As most people supplementing with vitamins know, the daily RDA for vitamin D has been set at 400 IU (in some countries up to 800 IU) daily, despite no evidence that such doses do anything beneficial, including even the basic target – preventing rickets. More recent studies have argues that the daily supplementation limit, especially in the winter, should be at least 5,000 IU daily. However, such studies usually get viciously attacked by public health authorities and Big Pharma with arguments that such doses carry high risk of dangerous side effects such as hypercalcemia, soft tissue calcification, kidney disease, and even seizures. The study below is perhaps the first to demonstrate that in order to achieve the optimal range of serum vitamin D levels, an adult needs to supplement with at least 2,000 IU daily, that at such doses there is virtually no risk of serious side effects, and that daily dosing is more effecting the than a high, bolus, weekly or monthly dosing. In fact, the study found that a significant portion of the general population (e.g. those with obesity, chronic inflammatory conditions, diabetes, etc) may need quite a bit more than 2,000 IU daily in order to achieve optimal serum levels.
https://www.mdpi.com/2072-6643/16/3/391
“…Further, the authors noted that randomized controlled trials (RCTs) testing 25(OH)D needs may be biased towards healthy people who may not accurately represent the general population, especially those with obesity. In fact, optimal serum 25(OH)D concentrations for most chronic diseases are slightly above 75 nmol/L (30 ng/mL). Thus, obese individuals, individuals with higher body mass index (BMI), and patients with malabsorption syndromes may require higher doses of vitamin D to increase their serum 25(OH)D levels. Some may not meet the threshold even after supplementing with daily 2000 IUs of vitamin D, like patients with inflammatory bowel disease during episodes of high disease activity.”
“…Recent RCTs like the Vitamin D and OmegA-3 Trial (VITAL) gathered safety data on using 2000 IU of vitamin D/day in general adult populations who showed no signs of vitamin D toxicity for 5.3 years, indicating the safety of this daily dosage. Further, a meta-analysis of 15 vitamin D RCTs found no increase in kidney stones when supplementing with ≥70 µg of vitamin D for at least one year.”
“…Adherence to conservative dosing regimens not exceeding 800 IU (20 µg) of vitamin D per day may not sufficiently treat vitamin D deficiency, considering the heterogeneity in inter-individual dose-response and accounting for the multiple clinical factors involved, such as obesity, malabsorption syndromes, and medications that impair vitamin D metabolism. This review revealed that daily vitamin D supplementation was more effective than intermittent bolus dosing in adults. However, precaution is needed for older and diseased individuals, who are more prone to adverse effects of vitamin D overdosing. “
