Reviewed by Jessie, BSc Biomedical Science · Formulation Lead, Purest Kids
Where mercury comes from
Mercury enters the ocean through industrial pollution and accumulates in fish tissue through a process called biomagnification. Small fish absorb mercury from contaminated water and the organisms they eat. Larger fish eat the smaller ones, concentrating mercury further. Fish oil supplements are made from smaller oily fish like sardines and anchovies — their mercury levels are lower than top predators, but "lower" is not "absent."
The concern for children specifically
Children are more vulnerable to mercury's neurotoxic effects than adults. The developing nervous system is more susceptible to damage, and children's smaller body mass means a given dose of mercury represents a higher concentration per kilogram of body weight. US FDA and EPA guidelines specifically warn against high consumption of high-mercury fish for children and pregnant women.
What quality fish oil manufacturers do
Reputable fish oil manufacturers use molecular distillation to remove contaminants including mercury. Independent third-party testing of heavy metal levels should be standard for any supplement intended for children. If a fish oil supplement does not publish heavy metal testing results, that is a gap worth noting.
How algae oil bypasses the issue
Algae oil is grown in controlled, land-based cultivation systems using purified water. There is no ocean supply chain, no fish, and no mechanism by which mercury enters the production process. For parents who want DHA without the mercury conversation at all, algae oil removes it from the equation entirely.
Omega-3 Mango Burstlets — algae-sourced, mercury-free by design →
References
- US FDA and EPA. "Advice about Eating Fish." FDA.gov, 2024.
- Oken E, Bellinger DC. "Fish consumption, methylmercury and child neurodevelopment." Current Opinion in Pediatrics, 2008.