Brain Health: How to Reduce your Risk of Alzheimer’s and Age-Related Cognitive Decline
AUTHOR: Cliff Harvey, PhD (Clinical Nutritionist & Researcher)
The aging global population has people questioning now, more than ever before, how they can prevent cognitive decline. Clinical Nutritionist and Researcher Cliff Harvey, discusses how we can optimize our brain health to reduce the risk of developing age-related brain conditions below.
In my clinical practice, we periodically survey our clients on the health conditions or outcomes that most concern them. In the early years, we would consistently hear that the biggest concern was quite simply, weight. Now though, weight and body fat have fallen behind brain health and day-to-day energy as major client concerns. This is unsurprising given the rising incidence of the neurodegenerative conditions Alzheimer’s and Parkinson’s, and other diseases that affect the brain and central nervous system.
What are ‘neurodegenerative disorders’?
Neurodegeneration is the progressive damage and destruction of neurons (brain and nervous systems cells) and/or components of those cells. This breakdown of cells results in age-related cognitive decline and in more serious cases the common neurodegenerative disorders; dementias such as Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis (known as Lou Gehrig’s disease) and Huntington’s disease. According to Alzheimer’s Disease International, someone in the world develops dementia every three seconds. Additionally, over 50 million people now live with dementia worldwide and this number is expected to double every 20 years. Neurodegenerative disorders cause progressive disability, incurring a loss of cognition, memory and physical function. Survival times are also typically short—for example, the average survival time post-diagnosis for Alzheimer’s disease is only three to nine years.
What causes cognitive decline?
Neurodegenerative disorders and age-related cognitive decline are both inherited (genetic) and also result from diet and lifestyle factors. These causes include head injuries, pesticide exposure (Parkinson’s), hypertension, lack of sleep, and a poor diet, along with additional risk factors of metabolic syndrome and diabetes, depression, excessive alcohol use and tobacco use1.
How can I improve my brain health and reduce my risk of cognitive decline?
1. Exercise your brain and body
Lifestyle factors can reduce your risk of cognitive decline and even improve cognitive function. These include engaging in leisure and physical activities, playing a sport, listening to music, and doing brain-taxing activities (such as crosswords)1,2. People who regularly and actively participate in a variety of social, cultural, and intellectual activities that challenge them, experience lesser cognitive decline, perform better on cognitive tests and are less likely to develop neurodegenerative disorders3. Physical activity shows a consistent, yet not always significant effect on cognitive decline and dementia4-6. It’s likely that the effects of physical activity alone on cognitive decline are limited and that the best effects come from a combination of physical activity, improved diet and regularly challenging the brain with new activities5,6.
2. Get enough sleep
Not sleeping enough, or poor sleep quality (i.e. insomnia and lack of REM sleep) is a risk factor for cognitive decline and dementia7,8. It is recommended that people get between seven and nine hours of high-quality sleep per night.
3. Eat a healthy diet based on natural, unrefined foods
There is a relationship between diet and cognitive decline and it’s likely that eating a diet (such as the Mediterranean diet) based mostly on natural, unrefined foods will reduce the risk of cognitive decline and dementia2. In a review of studies, it was shown that following a Mediterranean diet was associated with up to a 48% reduced risk of dementia, and those with pre-existing Alzheimer’s disease had a 73% lower mortality risk than those who did not adhere to the diet9.
4. Increased fruits and vegetables
Increased intakes of fruit and vegetables are associated with both a lower risk of dementia and slowing rates of age-related cognitive decline1-10. However, subtype analysis has demonstrated that this effect is restricted to vegetables (and not fruit), with the strongest effects from cruciferous (like cabbage and broccoli) and green leafy vegetables10. It has been further suggested that a minimum of three servings of vegetables should be consumed daily for this effect10.
5. Vitamin C
Maintaining healthy levels of vitamin C from nutrient-rich foods to avoid a deficiency (rather than mega-dosing) is likely to have a protective function against age-related cognitive decline11.
