Omega-3s from fish oil supplements no better than placebo for dry eye

April 13, 2018, National Eye Institute
Each daily dose of omega 3s contained 2000 mg eicosapentaenoic acid (EPA) and 1000 mg docosahexaenoic acid (DHA). Credit: National Eye Institute

Omega-3 fatty acid supplements taken orally proved no better than placebo at relieving symptoms or signs of dry eye, according to the findings of a well-controlled trial funded by the National Eye Institute (NEI), part of the National Institutes of Health. Dry eye disease occurs when the film that coats the eye no longer maintains a healthy ocular surface, which can lead to discomfort and visual impairment. The condition affects an estimated 14 percent of adults in the United States. The paper was published online April 13 in the New England Journal of Medicine.

Annual sales of fish- and animal-derived supplements amount to more than a $1-billion market in the United States, according to the Nutrition Business Journal. Many formulations are sold over-the-counter, while others require a prescription or are available for purchase from a health care provider.

"The trial provides the most reliable and generalizable evidence thus far on omega-3 supplementation for dry eye disease," said Maryann Redford, D.D.S., M.P.H., program officer for clinical research at NEI. Despite insufficient evidence establishing the effectiveness of omega-3s, clinicians and their patients have been inclined to try the supplements for a variety of conditions with inflammatory components, including dry eye. "This well-controlled investigation conducted by the independently-led Dry Eye Assessment and Management (DREAM) Research Group shows that omega-3 supplements are no better than placebo for typical patients who suffer from dry eye."

The 27-center trial enrolled 535 participants with at least a six-month history of moderate to severe dry eye. Among them, 349 people were randomly assigned to receive 3 grams daily of fish-derived in five capsules. Each daily dose contained 2000 mg eicosapentaenoic acid (EPA) and 1000 mg docosahexaenoic acid (DHA). This dose of omega-3 is the highest ever tested for treating dry eye disease. The 186 people randomly assigned to the placebo group received 5 grams daily of olive oil (about 1 teaspoon) in identical capsules. Study participants and the researchers did not know their group assignment.

Blood tests at 12 months confirmed that 85 percent of people in the omega-3 group were still compliant with the therapy. In the omega-3 group, mean EPA levels quadrupled versus no change in the placebo group. Mean levels of oleic acid, the constituent of olive oil, remained stable in both treatment groups.

Importantly, unlike in most industry-sponsored trials, all participants were free to continue taking their previous medications for dry eye, such as artificial tears and prescription anti-inflammatory eye drops.

"Omega-3s are generally used as an add-on therapy. The study results are in the context of this real-world experience of treating symptomatic dry eye patients who request additional treatment," said study chair for the trial, Penny A. Asbell, M.D., of the Department of Ophthalmology at the Icahn School of Medicine at Mount Sinai in New York City.

Patient-reported symptoms were measured as change from baseline in the Ocular Surface Disease Index, a 100-point scale for assessing dry eye symptoms, with higher values representing greater severity. After 12 months, mean symptoms scores for people in both groups had improved substantially, but there was no significant difference in the degree of symptom improvement between the groups. Symptom scores improved by a mean of 13.9 points in the omega-3 group and 12.5 points in the . A reduction of at least 10 points on the index is considered significant enough for a person to notice improvement. Overall, 61 percent of people in the omega-3 group and 54 percent of those in the control group achieved at least a 10-point improvement in their symptom score, but the difference between the groups was not statistically significant.

Likewise, there were no significant differences between the groups in terms of improvement in signs of dry eye. Signs of dry eye were evaluated by the clinician using standardized tests that measure the amount and quality of tears and the integrity of the cornea and the conjunctiva, the surface tissue that covers the front of the eye.

"The findings also emphasize the difficulty in judging whether a treatment really helps a particular dry eye patient," said the leader of the coordinating center for the study, Maureen G. Maguire, Ph.D., of the Department of Ophthalmology at the Perelman School of Medicine at the University of Pennsylvania, Philadelphia. "More than half the people taking placebo reported substantial symptom improvement during the year-long study."

