Fish and shellfish both contain essential nutrients that help maintain a healthy diet. Specifically, fish and shellfish are sources of high-quality protein, are low in saturated fat and contain omega-3 fatty acids. And aside from the nutritional value, fish are often a sustainable food source, meaning a lessened environmental impact.
However, almost all fish and shellfish contain mercury in trace amounts. For most people, the amount of mercury found in most fish and shellfish poses little threat. But mercury content in fish and shellfish can pose a very real risk to a child or fetus’s developing nervous system.
Who is at risk?
For most adults, the minute amounts of mercury found in fish and shellfish aren’t significant enough to have a harmful or lasting effect.
However, for children and unborn babies, the levels of mercury present in fish and shellfish can have a harmful effect on their developing nervous systems. For this reason the EPA and FDA have determined that the following individuals pay particular attention to the types and amounts of fish they eat:
- Pregnant Women
- Women Who May Become Pregnant
- Nursing Mothers
- Young Children
What are the Dangers?
Mercury is a dangerous contaminant because it is both odorless and invisible, making it impossible to detect. It cannot be cut or cooked away, meaning anyone that consumes fish is affected.
Once mercury finds its way into the human body, it acts as a neurotoxin, interfering and causing damage to the brain and nervous system. This integration into the body is referred to as mercury poisoning or methylmercury poisoning and can have adverse effects in children and adults.
- Mercury Poisoning in Children
In children, these damages to the brain and nervous system can result in mental retardation, cerebral palsy, deafness and even blindness. Even in low levels mercury can cause learning disabilities and delay developmental milestones. - Mercury Poisoning in Adults
In adults, mercury levels must be much higher to have a lasting effect. Even so, mercury poisoning in adults has been linked to low fertility and blood pressure irregularities, as well as memory loss, tremors, and vision loss.
How Can I Protect Myself?
To protect yourself and your family from mercury poisoning you must know how much mercury you typically consume and decrease your consumption of high-mercury fish. The following are tools that can help you make wise decisions concerning fish consumption:
- Guide to Mercury Levels in Fish
This guide produced by the Food and Drug Administration specifies fish and shellfish with the highest and lowest contamination levels. In general, you may enjoy larger portions of fish with lower contamination levels, and you should steer clear of highly contaminated fish altogether.- Fish and Shellfish Portion Guidelines
The Environmental Protection Agency has determined portion guidelines that will allow you to enjoy several types of fish and shellfish while keeping your blood-mercury count safely below recommended levels.- Mercury Calculator
This mercury calculator, created by the National Resource Defense Council, will give you a quick estimate of your mercury intake. While this calculator provides only an estimate, it can help you determine if you require further testing by a licensed physician. - Fish and Shellfish Portion Guidelines
Additionally, when looking to eat fish caught recreationally be sure to contact your local health department for any variance in fish mercury levels. Some water sources have higher mercury contamination than others, and fish caught locally could have higher or lower mercury levels than those indicated by the EPA and FDA.
Sources:
Mercury Contamination in Fish. National Resource Defense Council. Accessed: 10 Nov 2008. URL: http://nrdc.org/health/effects/mercury/protect.asp
What You Need to Know About Mercury in Fish and Shellfish. Food and Drug Administration. Accessed: 14 Nov 2008. URL: http://www.cfsan.fda.gov/~dms/admehg3.html
What You Need to Know About Mercury in Fish and Shellfish. Environmental Protection Agency. Accessed: 14 Nov 2008. URL: http://www.epa.gov/waterscience/fish/advice/#notp
