Our culture gives us access to a huge variety of foods that people didn't have access to 75 years ago. And while some people may have spent more time outdoors back then, they tended to cover themselves head to toe with clothing. From reading the Little House on the Prairie books, I happen to know that it was not considered attractive to get tans back in the 1800s. What all of this means is that there is no reason to think that people ate a wonderfully nutritious diet, or had perfect nutrition back then: we're far better off today.
My whole point is that, if you identify a bona fide nutrient shortage in your diet, you are far better off making up for it by adjusting your diet than by taking pills. Few, if any pills, are actual supplements--they contain several times the RDA, whereas a true supplement would not even contain a full RDA, since the idea would be to make up the shortfall in your diet. Unfortunately, people think that if, you need 20 mg of nutrient X to be healthy, it must be 1000 times as healthy to take 20,000 mg of it. That is simply not true. Aside from acute toxicity issues, there aren't a lot of studies on the long-term health effects of taking mega dosage supplements. That doesn't mean they're safe--just that those studies aren't being done yet. The few done so far indicate that mega-doses can, in fact, have very deleterious effects long-term.
And you know that 10,000 years is enough to correct the Vitamin D deficiency?? I don't think so.
In 10,000 years, some quite noticeable changes in human physiology have occurred. Teeth, for example, have been shrinking. People are larger. With strong selective pressures, it does not take long at all to observe evolutionary changes. I doubt it took anywhere near 10,000 years, in fact, to adapt to the lower sunlight levels reaching northern latitudes--where the native people are paper-white.
My training is in biochemistry, specializing in toxicology.
So?? Completely irrelevant.
"And while some people may have spent more time outdoors back then, they tended to cover themselves head to toe with clothing. From reading the Little House on the Prairie books, I happen to know that it was not considered attractive to get tans back in the 1800s.
You don't have to "get tan" to photosynthesize Vitamin D. And I hardly consider the "Little House on the Prairie" to be scientific.
"My whole point is that, if you identify a bona fide nutrient shortage in your diet, you are far better off making up for it by adjusting your diet than by taking pills.
Sorry, but for Vitamin D, it can't be done. Photosynthesis, as I recall, generates the equivalent of 20,000 IU/day. Checking "high in Vitamin D" foods shows no way to reach that kind of level by diet.
"Few, if any pills, are actual supplements--they contain several times the RDA, whereas a true supplement would not even contain a full RDA, since the idea would be to make up the shortfall in your diet."
Since the main source of vitamin D is photosynthetic, and NOT diet, your argument fails.
"Unfortunately, people think that if, you need 20 mg of nutrient X to be healthy, it must be 1000 times as healthy to take 20,000 mg of it. That is simply not true."
A ridiculous exaggeration.
"In 10,000 years, some quite noticeable changes in human physiology have occurred. Teeth, for example, have been shrinking. People are larger. With strong selective pressures, it does not take long at all to observe evolutionary changes. I doubt it took anywhere near 10,000 years, in fact, to adapt to the lower sunlight levels reaching northern latitudes--where the native people are paper-white."
Neither you nor I know, and we have no way of knowing, how long those changes took, or the extent to which they took place. Homo sapiens of 10,000 years ago had teeth just like homo sapiens of today. You keep asserting a degree of certainty which simply does not exist in science in areas where we simply don't know the whole (or even a significant part) of the story. "Through a glass, darkly" is as good as it gets.
And likewise, we simply don't know what the optimal amount of many nutrients are, because we have not had the analytical (both chemical and statistical) to isolate and identify and quantify more subtle forms of deficiencies.
Sorry, but I'll keep taking my "D" supplements, and will likely increase the dose yet again to try to get my blood levels off of "bottom dead center". And I'll keep reading the peer-reviewed literature on the topic. As I said, "I" find the weight of evidence to be in favor of increased supplementation.
And my degree is in chemistry (PhD), with emphasis on analysis. And forty years of practice in the field has given me a much higher level of humility as to what the unknowns in science are. We know very little as yet. Your absolutist statements sound more like those of a new graduate than a long-term practitioner.