It’s the mid 1800s, and a plumbing revolution is underway in North America and the British isles. Urban areas are installing huge piped water systems, replacing the collection of water by hand from rivers and wells. But what material should be used to make the pipes? The very same from which the word ‘plumbing’ gets its name: lead. Lead is the miracle metal that keeps on giving. It’s affordable, more durable than iron, and is slow to corrode. The Ancient Romans used lead in their plumbing, and the Romans knew a thing or two about plumbing. What could possibly go wrong?
Estimates suggest that lead levels in drinking water during the 19th and early 20th centuries were hundreds of times higher than what is considered safe today. Physicians had known about the toxicity of lead for millennia, but didn’t fully understand the health risks until the early 1900s, when the pipes began to be replaced with those made from safer materials. Since then, we have expunged lead from most everyday items.
Lead is a heavy metal – a group of elements with high atomic weight that can be toxic to living organisms. Other heavy metals include mercury and arsenic, and while their use has been greatly limited, they are still a public health concern today. Detox treatments, which claim to rid your body of various toxic substances, often cite heavy metals as one of their targets. Proponents will warn you that your body is full of these metals and that their treatments can help remove them. As with much pseudoscience, such treatments are often loosely based on legitimate science, but lacking any evidence to actually back them up. Let’s take a closer look at heavy metals. How harmful are they really, and are there any proven ways to get rid of them?
Heavy metals include lead, mercury, arsenic, cadmium, and chromium. Though not as common as they once were, some level of exposure to heavy metals is pretty much inevitable. Heavy metals can enter the food chain through contaminated soil, and are also present in consumer electronics and industrial pollution.
Though it’s possible to be poisoned by a high enough dose of heavy metals, the main danger of these elements for most people is their long-term effects. Heavy metals are not easily metabolised or excreted by the body, which means they tend to stick around for a long time. This means that even very small amounts of heavy metals can have a significant health impact because the damage they inflict builds up over a long period of time. Lead, for example, is cleared from blood and soft tissues with a half-life of about 2 months, while it can take over a decade to clear 50% of lead absorbed by bone tissue.
Heavy metals harm the body in multiple ways, including by interfering with the function of enzymes and generating inflammation. The kidneys, liver and brain may be particularly affected, and research has linked long-term exposure to heavy metals with many chronic diseases including neurodegenerative, autoimmune and musculoskeletal diseases.
Chronic exposure to heavy metals is unquestionably bad for your health, but for the average person who is not exposed to a lot of heavy metals, are these elements something to be concerned about? It’s a little difficult to say – the existing data is not as detailed as we might like, and there are a lot of confounding factors to contend with.
We do know that there is probably no level of exposure to heavy metals that is not harmful to health. How harmful? According to one study, going from a blood lead level of 1ug/dl (which is lower than the level found in 90% of the population) to a blood lead level of 6.7ug/dl (only 10% of the population have a higher level than this) was associated with a 37% increase in mortality from all causes. However, most health authorities do not consider a blood lead level of below 5ug/dl to be a concern. A study of blood mercury levels, on the other hand, found no association with all cause mortality.
Such studies are subject to many confounding variables, because heavy metal exposure is linked closely to other impactful factors like diet and pollution. Many health experts argue that heavy metals are just not something that the majority of people should be concerned about – especially given that many people forgo even basic yet highly impactful health practices. However, we are ultimately in need of more data about the effects of low levels of these elements.
Much like radiation, there’s a limit to how much you can realistically reduce your exposure to heavy metals, as they are naturally occurring elements present throughout the environment. Animal products (especially fish and red meat), leafy vegetables and rice tend to contain the highest levels of heavy metals. Processed foods also tend to be contaminated with more heavy metals than unprocessed foods. Cooking can sometimes reduce the heavy metal content of the cooked food, provided cooking water is not heavily contaminated. It’s also worth pointing out that for healthy foods, the effects of beneficial compounds contained within are likely to far outweigh those of the tiny heavy metal content.
Air and water pollution are other potential sources of heavy metal absorption. If you live in an area where such pollutants are high, you could invest in air and water filtration systems, some of which are effective in reducing heavy metal contamination. Is it worth the money and effort? It’s impossible to say with the current data, but it’s likely to depend on the level of contamination and on individual health status.
We would be remiss not to mention that smoking and vaping both expose the user to heavy metals. However, if you’re already actively sabotaging your health in this way, heavy metals should be among the least of your concerns.
