Problems with the RDA/RDI
However, the RDAs come with several pitfalls, especially within the data used to establish these supplementation recommendations. That means the RDAs typically underestimate the true individual nutritional needs.
In this article, you will learn about different types of dietary reference intakes and the evidence behind how they can fall short in meeting many nutritional needs.
Types of dietary reference intakes (DRI)
Before we explore the shortcomings of standard dietary recommendations, let’s break down what different recommendations mean and are used for. These recommendations fall under the umbrella of dietary reference intakes (DRI), which are defined quantitative nutrient estimates for healthy individuals. Originally, only RDAs existed before the broader DRIs were introduced. They contain several other factors that can help estimate required nutrient intake. The most common DRIs include the following:
Recommended daily allowance/intake (RDA/RDI) and estimated average requirement (EAR)
The recommended dietary allowance or intake refers to the average amount of a given nutrient that will sufficiently meet the nutritional requirements of 97-98% of the population. Notice that the RDA does not define the levels of nutrients required for optimal health–only for sufficient health.
Setting up the RDA involves establishing an estimated daily requirement (EAR). To calculate RDA, statisticians calculate the standard deviation of the EAR, which is how much the numbers differ from the average EAR. Then, the standard deviation is multiplied by a factor of 2, then added to the original EAR value. The formula looks like this:
RDA = 2*SD+EAR
One major pitfall of this system is that if an EAR cannot be set due to a lack of relevant data, experts won’t set an RDA. For this reason, enzymes and probiotics do not have an RDA set because no data exists to estimate them adequately. However, numerous studies have shown that these are beneficial and should be consumed regularly.
Adequate intake
Adequate intake (AI) is set when insufficient evidence exists to establish a standard RDA. AI values can be calculated from experimentally derived approximations. Alternatively, experts create them based on general observations of the average nutrient requirements of the overall population.
AI is more geared towards outlining estimations for individual intake because it does not require the same statistical calculations as the RDA. For example, the nutritional content estimations of mother’s milk represent one of AI’s most prominent uses to determine infants’ nutritional needs. The AI for the mother’s milk is set to the average intake of milk estimated to keep infants healthy. For larger infants, the real requirement may exceed AI, and for smaller ones, it may dip below the standard AI recommended.
Tolerable upper intake level (UL)
The tolerable upper intake level is defined as current data present as the highest tolerable amount of a certain nutrient. It is believed that if intake rises above the UL, the risk of adverse reactions to a certain nutrient will also increase. Some experts claim that no clear benefit exists when consuming nutrients above the RDA and AI limits. (However, some studies have established caveats and exceptions as we will cover later in this article.) As a result, they define the tolerable upper limits as “tolerable” rather than directly beneficial.
How the government came up with the RDA
Before the early 1910s, no one knew much about essential nutrients like vitamins and minerals. Thiamine, the first identified vitamin, was found to treat a condition known as beriberi, which causes listlessness, difficulty moving, and eventual paralysis.
Following the discovery of thiamine and its subsequent naming as vitamin B1, most other vitamins were discovered by the mid-20th century and found to treat different dietary deficiencies. For example, scurvy, which causes gum bleeding and loss of immune function, occurs due to vitamin C insufficiency.
Originally, doctors and researchers aimed to address diseases like beriberi and scurvy with dietary treatment approaches. For example, beriberi could be treated by simply substituting brown rice for white rice in the diets of Asian population groups. The brown husk of the rice contains high levels of thiamine, and patients who ate brown rice would see their beriberi symptoms resolve rapidly.
However, because chemically synthesizing vitamins is efficient and profitable, individual nutrient guidelines quickly supplanted whole-food guidelines. Additionally, the discovery of single-nutrient deficiencies resulted in food fortification, where food scientists would add extra vitamin or nutrient isolates. Global iodine deficiencies encouraged salt companies to add extra iodine to their salt.
