From Lab Results to Daily Dose: Understanding Contaminants in Supplements

SimpleLab offers a comprehensive suite of test kits for analyzing contaminants and minerals in supplements. But buying and using the test kit is only the first step in understanding the composition of your supplements. If you’ve received your results for one of our supplement testing kits, this blog post will lay out what to do next to figure out what the results mean for your daily exposure to minerals or contaminants.

Table of Contents:

• Comparing Results Directly
• Figuring Out Your Daily Dose
• Comparing Your Daily Dose
• Key Takeaways

Comparing Results Directly

In the US, we do not have direct regulations limiting contaminants in supplements to certain levels the way we do for drinking water, for example. The FDA regulates supplements as a category of food, which is more of a reactive process — the FDA can recall products after they’ve gone to market if they’re found to be unsafe or mislabeled, for example, but there are no distinct limits for contaminants like heavy metals in supplements that would prevent the products from going to market.

The European Union (EU), however, does have these kinds of regulations. As a first check, we can compare results for contaminants in supplements to the EU regulations directly. We’ll focus here on heavy metals as they are often tested in supplements and many of them have EU regulations—if you are interested in other contaminants, refer to the regulations directly as they cover a wide range of potential contaminants.[1]

EU regulations for certain contaminants in supplements (arsenic is not regulated):

• Lead: 3 mg/kg / PPM
• Cadmium: 1 mg/kg / PPM
• Mercury: 0.1 mg/kg / PPM

For example, let’s say you receive results back that show your supplements have 20 ug/kg (PPB) lead. Note that these are slightly different units than the regulations above so we’ll need to do a quick conversion: 20 ug/kg * 1 mg/1000 ug = 0.02 mg/kg

The EU regulation for lead in supplements is limited to 3 mg/kg, which is much higher than the example result of 0.02 mg/kg. We will do more calculations and comparisons below, but as a first rough cut, this lead result does not raise any red flags.

Figuring Out Your Daily Dose

The results of supplement analyses for either minerals or contaminants (e.g., lead, arsenic, etc) are reported in concentration units — mass of target analyte per mass of supplement (e.g., ug/kg or g/kg). These units are describing the amount of a contaminant or nutrient in a certain amount of the supplement in total. 

However, there are a few steps to go to get from these concentration units to the total amount of a nutrient or contaminant that you are consuming in a day, which is often what people are most interested to know.

Information You Need

Before sending in your supplement sample, make sure to note the following information:

• The number of pills/capsules/tables/etc. (if the supplement is in discreet units)
• The total mass of said pills (or total mass of powder or other form of supplement)

You also need to know the number of pills in a daily serving (or mass of daily serving for supplements that are not in discreet units), though you can determine this at any time.

Calculations

In determining the amount of the nutrient or contaminant that you are consuming daily, the first thing you need to calculate is the mass of a daily serving of your supplement. The sample calculations below assume the supplement is in the form of a capsule (or some other discreet unit). For a powder or similar format, you simply need to determine the mass of the supplement consumed per day.

Data you already have:

• Number of capsules in your sample, for example 160 caps
• Mass of capsules in your sample, for example 100 g
• Number of capsules in a daily serving, for example 5 caps

1. First, calculate the mass of a single capsule:
   Mass of capsules in your sample / number of capsules in your sample
   (Example calculation: 100 g / 160 caps = 0.625 g/cap)
   
   
2. Next, calculate the mass of a daily serving:
   Number of capsules in a daily serving * mass of a single capsule
   (Example calculation: 5 caps/day * 0.625 g/cap = 3.125 g/day)
   
   
3. Now we can use your results to determine the mass of the contaminant (or nutrient) that you consume per day.
   Concentration of contaminant/nutrient * mass of daily serving
   (Example calculation: Say your report shows that your supplements contain 20 ug/kg lead
   which = 0.02 ug lead/g supplement
   0.02 ug lead/g supplement * 3.125 g supplement/day = 0.0625 ug lead/day

So in this example, we have determined that an analytical result of 20 ug/kg lead in the supplement resulted in the daily consumption of 0.0625 ug of lead. This information alone may be enough for some folks! For others, a basis for comparison is necessary.

Comparing Your Daily Dose to Benchmarks

After calculating your daily dose of a contaminant, you may need more context in order to understand if your exposure is potentially hazardous or not, especially if there are no benchmarks available for direct comparison (like the EU regulations discussed above). 

Most potentially harmful contaminants only cause issues when consumed above specific quantities. As mentioned, in the US, we don’t have regulations for contaminant levels in supplements so we look to recommended limits on daily intake of the contaminants and compare these limits to the daily dose of applicable contaminants in your supplements. 

We’ll focus here, again, on heavy metals as they are frequently tested in supplements and many have established daily consumption benchmarks. The FDA has benchmarks for daily lead consumption called interim reference levels, or IRLs, for children (2.2 ug/day) and women of childbearing age (8.8 ug/day).[2] Beyond these, we look to the California Proposition 65 Safe Harbor levels for very conservative daily consumption levels for lead, cadmium and arsenic (mercury does not have safe harbor levels):[3]

• Lead: 0.5 ug/day
• Cadmium: 4.1 ug/day
• Arsenic: 10 ug/day

As you can see, the lead safe harbor level is much more conservative than the FDA IRLs for lead, even the value for children (2.2 ug/day v. 0.5 ug/day). 

To refer back to our example, we calculated a daily lead consumption of 0.0625 ug lead/day for the example supplement that was tested. This is much less than all of the lead benchmarks we have — the safe harbor level and both IRLs. Though it would, of course, be ideal for there to be no lead in the supplement, this level is low compared to all available benchmarks and thus is not likely to present a health hazard.

Key Takeaways

• Contaminants in supplements are not directly regulated in the US.
• You need to make sure to record the number of capsules/tablets/etc. and their total mass before sending in your supplement sample.
• Once you receive your concentration-based results, you can do some calculations to determine the total mass of contaminants (or beneficial minerals) you consume in a daily serving.
• When they’re available, comparing your daily consumption of contaminants to established benchmarks is helpful in understanding if your exposure to contaminants via your supplements is potentially harmful.