You need upwards of 5000 IU/day (from sun, food and supplements) to maintain a healthy Vitamin D status (25-hydroxy test). While the 1000 IU/day is helping, you should really get tested (if you haven't) to see how much it is helping. Labcorp and other labs usually show a reference range from around 20-100 ng/mL. However, if you're near 20 you are serverely deficient. Those ranges typically show 2 standard deviations of all people tested, and you know the bottom of that range are not people in good health. A good target is at least 50 ng/mL.
There is much to unpack here.
Please no one take this statement as a reason to take excessive vitamin D! It's not a good idea to make such statements on a forum like this. Do you have expertise in this area that others do not have? Physicians and dietitians know that the actual amount of vitamin D we should get is not very clear and has been revised over the years based on new evidence. Before 1997 the RDA was 200 IU, then adjusted upward to 400 to 600 IU, with 800 IU recommended for those over 70 due to decreased absorption. Some supplementation makes sense for many people. But please don't go overboard by stating we need 5000 IU a day without any evidence to back it up. You could cause a lot more harm than good. And stating that 1000 IU/day might not be enough without any evidence to back it up is also potentially dangerous.
Vitamin D toxicity can result in fatigue, impaired cognition, dehydration, kidney stones, and hypercalcemia. Most are associated with taking more than 10,000 IU daily, but it can be seen with lower doses if one takes too much calcium as well. I had a friend who sustained permanent damage to her cognition and her kidneys due to the combination of slight excess vitamin D and excess calcium a few years ago, not just resulting in hypercalcuria, but also kidney stones, kidney infection as a result, and sepsis.
Next:
The link between surviving COVID-19 and having higher vitamin D levels is observational, and there may be no actual link at all. Population studies are also notorious for resulting in bad information. They picked two things, rate of vitamin D deficiency and COVID-19 mortality rate. Just because they seemed to track in parallel, that does not mean that the two are related at all. They could have compared the rate of blue eyes vs COVID-19 mortality or COVID-19 infection rates, for all that it means. Which is essentially, nothing.
There are studies linking low vitamin D levels with higher mortality in actual COVID-19 patients. But low vitamin D may be related to a different nutritional deficiency, one that no one has even thought of, as far as we know. One cannot assume a cause and effect relationship here either. And does the vitamin D level in the blood measured on a severely ill patient correlate with total body vitamin D level? Perhaps our vitamin D level in the blood drops acutely during many severe illnesses, but has that question even been explored? People are grasping for answers when they don't even know if researchers are asking the right question.
What is most disturbing is that there have been recommendations of taking excessive and dangerous doses of vitamin D during the pandemic. Please do not do this. Take a reasonable supplement if you wish, but if you have any concerns, please seek advice from your doctor.
