Whered you put those keys again? What did you come in this room for? And remember that thing you needed to, um, remember for work? If only taking something like a fish oil supplement could bust through all your brain snags.

While the research is mixed on fish oil supplements, its clearer that its good for your brain when it comes to consuming fish oil via food (like putting salmon on your salad or grilling trout for dinner). Overall, research shows that fish intake helps with cognitive health and helps prevent a decline in cognitive abilities, says Puja Agarwal, PhD, a nutritional epidemiologist and assistant professor of internal medicine at Rush University Medical Center in Chicago. And the good news is that you may be able to reap these benefits with just one serving of fish per week, she says. (There's more on how much fish you should be consuming below.)

Heres why fish is thought to be so good for your brain. Fish oil contains certain omega-3 fatty acids, particularly EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), notes the National Center for Complimentary and Integrative Health (NCCIH). You can consume fish oil via eating fresh fish or seafood or by taking a supplement. (While fish oil contains two different types of omega-3s, not all omega-3s are fish oil.)

When it comes to your cognitive capacity, omega-3s play an important role in brain structure and function, and as such, these nutrients play an important role in defraying cognitive impairments.

Yes, because the omega-3 fatty acids found in fish support good brain health, these nutrients also support the functions of the brain which, of course, includes thinking and memory.

We have pretty good evidence on fish intake and its role in brain health. From meta-analyses and large cohorts of healthy adults, a higher fish intake is associated with a lower rate of memory decline over time, as well as a lower risk of developing Alzheimers disease, says Dr. Agarwal.

In astudy published in the American Journal of Epidemiology in May 2018 that looked at data from 23,688 people from five pooled cohorts, older adults who consumed four or more servings of fish per week experienced less memory loss over four to nine years of follow-up compared with people who typically consume less than one serving per week. That was the equivalent, researchers say, to having a brain that was four years younger. Another study published in JAMA in February 2016 found that moderate seafood consumption was associated with lower risk of having markers of Alzheimers disease than lower seafood consumption.

Fish, eaten at least one time per week, is an important component of the MIND diet, which has been shown to delay age-related cognitive decline, according to a September 2015 study in Alzheimers & Dementia.

But its important to note that the research so far suggests eating fish supports memory and thinking centers of the brain, Agarwal says. When it comes to fish oil supplements, the research so far has not found a benefit of the supplements in terms of slowing cognitive decline or preventing Alzheimers disease.

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The fish oil you get from eating healthy amounts of fish each week is good for your brain. Thats clear. But its not necessarily the case that higher amounts of fish oil (or upping fish oil consumption with supplements) necessarily boosts your cognitive abilities above and beyond the benefit youll get from simply getting enough fish oil from fish.

Taking fish oil will not make you smarter or help you remember more if you already have an adequate intake [of omega 3s], explains Hussein Yassine, MD, associate professor of medicine at Keck School of Medicine of USC in Los Angeles.

Unfortunately, if youre already at baseline, more is not going to be better. This is not an 'intelligent pill,' you cant take it and start remembering things, he adds.

When it comes to reaping the health benefits of fish oil, the evidence points to getting plenty of fish in your diet as the way to get the most benefit. The 20202025 Dietary Guidelines for Americansadvises that adults eat 8 ounces of seafood per week, equivalent to two 4-ounce servings of fish or seafood per week.

Its worth noting, however, that this recommendation is best for overall health and, while its a good target, even if youre only getting one serving of fish per week, the brain may benefit anyway.

Research shows that when comparing people who are consuming one or more servings of fish per week to those who are eating less, fish eaters are experience less cognitive decline over the years, Agarwal says. This research comes from Rush University researchers and was published in the May 2016 issue of Neurology.

This follows past research from the university, published in JAMA Neurology, that found people who consume one fish meal per week had a 60 percent lower riks of Alzheimers compared with those who rarely or never ate fish.

