The liver is where most ingested or UV-B produced vitamin D3 (cholecalciferol) is hydroxylated to become 25-hydroxyvitamin D (calcifediol or "calcidiol") which circulates in the bloodstream and which is measured in "vitamin D" blood tests. Neither of these function as hormones - the immune system does not use hormonal signaling.
The kidneys need about 20 ng/mL (50 nmol/L) circulating 25-hydroxyvitamin D to properly regulate calcium-phosphate-bone metabolism. They do this by hydroxylating it to create a very low level (~0.1 ng/mL) of circulating 1,25-dihydroxyvitamin D (calcitriol) which functions as a hormone (a long-distance, blood-borne signaling molecule whose concentration affects the behaviour of one or more types of cell anywhere in the body, including perhaps via the cerebrospinal fluid.
This is the one hormonal function of the three compounds, the first of which is a vitamin.
Many types of immune cells - and, as best we know, other cell types such as those involved in neurogenesis, including in-utero - rely on a good level of 25-hydroxyvitamin D in the bloodstream, so this can diffuse into the cells where it is ready to be used by each such cell's intracrine (inside each cell) or paracrine (to nearby cells) signaling systems.
Most doctors and immunologists - and far too many people who write vitamin D research articles - do not understand these signaling systems, since they have never been explained in a tutorial fashion in the peer reviewed literature. The kidneys are not involved in this at all, but good supplies of vitamin D3 and good liver function are required if the body is to maintain the 50 ng/mL (125 nmol/L = 1 part in 20,000,000 by mass) level of 25-hydroxyvitamin D the immune system needs to function properly.
Governments and many doctors recommend only the tiny amounts of supplemental vitamin D3 which are required to attain 20 ng/mL circulating 25-hydroxyvitamin D.
regulate calcium-phosphate-bone metabolism: about 20 ng/mL 50 nmol/L.
Since there is very little vitamin D3 in food, fortified or not, and since its production in ideally white skin by ultraviolet B light all year round is not practical for most people, and raises the risk of skin cancer, supplemental vitamin D3 in quantities determined by body weight and obesity status is the only safe, practical, way most people can attain the 25-hydroxyvitamin D levels (as measured in "vitamin D" blood tests) they need for full immune system function.
Healthy supplemental intakes such as 0.125 milligrams (5000 IU) a day, for 70 kg 154 lb body weight without obesity will attain at least the desired 50 ng/mL 25-hydroxyvitamin D level after several months. Many people have half or less of this level most or all their lives. This is gram every 22 years - and pharma grade vitamin D costs about USD$2.50 a gram ex-factory.
The recommendations above, such as 0.125 mg (5000 IU) a day vitamin D3, on average, for ages 12 and above, are about right, in general, but the best recommendations are Prof Wimalawansa's, since these take into account body weight and obesity status. The average daily supplemental vitamin D3 intake is specified as ratios of body weight, with higher ratios for those suffering from obesity, since obesity reduces the ability of the liver to hydroxylate vitamin D3 to 25-hydroxyvitamin D, and causes excess adipose tissue to absorb both compounds, without returning them to circulation.
Sepsis, including due to Kawasaki disease / MIS-C, kills many babies and children. Yet sepsis would be rare if everyone had 50 ng/mL or more circulating 25-hydroxyvitamin D. Sepsis killed about 11 million people, worldwide, in 2017: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(19)32989-7/ .
You really must not self treat. So much stuff you can injure yourself with. Getting proper advice from a homeo/naturopath is essential. A holistic nutritionist is a good also.
The liver is where most ingested or UV-B produced vitamin D3 (cholecalciferol) is hydroxylated to become 25-hydroxyvitamin D (calcifediol or "calcidiol") which circulates in the bloodstream and which is measured in "vitamin D" blood tests. Neither of these function as hormones - the immune system does not use hormonal signaling.
