- Micronutrient blood tests often do not correlate with the total nutrient status of the body, as they do not account for tissue and cellular levels.
- Indirect testing methods can help evaluate micronutrient status, but they may not be entirely accurate.
- Micronutrient supplementation without prior testing can be clinically beneficial, especially when there are symptoms of deficiency.
- Implementing a nutritious diet, taking a high-quality multivitamin, and healing underlying gut issues are likely more beneficial than testing for individual micronutrient levels.
Micronutrient tests are popular for their potential to show the exact levels of important vitamins and minerals in the body. Many people believe that micronutrient deficiencies can help explain a wide array of health symptoms and underlying health conditions, which can be resolved with nutrient supplementation.
However, in practice, micronutrient testing may distract from the larger picture of your overall health, as they provide a very granular look at your health status. Additionally, micronutrient blood tests often do not correlate with the actual nutrient status of the body, as they do not look at levels stored inside the body’s tissues and cells.
Some tests, such as intracellular micronutrient testing, try to resolve this issue but can still be unreliable and expensive.
As multiple micronutrient deficiencies often co-exist due to underlying risk factors like poor diet and GI disorders, it is likely more important to address your overall wellness rather than test for every single micronutrient level. A whole-foods nutritious diet, along with a high-quality multivitamin, often provide enough nutrients in order to avoid deficiency.
After establishing a sound health foundation, your doctor can help you identify any residual symptoms and assess for a suspected micronutrient deficiency. In most cases, micronutrients can be supplemented without the need to run a blood test.
What Does Micronutrient Testing Involve?
Micronutrient testing measures the levels of important vitamins, elements, and minerals in the body, most often through blood, urine, or hair analysis. These nutritional powerhouses assist in the body’s many biochemical reactions, including metabolism, hormone production, immune system function, bone development, and energy production.
Some commonly tested micronutrients include:
- B vitamins (B1, B2, B3, B5, B6, B9, B12, choline, and biotin)
- Vitamins A
- Vitamin D
- Vitamin C
- Vitamin E and K
Note: Micronutrients are not to be confused with macronutrients, which are frequently assessed during dietary counseling. Macronutrients include carbohydrates, fats, and proteins and are required by the body in a much larger quantity. They are important for proper growth, energy production, and overall functioning of the body.
Micronutrient testing panels often include a macronutrient assessment in order to evaluate individual amino acid and fatty acid levels in the body.
The Different Types of Micronutrient Testing
Sodium, potassium, and calcium are often checked during routine blood work with a comprehensive metabolic panel (CMP). This panel assesses basic metabolic functions in the body, like blood sugar levels, liver health, and electrolyte balance. A CMP and complete blood count (CBC) can also indirectly assess b vitamin, zinc, and iron levels in the body.
A CMP and CBC are frequently used in conventional and functional medicine, and are the most common way to assess basic micronutrient status. However, they offer a very small piece of overall micronutrient status.
Comprehensive micronutrient testing is much more extensive and assesses a much wider profile of vitamins, minerals, and trace elements that are not evaluated for during routine blood work. However, these panels are often offered by private laboratories and come with a significantly higher price point.
The most popular method of micronutrient testing is checking serum blood levels, but some companies offer panels that test nutrient metabolites in the hair and urine as well.
Is Micronutrient Testing Helpful?
In all reality, micronutrient testing may not be as clinically helpful as we may hope. Micronutrient blood levels often do not correlate with the actual nutrient status in the body’s organs and tissues.
For example, zinc deficiency is thought to be quite common in the general population. However, blood levels of zinc are not linked to health outcomes, as only a very small amount of zinc is stored in the blood.
Additionally, there is not a one-to-one relationship between dietary intake and micronutrient blood levels. Disrupted nutrient absorption in the GI tract, transportation into body tissues, and urinary or fecal excretion are not accounted for when checking micronutrient blood levels.
