Seaweed has surged in popularity as a health food and an ingredient in Asian inspired dishes, thanks to it being super tasty and nutrient rich with vitamins, minerals, and antioxidants. However, while it can be a beneficial addition to your diet, there’s a darker side to seaweed that you should be aware of: the potential presence of heavy metals.
Unfortunately, heavy metals can accumulate in marine environments due to pollution from various sources, the main culprits being industrial runoff and wastewater discharge. Seaweed, being a bioaccumulator, can absorb these contaminants from the water in which it grows.
Luckily here in New Zealand one company has done rigorous testing to ensure their seaweed products are totally safe for human consumption. Pacific Harvest’s seaweeds are tested according to the requirements in the ANZ Food Code. Where levels are not stated in the ANZ Food code, Pacific Harvest uses European guidelines as a base line for what is acceptable.
Click here to view the Pacific Harvest Testing Policy and Results
While seaweed can be a nutritious and flavourful addition to your diet, awareness of the potential risks associated with heavy metals, particularly lead, is crucial. By staying informed, choosing reputable brands, and consuming seaweed in moderation, you can enjoy its benefits while minimising health risks.
As consumers, our choices can drive demand for safer, higher-quality products in the market, ultimately leading to better health outcomes for everyone.
In seaweed products, common heavy metals of concern include:
Arsenic: Often present in two forms, organic (less harmful) and inorganic (highly toxic and a known carcinogen). Certain seaweed species, especially brown seaweeds like hijiki, tend to accumulate higher levels of inorganic arsenic.
Lead: Toxic even in small amounts, lead exposure can cause cognitive impairment, developmental issues, and cardiovascular problems. Seaweed grown in polluted waters can have higher lead concentrations.
Cadmium: Known for its toxic effects on the kidneys and bones, cadmium can accumulate in seaweed from industrial and agricultural runoff. It is especially concerning as it builds up in the body over time, even at low exposure levels.
Mercury: While more commonly associated with fish and shellfish, mercury can also be found in seaweed, particularly in regions affected by industrial pollution. Mercury exposure can impact the nervous system and cognitive development, posing serious risks over time.
Nickel: This metal is less commonly discussed but can still be found in some seaweed products. High levels of nickel exposure may lead to skin allergies, respiratory issues, and other health concerns.
Aluminium: Although not traditionally considered a “heavy metal,” aluminum is present in some seaweed products and can be harmful in large amounts, potentially affecting the nervous system.
The concentration of these metals in seaweed products can vary depending on the species of seaweed, its growing environment, and its processing methods.
The Importance of Testing and Regulations
Regulatory bodies and health organisations have begun to recognise the risks associated with heavy metals in seaweed. However, the level of scrutiny and testing varies by country and product.
Consumers should look for seaweed products that undergo rigorous testing for heavy metals and are certified by reputable health and safety organisations. Brands that are transparent about their sourcing and testing practices are more likely to provide safer products.
Tips for Choosing Safer Seaweed Products
To minimise the risk of heavy metal exposure from seaweed look for brands that provide detailed information about their sourcing and testing practices. Brands that prioritise quality and safety are more likely to have rigorous testing protocols in place.
Also seek products that have been tested for heavy metals and certified by recognised health and safety organisations. These certifications can provide assurance regarding the product’s safety.
Familiarise yourself with the regions from which the seaweed is sourced. Seaweed harvested from clean, regulated environments is generally safer.
While seaweed can be a healthy addition to your diet, like most things, moderation is key. Limiting your intake can help reduce the risk of exposure to heavy metals.
About The Author: Triona Backup
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