Introduction

The concept of vitamin and mineral supplementation, including food fortification, originated with the intent to supply essential dietary nutrients grossly lacking in some geographical regions and to shore up inadequate nutrient content of the general populations typical food intake to meet the Recommended Dietary Allowances (RDAs). Without supplementation, severe nutritional deficiencies would be widespread, as they once were.

By definition, RDAs are "the levels of intake of essential nutrients that, on the basis of scientific knowledge, are judged by the Food and Nutrition Board to be adequate to meet the known (current) nutrient needs of practically all healthy persons." They are not intended to be final, minimal or optimal. Rather, RDAs and the Dietary Guidelines are designed to prevent nutritional deficiencies by providing Americans with goals for adequate nutrient intake that most are not reaching.

However, despite the efforts of the scientific community, including the Food and Nutrition Board of the National Research Council and its RDAs, the general population is not adequately nourished. A recent study by the USDA demonstrated that 1% of Americans meet the minimum standards for dietary adequacy, with none in the study meeting the current goal amount. ⁴

Why the shortcoming? Factors to consider:

1. The majority of the general population does not possess the knowledge necessary to properly analyze foods, much less buy, prepare and ingest each in the proper array to meet daily requirements. If it could, dietitians would be needed for nothing other than medical nutrition therapy.
2. Todays sedentary environment, which is promoted by increasingly inactive modes of employment, convenient forms of communication, easy access to food, comfort and entertainment, prohibits most of the general population from consuming the calories necessary to reach these recommended nutrient levels without gaining weight.
3. Food preferences established early in life steer the populace away from more nutritional choices. For most people, the early introduction of sugar and fatty convenient foods (e.g. McDonalds) creates addictions to the aforementioned vehicles of satiation, leaving many chronically undernourished in terms of the RDAs. In other words, the foods most people normally choose are high in energy but low in nutrients.
4. Printed nutritional information regarding particular foods is not necessarily accurate. The true nutritional content of a given food is dependent upon such factors as its origin, time and maturity of its harvest, slaughter, cooking method, processing and shelf life. In addition, any calculations are vulnerable to analytical error.

The vitamin and mineral losses become cumulative. And while an argument can be made that the RDAs include a margin of safety to address some of these problems, many of the RDAs are established as "sub-optimal". No margin of safety can compensate for a nearly complete lack of an essential nutrient due to any of the above factors, especially soil content. This was illustrated, though inadvertently, in a study conducted by Clark, Combs and Turnbull. The studys subjects were selected from a region in the United States where there is little to no selenium in the soil. Therefore, the dramatic benefits witnessed in the selenium-supplemented group compared to the placebo users are most likely attributed to the lack of selenium in the food supply from this area.

Even trained professionals struggle with guidelines. In a 1995 study published in the Journal of the American Dietetics Association, dietitians were asked to design diets that met the 1989 RDAs and 1990 Dietary Guidelines while providing 2200-2400 calories (the average non-athletic female gains weight at 1800 calories) and remaining palatable to the individuals in the study. Using software designed specifically for creating a healthy diet, these trained dietitians were unable to accomplish the given objective. This begs the question, if health professionals cannot consistently reach the RDAs and dietary guidelines within an average amount of calories that promotes leanness while being universally palatable, how is the general public expected to do so?

The aforementioned issues suggest nutrient augmentation to food intake in order to meet the existing RDAs, which still may not be optimal but adequate for avoiding deficiency diseases.

Discussion

The original paradigm based on nutritional essentiality is undergoing a shift. Many well-informed health professionals and well-respected institutions are breaking precedent by recommending the use of a multiple vitamin and mineral supplement in conjunction with a well-balanced diet. This is the result of ongoing research into the amount of a nutrient required to prevent a chronic disease from occurring, rather than simply preventing a deficiency state. These revised recommendations are part of a forthcoming reconstruction of the current RDAs into the Dietary Reference Intakes (DRI).

The DRI approach includes four types of reference values:

Estimated Average Requirements (EARs)  Intakes estimated to meet the requirements of 50% of healthy individuals in a group.

RDAs  Average daily intake level sufficient to meet nutrient requirements of nearly all (97-98%) of the healthy individuals in a group.

Adequate intakes (AI)  Values, based on observed/experimentally determined approximations of nutrient intakes of groups of healthy people, to be used when data are insufficient for the determination of an RDA and EAR.

Tolerable upper intake limits (Uls) The highest level of daily intake that is likely to pose no risk of adverse health effects to almost all individuals in the general population.

RDA levels of specific nutrients will likely be increased, and wide ranges of safe and potentially efficacious intakes established (see Figure 1), thus making it nearly impossible for the general population to reach potentially beneficial amounts while remaining within a caloric allotment that would promote healthy body-fat levels without supplementation. The DRIs will provide a new framework within which recommendations of nutrient intake with clear health benefits can be established.