Hair and urine testing may be even more unreliable, as they only evaluate how much of a nutrient is excreted, not the amount stored in the body. If someone shows a high level of a micronutrient on a urine or hair analysis, it could potentially indicate a nutrient excess in the body.
However, it is equally likely that they have an underlying condition, like autoimmunity, that causes increased utilization and excretion of micronutrients. In this case, high levels in the hair and urine would actually indicate a deficiency in the body.
As you can see, micronutrient test results are difficult to interpret and may give little indication as to the body’s true nutrient status.
Ideal Nutrient Levels May Vary
Additionally, everyone probably has different micronutrient requirements, based on various factors such as:
- Chronic illness
- Certain medications
Using laboratory reference ranges to decide what the “best” micronutrient level is for someone does not give a complete picture of the patient and their individual needs. Assessing for underlying risk factors and looking at clinical signs and symptoms of deficiency is likely more telling of low nutrient levels in the body.
For example, the magnesium requirement for an active 10-year-old child who consumes healthy foods is going to be vastly different than that of a 60-year-old smoker who is on a fast food diet and takes a proton-pump inhibitor.
It’s worth noting that there are certainly still times when specific micronutrient tests can be helpful as one piece of the puzzle.
Let’s take a further look into some of the research behind testing for individual micronutrients.
Magnesium deficiency is becoming more common, partially due to the declining nutrient content of our foods . Aging, menopause, digestive disorders, and chronic PPI use are also common risk factors for magnesium deficiency .
Chronically low levels of magnesium are linked to a higher risk of mortality from any cause. It is also associated with poor glucose control, migraines and cardiovascular disease [3, 4, 5, 6, 7]. Additionally, magnesium deficiency may cause a wide array of symptoms, including:
- Muscle tension
- Decreased calcium and potassium levels
Despite being the most common way to measure magnesium status, blood levels have low sensitivity in detecting magnesium deficiency, and 50% of those who test within the “normal” range have a clinical deficiency [2, 8].
Intracellular testing that looks at magnesium levels inside the red blood cells is the preferred predictor of magnesium status but is still lacking in research to be considered a reliable method .
Fortunately, supplementation of magnesium in the presence of symptoms or suspected deficiency can lead to improved health outcomes. Magnesium supplementation is associated with clinical improvement in many conditions, including:
- Blood sugar dysregulation
- Insomnia and poor sleep quality
- Head injury recovery
So even though magnesium testing may not be sensitive in detecting a deficiency, supplementation is likely helpful in resolving related symptoms and conditions.
B vitamin deficiency is widespread as an improper diet, alcohol use, stress, malabsorption disorders, and pregnancy can all lead to decreased b vitamin levels. Common symptoms of general B vitamin deficiency include:
- Depression and anxiety
- Glossitis (inflammation of the tongue)
- Brain fog and memory loss
- Hair loss
Folate and cobalamin (B12) are most frequently checked through blood levels to assess for anemia. However, serum test results may be inaccurate and can miss a true deficiency. For example, serum folate levels are significantly influenced by food intake, and eating prior to blood work can easily mask a folate deficiency.
Measuring homocysteine levels is a frequent and indirect way to evaluate folate, B12, and B6 levels [9, 10, 11, 12, 13]. Homocysteine is an amino acid that is naturally created in the body and can become toxic to the nervous and cardiovascular systems at high levels. Homocysteine is broken down into a non-toxic form by folate and vitamin B12, and elevated homocysteine levels are associated with a folate and/or B12 deficiency [9, 10, 11, 12, 13].
Elevated homocysteine is linked to certain cardiovascular disorders, like stroke, heart failure, and coronary artery disease, and supplementation with folate and B12 has shown to significantly reduce homocysteine levels [14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24].
However, research shows mixed results on whether lowering homocysteine with B-vitamin supplementation actually reduces cardiovascular risk [25, 26, 27]. This discrepancy is likely due to an elevated homocysteine level being a sign of a larger problem, like poor diet, elevated blood sugar and lipids, and a lack of exercise.
