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BLOG: October 2008
Nutrients on the official hold
Any self-respecting nutritionist will admit that Dietary Reference Intakes (DRI) set by the Food and Nutrition Board are generally conservative in their assessment of our nutritional needs. Their antiquated "method" based on the average nutrient levels in "healthy" individuals defies logic and the obvious, ignores scientific evidence, and effectively elevates nutritionally inferior Western diet to the level of a nutritional standard.
The fact is, most people appear healthy before they get sick; with most of those that do get sick it takes a while to develop illness, and most have nutritional deficiencies and imbalances among the major causative factors. Time to update official figures? Not so fast - the officials need "more evidence".
Notorious example of this grand-scale official blunder is as known and as important a nutrient as vitamin C - probably the single most important antioxidant. Even if it is well known for decades how important it is in protecting the body from oxidative damage - which is the major contributor to a wide range of major diseases, from cardiovascular to cancer - the current DRI for it is still a pittance at 75mg and 90 mg a day for adult females and males, respectively.
Yes, that will probably keep you protected from scurvy, but it is by far insufficient to protect you from major degenerative diseases decimating the Western countries.
In this context, it is more sign of a weakness than strength when other institutions, with less of a prerogative to lead the nation nutritionally, come out with their own nutritional recommendations; in effect, corrections of those established by the Food and Nutrition Board. Just this month, the American Academy of Pediatricians (AAP) has decided to double the official minimum recommended daily intake of vitamin D for infants, children and teens.
The reason for this grass-roots initiative of medical professionals is very simple: the evidence. Pediatricians, who by the virtue of their profession find it more hard to neglect the importance of satisfying nutritional needs, are more likely to run into it. The most recent finding earlier this year, by the researchers at Children's Hospital in Boston, was that out of 365 "healthy" babies and toddlers, admitted for examination at age 9 and 18 months, 40% had suboptimal vitamin D level, and 13% were clinically deficient. About 1/3 of those deficient were showing evidence of bone loss.
Rate of deficiency was significantly higher in about 8% of infants that were exclusively breastfed, without receiving vitamin D supplementation. The reason is that mother's milk is a very poor source: babies get most of their vitamin D from vitamin D reinforced milk, baby formulas, and orange juice. Outdoor exposure doesn't seem reliable in preventing deficiency, due to babies being protected from the sunlight, or having only a small area of the skin exposed to it (since 2003, the Academy is recommending 200 IU of supplemental vitamin D for breastfed babies).
Keep in mind that the blood level standards for vitamin D are likely to be suboptimal as well, since they are also based on the average in small samples of "healthy" individuals. In other words, actual deficiency figures are likely to be significantly higher. Yet, there are already cautionary voices questioning the recommendation for higher vitamin D intake. In the editorial following the study, Dr. James A. Taylor states that there is no consensus among the "experts" on what is appropriate vitamin D intake, and no research data on possible long-term effects from early vitamin D deficiency.
Thus, he concludes that we are probably "medicalizing" who doesn't need to be medicalized.
It is sort of odd to have doctors express such concerns related to a natural body substance needed for health, and not related to any one, or all of the myriad of prescription drugs flooding the population to the extent that they
have become drinking and ground water contaminant.
This is part of the reason why nutrients in general are still on the official hold; doctors, in general, are thought and know little about their health importance. And they don't in good part because the mighty Big Pharma doesn't want them to.
This is why the official adult recommendation for vitamin D is still only 200IU a day, why the upper limit intake is maintained at 2000 IU a day, and why the cautionary tales of vitamin D toxicity ("hypervitaminosis D") are so persistent. The fact is that the body exposed to the sunlight will produce up to 10,000 IU of natural D3 vitamin a day,
without any signs of toxicity whatsoever.
The fact is that vitamin D toxicity tales originate from formerly prevalent use of its synthetic form (yeast-produced vitamin D2), which body cannot convert nearly as efficiently into its biologically active (useful) forms.
If your body makes up to 10,000 IU of natural vitamin D in less than half an hour of full body exposure to the summer sun (after that, further production is diverted to inactive metabolites), it is likely
because it needs it.
Scarcity of the vitamin D in foods has made the sun exposure its principal source for us. 10,000 IU is probably more than your body needs every day, since it is also likely that this rate of production roughly compensates for the time when it cannot synthesize the vitamin, either for the lack of sunshine, or for the lack of exposure. But if we assume that our gatherers/hunters predecessors were spending only a few hours a day on the open, on the average, that puts the likely optimum averaged daily use of vitamin D above 1,000 IU, possibly significantly.
For us today, spending significantly less time on the open, and with significantly smaller portion of the skin exposed to sunshine, daily supplementation close to 1,000 IU of natural vitamin D a day seems appropriate and logical. There is virtually no risk of toxicity; according to the government's Office of Dietary Supplements, consistent blood level of calcidiol (liver-converted form of vitamin D, up to five times more biologically active) over 200ng/mL are "considered potentially toxic". At the same time, it states that twice as high levels in animal studies have not shown adverse effects.
It also states that short-term daily doses as high as 10,000 IU of vitamin D3 for 8 weeks have not caused toxicity. Rather, the vitamin has been stored and used when the level of its synthesis in the skin was low - exactly as nature intended.
According to the Office, optimum blood level of calcidiol has not been established. A recent study (Vieth et al, The urgent need to recommend an intake of vitamin D that is effective, Am J Clin Nutr 2007) suggests that this level is at the ~30ng/mL level; also, that daily supplementation of 400 IU (double the official recommended daily intake)
only raises the blood level by 2.8-4.8ng/mL;
daily intake required to raise it to the desired level (32ng/mL) is, according to it, 1,700 IU.
Also, the official upper safe intake level of 2,000 IU of vitamin D a day has already being scientifically challenged several times within the past decade. Simply put, the evidence suggests that the upper safe intake level is at 10,000IU of vitamin D a day.
For some reason, when it comes to those who decide about the official recommendation, all this is not a sufficient reason for any changes. Not with respect to recommended vitamin D intake, or intake of any other vital nutrient. Business as usual. It is concerning, though, that after recent collapse of the U.S. stock market, it has found support in the strength of the pharmaceutical industry. What kind of future awaits a country whose strength comes from the money made on the sick?
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