Updated: Aug 23, 2022
Your brain is the most important organ in your body. It keeps your heart beating, lungs breathing and all the systems in your body functioning. That’s why it’s so important to focus your diet on nutrient-rich foods that support brain health and functioning.
We know that certain foods are superfoods for brain health, but there are also foods that have negative impacts on the brain that impact cognitive function and mood while increasing your risk for neurodegenerative diseases like dementia.
As you are slowly bringing in more and more brain healthy foods, slowly but surely start cutting out the foods that are causing your body and mind distress.
Remember this way of eating is NOT a diet – but a healthy lifestyle. Once you choose to live an overall healthier life for optimal wellness, cutting out foods that don’t make the cut becomes easy.
Here are the worst foods for your brain:
1. Sugary Drinks
Sugary drinks include beverages like soda, sports drinks, energy drinks and even certain fruit juices. These high sugary drinks not only spike blood sugar quickly - causing fat storage, weight gain, type 2 diabetes and heart disease - but they also have a negative effect on your brain.
Did you know that Alzheimer’s Disease is also called Type 3 Diabetes? Balancing your blood sugar is so very important for overall health, but especially brain and mental health. When blood sugar spikes you can be certain it is going to crash – this causes mood swings, anxiety, depression and energy rollercoasters.
A primary component of many sugary drinks is high-fructose corn syrup, which consists of 55% fructose and 45% glucose. A high intake of fructose can lead to obesity, high blood pressure, high blood fats, diabetes, brain inflammation, memory and learning impairment and more. Aspects of metabolic syndrome may lead to an increase in the long-term risk of developing dementia.
Though you would think that fruit juices are a healthier choice, these juices are missing the fiber content that the whole fruit contains – which helps to balance blood sugar. On top of that, many fruit juices also contain added sugars and other questionable ingredients.
It’s always safest to just drink filtered water! Other alternatives include unsweetened iced tea, brewed herbal teas (can be chilled and poured over ice) and no sugar added vegetable juices. You can check labels for fruit juices - some do have medicinal purposes and don't include added ingredients: cranberry, tomato, pomegranate, prune juice - but whole foods are a better choice always.
2. Refined Carbs
Refined carbohydrates include sugars and highly processed grains, such as white flour. These types of carbs generally have a high glycemic index (GI). This means your body digests them quickly, causing a spike in your blood sugar and insulin levels.
Also, when eaten in larger quantities, these foods often have a high glycemic load (GL). The GL refers to how much a food raises your blood sugar levels, based on the serving size. Foods that are high-GI and high-GL have been found to impair brain function. They are also missing all the quality nutrition that whole foods have. They are called empty calories or nutrient-void foods.
Research has shown that just a single meal with a high glycemic load can impair memory in both children and adults. This effect on memory may be due to inflammation of the hippocampus, a part of the brain that affects some aspects of memory, as well as responsiveness to hunger and fullness cues. Inflammation is recognized as a risk factor for degenerative diseases of the brain, including Alzheimer’s disease and dementia.
Optimally, you should be getting your carbohydrates from healthier, lower-GI foods like vegetables, fruits, legumes, starchy veggies like squash and sweet potatoes and whole grains including quinoa, oats and rice.
3. Foods High in Trans Fats
Trans fats are a type of unsaturated fat that can have a detrimental effect on brain health. While some trans fats occur naturally in animal products like meat and dairy, these are not a major concern. It’s industrially produced trans fats, also known as hydrogenated vegetable oils, that are the problem.
These artificial trans fats can be found in shortening, margarine, frosting, snack foods, ready-made cakes and prepackaged cookies just to name a few.
Research shows that when people consume higher amounts of trans fats, they tend to have an increased risk of Alzheimer’s disease, poor memory, lower brain volume and overall cognitive decline. Trans fats have a negative effect on many other aspects of health, including heart health and inflammation as well.
