Nutrition and Cognition
Optimizing brain health and cognition includes balancing three key areas: nutrition, building new cells, and breaking down old connections. While the average person does not have direct, conscious control over how the brain creates new and retires old, diet is a key tool in maintaining whole-body health, including cognition. Nutrition plays a major role in both physical health and mental health, a role that is particularly evident in the context of the brain. Supporting brain function may include memory, attention, concentration, and energy levels.
Vital Ingredients for Healthy Brain Function
With brain health and cognition, optimizing function includes supporting healthy levels of oxygen and fuel (glucose, lactate), as well as supporting healthy circulation and mitochondria for energy.
Oxygen
The brain is the body’s center of communication, and with proper access to oxygen, the brain is best positioned to function optimally. The amount of oxygen in the brain and the entire body depends on breathing rates, blood circulation, and a protein in blood called hemoglobin – which is responsible for carrying oxygen throughout the body. Lifestyle habits like physical activity can increase oxygenation in the body; additionally, taking deep breaths, meditating, and potentially being around plants regularly can help improve oxygen levels in the body and brain.1
Fuel
Glucose is the primary and preferred energy source in the body, and it is important for the brain in particular because it influences memory, concentration, and energy levels. Steady, consistent delivery rates for glucose paired with healthy circulation are among the best conditions for brain function.
Unstable blood glucose levels may result in hypoglycemia (low blood glucose), potentially leading to symptoms like fatigue, memory issues, irritability, poor concentration, and quick irritability. Panic attacks and anxiety have also been connected to varying blood glucose levels or reactive hypoglycemia.2,3 In addition, Alzheimer’s disease has often been referred to as “Type III diabetes” because some Alzheimer’s patients develop insulin resistance.
Lactate is another key metabolite important for brain health and cognition. Secondary to glucose, the brain can use lactate as an energy source to fuel brain metabolism, and it may also act as a signaling molecule in the brain.4 Lactate is formed from the breakdown of lactic acid, which is a byproduct of anaerobic metabolism – the production of energy in the absence of oxygen. From this breakdown, lactate is recycled for energy.
Red blood cells produce lactic acid through anaerobic metabolism because they lack mitochondria and thus access to aerobic metabolism. Muscle cells, which have mitochondria, utilize both aerobic and anaerobic pathways of metabolism, being able to produce energy when oxygen is not readily available – such as during short, high intensity bursts of physical activity.
Muscles generate the greatest amount of lactate, and the brain is one of a few organs that use it as fuel, along with the heart and the liver.4
Circulation
Circulation is another vital component of brain health and cognition – essential for the delivery of fuel to the brain. The brain doesn’t store oxygen and fuel like other body organs do, so keeping the flow of blood to the brain is a critical, 24/7 job. The adult brain uses 20 to 25 percent of the calories consumed through food in the diet for regular function (more so in children and at birth), so it is imperative that those nutrients are circulated and delivered on a regular schedule for optimal brain performance.
Gingko (Ginkgo biloba) is a medicinal herb shown to increase blood flow velocity in small blood vessels, including those in the brain, as well as stabilize mitochondria.
The Brain: Always Under Construction
The brain is constantly growing and changing. Every day, the brain adapts to learning new information, skills, and language as well as creating and storing memories. It does this by growing new neurons and microglia in addition to synaptic pruning, the targeted process of recycling functional synapses to promote overall brain health. This is similar to pruning older leaves and blooms from a plant to help the new buds grow. Experts estimate that as many as 86 billion neurons reside in the brain, each with countless connections to other neurons.5
The brain also undergoes construction through nerve growth factors (NGF), made by all nerves.6 NGFs have been shown to be helpful when addressing neuropathies, traumatic brain injury, and multiple sclerosis.7 Brain-derived neurotrophic factor (BDNF) is another brain factor that is vital for neuroplasticity and is associated with anti-inflammatory activity.8 BDNF has also been shown to help with anxiety and depression due to its anti-inflammatory properties.9
NGF and BDNF Support in the Diet
A handful of plants common in the diet as well as individual vitamins and minerals have been identified as supportive of brain function by promoting both NGF and BDNF.
