- Like vegetables grown in the soil, there are heavy metals in greens powders
- Heavy metals are only dangerous above a certain level
- Important to have 3rd party testing to ensure safe levels
Greens powder–a drinkable, smoothie-able powder that concentrates the most essential nutrients from fruits and vegetables–has taken the world by storm.
But there can be serious problems.
Many types of powders can be contaminated by heavy metals, including highly poisonous metals such as lead and cadmium.
Ironically, healthy food might poison you, but here we are. Here’s everything you need to know to stay safe!
Heavy metals are just metals with a relatively high density. Many metals qualify as heavy, although several of the most important ones do not.
Iron, for example, is not heavy metal, although it’s probably the most significant metallic element for your health.
Aluminum, too, is very light, and aluminum consumption has been linked to Alzheimer’s and other degenerative neural diseases. So we may focus on heavy metals, but that doesn’t mean other metals are safe.
Some heavy metals commonly present in the earth are nickel, zinc, and manganese. These are pretty much inactive in small quantities.
People with a severe nickel allergy may be more sensitive than others, and very large amounts of these metals can be harmful to anyone, but small doses are common and safe.
…most dangerous heavy metal that’s commonly found is much less famous: it’s cadmium
Other heavy metals, however, are quite dangerous. For example, copper is somewhat toxic, so copper cookware usually has a lining of a safer metal, such as tin. Lead is famous for being dangerous, and it’s cumulative, meaning the lead you ingest now will add to the lead you consumed ten years ago and could add up to a larger, more dangerous dose.
But the most dangerous heavy metal that’s commonly found is much less famous: it’s cadmium. Cadmium is a strong carcinogen, much worse than lead, although it causes more damage when inhaled than when eaten.
Mercury is also a heavy metal and is by far the most toxic metal of all, but it’s not commonly found in soil or vegetables; mercury risk mostly comes from fish and ocean life, so that we can ignore it for the topic of greens powder.
Arsenic is another toxic heavy metal, but it’s also found more in water than in soil or plants.
Proposition 65 is a bill passed in California, but its effects are much more far-reaching. The bill requires companies to provide a warning if they contain even one of a long list of chemicals.
Chemicals that are on the list have been shown to either cause cancer or cause reproductive or developmental harm. Reproductive harm can mean various things, from compounds that can make either men or women infertile to compounds that can harm a developing child in the womb.
Proposition 65 does not require that a label must say what material is actually flagged.
Many organizations can put something on the list: two Californian committees (the Carcinogen Identification Committee and the Developmental and Reproductive Toxicant Identification Committee, aka CIC and DARTIC), the EPA, the FDA, the US’s National Toxicology Program, and others.
Unfortunately, Proposition 65 does not require that a label must say what material is actually flagged.
Most warning labels say something like, “WARNING: This product contains chemicals known to the state of California to cause cancer and reproductive harm.”
That doesn’t tell you whether it contains lead (a common solder used to connect and attach parts on circuit boards in many electronic devices) or Benzedine-based dyes. Or whether it contains aspirin or alcohol, which are also on the list, mostly because pregnant mothers should not take either.
Many products sold outside of California and even outside of the United States still have Proposition 65 labels because it’s more expensive for companies to print some items with the labels and some without.
Although the labels required by Proposition 65 are often useful, they’re missing some of the most critical information.
They may not tell you what is actually the contaminant. Local businesses that don’t sell to California may not label the problems, and small businesses starting out may not have begun to label yet.
Here is a link to more information about Prop 65, a government resource from the state.
It should be fairly evident that heavy metals in vegetables are not a good thing, but in case it’s not, here’s some more information. Heavy metals such as cadmium have been strongly linked to cancer. It can also cause kidney disease and fragile bones, which builds up over time.
Lead is the most famously dangerous heavy metal, except for mercury. Lead also builds up in the body over time–it only leaves very slowly over decades. However, consistent exposure to minimal amounts of lead can still add up to a dangerous dose. Lead can cause joint pain, nausea and vomiting, learning disabilities, loss of appetite, irritability, headaches, and more.
These compounds were studied, along with many others, both in the soil and in various crops, and published in Frontiers of Environmental Science.
They found that there was much more lead than cadmium in their local soil.
They tested the amounts absorbed by coriander, onions, and tomatoes and found that coriander absorbed most of both elements. While tomatoes absorbed much more lead than onions, onions absorbed slightly more cadmium than tomatoes.
All of the amounts were comparatively small. The most significant quantity was in coriander, where the weight was two-millionths lead. Every other crop was less than one-millionth of both lead and cadmium.
(It’s written as mg/kg, or milligrams per kilogram. Since a kilogram is a thousand grams and a gram is a thousand milligrams, there are one million milligrams in a kilogram.)
The study also examined several other metals, but lead and cadmium are the most important since they are the most dangerous.
The point is this: some soil is highly polluted with heavy metals, and crops grown in that soil may absorb some of the metal. Therefore, anything made with those crops, including greens powder, will also be contaminated.
This is a significant risk, and it’s not just people talking. There have actually been heavy metal contaminants found in some powders.
So, let’s talk about that. A Consumer Lab test in 2016 found lead in four out of 13 products tested, almost one-third contained traces of heavy metals. One of them was also contaminated with cadmium, and another with arsenic.
A more recent test done in 2019 only discovered one product contaminated with lead out of ten tested. That’s still not a very good result, though. So, to say that now only 10% of powders are contaminated, instead of the previous 30%, is taking “looking on the bright side” a little far.
The dose makes the poison, and the FDA has recommended tiny amounts of technically safe lead. The recommended dose for children is at most 2.2 micrograms a day, and for adults, 8.8 micrograms.
A microgram is one-thousandth of a milligram, which, as already mentioned, is a thousandth of a gram, a thousandth of a kilogram. So that makes a microgram a billionth of a kilogram.
The FDA also recommends a dose of fewer than ten parts per billion of arsenic in drinking water. That’s not a daily amount, but people are advised to drink about 3.5 liters of water a day. This is because a liter of water weighs a kilogram. Ten billionths of 3.5 kilograms are 35 micrograms, so that’s the very maximum daily “safe” dose given by the FDA.
Cadmium is even harder to calculate. Regulations require food and drugs to contain less than 0.1 parts per million cadmium, and people usually eat about 1.5 kilograms of food per day.
So a basic calculation would suggest that an acceptable level of cadmium is 0.15 millionths of a kilogram, which is 0.15 milligrams or 150 micrograms, but that seems unreasonable. Remember that food isn’t really expected to have the full 0.1 parts per million, though, so these calculations are an extremely high estimate.
The FDA does not regulate dietary supplements, meaning nobody checks them for heavy metals. That’s why it’s important to ensure you find a powder that a third party verifies.
Consumer Labs is one company reviewing powders to ensure they’re not contaminated. And reviewing companies like them and Consumer Reports can be a way to find reliable products.
But you can also find seals from testers on the products themselves. Naturally, some poor-quality products may add seals from testing companies because they can’t get the real ones, so research which has certified your greens powder.
One of the most reliable marks to look for is NSF, the National Sanitation Foundation. They ensure not only the product but also the process that manufactures it.
It doesn’t matter exactly who’s certified your process, but you have to make sure someone did, and it’s someone reliable. Be careful out there!
Christine VanDoren is an NSCA-certified personal trainer and ACE nutritionist, she started spending her time training in the gym and online and creating content for Edge of Longevity, all of which is about how she has worked to better herself, and in turn, hopes to help others better themselves too. She believes the healthier one is, the happier one can be, and she hopes to spread that happiness to people in every country, every lifestyle, of every age and gender, and ethnicity.