Omega-3 polyunsaturated fatty acids contain essential nutrients that perform vital functions in the body. But a new study from Case Western Reserve University finds 85% of the global population isn't getting enough omega-3.
Lead researcher Timothy Ciesielski deemed the shortage a planetary and public health issue.
"The scale of this is important," he said. "It's not just that we need [omega-3] and a few people don't have enough — it's that most of us don't have enough."
The study, recently published in the journal AJPM Focus, determined that omega-3 deficiency is associated with preterm birth, neurocognitive decline and dementia, depression and anxiety, cardiovascular disease and rheumatoid arthritis.
Ciesielski said the rise in consumption of omega-6 is one reason for omega-3 deficiency. Omega-6, also a type of polyunsaturated fatty acids, is common in seed oils and processed foods, and can increase inflammation and interfere with the effects of omega-3 in the body, Ciesielski said.
The average diet is "now about a 20-to-one ratio of omega-6 to omega-3," Ciesielski said.
There are also environmental factors damaging the global omega-3 supply. Since marine life is a prominent source of the nutrient, Ciesielski said pollution, overfishing and climate change are contributing to the shortage.
For example, rising sea temperatures lead to less omega-3 production. Algae produce the fat to make their cell membranes fluid in cold water, Ciesielski said.
"If the water is not as cold, they don't need as much omega-3, they don't make as much, the fish don't concentrate as much and we have less," he said.
Omega-3 fatty acids support cardiovascular and brain health, according to Cleveland Clinic. They help lower triglyceride levels, which can raise the risk of heart attack and stroke when too high. Omega-3 can also lower the risk of some cancers, dementia and depression.
But the human body doesn't produce enough omega-3 naturally, meaning the fat must be eaten. Common foods that provide omega-3 include fish, nuts, flaxseed and canola and olive oil.
Ciesielski said about 15% of countries worldwide have achieved sufficient omega-3 levels in their food supply, mainly due to ocean access — suggesting that protecting our oceans and managing fisheries sustainably could help.
Only a few countries have omega-3 consumption levels high enough to help prevent both depression and preterm birth. They include Denmark, Iceland, Malaysia and Brunei. A few others, including Spain, the United Kingdom and Japan, have levels high enough to prevent preterm birth.
The United States does not have consumption levels sufficient to prevent either depression or preterm birth.
Mercury, which is found in most saltwater and freshwater fish, can lead to poisoning and brain damage, according to the Office of Environmental Health Hazard Assessment.
"We must reduce the contamination of our ocean based food," Ciesielski said. "Un-poisoning the well will not be easy, but we must do it for ourselves, even if we are unwilling to do it for the plants and animals in these ecosystems."
Ciesielski said he considers his findings a call to action, and hopes his findings stir up more conversation among other scientists and global leaders to seek solutions. He also said finding omega-3 from alternative sources — like a plant called purslane — and expanding regenerative aquaculture practices could improve omega-3 intake.
