DRIs and RDAs: Are nutrition guidelines worth consuming?

DRIs and RDAs: Are nutrition guidelines worth consuming?

In a world that is increasingly focused on nutrition and diet, it’s unsurprising that government-issued recommendations such as the Dietary Reference Intake (DRI) and the more commonly known Recommended Daily Allowance (RDA) have become something of a bible to health-conscious individuals. At first-glance, these comprehensive rules and guidelines seem remarkably clear and simple —a guide to what nutrients are essential to keep up to 98% of the population healthy — but as is so often the case with anything that sounds too good to be true, the notion of one-size-fits-all nutrition is flawed to say the least. While they are certainly useful as general guides, there are many reasons to look beyond DRIs and RDAs, particularly if you are committed to not just maintaining your health, but actively improving it.

What do DRI and RDA actually mean?

The DRI, which includes RDA values, is a set of dietary guidelines issued by the Institute of Medicine (IOM) of the National Academies in the United States. By identifying and quantifying the amounts of varying nutrients people need, the DRI aims to improve general health by providing easy-to-follow information on nutritional needs.

It is also used to:

  • guide policy in public institutions such as schools, prisons, and hospitals
  • regulate industries that produce food
  • and influence healthcare bodies and lawmakers.

An older edition of the RDA, not as frequently updated, is also used to create the nutritional labels we see every day.

So what’s the problem?

The fundamental issue with the notion of the DRI is that it grossly oversimplifies the complexity of human nutrition. By implying that eating well is as simple as ticking off boxes — 5mg of this, 0.4mg of that — it ignores what nutritional science is increasingly telling us: we all have different needs and attempting to meet them with one system is destined to fail. By trying to ensure that everyone attains merely the base level of a nutrient, there is a significant risk that systems such as the DRI give a false sense of security to those who might have very particular but no less important dietary needs.

For example:

  • men require significantly more zinc, magnesium, and vitamins A and C than women
  • older individuals struggle to absorb as much vitamin D or B-12 and have to compensate with diet
  • people with digestive disorders may have difficulty absorbing any number of a wide range of nutrients from food
  • pregnant and breastfeeding women need high intakes of B vitamins and almost twice as much iron as any other group.

While the DRI should, in theory, provide the nutrients that 97.5% of the population require to remain healthy, it is woefully inadequate at helping people identify their own individual needs.

Instead of promoting holistic nutrition, the DRI instead encourages a sort of collect-them-all style of diet where individuals must chase arbitrary numbers on the backs of boxes instead of investing in wholesome, unprocessed foods. After all, it’s much easier to convince yourself to buy a box of sugary cereal over nutritious granola when, according to the label, they both seem to have relatively similar quantities of some vitamins and minerals. Even worse, the information that is used to build those labels is, in many cases, decades out of date or based on inadequate or questionable data.

An oversimplified solution

One major problem with the way the DRI system divides nutrients into discrete items on a checklist is that it ignores the intricate web of interactions between what we eat, where we live, and our lifestyles and general health.

Nutrients depend on other nutrients

The DRI doesn’t accurately reflect that a number of nutrients rely on each other for effective absorption. The ability to absorb calcium, for example, is dependent on your levels of vitamin D. This is equally true of other nutrients such as vitamin C and iron.

Nutrients depend on your lifestyle and environment

Vitamin D, primarily tied to sun exposure, provides the most obvious example of the interplay between nutrition and environment, with individuals living in the northern hemisphere requiring vastly more of this essential nutrient in their diets in the darker, winter months. The DRI system, recommending a steady intake of vitamin D at the same level throughout the year, fails to adjust for this and many other seasonal and geographical variations in dietary needs.

Guidelines prevent deficiency but don’t promote good health

One of the things many people forget about the DRI is that it is actually designed to decrease incidence of nutritional deficiency, not promote long life and optimal health. Yes, if you follow the DRI for vitamin C there is little chance of you getting scurvy, but by the same token, you may not be ingesting enough to completely satisfy your needs. In fact, there is substantial evidence that the DRIs for some compounds such as vitamins C and D, and iodine may be too low, while others, such as for calcium, may be too high.

Dr. Paul Veugelers, Research Chair in Nutrition and Disease Prevention at the School of Public Health, University of Alberta, recently released a re-evaluation of the IOM’s calculations for the RDA of vitamin D, and made a very plausible argument that the correct value should be more than double its current amount.

An unsatisfying array of nutritional advice

Unfortunately, the problems with DRIs are merely a symptom of a larger issue within the medical community — nutritional information is relatively complex and opaque, and few are capable of providing it well. Even doctors, the foundation of individualized medical care, can be less helpful than you might hope.

A recent study from The Journal of the American College of Nutrition found that while 94% of internal medicine interns felt it was their duty to discuss nutrition with their patients, only 14% considered themselves adequately equipped to do so. Of the 40,000 hours that doctors spend in training, only a small proportion, an estimated 19 hours, is taken up by nutrition during medical schooling. And that number is getting smaller — in 2004, the average was 22.3 hours. The number of schools that meet the minimum standard of nutrition training is also waning. In 2004, the number was 38%; by 2009, it had dropped to 27%.

Part of the problem here is that many doctors simply don’t have time to keep up with the literature. A weighty 1.8 million academic papers are published every year, and while not all of them are medical in nature, such research hardly makes up a small proportion either. It is both unrealistic and unhealthy to assume that already-overworked general medical professionals can always afford the time to brush up on the latest research. Unfortunately, you’d be wrong if you assumed this dearth of knowledge only applies to family doctors either. A survey published in 2003 found that 84% of responding cardiologists did not know that low-fat diets could increase triglyceride levels in the blood, a risk factor for heart disease.

Because of their lack of training, doctors are prey to much the same problem as dietary guidelines: general recommendations and advice calculated on broad applicability to as many patients as possible tend to provide only the bare minimum of benefits while providing a false sense of security.

Reclaiming your nutritional freedom

As always, the best solution when faced with confusing, if not misleading, nutritional advice is to consider your own lifestyle, diet, individual needs, and health requirements, do your own research, and make your own informed decisions. While even the most cynical of us would admit that guides such as the DRI are attempting to improve general standards of nutrition, it is also true that basing your life around them to the exclusion of common sense and personal choice is a fool’s errand.

While doubtless comforting for their ease-of-use, broad dietary guidelines ignore the wide variations in what people need nutritionally — whether during different stages of life, due to illness or injury, or even due to specific genetic predispositions. These considerations might be a challenge to account for when creating nutritional policy, but perhaps that is simply a sign that nutritional education needs to be more nuanced and considered than it currently is.

Can supplements help?

If you’re concerned that you’re not getting everything you need from your diet, and think that the nutritional advice you’re receiving isn’t ideal for you, vitamin and mineral supplements offer an effective, simple, and safe way to top up on essential nutrients.

Antiaging Nutrition’s wide selection of high quality, scientifically developed vitamins, minerals, and other supplements offer you the ability to make your own nutrition decisions and put the focus back on your health as an individual, not as a series of numbers and percentages.