10 Superfoods That Help With Brain Fog, Ranked by the Evidence

Have you ever reread a sentence more than once without comprehending it? Forgotten what you were just about to say? Felt like you were thinking through a wet towel? Those are all symptoms of brain fog, although there’s no such official diagnosis.

There’s no magic food that will cure brain fog, but research has identified certain foods that appear to improve aspects of brain health like attention, processing speed, and working memory, all of which could help alleviate symptoms of brain fog.

Ranked by their strength of evidence (with the amount people ate or drank in studies listed so you can get an idea of a helpful amount), here are 10 foods that might help with your brain fog, counted down from 10 to 1.

How We Ranked These

Every food listed below has been the subject of at least one human study. The quality of evidence (i.e. how strong of a claim we can make about the food’s ability to improve mental performance) is reflected in the order of the list. Studies in which human volunteers are given a food or drink and then tested for cognitive performance both before and after receive priority over studies that show a positive correlation between cognitive performance and eating or drinking that food (correlation doesn’t necessarily mean causation). If there is a large study showing no effect, we’ll make note of that as well.

While there have not been any studies looking specifically at brain fog, many of the studies we’ve cited look at indicators of brain fog such as response time, memory, and ability to switch tasks (and the number of errors committed while doing so). Portion sizes reflect those used in the studies cited or USDA figures. Information is based on research studies, not marketing hype.

No. 10: Pumpkin Seeds

Pumpkin seeds also provide zinc and about 168 milligrams of magnesium in just one ounce, almost half of what most women need per day. In a 2023 study that included data from 6,001 UK Biobank participants, people with higher magnesium intakes had larger volumes of gray matter and the hippocampus (the part of the brain that’s involved in learning and memory) on brain scans, particularly women. While this isn’t a cause-and-effect study, and there aren’t any trials testing pumpkin seeds specifically for memory, if you’re in the mood for a snack at 3 p.m., you might want to swap your chips for pumpkin seeds.

No. 9: Dark Chocolate

Dark chocolate doesn’t fare much better. In one study, published in 2014 and conducted at Columbia University, older adults (aged 50 to 69) who consumed a high-flavanol cocoa beverage for three months did better on a memory test that exercises a hippocampal function known to decline with aging. But in a larger, three-year clinical trial (COSMOS-Mind), 2,262 older adults who received a cocoa extract providing 500 milligrams of flavanols daily did not show any improvement in overall cognitive function compared with a placebo.

There’s nothing wrong with having a square or two of dark chocolate, if you like it. But don’t expect it to sharpen your thinking.

No. 8: Walnuts

Of all nuts, walnuts probably get the most attention as being good for the brain. In a national survey of US adults, those eating walnuts (an average of 10 grams a day, or three or four walnut halves) had faster reaction times and performed better on memory tests than those who did not eat nuts. However, in a two-year trial in 708 older adults who ate walnuts (30 to 60 grams a day), cognitive performance did not hold up better compared to those not eating walnuts (except in the Barcelona group, which did have less cognitive decline). Walnuts may be good for you, but the research evidence that they protect the brain is not as strong as one might think.

No. 7: Avocados

Lutein is a pigment that’s found in high concentrations in the retina of the eye as well as in the brain. In a six-month Tufts study of 40 healthy older adults, those who ate an avocado a day saw their lutein levels rise 25 percent, while those who ate a potato or a cup of chickpeas were the comparison group. The avocado eaters also had higher concentrations of lutein in the eye and did better on a test of sustained attention. (Again, caveat: one small study.) Half an avocado, say, on toast or in a salad, is an easy way to get there.

No. 6: Eggs

Choline, which is found in abundance in eggs (about 150 milligrams per large egg), is used by the body to make acetylcholine, a chemical messenger that plays a role in memory. In the Framingham Offspring study, 1,391 adults who consumed more choline had better performance on verbal and visual memory tests. Choline intake years earlier was associated with less of the white-matter changes seen on brain scans that are related to aging. The Institute of Medicine sets 425 milligrams of choline a day as an adequate intake for women, which two eggs at breakfast would get most of the way to.

