You know omega-3-rich fish, berries and even dark chocolate are your brain’s best friends. But did you know that for every brainy food out there, there’s a tempting food that can undo all your good efforts?

Worse yet, you probably think some of these foods are healthy, when in fact they damage your memory and mood — and increase your risk of dementia.

Read on to discover the brain’s top four enemies, and get ready to be surprised…

  1. Fruit Juice

Excessive sugar leads to obesity, type 2 diabetes and even heart disease. A lot of people who are trying to cut down on sugar think fruit juice is a healthy option. Bad news: When it comes to sugar delivery, your favorite orange or apple juice is just as bad as soda.

High-sugar food and drink are detrimental to brain function– no matter where they come from. Although the sugar in fruit is natural – not added — it still boosts blood sugar, fast, especially when taken as juice. Juice subtracts all the fiber, which slows down sugar absorption and benefits you in many other ways.

A study in mice, published in the journal Neuroscience, revealed that a high-sugar diet leads to a significant loss of cognitive flexibility, which is a measure of your brain’s ability to adapt and problem-solve.1 Additionally, researchers found that long-term and short-term memory took a hit, as well.

P.S. I think moderate amounts of fruit are good for you. I eat fruit every day.  But juice is another story. It packs a concentrated sugar punch. For example, it can take three or four oranges to make a glass of  juice, while I rarely eat more than one if I’m eating the whole orange.

  1. Aspartame

More bad news for those of us with a sweet tooth. If you were thinking of aspartame as a substitute, think again.  This ubiquitous artificial sweetener is nothing more than a poison, in my humble opinion. Because this is a brain health newsletter, I’ll skip all the other damage it causes and just mention that aspartame can lead to behavioral and cognitive problems.

It’s made of phenylalanine, methanol and aspartic acid. Scientists have found that phenylalanine can cross the blood-brain barrier and might disrupt the production of the brain’s neurotransmitters, causing negative effects on learning and emotions when aspartame is consumed in excess.2 By the way, it’s also a carcinogen.

The guv’mint still insists aspartame is safe. The route by which it won FDA approval is one of the most sordid stories in the history of regulation (and that’s saying something). It was a pure political fix. FDA scientific panels repeatedly advised that the sweetener should NOT be permitted.

Ironically, people who drink regular soda are better off than those who drink diet sodas that owe their sweetness to aspartame. And since regular sodas are a major cause of diabetes (which in turn leads to heart attacks and cancer) – you can pretty much decide what that says about aspartame.

  1. Vegetable Oil

Wait, what could be wrong with any food that has ‘vegetable’ in the name? Plenty, it turns out! So-called “healthy” soybean, canola and sunflower oils contain higher levels of omega-6 oils, the type of fatty acid that promotes brain inflammation.

Experts widely agree that inflammation is what makes a good brain go bad A 2017 study published in Scientific Reports3 linked canola oil, for example, with impaired memory and Alzheimer’s disease. People who eat too many omega 6s (which is almost all of us) also have much higher rates of heart disease and diabetes. I suggest you eat oils such as fish oil that contain anti-inflammatory omega-3s.

Omega 6 oils are not all bad. It’s true that omega-6 fatty acids in vegetable oils offer health benefits for bones, skin and hair. The problem is that in our country we eat far too many of them, and almost no omega 3s. The ideal is to strike a balance between the two, which for almost all of us is going to mean fewer 6s and more 3s.

  1. Tuna

You might want to think twice next time you nosh on a tuna sandwich. While fish are a great staple in anyone’s diet, not all fish are created equal. Carnivorous fish – those that are high on the food chain — are chock-full of mercury, which can accumulate in and damage your brain when consumed in large amounts. Tuna, shark, salmon and swordfish are all in the hazardous category. I eat them from time to time, but not frequently.

Researchers at the University of Florida4 found that people with high levels of mercury in their bloodstream showed a five percent drop in cognitive function. Now, an occasional tuna sandwich is no big deal, but why not try other types of fish? For instance, sardines and mackerel are low in mercury and high in brain-boosting omega-3s. Flounder, catfish and sole are also healthy choices – with some reservations. This website has more details on safe fish: https://www.eatthis.com/fish/


  1. Neuroscience August 6, 2015
  2. European Journal of Clinical Nutrition volume62, pages451–462 (2008)
  3. Scientific Reports volume 7, Article number: 17134 (2017)
  4. todayspractitioner.com/wp-content/uploads/2013/11/Mercury-IMCJ113_Masley_32_40.pdf