the early stages of multiple sclerosis, a debilitating disease of the central nervous system. A publication in JAMA Neurology demonstrated that higher vitamin D levels at early diagnosis, as well as at 6, 12, and 24 months after diagnosis, help slow disease progression. Patients with higher vitamin D levels had slower expansion of brain lesions, fewer new lesions, and a lower rate of disability compared to those with low vitamin D levels.
Multiple sclerosis is characterized by the destruction of the myelin sheaths of nerve fibers, which disrupts the transmission of nerve impulses. This is an autoimmune disease in which the immune system mistakenly attacks the central nervous system’s own cells. Although there is no cure, modern therapies can significantly slow disease progression, improve quality of life, and reduce the risk of relapses.
Vitamin D plays an important role in regulating the immune system, exerting an anti-inflammatory effect and suppressing autoimmune reactions. In addition to vitamin D supplements, important approaches to the treatment of multiple sclerosis include the use of immunomodulators, physical therapy, and supportive rehabilitation. Early diagnosis and a comprehensive approach to treatment contribute to a more favorable outcome.
Premenstrual Syndrome (PMS)
A 2017 study published in Gynecological Endocrinology found that high doses of vitamin D reduce the severity of PMS symptoms and dysmenorrhea—painful cramps and pain during menstruation (according to Johns Hopkins Medicine). Vitamin D also has a positive effect on the emotional manifestations of PMS. While nonsteroidal anti-inflammatory drugs remain the mainstay of treatment for severe symptoms, scientists believe vitamin D may be a promising alternative.
Lupus
Lupus is a chronic inflammatory autoimmune disease in which the immune system attacks its own organs and tissues. People with the disease often have low vitamin D levels, which is facilitated by both sun avoidance recommendations and the use of corticosteroids, which can deplete the vitamin.
A 2022 study published in the British Medical Journal found that combining vitamin D and fish oil (rich in omega-3) for five years significantly reduced the severity of autoimmune diseases, including lupus. Patients taking the supplements experienced a 22% reduction in symptoms.
In addition to taking vitamin supplements, a healthy lifestyle plays a key role in disease management. Avoiding excessive exposure to ultraviolet rays is recommended, as it can trigger flare-ups. Patients should also follow a balanced diet rich in antioxidants and anti-inflammatory substances, which helps reduce inflammation and support the immune system.
Modern treatments for lupus include the use of immunosuppressants, nonsteroidal anti-inflammatory drugs, and biologics, which help control disease activity and prevent complications. Regular medical monitoring and laboratory testing allow for timely adjustments to therapy and improve patients’ quality of life.
Inflammatory bowel diseases
Deficiencies of important vitamins and minerals, including vitamin D, are common in people with gastrointestinal conditions that impair nutrient absorption. Patients with active ulcerative colitis, a type of inflammatory bowel disease, especially those receiving corticosteroids, often have vitamin D deficiency, according to a 2013 study in Digestive Diseases and Sciences. Some scientists believe that low vitamin D levels not only increase the risk of developing IBD but also influence the severity of the disease, as reflected in a study published that same year in Alimentary Pharmacology and Therapeutics.
Alopecia and Hair Loss
A 2013 study in the journal Skin Pharmacology and Physiology found that women with female-pattern hair loss have significantly lower vitamin D levels than those without the condition. Vitamin D promotes the transition of hair from the resting phase to the active growth phase. A 2014 study by Turkish researchers published in the British Journal of Dermatology found that patients with alopecia areata—an autoimmune disease that attacks hair follicles and causes hair loss throughout the body—had significantly reduced 25-hydroxyvitamin D levels. Furthermore, a correlation was found between the severity of the disease and the degree of vitamin D deficiency.
