Mercury in Seafood: Should It Concern You?

Mercury in Seafood: Should It Concern You?

Health trends are continuously changing with new ideas and discoveries each day. Fats, carbohydrates, and proteins are three key words used in health media and literature. While the long-term healthiness  of carbs and fats tends to be under constant scrutinizing change, the benefits of protein goes almost unchallenged. Protein plays a crucial part in our daily life and diet. From maternal seafood consumption through childhood and into adolescence, the protein from fish is an undeniably necessity for our optimal health.

Mercury levels and potential long term effects of high consumption has been indicated as a health concern. Almost everyone has an opinion of “healthy seafood habits” that reduce the risk of mercury exposure. Some consumers have even become so fearful of mercury levels that they avoid seafood all together. The following discussion is meant to review studies from all sides. Fear can often be relinquished by further education and understanding. 

Maternal Seafood Consumption

Pregnant women throughout modern medicine have struggled with eating or not eating seafood during their pregnancy. A common concern is negative developmental effects that can occur during child development when maternal intake of seafood is greater than 340 g per week. Doctors have preached about the dangerous impact of eating fish while pregnant. Modern studies are beginning to address this idea with new conclusions.

A published study in 2007 found evidence of beneficial effects on children’s development with a greater than 340 g per week of seafood. Less than optimal outcomes that are associated with the risk of consuming more than 340 g per week, in previous studies,  are prosocial behavior, dine motor, communication, and social development. The 2007 study determined that consuming less than 340 g per week might actually be detrimental to children in later phases of childhood. 

It is always suggested to speak with a health professional about your specific risks and benefits before drastically changing your diet. 


Childhood (5-12 years)

Noted in many published studies, the effects of MeHg exposure on children is highly influenced by the mother’s seafood intake before and during pregnancy. A New Zealand study compared mothers who frequently consumed seafood with mothers who had less exposure to MeHg. Hair-Hg samples were taken from each group of mothers during pregnancy. The children were retested at age 6- and 7-years old using scholastic and psychological tests. Initial results showed “...association between high prenatal mercury exposure and decreased test performances, using category variables for mercury exposure”. Conclusion of the New Zealand study found that chronic exposure to high/constant fish consumption indicates a mercury effect.

Adolescence (13-20 years) 

Fish consumption and the benefits it provides goes beyond bodily heath. Fish consumption was studied in adolescent aged children over a two year span. Sent out in 2000, the questionnaire was mailed to adolescent students. The findings, a year later, studied academic grades. Higher grades were found in students that consumed fish at least once a week than those who consumed less than once a week. 

In 2017, a published study emerged that found a correlation between fish consumption during adolescence and long-term performance benefits such as visual learning, memory, and attentional abilities. Participants recorded their fish intake during adolescence and then were retested on their performance at medial age of 30. Conclusions of the study indicated that participants that consumed fish at least twice per month did have positive performance results. Furthermore it was concluded that consuming fish more than twice per month did not indicate improved abilities. Statistically, no association was concluded between the species of fish consumed (e.g., high in MeHg).


Adulthood and Older

Published in Integrative Medicine, 2012, a study drew conclusions between mercury levels and seafood intake on cognitive function in adults. Balancing the risks and benefits of seafood includes being cautious of the mercury levels and balancing it with the beneficiary N3FA (n-3 fatty acids). The finalized research did find that moderate fish consumption (1-3 servings/wk) had benefits that outweigh the risks. Exception to this was selected fish species. Excessive seafood intake did show some causes of cognitive dysfunction due to high levels of mercury. Initially, N3FA at high intake did show improved cognitive function but was quickly overwhelmed by the mercury levels. 

As with all health concerns or questions, speaking with a healthcare professional can help you decide what is healthy for you.

Balancing Risk and Benefit

Literature review, conducted in 2012, found that qualitative studies “...emphasize the importance of maintaining or increasing fish consumption in the general population and minimizing exposure to toxic contaminant intake with published recommended or tolerable intake levels”. Studies on fish consumption and mercury levels show high levels of variety in methodology and results, meaning that the balance of risk and benefit needs to be taken at individual person level due to each person’s unique circumstances. Beneficial tables (e.g., daily recommended intake for DHA)

The Takeaway

Seafood is a delicious and healthy option. Understanding the risks of mercury levels but also understanding the bountiful benefits of seafood can help you feel more comfortable using seafood as a healthy food choice. Our bodies are unique and individual which means everyone reacts differently to seafood intake. Knowing your body and speaking with a healthcare professional can help with making a comfortable choice. 

Please note that this article was written using author opinion based on published scientific research. This article does not offer medical advice or suggestions. Consulting a doctor before making any drastic changes to your diet is highly suggested.