The kidneys need about 20 ng/mL (50 nmol/L) circulating 25-hydroxyvitamin D to properly regulate calcium-phosphate-bone metabolism. They do this by hydroxylating it to create a very low level (~0.1 ng/mL) of circulating 1,25-dihydroxyvitamin D (calcitriol) which functions as a hormone (a long-distance, blood-borne signaling molecule whose concentration affects the behaviour of one or more types of cell anywhere in the body, including perhaps via the cerebrospinal fluid.
This is the one hormonal function of the three compounds, the first of which is a vitamin.
Many types of immune cells - and, as best we know, other cell types such as those involved in neurogenesis, including in-utero - rely on a good level of 25-hydroxyvitamin D in the bloodstream, so this can diffuse into the cells where it is ready to be used by each such cell's intracrine (inside each cell) or paracrine (to nearby cells) signaling systems.
Most doctors and immunologists - and far too many people who write vitamin D research articles - do not understand these signaling systems, since they have never been explained in a tutorial fashion in the peer reviewed literature. The kidneys are not involved in this at all, but good supplies of vitamin D3 and good liver function are required if the body is to maintain the 50 ng/mL (125 nmol/L = 1 part in 20,000,000 by mass) level of 25-hydroxyvitamin D the immune system needs to function properly.
Governments and many doctors recommend only the tiny amounts of supplemental vitamin D3 which are required to attain 20 ng/mL circulating 25-hydroxyvitamin D.
Please read the research articles cited and discussed at: https://vitamindstopscovid.info/00-evi/ .
regulate calcium-phosphate-bone metabolism: about 20 ng/mL 50 nmol/L.
Since there is very little vitamin D3 in food, fortified or not, and since its production in ideally white skin by ultraviolet B light all year round is not practical for most people, and raises the risk of skin cancer, supplemental vitamin D3 in quantities determined by body weight and obesity status is the only safe, practical, way most people can attain the 25-hydroxyvitamin D levels (as measured in "vitamin D" blood tests) they need for full immune system function.
New Jersey based Professor of Medicine Sunil Wimalawansa makes such recommendations in his 2022 Nutrients article "Rapidly Increasing Serum 25(OH)D Boosts the Immune System, against Infections - Sepsis and COVID-19": https://www.mdpi.com/2072-6643/14/14/2997. His recently simplified recommendations are at: https://vitamindstopscovid.info/00-evi/#sjw-updated-ratios.
Healthy supplemental intakes such as 0.125 milligrams (5000 IU) a day, for 70 kg 154 lb body weight without obesity will attain at least the desired 50 ng/mL 25-hydroxyvitamin D level after several months. Many people have half or less of this level most or all their lives. This is gram every 22 years - and pharma grade vitamin D costs about USD$2.50 a gram ex-factory.
The recommendations above, such as 0.125 mg (5000 IU) a day vitamin D3, on average, for ages 12 and above, are about right, in general, but the best recommendations are Prof Wimalawansa's, since these take into account body weight and obesity status. The average daily supplemental vitamin D3 intake is specified as ratios of body weight, with higher ratios for those suffering from obesity, since obesity reduces the ability of the liver to hydroxylate vitamin D3 to 25-hydroxyvitamin D, and causes excess adipose tissue to absorb both compounds, without returning them to circulation.
Inadequate 25-hydroxyvitamin D causes or contributes to a vast range of human ill-health. The impact starts before birth with pre-eclampsia, pre-term birth, autism, ADHD and mental retardation and lasts a lifetime https://vitamindstopscovid.info/00-evi/#3.2, ending, for many, with dementia: https://vitamindstopscovid.info/00-evi/#3.3.
Sepsis, including due to Kawasaki disease / MIS-C, kills many babies and children. Yet sepsis would be rare if everyone had 50 ng/mL or more circulating 25-hydroxyvitamin D. Sepsis killed about 11 million people, worldwide, in 2017: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(19)32989-7/ .
You really must not self treat. So much stuff you can injure yourself with. Getting proper advice from a homeo/naturopath is essential. A holistic nutritionist is a good also.
Have you seen this interview? Andy Wakefield and Tracey Stroup, ND.
Worth watching.
This past Tuesday. Excellent information. About 44:00 minutes long.
https://www.buzzsprout.com/908758/15148668