Quote:
|
Originally Posted by sln88
Hutchinson : People with higher 25(OH)D levels live longest.
|
Here is a typical example.
Quote:
|
do the people that live the longest have the highest vit D naturally?
|
There is a higher rate of vitamin D deficiency in people with darker skin tone. The colour of your skin determines to some extent the amount of vitamin d that skin produces. Even getting a tan will reduce the amount of vitamin D synthesised, Tanning like natural skin tone helps protect the skin when prolonged outdoor sun exposure is unavoidable. However there are many other factors involved. Vitamin D3 is made by the conversion of cholesterol by UVB and so low cholesterol in skin inevitably means reduced D3 production. As skin ages the amount of cholesterol it contains reduces and so the potential for 25(OH)D synthesis is lower. So it's difficult to say that the reduced vitamin D level that is associated with longer life is the ultimate cause of that extended life or if we should give the credit for that to having a higher cholesterol level. The way one thing relates to another regarding diet/lifestyle/genes is so complex and interwoven that it's almost impossible to unravel cause and effect.
Quote:
|
I guess what I am asking, does supplementation really help or is there some reason that unhealthy people use up their natural vit D and healthy people don't?
|
If you take people with obesity or virtually any inflammatory condition it seems to be the case that these are associated with low vitamin D status.
If you look at this study [url=http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2551670/?tool=pubmed]you see that low 25(OH)D predicts metabolic syndrome[/quote] (which may lead to diabetes)
The question is will raising 25(OH)D to the level the human body naturally attains and maintains given regular full body sun exposure prevent, delay, reduce the onset of Metabolic Syndrome or reduce Diabetes incidence?
Until researchers start using EFFECTIVE amounts of D3 (and NOT D2) AND they MEASURE 25(OH)D status and demonstrate 25(OH)D levels above 55ng/ml have been attained and maintained for sufficient time for the body to adjust to having a reserve of D3 stored in tissue, we won't know for certain.
We are learning lots more about the mechanisms by which 25(OH)D is used in the body to have a reasonable expectation that in practice in human bodies, having a reserve of D3 will help fight inflammation and infection, but because so much of the research is being done with too little and still too often with the less effective form of Vitamin D and the levels being regarded as adequate are unrealistically low there is still a lot of confusing information.
Quote:
|
Is low vit D a reflection of the illness
|
YES People with chronic illnesses appear to use more D3 than healthy people.
If we take obese people Vitamin D3 is fat soluble, it's carried round the body by fat molecules so while blood glucose levels glucose burning takes place and fat is stored, taking with it the D3 that should be available for use. Ideally fat storage in Autumn provides a reserve of D3 to be released during winter but if people stay fat 12months of the year that D3 simply depletes in storage and is wasted.
NO that is too simplistic. As I explained thinner older people with lower cholesterol and lower capacity to make D3 fare worse than their slightly chubbier (higher reserves of cholesterol and greater D3 potential) peers. But as LarryAJ says it's chicken and egg, which comes first but we don't HAVE to know for certain. The cost of 5000iu/d is so trivial that everyone can afford it. If you ensure your daily basic needs are met from an effective strength supplement you can then rely on skin to homeostatic potential to adjust further D3 production to keep reserves of D3 at the natural primitive level our DNA evolved to function with.
It is thought atmospheric pollution led to the elimination of dinasaurs so it's possible current upper atmospheric dust pollution is reflecting back or absorbing the UVB that should be reaching the ground and thus lowering global 25(OH)D levels year on year. So those relying on casual face and hands UVB exposure only, simply aren't getting sufficient.