Published on December 30, 2020

What’s the best nutrient level for health?

Lab test results often come with a set of numbers next to the result called a “reference range.” What does this mean, and does it represent the optimal range for health? Before we further discuss what might be “optimal,” let’s define the reference range and describe the system-specific nature of how nutrients work within the body.

What is a Reference Range?

A reference range, sometimes called “normal values,” is a set of numbers representing the range of typical results. Each individual lab can establish their own reference range by calculating the range of values (after excluding the highest and lowest values) among a sample of “healthy” patients from within the population the lab serves. Since each lab can create its own reference range, these ranges can differ between labs and geographic regions. Differences in patient population, operating conditions, sample collection, criteria for “healthy” individuals, and environmental conditions can cause variation in reference ranges. Reference ranges can even change within an individual lab over time through ongoing re-assessment of their normal testing population.

Labs can also use the reference range published by the manufacturer of a particular test method or the reference range from another local lab if they can verify that the published reference range represents the population the lab serves. For some lab tests, a consensus range or decision limit for treatment determined by a consensus group of medical experts is used instead of a reference range. For example, specific limits for cholesterol and glucose have been established to indicate when diagnosis and treatment are needed.

Does a Reference Range Indicate the Optimal Range for Health?

Simple answer: NO. A reference range indicates the range of typical results found in the population the lab serves but does not necessarily indicate the optimal range for health. For example, a lab’s reference range for vitamin D levels may be 20 to 80 ng/ml. While this is the range found in the lab’s testing population, this is NOT the range for optimal health. Rather, the reference range reflects that a large majority of the population does not have optimal levels for vitamin D.

Our scientists’ consensus panel recommends achieving at least 40 ng/ml (100 nmol/L) up to 60 ng/ml (150 nmol/L) for optimal health. This is based on overwhelming evidence about the association between vitamin D and many diseases, such as those illustrated on our Disease Incidence Prevention chart. As can be seen on this chart, the level of vitamin D at which 99% of rickets can be prevented is around 20 ng/ml (50 nmol/L). However, the risk of several other diseases, including multiple sclerosis, diabetes, and several types of cancer, are decreased when vitamin D levels are within the 40-60 ng/ml range. In fact, an even bigger benefit can be seen for cancer risk reduction at levels of at least 60 ng/ml.

Can “Optimal” Depend on the Desired Outcome?

Most nutrients have many different functions within the body, with response curves varying by system (such as skeletal vs immune) and nutrient responses varying with basal nutrient status, dose/intake, and system-specific sensitivity. The above is an excellent example for vitamin D – while the skeletal benefits of vitamin D (to prevent rickets) are seen at much lower levels, cancer prevention benefits are seen at much higher levels.

The way the body responds to most nutrients can be described by an ‘S’ shaped curve, or Sigmoid Response Curve, such as described in the Nutrition and Medicine Webinar by Dr. Robert Heaney (from approximately 10:36 to 18:35). Understanding this curve is important to be able to define the appropriate amount of the nutrient that reduces risk of a specific health outcome.

A few key points to consider:

  • The benefit rises as intake rises up to a certain point (away from deficiency, and before toxicity).
  • Within the curve are null response regions; too low will not be enough to produce a response, and too high will not produce any further response (response has been maximized).
  • The same dose may produce a significant response in one system and a null response in another.

Click to Enlarge & Print

This next chart builds on this concept by illustrating that there may also be different, system-specific responses of a given nutrient to a given intake or dose. Let’s imagine the curves in the chart below represent the need of vitamin D to carry out specific functions within the skeletal system (curve A), respiratory immune response (curve B), and cancer response (curve C). The same change in a given intake will have varying effects in each system, as shown by each curve. When considering a specific intake, that same dose may produce a measurable response in one system (as illustrated by the green arrow with curve ‘A,’ representing the skeletal system) and a null response in another system (as illustrated by the red arrow with curve ‘C,’ representing the cancer response).

Click to Enlarge & Print

In conclusion, when determining an optimal intake or range for a specific nutrient, it is important to also consider the desired outcome or health benefit.

Other Nutrients Follow a Similar Concept

Omega-3 testing provides another example of the difference between the reference range and the optimal range for health. The lab used by GrassrootsHealth for the Omega-3 Index has a reference range for Omega-3 Index of 2.9% to 12.9%. However, studies show that an Omega-3 Index of at least 8% is important for heart, brain, joint, and eye health. The lab’s reference range for the omega-6 to omega-3 ratio is approximately 1.5 to 7.3 and for the AA to EPA ratio is approximately 2.6 to 62.0. However, the desirable ranges for health are generally between 3 and 5 for the omega-6 to omega-3 ratio and between 2.5 and 11 for the AA to EPA ratio. Some experts recommend an even lower AA to EPA ratio (1 to 3) for the resolution of cellular inflammation. (Click here for more information on Omega-3 testing including what these ratios mean).