Fats are essential to optimal health and brain function – but it’s important to choose the right ones. Include: seafood, avocado, olives and olive oil, coconut oil and other products, pasture-raised whole dairy and whole eggs, wild-caught seafood, nuts and seeds, grass-fed butter or ghee, etc. These good fats have been found to help protect against cognitive decline as well as support healthy blood sugar balance and overall mood.
4. Highly Processed Foods
Highly processed foods tend to be high in processed sugar, unhealthy fats – PUFAs (canola, sesame seed oil, sunflower seed oil, soybean oil, grapeseed, cottonseed, safflower, corn, etc.), processed salt, and other unhealthy additives (artificial coloring, MSG, preservatives).
They include foods such as chips, sweets, instant noodles, microwave popcorn, store-bought sauces and ready-made meals, just to name a few.
These foods are usually high in calories and low in essential nutrients. We call them nutrient-void foods. They’re exactly the kinds of foods that cause blood sugar imbalance, weight gain, decreased concentration, brain inflammation and irritate the brain causing impaired memory, learning, brain plasticity and the blood-brain barrier. Food colorings alone (Red 40, Yellow 5 and 6) have been shown to cause allergies, asthma, hyperactivity and even cancer.
The nutrient composition of processed foods in the Western diet negatively affects the brain and contribute to the development of degenerative diseases. Unfortunately, there are 1000s of ingredients allowed in food products in the United States that are banned in Europe. It is up to us to be mindful and educate ourselves on these ingredients and choose better for ourselves. Marketing companies are focused on sales, not health.
One of the ways processed foods may negatively impact the brain is by reducing the production of brain-derived neurotrophic factor (BDNF). This molecule is found in various parts of the brain, including the hippocampus, and it’s important for long-term memory, learning and the growth of new neurons. Therefore, any reduction can have negative impacts on these functions.
You can avoid processed foods by eating mostly fresh, whole foods such as fruits, vegetables, nuts, seeds, legumes, meat and fish. Shopping the exterior of the grocery store is a good rule of thumb.
Aspartame is an artificial sweetener used in many sugar-free products. People often choose to use it when trying to lose weight or avoid sugar due to diabetes. The unfortunate truth is that it still raises blood sugar levels by dramatically changing the makeup of the gut microorganisms, mainly bacteria, that live within the intestines. These healthy microorganisms support gut health, nutrient absorption and a robust immune system.
Aspartame is also found in many commercial products not specifically targeted or marketed for those with diabetes. This widely used sweetener has also been linked to behavioral, emotional and cognitive problems and is a chemical stressor that can increase the brain’s vulnerability to oxidative stress.
When consumed in moderation, an organic glass of red wine can be an enjoyable addition to a nice meal. However, alcohol is considered a poison and excessive consumption can have serious effects on the brain.
Chronic alcohol use results in a reduction in brain volume, metabolic changes and disruption of neurotransmitters which can lead to memory loss, behavioral changes and sleep disruption. People with alcoholism often have nutrient deficiencies, especially in vitamin B1. This can lead to a severe damage to the brain, including memory loss, disturbances in eyesight, confusion and unsteadiness.
‘Binge drinking' episodes can cause the brain to interpret emotional cues differently than normal and is associated with poor sleep quality, which can lead to chronic sleep deprivation.
Overall, you should avoid excessive alcohol consumption, especially if you’re a teenager or young adult, and avoid binge drinking entirely. If you are pregnant, it's also safest to avoid drinking alcohol altogether.
7. Fish High in Mercury
Mercury is a heavy metal contaminant and neurological poison that can be stored for a long time in tissues. Long-lived, predatory fish are particularly susceptible to accumulating mercury and can carry amounts over 1 million times the concentration of their surrounding water.
For this reason, the primary food source of mercury in humans is seafood. After a person ingests mercury, it spreads all around their body, concentrating in the brain, liver and kidneys. In pregnant women, it also concentrates in the placenta and fetus.
