Why Rdas Are Too High
Before entering into a discussion of how RDAs are set, it is appropriate to distinguish between Recommended Dietary Allowance (RDA) and Minimum Daily Requirement (MDR). These are not the same, though MDRs are usually set unduly high, as are the RDAs.
RDAs are set by the Food and Nutrition Board of the National Research Council. Minimum Daily Requirements are mandatory on labelling of processed foods. They are required by the FDA, who has published the MDRs. MDRs generally closely parallel the RDAs. Supposedly the minimum requirement is the least amount you can ingest and adequately meet need. RDAs are recommended as intake to be on the safe side. RDAs are, therefore, higher than MDRs.
In setting RDAs, the NRC has criteria for each nutrient, vitamin or mineral. For instance, it figures vitamin C need based on what is required as a minimum. Say this minimum is set at 15 milligrams daily, which is the generally recognized minimum in much of the world. The NRC figures there is perhaps a 30% difference between individuals in their vitamin assimilation abilities. Thus they add on 30% to this minimum.
Further, the NRC gives a biologic value of about 2/3 to dietary vitamin C (could this be due to cooking or due to synthetic C or both, making 1/3 not available?) Instead of 19.5 mg, we now have 30 mg. As a margin of safety, the recommendation allows an extra 100%.
Thus, a man of say 154 pounds is said to need 60 mg of vitamin C daily. This is the RDA when, in point of fact, the needs of a healthy person are amply met on an intake of 15 to 20 mg daily. But, as this water-soluble vitamin in its natural form is easily excreted, there is no great danger in an intake of 60 mg daily. In fact, a natural diet furnishes 200 to 500 mg daily.
While establishing an RDA some four times in excess of what a healthy individual really needs is not harmful in the case of natural vitamin C, in other cases the RDA is positively pathogenic! This “generosity” amounts to recommended overfeeding. In people’s minds the RDA becomes a mandatory minimum and they add on perhaps another 100% just to be sure! In the case of protein this is a great contributing cause of widespread disease!
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As a Hygienist, be ever cognizant of those principles that go like this: The healthier you are, the more efficient your body becomes up and down the line. On a proper diet the biological value of nutrients is at or near 100%! The food will not be deranged by cooking or processing. Further, it will be 100% in accord with human digestive adaptations and capabilities. The healthy person will have about 100% uptake of dietary intake up to an optimum point and nearly 100% usage. Hence most RDAs are some 200% to 1,000% too high at the least!
Why get into a meaningless numbers game when all that we need in nutrients to repleteness is amply furnished with a great margin of safety by a modest diet consisting mostly of fresh fruits with some vegetables, nuts, seeds and perhaps some dried fruit. All, of course, must be eaten in the raw or live state to assure nutrient integrity on the one hand and non-toxicity on the other.