- Mushrooms: Lion’s Mane (Hericium erinaceus) is a type of medicinal mushroom shown to stimulate NGF and increase brain plasticity, which allows the brain to adapt to change and a variety of stimuli.10 In addition, Lion’s Mane improves memory and has BDNF-like activity in the hippocampus, which supports memory.11
- Green Tea has shown to improve NGF function. Whole green tea extract may work better than certain isolated forms and has been proven to allow low levels of NGF to increase to 25 times higher.12
- Blueberries contain anthocyanins, which are known for their antidiabetic, anticancer, anti-inflammatory, antimicrobial, and anti-obesity properties.13 Specifically for the brain, one study found that anthocyanins raise BDNF levels to enhance memory.
Other herbs, vitamins, and foods shown to improve BDNF function:
- Extra virgin olive oil
- Rhodiola (Rhodiola rosea)
- Saffron (Crocus sativus)
- Magnolia
- Vitamin D
- Magnesium
- Zinc
BDNF levels may be suboptimal as a result of lifestyle choices and conditions such as a poor diet high in both sugar and fat, obesity, insulin resistance, excessive consumption of calories, poor sleep, stress, and smoking.14 Other herbs and nutrients shown to protect BDNF levels:
- Ginseng (Panax quinquefolium)
- Gotu Kola (Centella asiatica)
- Ashwagandha (Withania somnifera)
- Bacopa (Bacopa monnieri)
- Omega-3 fatty acids
- Cocoa
Maintaining a healthy, active lifestyle is essential for the body’s muscles, bones, organs, and especially the brain. Support the brain and the body daily by consuming a variety of fruits, vegetables, whole grains, herbs, and lean proteins, in addition to daily movement and mindful habits.
Nutritional Deficiencies and Cognitive Decline
Nutrition can support brain health throughout the entire lifespan — from early development to childhood and even into older adulthood.15,16 The brain is a metabolically active organ and therefore has high nutrient and energy demands.17 When nutritional deficiencies occur, it can have a significant impact on brain health and function, contributing to cognitive decline, poor memory, issues with focus, and overall poor brain health.
Vitamin B12
Vitamin B12 is involved in myelination which supports nerve function and contributes to healthy cognitive processes. When vitamin B12 is deficient, it can result in many symptoms including impaired cognition, confusion, poor memory, and mood.18
Low vitamin B12 is also often seen alongside elevated homocysteine and methylmalonic acid levels which are associated with poor cognitive outcomes.18 Vitamin B12 is found in animal products such as meat and dairy, as well as in fortified foods including fortified cereals. Supplementation may be necessary for groups at higher risk of insufficient intake including vegans and older adults.15
Omega-3 Fatty Acids
Omega-3 fatty acids are extremely important for the brain. They comprise over a quarter of the weight of the brain, with DHA accounting for more than 40% of total fatty acids in neuronal tissue, including in the gray matter.19
DHA rapidly accumulates in the brain during pregnancy and the first 18 months after birth as part of neuronal membranes and contributes to healthy neurotransmission.19 Omega-3 fatty acids also promote cognition and help preserve neurons, protecting against neurodegeneration as well as neuroinflammation.19 They also help decrease oxidative stress in the brain and reduce apoptosis, which protects brain health.19
Increasing consumption of omega-3 fatty acids has been associated with a reduced risk of several chronic diseases.20
Omega-3 fatty acids can be found in fatty fish, like salmon, as well as flaxseeds and walnuts. Conversion of precursors to the essential fatty acids DHA and EPA is low and the Standard American Diet is very high in omega-6 fatty acids while being low in omega-3 fatty acids. Because of this, most people would benefit from including an omega-3 fatty acid supplement as part of their daily routine. Symptoms of a diet that is low in omega-3 fatty acids may include poor memory, depression, and skin issues.
Iron
Iron is a component of hemoglobin, a major oxygen transporter throughout the body. Without sufficient iron, oxygen transport can become impaired, including to the brain.15 The brain also appears to be very sensitive to changes in iron homeostasis and if levels decline, important processes can be disturbed including axon myelination and neural transmission.17 Beyond oxygen transport, iron plays a role in neurotransmitter metabolism, which can affect behavioral and cognitive functions of the brain.15
Iron deficiency is a very common nutritional deficiency throughout the world.15 Common symptoms include fatigue, poor concentration, and impaired cognitive development in children.
Dietary sources of iron include red meat as a source of heme iron which tends to be more bioavailable while non-heme sources of iron include beans and spinach. For some individuals, supplementation with iron may be necessary to replete stores although this should be done under medical guidance.
