an article published in journal bmj case reports earlier this week described the rare — but very harmful — situation of overdosing on vitamin d. “globally, there is a growing trend of hypervitaminosis d, a clinical condition characterized by elevated serum vitamin d3 levels,” the authors wrote. generally, women, children and surgical patients are the most likely to experience this kind of overdose, they added.
the article describes a middle-aged man in the u.k. who was put on an “intensive” regimen of supplements by an unidentified “nutritional therapist,” whose methods certainly sound questionable. the man, who had previously had health problems including tuberculosis, an inner ear tumour, and bacterial meningitis, was apparently told to take 150,000 iu (international units) of vitamin d every day — upwards of 20 pills (the mayo clinic suggests adults should get between 600 and 2000 iu per day). he also took vitamin k2, vitamin c, vitamin b2, vitamin b6, and vitamin b9, among several other nutrient and probiotic supplements.
“given its slow turnover (half-life of approximately 2 months), during which vitamin d toxicity develops, symptoms can last for several weeks,” according to the study authors. since vitamin d is fat-soluble, gizmodo explains , it takes a long time to dissolve once it’s been absorbed into fatty tissue.
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some of the other symptoms of hypervitaminosis d can include drowsiness, confusion, constipation, inflammatory eye disease, joint stiffness and peptic ulcers. in some cases it can have very severe effects, including depression, psychosis, pancreatitis , hearing loss or kidney failure.
in small amount, vitamin d is good for us: it helps the body absorb calcium and phosphorus, which are crucial to bone health. it can also reduce inflammation and help with infections and, in some cases can even reduce cancer cell growth, according to harvard’s school of public health . but that calcium absorption can become harmful in very high amounts, which is what accounts for many of the troubling symptoms of hypervitaminosis d.
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healthy amounts of vitamin d can be found in fish (tuna, salmon, herring, swordfish, sardines, cod liver oil) as well as mushrooms, beef liver, and egg yolks. many kinds of orange juice, milk (both dairy and plant), and cereal are fortified with vitamin d. our bodies also make vitamin d from the uv lights in the sun. (although that doesn’t mean you should skip sunscreen! )
certain people are at risk of vitamin d deficiency and should consider taking vitamin d supplements in healthy amounts. (again, that means aiming for somewhere between 600 and 2000 iu each day.) these people include the elderly, anyone taking long-term steroids, anyone who’s pregnant or breastfeeding, post-menopausal women, and people with chronic kidney disease or parathyroid disease.