Homocysteine testing may be a helpful piece of the puzzle. But a holistic perspective is often best when lowering cardiovascular risk, and reducing just one marker of heart disease is likely a too limited approach. Combining vitamin supplementation with a nutritious diet, exercise, and stress management is likely more effective in both reducing homocysteine levels and improving overall health.
Zinc deficiency symptoms include:
- Hair loss
- Diminished sense of taste and smell
- Keratosis pilaris (rash-like bump often located on the arms)
- Low immune function and recurrent illness
- Low white blood cell counts
While serum testing is effective in detecting broad zinc deficiency across a population, like in clinical trials, it may not be sensitive enough to detect deficiency on an individual level . Unfortunately, this likely makes serum zinc testing not highly beneficial for use in clinical practice.
Serum zinc levels are not a strong indicator of a zinc deficiency, as blood levels are unpredictable and fluctuate throughout the day. Furthermore, blood zinc levels represent a very minimal amount of the total zinc stored in the body. For these reasons, there does not appear to be a strong correlation between serum zinc levels and clinical disorders [28, 30, 31, 32, 33].
Alkaline phosphatase (ALP) is a body-wide enzyme that is routinely measured on a CMP. As zinc is a cofactor for ALP, low ALP levels are thought to be an indirect marker of low zinc status in the body. However, a systematic review found that ALP is not a significant indicator of zinc deficiency .
Thankfully, treating a suspected zinc deficiency or clinical symptoms with supplementation is likely beneficial even without taking a zinc test first .
As with other micronutrient deficiencies, emphasis should be placed on improving symptoms through a multi-faceted approach involving diet, a therapeutic-grade multivitamin, and resolving underlying conditions that contribute to impaired zinc absorption and utilization.
As copper deficiency is infrequent across the general population, testing copper levels without having a suspected copper overload is likely not very beneficial . However, true copper deficiency may be more common in those following a strict vegan or vegetarian diet, as animal protein helps the absorption of copper in the digestive tract .
Common symptoms of copper deficiency include:
- Low white blood cells
- Iron deficiency
- Memory loss
- Bone loss and fracture
However, most diets appear to provide all of the copper that the body needs, making testing for a deficiency likely unnecessary. Additionally, copper follows the same trend as zinc — blood levels can vary significantly between individuals, and are dependent on age, sex, and ethnicity [38, 39, 40].
Furthermore, elevated copper levels in the body may be associated with certain chronic diseases, like colorectal cancer, Alzheimer’s, bone fracture, and metabolic syndrome [41, 42, 43, 44]. As deficiency is uncommon and excess copper in the body may increase your risk for certain disorders, copper supplementation is probably not clinically helpful.
The goal should be on maintaining a proper balance between copper and zinc levels. Research shows that a 10:1 ratio of zinc to copper is likely most helpful for preventing adverse health conditions [45, 46]. Fortunately, most high-quality multi-vitamins already include copper and zinc dosages that maintain this ratio.
Connecting the Dots: Micronutrient Testing
Research supports that micronutrient deficiencies are common. However, testing blood levels comes with the disclaimer that results are likely unreliable at best. As serum blood levels don’t account for total micronutrient levels in the body, they do not appear to represent overall nutrient status.
Testing for every one of these potential deficiencies can be expensive, time consuming, and inaccurate. Additionally, everyone’s ideal micronutrient levels are different, based on age, sex, and underlying factors, like pregnancy. Assessing symptoms and risk factors of micronutrient deficiency is likely more clinically beneficial.
Poor diet and malabsorption are two leading causes of micronutrient deficiencies, making an isolated nutrient deficiency likely uncommon.
It is more important to treat the causes of poor nutrient status by improving your diet, taking a high-quality multivitamin, and healing your gut to improve nutrient absorption. A healthcare provider can then help assess your residual symptoms for overt nutritional deficiencies.
If you are interested in addressing any potential micronutrient deficiencies, our clinic is currently accepting new patients. Additionally, you can learn about healing the gut and improving nutrient absorption in my book, Healthy Gut, Healthy You.