Vitamin D
Vitamin D is a fat-soluble vitamin that has diverse functions in the body, including supporting brain function. Vitamin D exerts anti-inflammatory effects, increases neurotrophic factors such as nerve growth factor, and promotes the clearance of amyloid proteins in the brain.21 It is also involved in neurotransmitter regulation, contributing to mood and cognitive function.21
Vitamin D deficiency has been associated with Alzheimer’s disease and cognitive impairment and pre-clinical studies indicate low vitamin D is linked to attentional, behavioral, and cognitive problems.21
Symptoms of vitamin D deficiency include fatigue, muscle weakness and mood changes. Consuming fatty fish and fortified foods can help ensure an adequate intake of vitamin D, especially in regions with limited sun exposure. Supplementation can also help individuals obtain enough vitamin D during winter months or if dietary intake is insufficient.
Magnesium
In recent years, magnesium has received increased attention for its role in supporting brain health, including its ability to regulate cognitive status and wellbeing.22 Magnesium is involved in neurotransmitter release, neuronal excitability, and synaptic plasticity, all of which contribute to cognitive ability.22
Magnesium is also critical to many cellular processes including protein synthesis and membrane stability.22 If magnesium is lacking, cellular health can become compromised and impact brain health.
Symptoms of magnesium deficiency may include loss of appetite, anxiety, depression, and brain fog. Dietary sources of magnesium include leafy green vegetables, nuts, seeds, and whole grains; however, supplementation is a good option for individuals who may need help consuming enough magnesium every day.
Zinc
Similar to magnesium, zinc is an essential mineral that supports hundreds of biochemical processes in the body. Within the brain, zinc is stored in neurons and involved in synaptic plasticity, neurogenesis, and neurotransmitter function.23, 24
Cognitive symptoms of deficiency include memory impairment and mood disorders and severe zinc deficiency has been associated with cognitive decline and can contribute to neurodegenerative diseases.23, 24
Dietary sources of zinc include meat, shellfish, and legumes and supplementation remains a great option for individuals concerned about their zinc intake.
Maintaining a healthy, active lifestyle is essential for the body’s muscles, bones, organs, and especially the brain.
Consuming a healthy diet, full of a variety of fruits, vegetables, whole grains, herbs, and lean proteins can help supply the body with essential micronutrients that support brain and cognitive health. And when necessary, dietary supplements can help fill nutrient gaps and keep the body performing at its best.
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- Claudio L. (2011). Planting healthier indoor air. Environmental health perspectives, 119(10), A426–A427. https://doi.org/10.1289/ehp.119-a426
- McNay, E. (2015). Recurrent hypoglycemia increases anxiety and amygdala norepinephrine release during subsequent hypoglycemia. Frontiers in endocrinology, 6, 175.
- Aucoin, M., & Bhardwaj, S. (2016). Generalized anxiety disorder and hypoglycemia symptoms improved with diet modification. Case reports in psychiatry, 2016.
- Riske, L., Thomas, R. K., Baker, G. B., & Dursun, S. M. (2017). Lactate in the brain: an update on its relevance to brain energy, neurons, glia and panic disorder. Therapeutic advances in psychopharmacology, 7(2), 85–89. https://doi.org/10.1177/2045125316675579
- Voytek, B. (2013). Are there really as many neurons in the human brain as stars in the milky way?. Obtenido de Nature
- Aloe, L., Rocco, M. L., Bianchi, P., & Manni, L. (2012). Nerve growth factor: from the early discoveries to the potential clinical use. Journal of translational medicine, 10(1), 1-15.
- Bisht, B., Darling, W. G., Shivapour, E. T., Lutgendorf, S. K., Snetselaar, L. G., Chenard, C. A., & Wahls, T. L. (2015). Multimodal intervention improves fatigue and quality of life in subjects with progressive multiple sclerosis: a pilot study. Degenerative neurological and neuromuscular disease, 5, 19.
- Cunha, C., Brambilla, R., & Thomas, K. L. (2010). A simple role for BDNF in learning and memory?. Frontiers in molecular neuroscience, 3, 1.
