By Dr. Linda J. Dobberstein, DC, Board Certified in Clinical Nutrition
Daylight is getting shorter and the angle of the sun is lower in the sky. This change of season interferes with your ability to make adequate vitamin D from the sun. The angle of the sun is not sufficient for those in the northern latitudes >40° N (the northern half of the United States) from now until April. Even those who live in sunny equatorial latitudes may not get enough vitamin D. As you prepare for winter, make sure to support your body’s needs with vitamin D! This is especially important if you take medications. Do you know your vitamin D level?
Essential for Health
Vitamin D is a vitamin and hormone used by nearly all tissues in your body. It is essential for the normal function and maintenance of the immune system, bones, teeth, absorption of calcium and phosphorus, muscle function, and growth in children. It contributes to your mood, sleep, cell signaling and gene activity, thyroid, adrenal glands, ovaries, blood sugar, cholesterol management, mitochondria function, prenatal development, cognitive function, skin health, and more.
Optimal Vitamin D Levels
Vitamin D insufficiency occurs when 25-hydroxyvitamin D (25OHD) is between 20-29 ng/mL. Levels at or below 20 ng/mL are considered vitamin D deficient. An optimal level is between 50-80 ng/mL.
Vitamin D toxicity is rare. It may occur from very high, prolonged intake of vitamin D2 or D3. However, this more commonly reflects an underlying medical issue that should be properly evaluated.
Vitamin D activation and tissue levels are affected by age, skin tone, use of sunscreen, outdoor exposure, diet, adequate magnesium and glutathione status, obesity and metabolic syndrome, and other factors. Several medications also affect your vitamin D status.
Medications that Deplete Vitamin D
A 2012 randomized controlled trial showed that individuals on any medication had a lower vitamin D status. Individuals chronically using multiple medications are at great risk for vitamin D insufficiency and its complications.
Numerous drugs affect vitamin D metabolism which creates other negative effects with bone loss, softening of bones, or other health concerns. This warrants the need to be proactive, aware, and increase your vitamin D intake.
Medications include:
• ACE Inhibitors
• Antibiotics – please check with your pharmacist or prescribing MD for specifics.
• Antidepressants - SSRIs (selective serotonin reuptake inhibitors) may possibly interfere with vitamin D metabolism.
• Anti-Epileptic/Anti-Seizure Drugs: Carbamazepine, phenobarbital, and phenytoin, valproic acid,9 and possibly other newer medications. One study showed that 37.5% of children given valproic acid for seizure treatment developed vitamin D insufficiency10 after 3 months of medication use.
• Antimicrobials, i.e., isoniazid and rifampicin.
• Antiretroviral Therapy, High Active (HAART).
• Bile Acid Sequestrants such as cholestyramine bind onto vitamin D and other fat-soluble vitamins. It can lead to softening of bones.
• Calcium Channel Blockers: verapamil, diltizem, and nefidipine.
• Chemotherapy drugs: tamoxifen, docetaxel, paclitaxel, ifosfamide etoposide, vinblastine, vincristine, cyclophosphamide, imatinib, and irinotecan.
• Diabetes Medications: The popular type 2 diabetes drug Metformin and others such as thiazolidinediones/glitazones (Actos, Avandia) may affect vitamin D status, weaken bone density, and lead to increased risk of fracture.
• Diuretics/Water Pills: Thiazide diuretics, loop diuretics, and potassium sparing diuretics may interfere with vitamin D metabolism. Vitamin D may build-up or become depleted.
• Gastric Medications: Proton Pump Inhibitors (PPIs) and H2-Receptor Antagonists (H2RAs).
• Heparin
• Hydroxychloroquine
• Laxatives: These meds alter the movement of foods and liquids through your gut. It becomes more difficult to absorb fat soluble vitamins like vitamin D as well as minerals.
• Lipase Inhibitors such as Orlistat.
• Statin cholesterol lowering medications effect on vitamin D is controversial. However, it is found that individuals with low vitamin D status and use statin drugs are more likely to experience muscle pain side effects.
• Steroid Medications: oral and inhaled glucocorticoids.
• Sulfonamides and Urea Derivatives
• Warfarin/coumadin/Vitamin K Antagonists
• Others: This list may not include all known or suspected medications that deplete or interfere with vitamin D. Research results may conflict as well. Thus, the need to have personalized, proactive support.
Sources of Vitamin D
Sunshine exposure allows your body to make vitamin D. Common vitamin D food sources are egg yolk, fatty fish, beef liver, and fortified dairy products. Plant-based diets do not provide vitamin D with one exception, i.e., 100 grams of sun-exposed mushrooms can provide the RDA of 400 IU of vitamin D2.
Expert Guidelines and Common Sense for Vitamin D Supplementation
A 2022 Expert Consensus Statement for Central and Eastern Europe gave these guidelines for testing vitamin D. They recommended that individuals with osteoporosis, osteomalacia, musculoskeletal pain, chronic kidney disease, liver failure, malabsorption syndromes (e.g., cystic fibrosis, inflammatory bowel diseases, bariatric surgery, radiation enteritis), hyperparathyroidism, chronic treatment with medications that influence vitamin D metabolism, chronic autoimmune diseases (e.g., multiple sclerosis, rheumatoid arthritis), pregnant and lactating women, institutionalized or hospitalized patients, older adults (>65 years) in general, older adults with history of falls or nontraumatic fractures, granuloma-forming disorders (e.g., sarcoidosis, tuberculosis, histoplasmosis, berylliosis, coccidiomycosis), obesity (BMI ≥ 30kg/m2), and dark skin pigmentation should be tested.
Have you ever asked your medical practitioner to measure your vitamin D levels in a blood test? Was their reply “No, you don’t need to. You’re fine.”?
Professionals across the globe recognize that vitamin D deficiency is prevalent in all age groups. European countries cry out because of a concern of vitamin D deficiency pandemic! Yet, they don’t want to test.
If your levels have not been measured recently, or ever, how do they know your vitamin D status is adequate or even optimal? It’s like looking at a box of food in the cupboard for the first time without the ability to pick it up, shake it, and/or look inside to see the contents. You cannot tell if the box is full, partially consumed, or empty simply by viewing the outside container.
The Bare Minimum
Randomized clinical trials suggest that a minimum of 800 - 1000 IU per day of vitamin D3 is required to maintain a blood level of 20 ng/mL in healthy adults, which is a deficiency level according to the Endocrine Society’s guidelines. Vitamin D deficiency, insufficiency, and sufficiency is defined as serum concentrations of 25(OH)D of <20 ng/ml, 21-29 ng/mL, and 30-100 ng/mL respectively.
If you follow a plant-based diet, lack adequate magnesium intake, use medications, stay indoors, use sunscreen when outdoors, etc, it is likely that your health is suffering from insufficient vitamin D intake. Your genes and nearly all tissues need it to function.
I recommend 5,000 IU/day until your lab values have been determined and then adjust the dosage accordingly. Vitamin D works with calcium, magnesium, vitamin K, and glutathione. Vitamin D at bedtime can help support tissue repair and recovery as well as quality of sleep.
Give yourself some extra TLC. Check your vitamin D levels and optimize your vitamin D status!
Additional Resources
Vitamin D and Your Immune System – Are You Getting Enough?
Vitamin D and DHA Needed for Serotonin, Mood, and Impulse Control
Glutathione and Vitamin D: A Powerful Essential Connection
Vitamin D and Magnesium: Essential Partnership for Health
B12 and Vitamin D Needed for Rotator Cuff Health
New Discoveries Highlight the Importance of Vitamin D