Now we come to the titular question. We previously put together a deep dive into how most ‘detox’ methods are not supported by scientific evidence. However, detoxification is a legitimate set of processes that take place in the body to metabolise and/or remove toxic substances, including heavy metals. It’s entirely reasonable to ask whether there are any ways of accelerating these processes, potentially reducing the burden of heavy metals in the body and reducing the risk of chronic disease later down the line. Let’s go through some of the most common claims about heavy metal clearance and see if there’s any evidence to back them up.
Chelation therapy involves injecting chemicals called chelating agents into the blood. These chemicals bind to heavy metals, which allows them to be cleared by the kidneys more effectively. Chelation therapy is used to treat heavy metal poisoning, and it does work. However, chelating agents are themselves toxic and must be administered with great care, as they can have dangerous side effects including death.
It might sound logical that chelation therapy should reduce risk of chronic diseases like cardiovascular disease and neurodegenerative disease, since heavy metal exposure is associated with these conditions. However, there is no such evidence to date, and most reputable health organisations do not support the use of chelation therapy for any purpose other than the treatment of heavy metal poisoning.
Supplements and Diet
Though much of it comes from animal models, there is evidence that certain nutrients can reduce the levels of heavy metals in the body. Essential metals like zinc, calcium and iron may compete with heavy metals for the binding sites of proteins. Vitamins B1, B6, C and E may act as non-toxic chelating agents, while their antioxidant properties protect against damage caused by heavy metals.
There are plenty of good reasons to ensure you are consuming enough of these nutrients, but how much (if any) of their benefits are down to heavy metal clearance remains uncertain.
While it may sound dubious, there is evidence that you can ‘sweat off’ some heavy metals. Research suggests that adults secrete more heavy metals in their sweat during strenuous exercise than they do in their urine.
Another study in 12 young, healthy participants compared the excretion of heavy metals in sweat during a sauna session and during exercise, and found that while both sweating methods resulted in heavy metal excretion, the concentrations of nickel, lead, copper and arsenic were higher in the sweat of treadmill runners than in sauna users.
Can you excrete enough heavy metals in this way to have a meaningful impact on health? Treadmill runners excreted lead at a concentration of 50ug per litre of sweat. If we suppose that your blood lead concentration is half of what is considered safe, then you would need to sweat about 2.5 litres in order to clear all of the lead in the blood, which would take about 2.5 hours of exercise for the average person. This would assume that the concentration of lead excreted in the sweat didn’t decrease with the blood concentration, and also doesn’t take into account the lead stored in the bones, which is most of it. Nevertheless, perhaps regular exercise or exposure to elevated temperature in a sauna could have a meaningful health impact via heavy metal removal. There are certainly plenty of other benefits to justify both sauna use and regular exercise for general health and wellbeing.
There are proven ways to reduce the absorption of heavy metals and perhaps help the body to excrete them faster. The dangers of heavy metal poisoning are undeniable. However, we should remember that for the quantities of heavy metals that most people are exposed to, the extent of the health impacts aren’t entirely clear, and the benefits of detoxification practices are even less so. We should be cautious about heavy metals within reason, but unless you work with them on a regular basis, you probably shouldn’t be losing any sleep over heavy metal toxicity.
Title image by Patrick Pankalla on Upslash
Getting the Lead Out: https://www.sciencehistory.org/distillations/getting-the-lead-out#:
Mechanism and Health Effects of Heavy Metal Toxicity in Humans: DOI: 10.5772/intechopen.82511
Effect of heavy metals on, and handling by, the kidney: https://doi.org/10.1159/000083981
Concentration of heavy metals in vegetables and potential health risk assessment in China: https://doi.org/10.1007/s10653-017-9909-6
Effects of processing of heavy metal content of foods: https://doi.org/10.1007/978-1-4615-4853-9_13
Removal of Heavy Metals during Primary Treatment of Municipal Wastewater and Possibilities of Enhanced Removal: A Review: https://doi.org/10.3390/w13081121
Dietary Strategies for the Treatment of Cadmium and Lead Toxicity: https://doi.org/10.3390%2Fnu7010552
Comparison of the Levels of Five Heavy Metals in Human Urine and Sweat after Strenuous Exercise by ICP-MS: http://dx.doi.org/10.4236/jamp.2016.42022
Excretion of Ni, Pb, Cu, As, and Hg in Sweat under Two Sweating Conditions: https://doi.org/10.3390%2Fijerph19074323