For many nutrients, we are gathering the data and working with the scientists to determine and achieve an expert consensus on the optimal range of each for overall health. By testing your nutrient levels and completing the health questionnaire, YOU are helping to achieve that goal for yourself and others.

Do You Have Specific Health Concerns?

By joining the GrassrootsHealth projects, you are not only contributing valuable information to our study, but you are also gaining knowledge about how you could improve your own health through measuring and tracking your nutrient status, and educating yourself on how to improve it. Do you know what your status of vitamin D, omega-3s, and other essential nutrients is? Could your levels be improved? Test now to find out!

We now have a NEW GIFTING SERVICE that allows you to quickly send ‘Gift Cards’ to friends, family and coworkers who you consider might need immediate access to testing, and to Claim the Joy of Your Health TODAY. Give the gift today!

What does the Research Say about Vitamin D & COVID-19?

It’s TIME to start saving lives! If you can help PREVENT the majority of the death, it’s time! What’s it costing you/us not to take action NOW?

There is much published research that supports a clear link between vitamin D and COVID-19 showing that higher vitamin D levels are related to:

a decreased risk of testing positive for COVID-19

increased viral SARS-CoV-2 RNA clearance

better clinical outcomes among patients with COVID-19

less severe COVID-19 disease

decreased risk of death due to COVID-19

Be sure to educate yourself on the benefits and importance of vitamin D for immune health, and take steps to ensure you and your loved ones are getting enough.

You can review all of the COVID-19 and immune health information we have shared on this page.

What Does it Take YOU to Get Your D to 40 ng/ml (100 nmol/L)?

Did you know your health could be greatly affected by making sure you have a vitamin D level of at least 40 ng/ml (100 nmol/L)? Help us help you.

STEP 1 - Do you know what your vitamin D level is? If not, be sure to test today to find out.

STEP 2 – Determine your target level. Are you at your target level? Experts recommend a level of at least 40-60 ng/ml (100-150 nmol/L).

STEP 3 – Need to boost your level? Use the D*calculator to see how much vitamin D it may take to reach your target. Opt for the Loading Dose for a quicker boost.

STEP 4 – Optimize how your body absorbs and utilizes vitamin D with co-nutrients and these simple steps.

STEP 5 – Re-Test! This is an important step to make sure you have reached your target level, and to ensure you are not taking too much! Re-testing after 3-4 months is recommended.

STEP 6 – Adjust, Repeat…

Give your immune system the nutrients it needs to support a healthy you and protect yourself from unnecessary diseases, especially COVID-19.


The first Randomized Controlled Trial on vitamin D and COVID-19 has shown a 96% lower risk of ICU admission for those receiving vitamin D (as 25(OH)D to quickly boost vitamin D blood levels) along with the standard treatment, compared to those receiving standard treatment alone.

These results support many previous observational studies showing a relationship between vitamin D levels and intake and COVID-19 severity.

Review the Latest Nutrient Research for COVID-19

GrassrootsHealth Nutrient Research Institute has launched the new Immune Boost project with the use of our myData-myAnswers nutrient health system that nearly 15,000 people are already using for their health. Specific markers that influence immune health are suggested for testing as part of this project including:

  • Vitamin D
  • Omega-3 Index
  • Essential elements magnesium, selenium, and zinc
  • hsCRP

Our goal is to demonstrate how one can use the Nutrient Research Model established by Dr. Robert Heaney to show the effect of vitamin D serum levels of at least 40 ng/ml (100 nmol/L) on risk reduction for all ethnicities in the population. Status and intake of other nutrients will also be analyzed for any type of relationship to immune status and symptom severity. Join the project today!

Please let us know if you're interested in helping sponsor this project.

CLICK HERE for updates and new information about the project.

Through GrassrootsHealth Nutrient Research Institute, you can also test your essential elements magnesium, copper, zinc and selenium, toxins such as lead, mercury and cadmium, as well as your omega-3 levels, inflammation levels and thyroid stimulating hormone (TSH) level. Find out your levels today! Log on to the test selection page (click the link below) to get your tests and see for yourself if your levels can be improved.

Make sure you track your results before and after, about every 6 months!

Click Here to Access the Test Page

How can I track my nutrient intake and levels over time?

To help you track your supplement use and nutrient levels, GrassrootsHealth has created the Personal Health Nutrient Decision System called

For each specific supplement, you can track what days you take it, how much, and many other details.  This will help you know your true supplemental intake and what patterns of use work for you to reach and maintain optimum nutrient levels. Check it out today!