The first official RDA guidelines were published in 1941, but they did not start serving as a reference point for food labeling until 1972. Food policy in the US became primarily focused on helping the general population meet the RDA for the most important nutrients. In 1980, the US government began systematizing specific nutritional recommendations, as well as setting ULs. The RDAs were then revisited and revised in 1993 when a committee of various nutritional experts began to see some of the obvious flaws within the RDA system.
Why the RDA tends not to be adequate to keep you healthy
Unfortunately, most people aren’t even hitting their RDAs each day. Coincidentally, chronic illness and obesity levels have skyrocketed in the past half-century. Often, the suboptimal nutrient levels contribute to the development of these health conditions.
Additionally, RDAs estimate nutrient levels for healthy individuals. Resultantly, in many cases, the RDA is not sufficient for people dealing with chronic illness and nutrient deficiencies. Here are four major reasons why the RDAs may not be sufficient for you if you suffer from chronic illness or poor nutrient levels.
1. Lack of personalization
RDAs are not personalized based on age, activity levels, and other lifestyle factors since they provide just a basic framework for children and adults. While experts have begun to consider the role the environment can play in suboptimal nutrition, the current RDAs do not have clear personalized guidelines. Their very nature prevents personalization, as they are calculated based on the average needs of 97-98% of the population.
Also, as mentioned previously, RDAs only provide guidelines for healthy individuals. Over 45% of the US population are currently diagnosed with at least 1 chronic illness, which means that RDAs cannot be fully applicable to roughly 148,275,000 million people.
The revision of RDAs and incorporating them into DRIs are beginning to address this problem. However, researchers must conduct more studies to generate more accurate nutrient intake estimates for people with chronic illnesses.
2. Food grown in nutrient-depleted soil
Many foods that used to be nutrient dense just don’t pack the same punch as they did 50 years ago. Soil quality has drastically plummeted globally, and foods that used to deliver optimal levels of nutrients no longer can. The use of nitrogen fertilizer can severely deplete soil nutrients, meaning individuals may need extra supplementation to make up for lost soil nutrients. Currently, there is no mention of specific recommendations regarding nutrient loss due to soil within the RDAs or DRIs.
3. Modern stress and toxic exposure deplete nutrient levels
The continual stresses and toxins presented by modern life, from food additives to work stress to pollutants, can continually deplete nutrient levels. Stress depletes several key nutrients, including magnesium, zinc, calcium, and niacin. Toxic exposure to substances like pollutants, mold, and pesticides can also severely deplete nutrients over time.
4. Preexisting suboptimal nutrient levels
As seen in the above chart, many people are already functioning on suboptimal levels of vital nutrients. Several different factors can also compound the deficiencies, such as poor digestion and nutrient absorption. Some people also cannot absorb or activate certain nutrients well due to genetic variants.
Some people may also experience poor nutrient synthesis, where they cannot produce enough of one nutrient. For example, individuals with an impaired microbiome may not be able to synthesize proper levels of vitamin B.
Consequences of suboptimal nutrient levels
In the past, nutritional science primarily focused on eliminating outright nutrient deficiencies. But recently, nutritional experts have begun recognizing suboptimal nutrient levels as a serious threat. They do not always cause debilitating symptoms the way outright nutrient deficiencies do, such as in the case of beriberi and scurvy. However, they can continually undermine your optimal well-being. The following are examples–not an exhaustive list–of frank nutrient deficiencies vs suboptimal nutrient levels.
Vitamin C
Severe vitamin C deficiency causes clinically presentable scurvy with characteristic symptoms such as bleeding gums, spots on the skin, and intense joint pain. However, less severe vitamin C deficiency can cause latent scurvy, which often presents as muscle pain, fatigue, and irritability. Because latent scurvy does not present as severe or distinct symptoms, it can regularly go undiagnosed and untreated.
Vitamin D
As with vitamin C, a clear distinction exists between severe vitamin D deficiency and suboptimal vitamin D levels. Rickets, a disease often caused by vitamin D deficiency, presents with many severe symptoms such as bone weakness. The clinical presentation of suboptimal levels is reduced in severity. Today, vitamin D fortification in dairy products has dramatically reduced severe deficiency.
