Also you generally only need to be in the sunlight 30 minutes a day to maintain regular levels of Vitamin D. It's not like you have to be a day laborer toiling away outside for 8 hrs a day.
I live in sunny Arizona and run in bright sun every day at midday in t-shirt and shorts most of the time (not supplementing). Vit D was just tested at 32 ng/ml, which is low normal. I honestly don’t think it’s possible to have adequate Vit D levels in the winter from sun exposure alone.
You do understand there is a lot of individual variation with things like this. How much sunscreen do you apply? How dark is your skin.
Also, being "low normal" is fine. The key is "normal".
Correlation is not the same as causation. Has there ever been a study that linked Vitamin D supplementation to positive health effects? Vitamin D levels being associated with positive health effects is not the same as Vitamin D supplementation causing positive health effects. It could just be that sunlight is good for you, and it also happens to increase Vitamin D levels, with some other mechanism other than Vitamin D doing the good work.
I say that because a lot of studies have been done on Vitamin D supplementation, and they don't show the same good health effects and having high Vitamin D levels.
I am taking some Vitamin D because I don't get any sun in the winter (in high latitude), but it's more cheap insurance than belief it actually does anything.
In summary, vitamin D deficiency was common in the US population, especially among blacks and Hispanics. Given that vitamin D deficiency is linked to some of the important risk factors of leading causes of death in the United States.
Keep in mind that merely "not having deficiency" does not mean "in good health". The benefits continue to accrue eat levels well above "non-deficient". So it is very safe to say that MOST Americans would benefit from D3 supplementation and/or better sun exposure.
Fisky here. I periodically review literature on Vitamin D to see if anything new pops up. This time, I found some interesting studies that I missed previously. I'll summarize them in order of the links.
In summary, current evidence supports the links between vitamin D and COVID-19 and the benefits of vitamin D supplementation for managing or treating this condition. ...Some [reports] even report a decreased incidence of infection as a result of prior supplementation. ...vitamin D deficiency should be corrected wherever possible since vitamin D supplementation is safe and the potential for toxicity is strongly outweighed by the potential benefits in relation to protection from COVID-19.
A study of healthy overweight men ages 20-49 over one year found that D supplementation increased testosterone levels by... 25%! Since aging distance runners are plagued by low-T levels, this is of significant interest. However, subsequent studies showed no T-level increase in men with normal T-levels. I'd like to see a study in middle aged distance runners to see if D + exercise increased T-levels compared to a placebo + exercise. If anyone knows of such a study, please post a link.
Meanwhile, here's the first review study of vitamin D and covid.
The novel coronavirus severe acute respiratory syndrome (SARS-CoV-2) has progressed rapidly from an outbreak to a global pandemic, with new variants rapidly emerging. Coronavirus disease 2019 (COVID-19), the disease resulting...
The male reproductive tract has been identified as a target tissue for vitamin D, and previous data suggest an association of 25-hydroxyvitamin D [25(OH)D] with testosterone levels in men. We therefore aimed to evaluate wheth...
Fisky here. I periodically review literature on Vitamin D to see if anything new pops up. This time, I found some interesting studies that I missed previously. I'll summarize them in order of the links.
In summary, current evidence supports the links between vitamin D and COVID-19 and the benefits of vitamin D supplementation for managing or treating this condition. ...Some [reports] even report a decreased incidence of infection as a result of prior supplementation. ...vitamin D deficiency should be corrected wherever possible since vitamin D supplementation is safe and the potential for toxicity is strongly outweighed by the potential benefits in relation to protection from COVID-19.
A study of healthy overweight men ages 20-49 over one year found that D supplementation increased testosterone levels by... 25%! Since aging distance runners are plagued by low-T levels, this is of significant interest. However, subsequent studies showed no T-level increase in men with normal T-levels. I'd like to see a study in middle aged distance runners to see if D + exercise increased T-levels compared to a placebo + exercise. If anyone knows of such a study, please post a link.
Meanwhile, here's the first review study of vitamin D and covid.
Of 1176 patients admitted, 253 had records of a 25(OH)D level prior to COVID-19 infection. ...Patients with vitamin D deficiency (<20 ng/mL) were 14 times more likely to have severe or critical disease than patients with 25(OH)D ≥40 ng/mL
Let me explain why these findings strongly support vitamin D supplementation.
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3. The therapeutic level (>40 ng/ml) is rarely found without vitamin D3 supplementation.
Since correlation ≠ causation and this study didn't ask about D supplementation, I wondered if we might be able to deduce if some of these high D patients were taking vitamin D.
Based on previous studies of vitamin D deficiency in Israel, about 95% of patients should have been under 40ng/ml or about 12 subjects. Instead, this study had 40 patients over 40ng/ml...
A second indication is the much wider range of SD in this study compared to older, pre-covid vitamin D studies. Large studies have shown Israeli D levels average 22 with a SD ± 10. In this study, the average D level was 25 with a SD ± 19.
To me, it's pretty obvious that a lot of subjects in this study were taking supplemental vitamin D. After all, it should be common knowledge in Israel that vitamin D is beneficial because...
one of the world's largest studies on vitamin D and covid was announced in July 2020. It appeared in The Times of Israel and other Israeli media at the time and involved 7,000 Israelis. It found that low D levels increased the risk of hospitalization by 45%.