"The results of the DREAM study do not support use of for patients with moderate to severe ," Dr. Asbell concluded.

Explore further: Trial of omega fatty acid supplementation in toddlers born preterm shows promising results

More information: The Dry Eye Assessment and Management Study Research Group. 2018. Omega-3 fatty acid supplementation for treatment of dry eye disease. N Engl J Med. Published online April 13.

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Shakescene21
1 / 5 (1) Apr 13, 2018
"Overall, 61 percent of people in the omega-3 group and 54 percent of those in the control group achieved at least a 10-point improvement in their symptom score, but the difference between the groups was not statistically significant."

That's enough to convince me to take the fish oil supplements. If these good results weren't statistically significant, then the sample size may be too small or the significance level might be too high given the confounding factors.

Fish oil had no reported negative effects, they are cheap, and they have cardivascular and brain benefits aside from the possible benefits shown in the study.
grandpa
3 / 5 (1) Apr 13, 2018
This study is just noise. People should eat fish, because people always ate fish. Our bodies are adapted to what they have done over hundreds of thousands of years. There are probably 100,000 aspects to health. How are we going to tease out the perfect diet when we have 100,000 processes to optimize. The best we can do is go with traditional diets and activities. Eat fruit, mushrooms, vegetables, nuts, legumes, mammals, birds, and fish and other traditional meats. Use traditional spices.
jhnycmltly
not rated yet Apr 14, 2018
One might wonder which fatty acids are different then, between fish oil or plant oils like soya or flax .. ?

"SOYA lecithin, an ingredient found in margarine, has been found to cure and prevent dry eye syndrome."
"Flaxseed Oil Supplements May Help Dry Eyes"

Must be that alpha-linolenic acid .. not found in fish .. but found in plants ..

"Schepens Eye Research Institute have found for the first time that topical drop application of alpha-linolenic acid (ALA) led to a significant decrease in clinical signs of dry eye syndrome (DES) in animal models. ALA is a fatty acid that cannot be made by the body and must be supplied in the diet. "

A curious thing, vegetarians are shown to have more alpha-linolenic acid in their spit, than meat eaters.

"A greater salivary concentration of alpha-linolenic acid (18:3 n-3) (2.82) was found in V than in M subjects"
IronhorseA
not rated yet Apr 14, 2018
"vegetarians are shown to have more alpha-linolenic acid in their spit, ..."

And less vitamin B-12 in their blood, unless they take supplements created in lab. :)
mackita
not rated yet Apr 15, 2018
The usage of mouthwash before going to bed may contribute to dry eye syndrome - I presume it inhibits not only bacteria, but also motion of ciliated epithelium, which transports tears toward eyes...
barakn
not rated yet Apr 16, 2018
"Overall, 61 percent of people in the omega-3 group and 54 percent of those in the control group achieved at least a 10-point improvement in their symptom score, but the difference between the groups was not statistically significant."

That's enough to convince me to take the fish oil supplements. -Shakescene21

Oh, really? Perhaps you missed this important tidbit: "all participants were free to continue taking their previous medications for dry eye, such as artificial tears and prescription anti-inflammatory eye drops." If there's no statistical difference between the groups and general improvement in both, then the likely the other medications are the reason for the improvement.
jhnycmltly
not rated yet Apr 16, 2018
"vegetarians are shown to have more alpha-linolenic acid in their spit, ..."

And less vitamin B-12 in their blood, unless they take supplements created in lab. :)


That is a fallacy. Vegetarians are no more lacking in B-12 than their meat eating counterparts.Their vegetarian/low iron diet allows for the proper bacteria in the gut to flourish, thereby fueling the bacteria which produces B-12.
"Lactobacillus reuteri may counteract side effects produced by vitamin B12 deficiency."
"Lactobacillus and Bifidbacterium are lactic acid bacteria, their growth is inhibited by the iron."

And since meat is considered to be 'high iron', therefore incompatible to humans, evidenced by the pathogenic microbiome, the natural vegetarian diet would have plenty of B-12 and alpha-linolenic to cure the dry eye.

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