by dotFIT experts
Defining the perfect diet has been a laborious task for the nutritional sciences for decades. Likewise, specifying the optimal intake of vitamins and minerals is difficult in the face of continuing nutrient research. This makes giving concrete nutrient recommendations challenging. For most nutrients, there is a large therapeutic range within which the average person will receive benefit and simultaneously remain below the threshold that can yield adverse events. It is one matter to define nutrient recommendations and another to actually consume the recommended dosages through the course of a normal day with typical foods. The notion that you will satisfy all physiological needs of the body for proper and ideal nutrient intake with food alone is impractical and outdated. Some of the obstacles to proper eating and ideal nutrient intake include insufficient food intake, increased needs that are not met by food alone, and dislike or avoidance of essential food groups.
Therefore, at worst vitamin and mineral supplementation acts as insurance against short and long-term dietary lapses, and guesswork in nutrient intake, including the ability to define the optimal diet. At best, using valid science to increase the nutrient content of available and typical food intakes may yield optimal functioning for an extended period, as compared to a non-supplemented state.
The notion of vitamin and mineral supplementation, including the fortification of food, began with the intent to supply essential dietary nutrients significantly lacking in some geographical regions and to shore up inadequate nutrient content of the general population’s typical food intake to meet the Recommended Dietary Allowances (RDAs). Without supplementation, severe nutritional deficiencies would be widespread, as they once were.(1)
The RDAs are, by definition, “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 (97-98% of the population) healthy persons.”(2) 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.(3,4,5,6,7,8,9,10,11)
Dietary nutrient recommendations for achieving health are continuously being revised and generally trend upward as the scientific community gathers more data related to how different nutrient intake levels may affect overall health and longevity. Therefore, rather than simply updating the RDAs, which are set only for the average person to avoid deficiencies, the US Food and Nutrition Board, now an element of the Institute of Medicine, released the new Dietary Reference Intakes (DRIs) in 1994 and have updated them since. These evidence-based standards go beyond amending deficiencies; they also suggest the amount of nutrients needed for enhancing health. DRIs are as follows:
- Recommended Dietary Allowance (RDA) is the average daily dietary intake level that is sufficient to meet the nutrient requirements of nearly all (97 to 98 percent) healthy individuals in a specific life stage and gender group. The RDA is intended primarily for use as a goal for daily intake by individuals.(12)
- Estimated Average Requirement (EAR) is the daily intake value that is estimated to meet the requirement, as defined by the specified indicator of adequacy, in 50 percent of the individuals in a life stage or gender group. At this level of intake, the other 50 percent of individuals in a specified group would not have their nutritional needs met. The EAR is used in setting the RDA.(12)
- Adequate intake level (AI) is a value based on experimentally derived intake levels or approximations of observed mean nutrient intakes by a group (or groups) of healthy people.(12)
- Tolerable Upper Intake Level (UL) is the highest level of daily nutrient intake that is likely to pose no risks of adverse health effects in almost all individuals in the specified life stage group. As intake increases above the UL, the risk of adverse effects may increase. The intent is to set the UL so that it is below the threshold of even the most sensitive members of a group.(12)
Why the Inadequacies?
1. The majority of the general population does not have the ability to properly analyze foods, much less buy, prepare and consume each in the proper array to meet daily requirements.(14,15).
2. Today’s sedentary environment, which is promoted by increasingly inactive jobs, 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.(16,17,18,19,20,21,22,23,24,25,26,27,28,29) In addition, because of the lack of movement in today’s society, the large portion of the American adult population participating in weight reducing diets are forced to severely restrict food intake in order to sustain weight loss, a condition that all but assures nutrient inadequacies without supplementation.(30,31,32)
3. In general, food preferences established early in life keep people from more diverse nutritional choices. For most, the early introduction of sugar and fatty convenient foods (e.g. fast food outlets) creates addictions to these types of food, leaving many undernourished in terms of the RDAs for the long term. In other words, the foods most people normally choose are high in energy but low in nutrients.(33,34,35)
4. Available 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.(13,36,37)13 In addition, any calculations are vulnerable to analytical error.(38,39) These factors illustrate that just because a list of nutrients associated with a food is published, those nutrients are not guaranteed to actually enter the body. Performing an ingredient test on each food before it enters the body is not a practical solution.