Establishing nutrient levels with myriad potential benefits and little to no risks

The issue still pending is just how much of each nutrient is needed, in general, to receive an optimal physiological response to fulfill a particular organisms potential for health and performance. Though these exact amounts are currently unknown and will always vary by individual, volumes of information exist on approximate values within a wide range of safety that suggest efficacy for the general population. In other words, the benefits of doses properly extrapolated from current research would greatly outweigh any unlikely risks from these doses, especially when compared to the risks involved resulting from no supplementation at all.

Using information available today, we must consider three levels of nutrient activity:

1. The amount of the nutrient to prevent overt deficiency disease.

Approximately between 2/3 of the current RDAs and the actual RDAs.

2. When applicable, the amount of a nutrient that may support optimal benefits.

Approximately between the current RDAs and the No Observed Adverse Effect Level (NOAEL).

3. The amount of a nutrient that may cause adverse reactions.

Figure 1 illustrates how, within a wide range of safety, the amount of a nutrient required to achieve optimal benefits in performance and health can be approximated. As the concentration of nutrient intake increases, different levels of biological function (total benefits) are approached:

1. Overt nutritional deficiency.
2. Typical intakes (2/3 of RDA, thus sub-optimal).
3. The RDAs, which we have established as sub-optimal for many nutrients.
4. NOAEL - A safe intake far greater than the RDAs, and it is likely between this nutrient amount and its RDA where the optimal level of intake exists.
5. LOAEL  An intake that is not safe for all consumers, therefore should generally be considered sub-optimal.

Dosages extrapolated from studies that suggest benefit and indicate safety

Careful review of existing information following the above criteria suggests total nutrient intake to fall somewhere within the ranges shown in Table 1. Any nutrient not appearing or not referenced in the table indicates that too little information exists to establish a range. Therefore, consuming a balanced diet will presumably cover the currently known need. These totals would include the nutrient content of food intake and supplementation. Considering most nutrient ranges shown in Table 1 fall well within known safety margins and the often small contribution food makes to most of these desired levels, it would generally not be necessary for individuals to compile the nutrient content of daily food intake. Respecting this, daily supplementation should be no higher (maybe lower when marked) than upper amount listed, which is commonly well below the tolerable upper limit. Larger, more active individuals may maintain intakes closer to the higher side of the range.

These doses, even at the high end, are meant to enhance natural physiology (fulfill an organisms potential related to health). They are not in pharmacological amounts that would be used to treat symptoms of disease. The use of vitamins and minerals for therapy should be conducted by a qualified physician. Though some studies cited relate to treatment of disease, they are only included here to help establish safety.

Table 1
Safe and Probable Optimal Range Including Food Sources

Chronic ingestion of nutrients anywhere in the range illustrated in Table 1 has been established as safe for the general population and may prove to be highly beneficial.

Method of ingestion

The synergy of these nutrients, including their daily levels, mandates that they be consumed together but distributed as equally as possible throughout a 24-hour period to avoid over-saturation and losses. Individuals should start by following a healthy food plan as closely as possible, including a calorie intake that promotes healthy body fat levels. Add controlled-release preparation to meet the appropriate nutrient levels.

Using an acceptable pill size, these amounts could be reached through ingestion of a multiple vitamin and mineral formula with breakfast, complementing anti-oxidant preparation at lunch (i.e., vitamins C, E, beta carotene and any other nutrient lacking or missing from the multiple vitamin) and a second multiple vitamin and mineral tablet with dinner. This method would help maintain tissue target levels throughout the day as opposed to ingesting the total amount in smaller increments, which would diminish the desired result.

Conclusion

Vitamins and minerals ingested as described may allow the body to operate at full capacity without disturbing its natural physiology. Unfounded is the belief that every day individuals consume each health and performance-related compound in optimal doses, ratios, and at proper times from food, especially when all obstacles are taken into account, including the inability to define these levels. Additionally, it is common knowledge that the general population does not consume more than what is needed of all necessary substances from their diets. These issues collectively indicate that any compound contributing to cellular performance has the potential to be sub-optimal when food alone is the matrix.

Because of the safety margins of most nutrients, and paying strict attention to tolerable upper limits, distinctions can be made between the strongest possible evidence and instances where the evidence becomes strong enough regarding ingesting levels of nutrients that show potential in staving off chronic disease. In other words, when supplementing properly, potential benefits would greatly outweigh any unlikely risks. Therefore, at worst, vitamin and mineral supplementation acts as insurance against acute and chronic dietary lapses, and conservative guesswork in nutrient intake, including the ability to define the optimal diet. At best, using careful extrapolations from current science to augment the nutrient content of available and typical food consumption may allow an organism to function at its potential for an extended period as compared to the organism in a non-supplemented state.