Despite the benefits companies tout and the billions of dollars spent, experts warn Americans to be wary of fish oil supplements: They’re not as great as you might think.
Most fish oil supplements, long touted for improving heart, joint, eye and skin health, make health claims that science does not support, a study suggests.
Researchers at the University of Texas Southwestern Medical Center (UTSMC) in Dallas looked at nearly 3,000 fish oil supplements, three-quarters of which made at least one health claim.
They found that about 80 percent made broad claims, such as “supporting heart health,” that scientific evidence may not be true, making them misleading to customers.
The researchers even suggested that taking too much fish oil, an industry worth $2.3 billion worldwide, could even increase the risk of heart problems such as atrial fibrillation or irregular heartbeat, which could lead to stroke and heart failure.
Experts told DailyMail.com that not all fish oil supplements are ‘equal’, and the lack of scientific basis for their claims creates a ‘confusing’ landscape for consumers.
Researchers at the University of Texas Southwestern Medical Center (UTSMC) found that about 80 percent of fish oil supplements made broad claims, such as “supporting heart health,” that are not supported by scientific evidence, making them misleading to customers
About 80 percent of supplements with a health claim used structure/function claims, which broadly describe a health effect, such as “improves heart health.” These cannot be proven by studies or regulated by authorities such as the Food and Drug Administration (FDA)
Dr. Ann Marie Navr, a cardiologist at UTSMC and lead author of the study, said: ‘About one in five Americans over the age of 60 take fish oil supplements, often because they think it helps their heart.
“But extensive research has shown that for most people there is no cardiovascular benefit from taking over-the-counter fish oil supplements, and at high doses they can even increase the risk of atrial fibrillation.”
The study analyzed 2,819 fish oil supplement labels obtained from the National Institutes of Health Dietary Supplement Database, which catalogs all information printed on labels of dietary supplements sold in the US. Of the people surveyed, 2,082 made at least one health claim.
About 80 percent of supplements with a health claim used structure/function claims, which broadly describe a health effect, such as “improves heart health.” These cannot be proven by studies or regulated by authorities such as the Food and Drug Administration (FDA).
A structure/function claim simply refers to how a substance affects the structure and/or function of the body, such as ‘calcium helps create strong bones’. It is required to have a disclaimer stating that the substance is not intended to diagnose, treat, cure or prevent any disease. These claims are not regulated, audited or scientifically justified.
However, a health claim refers specifically to how a nutrient or ingredient affects a disease or health condition. These types of claims are “authorized” and “qualified,” meaning they have significant scientific agreement based on health information or are supported by significant amounts of evidence.
Carolyn Williams, a registered dietitian in Alabama, told DailyMail.com that structure/function claims on fish oil supplement labels are ‘very confusing’
“Structure/function claims are permitted by the FDA, but they can be vague and misleading,” said Dr. Navar. ‘And they are made for fish oil for many organ systems, including the heart, brain, joints, eyes and immune system.
“We believe this type of language can be very confusing to consumers, who may not be aware that these statements do not require support from randomized trials.”
Carolyn Williams, a registered dietitian in Alabama who was not involved in the study, called structure/function claims “the wild, wild west” and said they are misleading to consumers.
“It’s very confusing,” she told DailyMail.com.
“You can say, ‘increases immunity,’ ‘improves brain health,’ ‘increases heart health.’ These are all things that are actually impossible to measure. And for some reason, if you’re a manufacturer and you’ve formulated it as a structure/function claim, you can say pretty much anything you want.”
In addition to identifying these claims, researchers also compared the amounts of two key omega-3 fatty acids in 255 of the supplements: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
These have been shown to lower levels of fats called triglycerides in some patients, which could lower blood pressure. They have also been shown to support immune function and proper fetal development.
EPA and DHA are mainly found in oily fish such as salmon, herring, sardines, mackerel, trout, some oysters, shrimp, tuna and lobster, but also in algae.
The recommended daily amount to lower blood pressure is 2,000 to 3,000 milligrams.
However, only one in ten supplements examined met these EPA and DHA values.
“Not all fish oils are created equal,” Ms. Williams said.
“You really want the majority of that (dosage) to be EPA and DHA.
“The fish oil supplements that actually contain little to no EPA or DHA really cannot live up to the claims they make.”
Ms Williams added that the ideal fish oil supplement should contain 60 per cent EPA and 40 per cent DHA.
“The majority of Americans simply aren’t getting enough EPA and DHA,” she said.
Joanna Assadourian, co-author of the study and a fourth-year medical student at UT Southwestern, said, “Supplement labels can be confusing to even the savviest consumers.”
‘Patients should talk to their doctor about what supplements they are taking and why they are taking them. They may be surprised to learn that they are not getting the health benefits they think they are getting.”
The research was published in the journal last month JAMA Cardiology.