Vitamin and mineral losses become cumulative. 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,” as demonstrated by the continual upward trend.(40,41) 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.(42) The study’s subjects were selected from a region in the United States where there is little to no selenium in the soil. The dramatic cancer preventative 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. All these uncontrollable issues become the strongest argument in support of the current scientific approach that no matter how well you plan your diet, you need “insurance.”(43,44,45)
Even trained professionals struggle with guidelines. In a 1995 study published in the Journal of the American Dietetic Association,(46) 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)(47) 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 objective.(46) 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?
Poor nutrition has been linked to an increased risk of many diseases including cancer, heart disease, and diabetes. One highly regarded researcher proposes that nutrient inadequacies may actually illicit a triage response where the body would prioritize the use of lacking nutrients by urgency which, if true, would accelerate cancer, aging, and neural decay but would leave critical metabolic functions intact; basically favoring short-term survival at the expense of long-term health.(48)
Collectively, the aforementioned circumstances strongly suggest nutrient augmentation to food intake in order to meet the existing DRIs, which still may not be optimal (40,41,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,6566,67,68) but are adequate for avoiding deficiency diseases.
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 (VMS) in conjunction with a well-balanced diet.(43,44,48,69,70,71) Aside from the “insurance” value, the changing views on VMS recommendations are also a 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.(2,63,72,73,74,75,76,77) These revised recommendations led to the reconstruction of the RDAs into the Dietary Reference Intakes (DRI).(2,12,78,79,80)
RDA levels of specific nutrients will continue to be revised, and wide ranges of safe and potentially effective intakes established (see Figure 1). This makes it nearly impossible for the general population to reach potentially beneficial amounts while remaining within a calorie level that would promote healthy body fat levels without supplementation.(47,49,74,81,82,83) The DRIs provide a new framework within which recommendations of nutrient intake and clear health benefits can be established.
Establishing beneficial nutrient levels with little to no risk
The issue still pending is just how much of each nutrient is needed, in general, to receive an optimal physiological response that fulfills the 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.40,41 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 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.(14)
- Approximately between two-thirds 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.(40,41,86)
- Lowest Observed Adverse Effect Level (LOAEL) and higher.
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 concentrations of nutrient intake increases, different levels of biological function (total benefits) are approached.
Figure 1: Ultimate Goal of Nutrient Augmentation
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 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.
Safe and beneficial dosages
Cautious review of existing information following the criteria in Figure 1 suggests total nutrient intake to fall somewhere within the ranges shown in Table 1. Any nutrient not appearing in the table indicates that too little information exists to establish a range. Therefore, consuming a balanced diet will presumably meet the currently known need. These totals 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 the upper amount listed, which is commonly well below the tolerable upper limit. More active individuals may maintain intakes closer to the higher side of the range. Recently, it has been proposed that the age and gender of an adult determines the appropriate levels of certain nutrients.
These doses, even at the high end, are meant to enhance natural physiology (fulfilling 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.
Table 1: Safe and Probable Optimal Range Including Food Sources
1. Supplemental amount can be zero if daily intake of beta carotene is within the safe and optimal range.
2. Smokers, those likely to develop, or those that already have lung cancer, should avoid beta carotene supplementation.
3. Upper range amount is from supplements only.
4. From supplements only.
5. Supplemental amounts should be close to the low numbers shown
* Currently being revisited.
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.
The synergy of these nutrients, including their daily levels, require they be consumed together but distributed as equally throughout a 24-hour period as possible 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, and adding a controlled-release multiple vitamin and mineral 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 one to two times daily with meals. Generally, a separate calcium and Vitamin D supplement may need to be included in order to reach desired levels, which would also be consumed in split doses. This method helps maintain tissue target levels throughout the day, as opposed to consuming the total amount at one time which would diminish the desired result.
Vitamins and minerals ingested as described may allow the body to operate at full capacity without disturbing its natural physiology. The belief that individuals consume each health and performance-related compound in optimal doses, ratios and at proper times from food every day is unfounded, especially when all obstacles are taken into account, including the inability to define these levels. In addition, it is common knowledge that the general population does not consume more than what is needed of all necessary substances in their diets. These issues collectively indicate that any nutrient contributing to cellular health and perform¬ance has the potential to be lacking when food is the only delivery system.
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 short and long term dietary lapses, and guesswork in nutrient intake, including the ability to define the optimal diet. At best, using valid science to increase the nutrient content of available and typical food intakes may yield optimal functioning for an extended period, as compared to a non-supplemented state.
Content utilized by permission from The National Academy of Sports Medicine.
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