Mental Fatigue Getting the Best of You? Nourish Your Brain

By Dr. Linda J. Dobberstein, DC, Board Certified in Clinical Nutrition

August 22, 2022

Mental Fatigue Getting the Best of You? Nourish Your Brain
My brain hurts! Do you ever hear your kids say that after studying for exams? How about you after a long day at work focusing on complex tasks or learning new skills? You know how it feels to experience mental exhaustion and the accompanying “brain pain”. Mental fatigue is as real as physical exhaustion and needs similar attention to recover effectively.

Scientists have explored what happens to the brain during long, intensive mental work periods. Recent findings shed more insight into why your brain feels fatigued or “hurts” after a long period of high demand mental tasks.

Study Demonstrates Cognitive Fatigue

In a recent study published in the August 2022 Current Biology, scientists evaluated healthy adults on simulated work tasks. One group was involved with intense concentration, decision making, and cognitive work, while the other group had easier jobs to perform. Magnetic resonance spectroscopy was used to measure brain metabolites to see function.

At the end of the work period, the group required to work harder was found to have higher glutamate levels in the region of the brain involved with cognitive skills. It was also found that as individuals experienced fatigue, more neurons were recruited to keep up with the work demands, resulting in decreased efficiency and more oxidative stress.

Another test of cognitive reasoning and measure control was given at the end of the study. Participants were given choices for gratification/reward benefits to measure executive control function with high fatigue levels. Participants could receive a low-cost reward immediately or wait and receive a more expensive reward later.

Results showed that fatigued individuals with high brain glutamate levels chose instant gratification with low cost rewards rather than waiting for “smarter choices” with high economic rewards reflecting less “executive” control over economical decision making.


Glutamate is an excitatory neurotransmitter and amino acid made in your brain and gut. Your diet also contributes to glutamate levels. Glutamate is tightly controlled and balanced by various mechanisms. It is primarily balanced by GABA, the brain’s primary relaxant neurotransmitter.

You need glutamate to maintain wakefulness. It helps you focus, be on high alert, and is involved in information transfer in different parts of your brain. Glutamate plays a significant role in protein metabolism, cell signaling, receptor site function, calcium movement, and is also involved with glutathione and folate/folic acid cofactor metabolism.

Glutamate excess and imbalances are linked to mood stress, microglial cell and neuro-inflammation, hearing loss, neurodegenerative changes, and more. Imbalances in glutamate levels also stress brain mitochondria.

Nourish Your Brain

Keeping your brain nourished is critical to get through a demanding workload. No matter your age, you must feed your busy, energy demanding brain and buffer against stress. Here are several tips to keep your brain engaged in the game and avoid the brain drain.

1. Meals

Breakfast is the most important meal of the day. Don’t skip lunch to keep working. Low blood sugar level from not eating, rapid drops from high sugar intake, or from low quality diet and poor blood sugar regulation is stressful to your brain. Overnutrition with high fat, high sugar, nutrient poor diet, and poor gut health also inflames and ages your brain contributing to brain fatigue.

Consume at least 15-30 grams of protein with complex unrefined carbohydrates, good fats, and 1-2 servings of fruits and vegetables with each meal. Dietary trends with intermittent fasting, keto diets, or other specialty diets often fail to provide adequate daily nutrients unless planned very well. Specialty diets generally require significant nutritional supplementation.

Stay hydrated. Even mild dehydration affects the energetic demands of your brain. Consume at least 6-8 eight-ounce glasses of water per day. Hot summer days, athletic activities, and diuretic/water pills may affect your fluid and electrolyte needs. Stay attentive to your needs. Soda pop, iced teas, and lattes don’t fully hydrate you and are loaded with empty calories. More caffeine may temporariliy alleviate the fatigue, but can stress your brain and body more so in the long-run.

2. Rest Breaks

When you are maxed out with thinking, cognitive tasks, and projects make sure to take breaks. Schedule breaks and rest time into your day. Take a break for a few minutes every hour if possible while working. Balance your day with other less intense mental activities. Taking a break also helps protect your eyes from excessive near focus and eye strain from the computer. Breathe, exercise, stretch, play, run an errand, or do some yard or housework.

3. Address Underlying Energy Drainers

Nutrient deficiencies can impair tissue oxygenation, reduce tolerance for mental activity, and worsen brain fatigue. Key nutrients required for your blood to carry oxygen include iron, vitamin B12, folate, zinc, copper, magnesium, potassium, vitamin C, and several other B vitamins, etc. These nutrients are also needed by the nerves and mitochondria to make energy and neurotransmitters, etc. Optimal nutrient reserves help keep things running smoothly, like keeping oil levels in your car engine at the manufacturer’s recommendations.

