Are RDA Nutrient Levels Safe?

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Health

Legislation

RDAs or Recommended Dietary Allowances of vital nutrients such as vitamins and minerals, are being promoted by health authorities as the level of consumption at which we may feel comfortable about having "taken care of our needs" - but is that really the truth?

Developed during the wartime 40s, the purpose was to identify a diet that would allow US soldiers to fight as well as those staying home to survive without getting sick from malnourishment. After the war, dietary allowances became a part of standard health practice in many western countries. Note that there was no intention to assure optimum health, merely the absence of those deficiency diseases that had been identified at the time. Although refinements have taken place over the years, the basic philosophy of RDAs has remained the one implicit in the original purpose.

Legislation proposed in the international food standards body, the Codex Alimentarius and in a regional context, such as the European Food Supplements Directive, the Australia/New Zealand trans-tasman harmonization of health products regulation and a Canadian health products initiative propose to "ensure the safety" of those vitamins and minerals we can add to our daily food. There is talk of limiting, for safety reasons, the available dosage of supplements, so the question becomes quite legitimate: What is safer, a low dose (RDA level) vitamin intake or a high dose (optimised) intake of these nutrients?

In this a recently published newsletter, James A. South discusses the implications of the RDA standard for our health and the relative safety of a higher level of vitamin intake.

He answers our question: Are RDAs really safe?

Vitamin Safety, RDAs and the Assault on Vitamin Freedom
by James South, M.A.
(Original found on this site)

Once again, the right of Americans to purchase high potency nutritional supplements is under attack. The enemies of supplement freedom, such as U.S. Senators Richard Durbin (D-Ill.) and Hillary Clinton (D-N.Y.), and Representatives John Dingell (D-Mich.) and Henry Waxman (D-Calif.), are pushing bills in Congress (SB 722 and HR 3377) that would empower the FDA to ban almost any supplement, as well as force costly pre-marketing approval and post-marketing surveillance on the vitamin industry that would radically increase supplement prices.1

Indeed, the proposed regulations would be more restrictive than those governing the prescription and over-the-counter drug industries! Underlying this assault on vitamin freedom is the (erroneous) belief that nutritional supplements are extremely dangerous, and that only nutrients with an officially defined DRI (dietary reference intake), at levels no more than 150 percent of the DRI, should be allowed to be sold.

To add insult to injury, the Institute of Medicine of the National Academy of Sciences, which sets the DRIs for various nutrients, is proposing a drastic lowering of the DRI for all nutrients. The term “DRI” actually refers to a group of related reference standards, including the Recommended Dietary Allowance (RDA) and Estimated Average Requirement (EAR). The Institute of Medicine is recommending that the national standard for nutrient intake be shifted from the RDA to the EAR.2

As noted in the DRI handbook, the RDA “… is the average dietary intake level that is sufficient to meet the nutrient requirement of nearly all (97 to 98 percent) healthy individuals ” (emphasis added).3 “The EAR is the daily intake value that is estimated to meet the requirement...in half of the healthy individuals in a...group. At this level of intake, the other half of a specified group would not have its nutritional needs met.”4 Thus, the new DRIs, which the FDA uses to set its daily reference intake, will be significantly lower than the already low current RDA-DRIs.

The assault on vitamin freedom has always revolved around two key questions: Is the RDA (DRI) level of nutrient intake adequate to promote robust, vibrant, high energy optimal health, and are high potency vitamin supplements really safe?

The RDAs

The National Academy of Sciences and the FDA have been setting RDAs since 1943, revising them periodically. The 1989 RDA revisions lowered many RDAs from their 1980 levels.

For example, the 1989 RDA for folic acid was reduced from 400 to 200 mcg, a level more in line with average U.S. consumption of folic acid.5 The 1989 RDA for vitamin E was reduced from 30 IU to 15 IU, with typical U.S. intakes being 10-15 IU (7-10 mg).6

The general lowering of the (already modest) RDAs in the 1989 revisions was based in part on the question-begging “logic” that assumes Americans are a basically healthy people, and since they routinely fail to consume diets containing the earlier, higher RDAs of most nutrients, the new, lower RDAs are all that is necessary for good health. (The DRIs set from 1998-2003 are generally the same or lower than the 1989 RDAs.)