Nevertheless, vitamin D deficiency can lead to chronic symptoms such as muscle weakness, fatigue, and bone pain. Low blood vitamin D also correlates with increased all-cause mortality, obesity, cardiovascular risk, dysregulated hormone levels, depression, autoimmune diseases, and many more conditions. Eventually, insufficient vitamin D can lead to hyperparathyroidism, calcium deficiency, and eventually osteoporosis.
When looking at vitamin D deficiency based on RDA, the NIH states that 1 in 4 people are deficient in the vitamin. However, one hospital found that roughly 94% of elderly patients admitted had serum levels of vitamin D below the optimal range defined at 80 nmol/L. Additionally, 11% of these patients presented with severe vitamin D deficiency. When the hospital staff had their vitamin D levels tested, a whopping 82% of them were found to be vitamin D-deficient.
Magnesium
Deficiency in magnesium, a very important mineral for overall health, is also rampant in today’s society. Magnesium deficiency often goes undetected, because serum magnesium levels do not always reflect the actual amount of magnesium present in cells.
Older studies based on RDA estimated that magnesium deficiency occurred in 15-20% of the population. However, recent research indicates that over half the US population has some form of low-level magnesium deficiency, which can still cause symptoms like fatigue, muscle tension, and nervousness. In the long run, low magnesium can affect cardiovascular health, play a role in diabetes development, interfere with sleep quality, and affect mental health.
Over 50% of the population does not even meet standard RDAs for magnesium. Furthermore, experts have called for a reexamination of the magnesium RDA, because many individuals require higher dosages to function optimally.
Calcium
Another highly important mineral, calcium, is reported as deficient in over 40% of the US population, although an estimated 20% of adults actually exceed the calcium RDA. Calcium deficiency can result in bone weakening and loss, and it can also affect the muscles because calcium plays a vital role in the signaling necessary for contracting and relaxing muscles.
However, increasing calcium supplementation or fortification alone may not always be beneficial. If the body is not equipped to properly absorb it, excess calcium can build up in soft tissues, leading to very serious conditions including cardiovascular diseases. Calcium works with vitamin D, vitamin K, magnesium, and several other nutrients. Resultantly, people trying to increase calcium intake without adding other nutrients that work with it can actually do more harm than good, especially if they already have too much.
Conclusion: Dealing with suboptimal nutrient levels is essential
While RDAs by design prevent outright nutrient deficiencies, they are often ill-equipped to provide insight on how to manage suboptimal nutrient levels, especially in people who havechronic illness. Also, if you’re already deficient in a nutrient, sticking to the RDA to address that deficiency is analogous to filling a dried up lake with a spoon.
To address some of these nutrient deficiencies, many practitioners prescribe an initial loading dose before stepping down to a maintenance dose. Researchers have already reported several positive examples of improved health that occurred due to increasing nutrient intake above the RDA. For patients dealing cardiovascular disease, magnesium supplementation doses of up to 800 mg, which is twice the RDA, have proven to effectively regulate blood pressure.
Additionally, pregnant women who struggle with vitamin D deficiency may benefit from taking up to 4000 IU, ten times the normal RDA. Many conflicting reports and recommendations exist for vitamin D’s RDA, which was set to 400 IU/day. However, many researchers and clinicians have realized that higher doses of vitamin D can benefit the body without causing adverse side effects.
While the current tolerable uptake level for vitamin D is set at 10,000 IU, many doctors have begun to prescribe doses far above that. For daily use, some clinicians recommend up to 15,000 IU per day. For those with severe deficiency, doctors may prescribe a vitamin D dosage as high as 50,000 IU per day for a couple weeks, before recommending patients retest.
If you’re looking to replenish your nutrient deficiencies, we recommend working with a qualified naturopathic doctor or nutritionist. They can order a test for you to determine your nutrient levels and prescribe an appropriate protocol to bring your nutrient levels into optimal ranges.