No. 5: Fatty Fish

Fatty fish (think salmon, sardines, mackerel) contain an omega-3 fat called DHA that’s an important component of fat in your brain’s cell membranes. Eating fish may help protect your brain in the long run: a 2016 meta-analysis of 21 studies involving 181,580 people found that for every additional serving of fish eaten per week, people had a 5 percent lower risk of developing dementia and a 7 percent lower risk of developing Alzheimer’s disease. We’re talking about a potential effect over years, not necessarily brain fog later that afternoon, but this is probably the best evidence of any food on this list that has a long-term effect on your brain. Aim for two servings per week.

No. 4: Coffee

Caffeine has been shown in a 2013 review of double-blind, placebo-controlled studies to enhance alertness and attention (both in simple tasks and in more complex ones that require executive control). Importantly, the benefits seen in these studies went beyond just the alleviation of withdrawal symptoms. That said, caffeine later in the day (for many people, after around noon) can interfere with sleep, and poor sleep is the most common cause of brain fog. For many people, one or two cups of coffee before noon is the sweet spot.

No. 3: Blueberries

Of all the fruits, blueberries have been studied the most. In a 2018 randomized, placebo-controlled trial, 37 older adults (aged 60 to 75) ate 24 grams of freeze-dried blueberry each day for 90 days, the equivalent of about a cup of fresh berries. Those who ate blueberries made fewer repetition errors on a verbal learning and memory test and took less time to switch from one task to another than those who took a placebo. And in another small study, nine older adults with early memory problems did better on a word recall test after drinking wild blueberry juice daily for 12 weeks. (Frozen wild blueberries are usually reasonably priced and can be added to oatmeal or yogurt just as easily.)

No. 2: Spinach and Leafy Greens

Spinach and other leafy greens top the list for having the most compelling long-term study results. In the Memory and Aging Project, 960 adults between the ages of 58 and 99 were followed for an average of 4.7 years. Those who ate the most greens, an average of 1.3 servings per day, showed a slower decline in their scores on cognitive tests. The difference in decline was equivalent to an 11-year difference in age. Nutrients found in spinach and other leafy greens that were associated with better cognitive performance included vitamin K, lutein, folate and nitrate. (And no, it’s not the iron, since spinach’s iron is not well absorbed.) A big handful of spinach in eggs, a smoothie or a salad counts as one serving.

No. 1: Green Tea

Green tea tops the list because it’s the one food here with trial evidence for the thing brain fog actually takes away, which is attention, within the hour. Green tea contains both caffeine and an amino acid called L-theanine. One trial involving 27 adults found that a combination of 50 milligrams of caffeine and 100 milligrams of L-theanine (roughly the amount you’d get from two or three cups of green tea) resulted in quicker and more accurate attention switching, as well as improved resistance to distraction on a memory test, when compared to a placebo, at the one-hour mark. And in another study involving 1,003 Japanese adults over age 70, those who drank two or more cups of green tea a day had roughly half the odds of cognitive impairment as those who drank three cups per week or less.

When It Is Not About Food

Blueberries aside, before you make a beeline for the grocery store, consider whether your brain fog may have a more mundane explanation. It could be dehydration. Research shows that even mild dehydration (just 2 percent) can impair attention and short-term memory. Or it could be poor-quality or insufficient sleep.

It’s also one of the most commonly reported symptoms of perimenopause and menopause, and a side effect of some medications, including antihistamines and some medications used to treat blood pressure or sleep problems. Less commonly, brain fog can be a sign of an underlying medical condition, such as low thyroid function, low vitamin B12 levels, anemia or sleep apnea. The good news is that all of these can be evaluated with routine bloodwork or other tests.

If your brain fog has been happening on and off for more than a few weeks, or if it’s getting progressively worse, talk with your clinician about what might be going on and whether additional workup is warranted.

Where to Start

But don’t expect any of these foods to be a magic brain-boosting switch. In studies that showed an effect, people consumed the food in question on a daily basis for weeks or months. So, pick two or three you like, such as a cup of blueberries, a handful of greens, or a cup of green tea before lunch, and see how you feel after a month. If your mind doesn’t seem any clearer, at least you’ll have nourished your body well and can move on to other solutions, like better sleep, more hydration or even blood work.

Kaelyn Johnson, MPH, R.D.

Kaelyn Johnson is a Registered Dietitian from Southern California who has worked as a clinical dietitian and is now a freelance writer.