In a land where $1.6 trillion (almost one sixth of total national income) is spent annually on “health” (i.e., disease) care; where cancer is one of the leading causes of death in children; where one-third of the population is medically obese; where many tens of millions suffer from diabetes, asthma, allergies, arthritis, ulcers/heartburn, chronic insomnia, depression, alcoholism, drug addiction, heart disease, high blood pressure and cancer, to assume that Americans are healthy just because they don’t suffer classical nutritional deficiency diseases such as scurvy (vitamin C), rickets (vitamin D), or beri-beri (vitamin B1), is rather Alice-in-Wonderland “logic,” indeed.

There is, however, a deeper conceptual and scientific falseness to the RDAs beyond their recent specious downward revisions. Part of the problem stems from the conceptual framework of the RDAs as such. The 1980 Recommended Dietary Allowances states:

RDAs are recommended for healthy populations. Special needs for nutrients arising from such problems as premature birth, inherited metabolic disorders, infections, chronic diseases and the use of medications require special dietary and therapeutic measures. These conditions are not covered by the RDAs…. The requirement for a nutrient is the minimum intake that will maintain normal function and health…. For certain nutrients, the requirements may be assessed as the amount that will just prevent failure of a specific function or the development of specific deficiency signs—an amount that may differ greatly from that required to maintain maximum (i.e., optimum) body stores” (emphasis added).7 With regard to the first three statements, since the majority of Americans suffer chronic diseases such as diabetes, heart disease, arthritis, allergies, asthma, depression, etc., and routinely use over-the-counter or prescription medications such as aspirin, allergy medications, antacids, laxatives, anti-depressants, high-blood pressure drugs, statin-drugs, etc., then, by the RDA Committee’s own statement the RDAs are inadequate for their required nutrient intake.

The last two statements focus on minimum nutrient intake, and on (just barely) avoiding specific physiologic function failure and/or specific nutritional deficiency symptoms. This makes it clear that the RDAs were never formulated as a guide to maintaining robust, vibrant, high energy optimal health, but are merely intended to keep people “healthy” enough to (just barely) avoid classical nutritional deficiency diseases such as scurvy or pellagra, or to avoid their heart or liver or brain failing today or tomorrow—but who knows about next month or next year?

Five Stages of Nutrient Deficiency

In 1964 Myron Brin published a classic analysis of the five stages in the development of a vitamin or nutrient deficiency. He illustrated the schema with reference to vitamin B1 (thiamin).

In the first, or preliminary stage, inadequate B1 availability due to faulty diet, malabsorption or abnormal metabolism leads to a greatly reduced urinary B1 loss. In the second, or biochemical stage, the activity of a key enzyme—transketolase—which is activated by B1, is significantly reduced. Adding B1 to a blood sample from a person at this stage increases his or her transketolase activity. In the third, or physiologic stage, various general symptoms develop, such as lessened appetite, insomnia, increased irritability, and malaise. In the fourth, or clinical stage, a constellation of symptoms classically specific to B1 deficiency disease (beri-beri) develops: e.g., intermittent claudication, polyneuritis, bradycardia, peripheral edema, and ophthalmoplegia. In the fifth, or anatomical stage, histopathological changes due to cellular structural damage are seen, such as cardiac hypertrophy, degeneration of the cerebellar granule layer, and swelling of the microglia.8

Although Brin’s five-stage deficiency schema is exemplified with regard to B1, it is in principle applicable to any nutrient, as Brin himself notes. Brin’s schema is especially illuminating with regard to the RDAs, since the “just preventing failure of specific functions” and “just preventing specific deficiency signs” criteria of nutritional requirement, which is the basis of the RDA concept, are only evidenced in the fourth (clinical) and fifth (anatomical) stages of developing nutritional deficiency disease.

The first three stages, although they are objectively, empirically measurable and observable phases of a developing nutrient deficiency, do not involve either “specific deficiency symptoms” or “failure of a specific nutrient-related function.” What follows from this is quite simple. The RDA level of nutrient intake may keep most people out of the severe illness-leading-to-death fourth and fifth nutrient deficiency stages, but RDA nutrient levels cannot be presumed to be adequate to keep one out of the first three stages of “subclinical” deficiency, let alone in a more optimal, vibrant, energized state of health.

Genetic Need for High-Dose Vitamins

A recent major scientific review article by famed nutrition researcher Bruce Ames and colleagues makes