That should be encouraging, because this is a simple lifestyle modification to maintain brain health in old age, Agarwal says.

So will anyone benefit from taking a fish oil supplement?

Overall, the research for eating fish is stronger compared with taking a fish oil supplement, Agarwal says. We see mixed findings when looking at supplements, she adds.

Dr. Yassine agrees, noting that overall, fish supplementation trials have been inconclusive. In the future, he says, we need more trials that look at how fish oil supplements might work and which people might benefit from supplementation. A study I led has found that regular over-the-counter supplements do not produce robust increases [in omega-3s] in the brain, Yassine explains. You need four to five capsules of an OTC supplement in cerebrospinal fluid (which Yassines group says is a reflection of what would be in the brain) get a sufficient increase, he explains. (That research, which was small in size including only 33 men, was published in the journal EBioMedicine in September 2020.) It seems to be something about getting these specific omega-3s from fish itself that has a greater effect on the brain, he says.

Fish is complex. Even the actual DHA and EPA in fish is not the same as what is present in supplements, says Yassine. That doesnt mean that DHA and EPA are not the active ingredients in fish oil supplements they are but that they may be packaged in a way that allows them to be more effective in fresh fish and seafood compared with supplements, he says.

What types of fish and seafood are the best sources of fish oil? Fatty fish, which contains the highest amounts of EPA and DHA, is best. These fish include salmon, mackerel, or trout. But its important to note that all fish and seafood, including shrimp and crab, has some fish oil, according to Seafood Health Facts.

Any kind of fish will help. You can have a variety, but watch how you cook it, Agarwal says. Choose methods like baking, broiling, and grilling over deep frying.

A study in the American Journal of Preventative Medicine concluded that cognitively healthy people who ate baked or broiled fish at least once a week had less gray matter loss (a sign of a healthier brain) in certain brain regions that govern memory and learning compared to non-fish-eaters.

If fish is not included in your diet, consume plant-based foods high in omega-3 fatty acids, like walnuts, chia, and flax, recommends Agarwal. (These contain alpha-linolenic acid, ALA, which can be converted into EPA and then to DHA in the body, but not very efficiently, which is why consuming foods with DHA and EPA is preferable, according to a report published in November 2020 in the Journal of the American College of Cardiology.)

Everyone, regardless of if they eat fish or are a vegan or non-fish-eater, is recommended to consume a certain amount of ALA per day. The National Institutes of Health says that adult males should consume 1.6 grams of ALA per day and adult females should aim for 1.1 grams per day.

If you opt for an omega-3 supplement, whether a fish oil or vegan version, keep in mind that it cannot fix or overcome an unhealthy diet, Agarwal says.

In general, brain fog is when your thinking could be described as slow or fuzzy, says Harvard Medical School. Fish oil could possibly help you think clearer, but perhaps only if you are deficient in omega-3s to begin with.

One study, of nearly 300 healthy women ages 18 to 35 found that those who had the lowest levels of omega-3s (in blood samples) scored lower on cognitive tests measuring attention compared to women with mid-range or high omega 3 levels, according to the research in Lipids in Health and Disease in November 2019. Though its worth noting that in that study, those cognitive scores were only slightly higher in women with higher levels of omega-3s.

Even the lowest group still had cognitive scores in the normal range, but it still shows that their brain function wasnt at its best.

Omega 3s have anti-inflammatory properties, which means they may protect the brain from damage from free radicals that leads to disease and aging. (People with higher levels of inflammation have been found to have a sharper decrease in cognitive abilities with age, concluded a March 2019 study in Neurology.)

The Lipids in Health and Disease studys authors suggest in that paper that this effect may support function and firing of neurons, and they may also influence dopamine pathways involved in attention and memory.

But given the lack of robust evidence on whether fish oil can help with brain fog, the answer to that question is still not conclusive.

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What Are the Benefits of Fish Oil for Memory? - Everyday Health