The Fish Quandary: Getting Essential Oils without the Heavy Metals

DHA and other omega-3 oils are especially good for infants and children, adds Bost. Because they're incorporated into cell membranes, DHA and Omega-3 fatty acids are important to the rapid cell growth that occurs in children. "In a child's early growth and development, there's a lot of cell growth and division. If you don't have the structure and building blocks to make those cells, there's a deficiency," Bost explains. Nutrients from DHA—mainly omega-3 fatty acids—can also help young brains develop and protect against heart disease.

DHA can combat depression as well. For example, research shows that mothers who experience postpartum depression have depleted fatty acids, says Bost, and that depression can be eased if the mother consumes DHA.

Given the advantages of DHA and other omega-3 fatty acids, it's critical to ensure your family gets enough of them. But that's not an easy goal to achieve, knowing the potential for fish and fish oil to be contaminated with heavy metals, says Dr. Perlmutter.

To ensure kids and moms-to-be don't consume contaminants, parents should avoid the following:

• shark
• swordfish
• tilefish
• king mackerel

Larger fish have the highest levels of methylmercury because the toxins have more time to accumulate. Parents should also avoid farm-raised fish, which are often trapped in an environment that contains their own waste, says Dr. Perlmutter.