Healthy blood pressure is also required for cognitive energy and recovery. Low blood pressure can be a substantial energy drainer for your brain. Both high and low blood pressure issues stress your brain.

4. Sleep Quality

Sleep apnea, waking up multiple times at night to use the restroom, high cortisol levels and stress hormones at night, and poor blood sugar regulation affect your sleep quality and impairs brain repair time.

Your brain relies on adequate quality sleep to manage its glymphatics housekeeping time. Cutting corners with sleep interferes with energy levels and clearance of metabolic waste products from the previous day’s work. Schedule a consistent bedtime.

5. GABA Support

A healthy gut microbiome naturally supports GABA production. Many whole foods also naturally supply GABA. These foods include adzuki beans and other beans, peas, tomato, kale, broccoli, spinach, mushroom, buckwheat, oat, wheat, barley, rice, sweet potato, wild celery, white tea, and black raspberry juice. Fresh, sprouted, and/or raw sources of these foods provided higher content of GABA than processed, refined products. Routinely include these foods in your diet to combat symptoms of restlessness, anxiety, inner tension, hyperactivity, and fitful sleep.

Lemon balm, passion flower, ashwagandha, lavender, chamomile, taurine, and theanine from green tea naturally interact with GABA receptor sites to support relaxation in your brain.

6. Antioxidant Support for your Brain

Set goals to consume at least 8-9 servings of vegetables and fruits per day. Your children need them too! If you don’t get it from your diet, you need to support brain health with nutritional supplements. Optimize your antioxidant status for high demands and stress needs.

Extra nutritional support can be highly beneficial to fortify and protect your brain for prolonged focus and cognitive demands. Excellent choices for nerve and microglial antioxidant support includes Brain Protector, Fisetin, Daily DHA, Daily Super E, Astaxanthin, Grape Seed Extract and herbal adaptogens like Rhodiola.

Nutrients that support brain-energetic demands include B vitamins, magnesium, R-alpha lipoic acid, choline/alpha-GPC and others. Clinical trials have demonstrated that coenzyme Q10, NADH – a specialized form of niacin, melatonin and zinc are very helpful in reducing significant physical and mental fatigue.

7. Glutamate

Consider reducing intake of foods rich in glutamate if your brain is stressed. Research suggests that about 50 percent of packaged food contains monosodium glutamate (MSG) as a flavor enhancer.

Foods with naturally occurring glutamate include caviar, cheese, crackling, chips, dried cod, fermented beans, fish sauces, gravies, instant coffee powder, meats, miso, mushrooms, noodle dishes, oyster sauce, Parmesan cheese, ready-to-eat meals, salami, savory snacks, seafood, seaweeds, soups, soy sauces, spinach, stews, tomato, tomato sauce. Note that some foods contain both GABA and glutamate. Natural foods provide a diverse array of nutrients including phytochemicals and antioxidants that help balance things as opposed to man-made flavor enhancers.

Recent research demonstrated that acetyl-l-carnitine can modulate glutamate levels in the brain. Low levels of acetyl-l-carnitine have been found in individuals who experience significant chronic brain fatigue.

8. Grocery Shopping

Who hasn’t had the urge to consume junk food after an exhausting day? Even though you know it isn’t the best choice, you reach for it anyway.

It is best to avoid grocery shopping when you are hungry, as you end up purchasing foods that are not as healthy. Try to make it a habit to do your grocery shopping and meal planning when you are refreshed and not overworked.

Fortify your brain before it is taxed; it helps put the odds in your favor for successfully navigating through fatigue, “brain pain,” reduced risk for poor choices, and to stay mentally sharp!

Additional resources your may find helpful.

GABA: Managing Brain Stimulation, Anxiety, and Other Consequences

Brain Fatigue 101

GMOs, Roundup, and Sunscreen Linked with Diminished Brain Resiliency

Feed Your Busy Brain

Low Blood Pressure Causes Fatigue and Brain Stress

Low Blood Pressure Linked with Brain Atrophy

Glymphatics: Keeping the Brain’s Waste Removal System Healthy

Sleep – Molecular Clean Up Time for the Brain

Theanine: Stress Management and Beyond

Adaptogen Rhodiola Helps Stress Resilience, Cognitive Function, and Mood

Fisetin: A Smart Nutrient

Top 7 Nutrients for Stress Resiliency, Sleep, and Mood

Plant-Based Diets Lack Taurine

Nutritional Interventions to Help Your Gut and Anxious Brain

Childhood Eyesight – Effects of Pandemic and Screen Time

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