Heavy metals are naturally occurring environmental elements. While some heavy metals are essential for our health in trace amounts, excessive exposure to particular types can lead to serious health risks. As consumers, it's crucial to be aware of high-risk foods and understand the potential health implications associated with heavy metal consumption. In this blog article, we will explore different types of heavy metals, identify foods commonly high in them, discuss the health risks associated with their ingestion, and finally, how to reduce your heavy metal load.
Understanding Heavy Metals
Heavy metals are elements with a high density and atomic weight. Common types of heavy metals include lead, cadmium, mercury, arsenic, and chromium. While some heavy metals are essential for various physiological processes, such as iron and zinc, excessively toxic heavy metals can harm human health.
When manufacturing medicines to be listed on the Australian Register of Therapeutic Goods (ARTG) and adhering to strict Good Manufacturing Practices (GMP), the following heavy metals are explicitly tested for:
More about this later!
Foods High in Heavy Metals
a. Seafood: Some fish and shellfish species can accumulate high levels of mercury, giant predatory fish like sharks, swordfish, and king mackerel. Mercury enters the ocean through industrial processes and can be converted into methylmercury. This highly toxic form accumulates in seafood. (1)(2)
b. Rice and Grains: Cadmium is a typical heavy metal found in rice and grains, with rice being particularly susceptible due to its ability to absorb cadmium from contaminated soil. Regular consumption of cadmium-contaminated rice can lead to kidney damage and bone-related issues. Despite being healthier than white rice, brown rice contains more inorganic arsenic. (3)
c. Leafy Greens: Certain leafy greens, including spinach and kale, may contain elevated levels of heavy metals like lead and cadmium. These metals can be absorbed from the soil and water used for irrigation.
d. Chocolate: Cocoa plants can accumulate heavy metals from the soil, and studies have detected cadmium and lead in various chocolate brands, with darker chocolates generally containing higher levels. Oh no! Really dark chocolate is my favourite! (4)
e. Coffee Beans: While coffee beans have relatively low levels of heavy metals, the soil and water quality in coffee-growing regions can impact heavy metal contamination in coffee. (5)
f. Herbs and Spices: A study by CHOICE found that out of 70 supermarket spice samples they tested, 100% had traces of lead and 86% contained arsenic. (6)
Heavy Metals in Baby and Toddler Foods
An interesting study examined rice-based products for children bought in Melbourne, Australia. 75% of products tested had concentrations of inorganic arsenic exceeding the European guidelines for babies and toddlers! Beyond this, the highest arsenic concentrations were from US-made rice foods (high groundwater contamination), and the lowest were from China-made rice foods. Brown rice products had higher arsenic levels. (7)
Unfortunately, buying organic rice based baby food does not avoid heavy metal exposure.
Risks Associated with Heavy Metal Consumption
a. Neurological Disorders: Mercury and lead affect the central nervous system, leading to neurological disorders, cognitive impairment, and developmental delays, especially in children.
b. Kidney Damage: When ingested excessively, cadmium can accumulate in the kidneys and cause kidney damage over time.
c. Cardiovascular Issues: Arsenic exposure has been linked to cardiovascular problems, including an increased risk of heart disease.
d. Gastrointestinal Problems: High levels of heavy metals in the diet may lead to gastrointestinal issues, such as stomach pain, nausea, and vomiting.
e. Developmental and Reproductive Disorders: Some heavy metals, like mercury and lead, can cross the placenta and affect fetal development, potentially leading to congenital disabilities and developmental disorders.
It is important to note that by following a well-balanced diet and lifestyle, you are unlikely to experience these adverse effects.
Regulation of Heavy Metal Levels
Each country has its own body. Food Standard Australia New Zealand (FSANZ) is the responsible body in our country. A long list of different 'cutoffs' are provided for various foods (8). It is important to remember that testing the vast number of food sources available to consumers is impractical and occurs occasionally rather than as a controlled process required to release a batch of food to supermarkets. Many of the foods high in heavy metals are also imported from overseas. This means the foods you consume are not guaranteed to be below the set limits for heavy metals.
What about sports or nutritional food supplements (powdered forms like pre-workout powders or 'greens' powders)? These fly under the radar to some extent as they are not regulated as medicines in Australia. They are not held to the same standard.
