consider the benefits of fish oil — along with the toxins, side effects and sustainability issues.
Toxins can be a problem
Although the good omega-3s reside in the fatty tissue of fish, that is also the very place where environmental contaminates bioaccumulate, which means that oil derived from these tissues may contain high concentrations of environmental contaminants.
Heavy metals such as arsenic, cadmium, lead and mercury come to us by way of industry and are not easily broken down, and thus end up throughout the environment at low levels, especially in fish. And fish oil. Adverse effects from ingesting heavy metals can include cognitive impairments, nervous system dysfunction, blindness, lack of coordination, deafness, development of certain cancers, irreversible liver and kidney damage and death.
Along with heavy metals, there are also other toxic compounds that bioaccumulate in fish. Polychlorinated biphenyls (PCBs) can lead to skin problems, muscle spasms, chronic bronchitis and nervous system disorders; and dioxins and furans have been linked to a number of adverse health effects including skin, liver and immune system problems, endocrine and reproductive disruptions and the development of certain cancers.
One of the trickiest parts about navigating which fish to eat, for many people, is figuring out which fish have the least amount of toxins versus which fish are sustainable. To help with similar issues when selecting fish oil, you can check with the International Fish Oil Standards Program (IFOS) which is a third party toxin testing and accreditation program for omega-3 fish oil products.
Fish oil is served with a side of side effects
We generally don’t consider the impact of side effects with our nutritional supplements, you know, the things we take to make us healthier. But fish oil offers side effects in spades. Here is a list from the Mayo Clinic. (Just for fun, read them in the hushed, calming tone of an actor listing prescription drug side effects on a television commercial.)
Fish oil supplements may cause nausea, diarrhea, loose stools, decreased appetite, constipation, vomiting and fat in the stool. Gastrointestinal side effects may be minimized if fish oils are taken with meals and if doses are started low and gradually increased.
There are rare reports of mania in patients with bipolar disorder or major depression. Restlessness and formication (the sensation of ants crawling on the skin) have also been reported.
Other potential side effects include loss of short-term memory, headache, hemolytic anemia, depression, somatic disorders, increased risk of colon cancer, nasopharyngitis, worsening of asthma symptoms, decreased physical activity, increased appetite, increased blood pressure and an uncomfortable feeling.
Omega-3 fatty acids may increase blood sugar levels. Caution is advised in patients with diabetes or hypoglycemia, and for those taking drugs, herbs, or supplements that affect blood sugar. Blood glucose levels may need to be monitored by a qualified healthcare professional, including a pharmacist.
Omega-3 fatty acids may increase low-density lipoprotein cholesterol levels, may worsen symptoms for patients with ventricular tachycardia, may increase the risk of bleeding, and may decrease blood pressure.
Fish oil taken for many months may cause a deficiency of vitamin E and may increase the risk of vitamin A or D toxicity — so use large amounts cautiously.
Individuals at risk for hormone imbalance or those undergoing hormone replacement therapy should use cautiously, as decreased estrogen receptor production has been associated with fish oil supplementation.
Patients with asthma, inflammatory bowel disease, or liver disease, and patients at risk for colon cancer should use cautiously, based on potential adverse effects associated with fish oil use.
The moral of the story here: Check with your doctor before taking fish oil.