Too much of a good thing: vitamin D overdose on the rise, doctors warn

06 Jul 2022 --- While the benefits of vitamin D have long been touted by industry and policy alike, researchers are flagging that hypervitaminosis D is on the rise. The condition arises from overconsumption of the “sunshine vitamin.”

Scientists documented the case of a middle-aged man, who was taking high doses of more than 20 over-the-counter supplements every day, according to a study published in BMJ Case Reports, 

“Globally, there is a growing trend of hypervitaminosis D, a clinical condition characterized by elevated serum vitamin D3 levels,” with women, children and surgical patients most likely to be affected, write the authors.

Myriad of symptomsThe paper warns that consuming over the recommended daily dose can have severe and long-lasting effects.
The case concerns a middle-aged man who was referred to the hospital by his family doctor after complaining of recurrent vomiting, nausea, abdominal pain, leg cramps, tinnitus (ringing in the ear), dry mouth, increased thirst, diarrhea, and weight loss of 12.7 kg, the research notes. 

Symptoms appeared after one month, and although he stopped taking the supplement cocktail once he began to feel the symptoms, they remained for nearly three months.

His supplements contained 150,000 IU of vitamin D, while the daily requirement is 10 mcg or 400 IU. The vitamin K2 levels were at 100 mcg (daily requirement 100–300 mcg), while vitamin C and vitamin B9 (folate) were at 1000 mcg compared to the daily requirement of 400 mcg.

His vitamin B2 (riboflavin), vitamin B6 and omega-3 consumption were at 2000 mg twice daily, whereas the daily requirement is 200–500 mg. The man also consumed several other vitamin, mineral, nutrient, and probiotic supplements. Blood tests revealed that he had very high calcium levels and slightly raised magnesium levels. His vitamin D level was seven times over the level required for sufficiency. 

The symptoms of hypervitaminosis D are caused by excess calcium in the blood, the authors note. They include drowsiness, confusion, apathy, psychosis, depression, stupor, coma, anorexia, abdominal pain, vomiting, constipation, peptic ulcers, pancreatitis, high blood pressure, abnormal heart rhythm, and kidney abnormalities, including renal failure. 

Other associated features, such as keratopathy (inflammatory eye disease), joint stiffness (arthralgia), and hearing loss or deafness, have also been reported, they add.

Hospitalized after vitamin D overconsumption
Another problem that the patient faced was the overdose’s long-lasting symptoms. “Given its slow turnover (half-life of approximately two months), during which vitamin D toxicity develops, symptoms can last for several weeks,” the authors stress. 

In this case, the patient was hospitalized for eight days. During that time, he was treated for an acute kidney injury, likely due to the vitamin’s ability to increase the rate of calcium absorption. 

He was given intravenous fluids to help cleanse his system and treated with a drug usually reserved for those who need to strengthen their bones or lower their calcium levels. 

Why the sudden interest?
COVID-19 may be the culprit behind vitamin D’s increasing popularity, as reported in a 2021 survey by the Council for Responsible Nutrition. Numerous recent studies have hailed the vitamin’s effects on COVID-19. Some have connected it to improved COVID-19 outcomes. Another study noted that it could reduce inflammation caused by COVID-19 when combined with vitamin K. 

Moreover, last February, a US Congressman called for the Centers for Disease Control and the US Food and Drug Administration to update their guidance and encourage people to take more vitamin D supplements. At the time of the congressman’s request, a study in Brazil had already cast doubt on the vitamin’s ability to reduce hospital stays of COVID-19 patients. 

Since then, other studies have shown that vitamin D likely provides no benefits in relation to the virus. All things in moderation

A necessary nutrientAdequate vitamin D levels can be reached through proper use of supplements and sunlight.
There are, of course, numerous health benefits to taking vitamin D supplements. For instance, some recent studies have hailed its seeming ability to fight different cancers, including colorectal and breast cancers, in some patients. Yet, consumers should only take supplements to meet the daily recommended requirements, which the authors say are 400 IU’s, or about 600 mg. 

Additionally, the adverse effects of vitamin D deficiencies have also been well documented. Studies have linked deficiencies to increased risk of cardiovascular disease, high blood sugar, high blood pressure, abnormal cholesterol levels and can even affect circadian rhythms and sleep schedules. 

Recently, the UK’s Office for Health Improvement and Disparities launched an investigation into how vitamin D supplements can be used to improve the overall health of its citizens, stating that 16% of adults and 20% of children are not getting the government-recommended amount in their diets. 

Edited by William Bradford Nichols