ARTG-listed medicines are subject to different legislation. Herbs and herbal extracts, just like spices, may contain traces of heavy metals. The difference is that when producing a therapeutic medicine, the raw ingredients are tested to ensure compliance AND each batch of the final product is tested to ensure strict standards are met. This is part of the GMP process and required of Therapeutic Goods Administration (TGA) registered facilities in Australia when producing listed or registered medicines. Here is what the certificate of analysis heavy metal testing section for one of our products looks like:
It's nice to know what you are getting is compliant and not going to pose a health risk from heavy metals!
Reducing Heavy Metals in your Body
A 'heavy metal detox' programme involving chelation is not required for most people. If you have reason to think you have had very high exposure, it is best to discuss it with your doctor. Otherwise, try the following:
- Reduce consumption of foods known to be high in heavy metals, e.g. large predatory fish.
- Avoid sites of environmental pollution at industrial workplaces such as metal mining, foundries and smelters.
- Rinsing produce like vegetables can remove some but not all of the heavy metals (e.g. lead) (9).
- Brown rice should be rinsed and boiled in extra water (e.g. 6x the rice amount) followed by draining. Rice-based products should be reduced in infants.
- When consuming supplements containing herbs, ensure they are produced via a certified GMP manufacturing process. Additionally, listed medicines like ours, require even higher standards than many supplements you can buy online! Opt for ARTG-listed medicines/supplements in Australia.
- High-intensity exercise promotes the mobilisation and excretion of some heavy metals via sweat (10).
- Infrared sauna: there isn't currently sufficient research, but there is plausible rationale and some successful case studies. Regardless, regular sauna use has been associated with increased longevity! (11)
- Consume a balanced diet containing fruits, vegetables and other antioxidants to enhance detoxification.
- Time: by reducing exposure and giving your body time, many heavy metals are excreted, e.g. via the urine. This can take many months or longer.
In conclusion, heavy metals are a cause for concern, but it is not possible to avoid them altogether. Small amounts can be consumed without any significant adverse effects.
Awareness of high-risk foods and reducing occupational heavy metal exposure is essential. While regulatory authorities strive to set safety standards for heavy metal levels in food, consumers also play a vital role in minimising their intake and optimising detoxification and excretion processes. Medicines manufactured to GMP standards and especially those listed on the ARTG in Australia maintain strict compliance with heavy metal testing.
- Bosch AC, O'Neill B, Sigge GO, Kerwath SE, Hoffman LC. Heavy metals in marine fish meat and consumer health: a review. J Sci Food Agric. 2016 Jan 15;96(1):32-48. doi: 10.1002/jsfa.7360. Epub 2015 Sep 7.
- Di Bella C, Traina A, Giosuè C, Carpintieri D, Lo Dico GM, Bellante A, Del Core M, Falco F, Gherardi S, Uccello MM, Ferrantelli V. Heavy Metals and PAHs in Meat, Milk, and Seafood From Augusta Area (Southern Italy): Contamination Levels, Dietary Intake, and Human Exposure Assessment. Front Public Health. 2020 Jul 7;8:273. doi: 10.3389/fpubh.2020.00273.
- Winiarska-Mieczan, A., Jachimowicz, K., Kislova, S. et al. Cadmium and Lead Concentration in Drinking Instant Coffee, Instant Coffee Drinks and Coffee Substitutes: Safety and Health Risk Assessment. Biol Trace Elem Res 201, 425–434 (2023). https://doi.org/10.1007/s12011-022-03129-2
- Gu Z, de Silva S, Reichman SM. Arsenic Concentrations and Dietary Exposure in Rice-Based Infant Food in Australia. International Journal of Environmental Research and Public Health. 2020; 17(2):415. https://doi.org/10.3390/ijerph17020415.
- Augustsson A, Lundgren M, Qvarforth A, Hough R, Engström E, Paulukat C, Rodushkin I. Managing health risks in urban agriculture: The effect of vegetable washing for reducing exposure to metal contaminants. Sci Total Environ. 2023 Mar 10;863:160996. doi: 10.1016/j.scitotenv.2022.160996.
- Kuan WH, Chen YL, Liu CL. Excretion of Ni, Pb, Cu, As, and Hg in Sweat under Two Sweating Conditions. Int J Environ Res Public Health. 2022 Apr 4;19(7):4323. doi: 10.3390/ijerph19074323.
- Laukkanen T, Khan H, Zaccardi F, Laukkanen JA. Association Between Sauna Bathing and Fatal Cardiovascular and All-Cause Mortality Events. JAMA Intern Med. 2015;175(4):542–548. doi:10.1001/jamainternmed.2014.8187