- Chagnon, Y. C., Potvin, O., Hudon, C., & Préville, M. (2015). DNA methylation and single nucleotide variants in the brain-derived neurotrophic factor (BDNF) and oxytocin receptor (OXTR) genes are associated with anxiety/depression in older women. Frontiers in genetics, 6, 230.
- Lai, P. L., Naidu, M., Sabaratnam, V., Wong, K. H., David, R. P., Kuppusamy, U. R., ... & Malek, S. N. A. (2013). Neurotrophic properties of the Lion's mane medicinal mushroom, Hericium erinaceus (Higher Basidiomycetes) from Malaysia. International journal of medicinal mushrooms, 15(6).
- Martínez-Mármol, R., Chai, Y., Khan, Z., Kim, S. B., Hong, S. M., Gormal, R., ... & Meunier, F. A. (2020). Hericerin derivatives from Hericium erinaceus exert BDNF-like neurotrophic activity in central hippocampal neurons and enhance memory. bioRxiv.
- Gundimeda, U., McNeill, T. H., Schiffman, J. E., Hinton, D. R., & Gopalakrishna, R. (2010). Green tea polyphenols potentiate the action of nerve growth factor to induce neuritogenesis: possible role of reactive oxygen species. Journal of neuroscience research, 88(16), 3644-3655.
- He, K., Li, X., Chen, X., Ye, X., Huang, J., Jin, Y., Li, P., Deng, Y., Jin, Q., Shi, Q., & Shu, H. (2011). Evaluation of antidiabetic potential of selected traditional Chinese medicines in STZ-induced diabetic mice. Journal of ethnopharmacology, 137(3), 1135–1142. https://doi.org/10.1016/j.jep.2011.07.033
- Gomez-Pinilla, F. (2008). The influences of diet and exercise on mental health through hormesis. Ageing research reviews, 7(1), 49-62.
- Black, M.M. (2003). Micronutrient Deficiencies and Cognitive Functioning. J Nutr, 133:3927S.
- Khalid, N.M., Haron, H., Shahar, S., Fenech, M. (2022). Current Evidence on the Association of Micronutrient Malnutrition with Mild Cognitive Impairment, Frailty, and Cognitive Frailty among Older Adults: A Scoping Review. Int J Environ Res Public Health, 19:15722.
- Ferreira, A., Neves, P., Gozzelino, R. (2019). Multilevel Impacts of Iron in the Brain: The Cross Talk between Neurophysiological Mechanisms, Cognition, and Social Behavior. Pharmaceuticals (Basel), 12(3);126.
- Jatoi, S., Hafeez, A., Riaz, S.U., Ali, A., Ghauri, M.I., Zehra, M. (2020). Low Vitamin B12 Levels: An Underestimated Cause of Minimal Cognitive Impairment and Dementia. Cureus, 12(2):e6976.
- Dighriri, I.M., Alsubaie, A.M., Hakami, F.M., Hamithi, D.M., Alshekh, M.M., Khobrani, F.A., et al. (2022). Effects of Omega-3 Polyunsaturated Fatty Acids on Brain Functions: A Systematic Review. Cureus, 14(10):e30091.
- National Institutes of Health Office of Dietary Supplements. Fact Sheet for Health Professionals: Omega-3 Fatty Acids. [Last Update February 15, 2023]. Available at: https://ods.od.nih.gov/factsheets/Omega3FattyAcids-HealthProfessional/.
- Sultan, S., Taimuri, U., Basnan, S.A., Ai-Orabi, W.K., Awadallah, A., Almowald, F., et al. (2020). Low Vitamin D and Its Association with Cognitive Impairment and Dementia. J Aging Res, 2020:6097820.
- Hoane MR. The role of magnesium therapy in learning and memory. In: Vink R, Nechifor M, editors. Magnesium in the Central Nervous System [Internet]. Adelaide (AU): University of Adelaide Press; 2011. Available from: https://www.ncbi.nlm.nih.gov/books/NBK507270/.
- Sun, R., Wang, J., Feng, J., Cao, B. (2022). Zinc in Cognitive Impairment and Aging. Biomolecules, 12(7):1000.
- da Silva de Vargas, L., Jantsch, J., Fontoura, J.R., Dorneles, G.P., Peres, A., et al. (2023). Effects of Zinc Supplementation on Inflammatory and Cognitive Parameters in Middle-Aged Women with Overweight or Obesity. Nutrients, 15(20):4396.