Only a few foods contain vitamin D3, and the quantities are so small (except as noted below, in breast milk from 25-hydroxyvitamin D replete mothers) that no practical amount of food can supply anywhere near enough vitamin D3 for us to attain (via hydroxylation, primarily in the liver) the 50 ng/mL (125 nmol/L = 1 part in 20,000,000 by m…
Only a few foods contain vitamin D3, and the quantities are so small (except as noted below, in breast milk from 25-hydroxyvitamin D replete mothers) that no practical amount of food can supply anywhere near enough vitamin D3 for us to attain (via hydroxylation, primarily in the liver) the 50 ng/mL (125 nmol/L = 1 part in 20,000,000 by mass) level of circulating 25-hydroxyvitamin D which the immune system needs to function properly.
Ultraviolet B light on ideally white skin can create sufficient vitamin D3 for full immune system function, but far from the equator, this is only available naturally in sufficient quantities in the middle of cloud-free summer days. UV-B always damages DNA and so raises the risk of skin cancer.
Fortunately we can now supplement vitamin D3 to attain the level of 25-hydroxyvitamin D our immune system needs all year round without raising the risk of skin cancer. This is an important exception to the principle that we can and should obtain all the nutrients we need from food. Average weigh adults need about a gram every 22 years.
This is true for everyone except for those who already have substantial year-round UV-B exposure of ideally white skin and babies substantially breast fed by mothers who have good 25-hydroxyvitamin D levels.
Both vitamin D3 and 25-hydroxyvitamin D are present in breast milk, in proportion the mother's circulating levels. The research on this is quite scattered, but Tsugawa et al. 2021 https://www.mdpi.com/2072-6643/13/2/573 measured these low levels very carefully and found approximately equal amounts of vitamin D3 cholecalciferol and 25-hydroxyvitamin D in breast milk. Only about 1/4 of ingested vitamin D3 is hydroxylated to the circulating 25-hydroxyvitamin D the immune system needs, while ingested 25-hydroxyvitamin D is easily absorbed and goes straight into circulation. So the 25-hydroxyvitamin D content of milk from 25-hydroxyvitamin D replete mothers plays the predominant role in boosting her baby's 25-hydroxyvitamin D level.
Since breast milk is food, this is the only instance in which food can be sufficient to attain the good levels of 25-hydroxyvitamin D the immune system needs to function properly.
Its amazing how our ancient ancestors lived for thousands of years without any supplements at all and were healthy enough to propagate without medical assistance. Could it be they were in a warmer climate and had no clothes? Perhaps, the atmosphere was free of pollution and the sun rays were not blocked. Today, people need supplements because pollution hs destroyed the air, water and soil.
Only a few foods contain vitamin D3, and the quantities are so small (except as noted below, in breast milk from 25-hydroxyvitamin D replete mothers) that no practical amount of food can supply anywhere near enough vitamin D3 for us to attain (via hydroxylation, primarily in the liver) the 50 ng/mL (125 nmol/L = 1 part in 20,000,000 by mass) level of circulating 25-hydroxyvitamin D which the immune system needs to function properly.
Please see my two comments below and the research cited and discussed at: https://vitamindstopscovid.info/00-evi/.
Ultraviolet B light on ideally white skin can create sufficient vitamin D3 for full immune system function, but far from the equator, this is only available naturally in sufficient quantities in the middle of cloud-free summer days. UV-B always damages DNA and so raises the risk of skin cancer.
Fortunately we can now supplement vitamin D3 to attain the level of 25-hydroxyvitamin D our immune system needs all year round without raising the risk of skin cancer. This is an important exception to the principle that we can and should obtain all the nutrients we need from food. Average weigh adults need about a gram every 22 years.
This is true for everyone except for those who already have substantial year-round UV-B exposure of ideally white skin and babies substantially breast fed by mothers who have good 25-hydroxyvitamin D levels.
Both vitamin D3 and 25-hydroxyvitamin D are present in breast milk, in proportion the mother's circulating levels. The research on this is quite scattered, but Tsugawa et al. 2021 https://www.mdpi.com/2072-6643/13/2/573 measured these low levels very carefully and found approximately equal amounts of vitamin D3 cholecalciferol and 25-hydroxyvitamin D in breast milk. Only about 1/4 of ingested vitamin D3 is hydroxylated to the circulating 25-hydroxyvitamin D the immune system needs, while ingested 25-hydroxyvitamin D is easily absorbed and goes straight into circulation. So the 25-hydroxyvitamin D content of milk from 25-hydroxyvitamin D replete mothers plays the predominant role in boosting her baby's 25-hydroxyvitamin D level.
Since breast milk is food, this is the only instance in which food can be sufficient to attain the good levels of 25-hydroxyvitamin D the immune system needs to function properly.
Its amazing how our ancient ancestors lived for thousands of years without any supplements at all and were healthy enough to propagate without medical assistance. Could it be they were in a warmer climate and had no clothes? Perhaps, the atmosphere was free of pollution and the sun rays were not blocked. Today, people need supplements because pollution hs destroyed the air, water and soil.