The effects of mercury toxicity include disruption of the central nervous system and neurotransmitters and stimulation of neurotoxins, resulting in damage to the brain.
For developing fetuses and young children, mercury can disrupt brain development and cause the destruction of cell components. This can lead to cerebral palsy and other developmental delays and deficits.
However, most fish are NOT a significant source of mercury. In fact, fish is a high-quality protein and superfood that contains many important nutrients, such as omega-3s, vitamin B12, zinc, iron, magnesium and so much more. Therefore, it is important to include fish as part of a healthy diet but choose low mercury fish as often as possible.
Generally, it is recommended that adults eat 2-3 servings of fish per week. However, if you’re eating higher mercury fish like shark, orange roughy, tuna or swordfish, spread out this specific intake overtime.
The best low mercury fish to consume:
Clams and mussels
Mackerel (north Atlantic)
8. Factory Farmed Meat and Poultry
Unfortunately, commercially raised animals, especially chickens and cows, contain excessive levels of several different dangerous chemicals in an attempt to keep animals "healthy" and to artificially increase their size. These chemicals include antibiotics, arsenic, tranquilizers, steroids, growth hormones, medicines, vaccines, and parasiticides. We are what we eat and eating this degraded meat supports traces of these chemicals to pass into our own system.
Factory-farmed animals can have unhealthy diets. To keep production costs low, animals raised in factory farms are typically fed cheap grains and feeds containing “by-product feedstuff”. Simply put, by-product feedstuff includes not-so-healthy and nutrient-void items. Their bad diet can become your bad diet, which can become counter-productive to your health.
Cattle, dairy cows, goats, bison, and sheep were designed to eat fibrous grasses, plants, and shrubs—not starchy, low-fiber grains, and feedstuffs. When these animals are switched from pasture greenery to grains, many can wind up suffering from a number of disorders and painful conditions. These animals can also be given chemical additives, plus constant, low-level doses of antibiotics – killing off their healthy microbiome while creating 'superbugs' that become resistant to them. Gut health is everything. The health of the animal matters to your health as well.
Factory-farmed meat can also be a less nutritious product in general. It may come as no surprise that animals fed an unhealthy diet will make for a less nutritious meal. Compared to grass-fed animals, factory-farmed, grain-fed meats have less vitamin E, beta-carotene, and little of the two health-promoting fats: omega-3s and conjugated linoleic acid or CLA (CLA is associated with a lowered risk of heart disease and may help prevent and manage type 2 diabetes by improving glucose tolerance and insulin sensitivity).
Lastly, the animals can experience a lot of stress. In factory farms, animals are typically raised in inhumane conditions, tightly packed into cages and pens, unable to practice normal behaviors, such as rooting, grazing, and roosting. In these conditions, the animals can become stressed and wind-up producing products that are lower in a number of key nutrients that naturally get depleted in stressful conditions.
Try to choose grass-fed, pasture-raised, free-range animal products to ensure that you’re eating nutritious and healthy meats, as nature intended. Grass-fed meats offer serious amounts of nutrients that are already in their naturally active forms and absorb efficiently.
It’s also important to cook meats low and slow – cooking at high temperatures can increase the formation of AGEs (advanced glycation end products) which can promote inflammation and oxidative stress.
The bottom line is that your diet definitely has a big impact on your brain. Inflammatory diet patterns high in unhealthy fats, sugary drinks, refined carbohydrates, artificial sweeteners like aspartame, alcohol, factory-farmed meat, and highly processed foods are linked to brain aging and decline.
What foods will benefit your brain health and overall cognitive health? Consider a whole foods diet high in organic fruits and vegetables, wild-caught seafood, pasture-raised poultry, olive and coconut oils, nuts and seeds high in omega-3s, and grass-fed, pasture-raised red meat on occasion.
Check out Brain Superfoods for the best foods for your brain and mental health.