6. Omega-3 fats
The omega-3 fats EPA and especially DHA, play an important role in brain development and healthy functioning of the brain and central nervous system12. Omega-3 fats are linked to reduced mental fatigue13, improved memory and cognition and reduced cognitive decline1,14,15, reduced rates of depression and improved structural integrity of the brain16,17. Plausible mechanisms also exist to suggest a protective role for fish oil in neurodegeneration in Parkinson’s disease18.
7. Coffee and tea
Caffeine is a well-known cognitive enhancer. Evidence shows that caffeine improves attention, vigilance, reaction times, and problem-solving (especially in sleep-deprived people)19,20, and improved mood and reduced fatigue even at low doses of caffeine-containing beverages (≈1 cup of tea or coffee per day)20,21. In addition to its acute effect on mood and cognition, caffeine-containing beverages may be protective against cognitive decline and dementia22, and coffee and tea are also associated with a reduced incidence of Parkinson’s disease23,24. Tea constituents other than caffeine (L-theanine and epigallocatechin gallate) could also improve cognition. A review of the research in this area suggested that caffeine combined with theanine (as found in tea) improved alertness and attention more than caffeine alone25.
8. Multi – vitamins and minerals
Many people do not consume sufficient essential and secondary nutrients from diet alone26,27. Multivitamin/mineral supplements have resulted in improved cognitive and memory performance in trials and reduced stress and anxiety28,29, and it is likely that supporting nutrient-sufficiency of the diet could improve long-term brain health and reduce cognitive decline.
9. Medium-chain triglycerides
Medium-chain triglycerides (MCT) are naturally occurring fats found in small amounts in dairy products and greater amounts in coconut oil. They are also commonly used as isolated supplement oils. MCT supplemented diets improve mental performance in those with Alzheimer’s Disease and age-related cognitive decline30,31, and a single dose of 20g MCT has been shown to improve cognition32.
10. Lion’s mane mushroom
Lion’s mane or Hericium erinaceus is an edible and medicinal mushroom native to North America, Europe and Asia belonging to the tooth fungus group. Lion’s Mane has been shown to increase ‘nerve growth factor’33, which helps nerves and brain cells to grow and repair34-39. Because of this brain-repair effect, lion’s mane is being considered as one of the most promising preventatives for dementia and cognitive decline40,41. It’s also been demonstrated to significantly reduce depression and anxiety35, as well as improve cognitive function42.
There is also evidence for a range of other nootropic or cognitive ‘boosting’ supplements which may help to prevent cognitive decline. See our article on nootropics to find out what they are and how they may help.
- Plassman BL, Williams JW, Jr., Burke JR, Holsinger T, Benjamin S. Systematic Review: Factors Associated With Risk for and Possible Prevention of Cognitive Decline in Later Life. Annals of Internal Medicine. 2010;153(3):182-93.
- Klimova B, Valis M, Kuca K. Cognitive decline in normal aging and its prevention: a review on non-pharmacological lifestyle strategies. Clinical interventions in aging. 2017;12:903-10.
- Wajman JR, Mansur LL, Yassuda MS. Lifestyle Patterns as a Modifiable Risk Factor for Late-life Cognitive Decline: A Narrative Review Regarding Dementia Prevention. Current Aging Science. 2018;11(2):90-9.
- Blondell SJ, Hammersley-Mather R, Veerman JL. Does physical activity prevent cognitive decline and dementia?: A systematic review and meta-analysis of longitudinal studies. BMC Public Health. 2014;14(1):510.
- Brasure M, Desai P, Davila H, Nelson VA, Calvert C, Jutkowitz E, et al. Physical Activity Interventions in Preventing Cognitive Decline and Alzheimer-Type Dementia: A Systematic Review. Annals of Internal Medicine. 2018;168(1):30-8.
- de Souto Barreto P, Demougeot L, Vellas B, Rolland Y. Exercise Training for Preventing Dementia, Mild Cognitive Impairment, and Clinically Meaningful Cognitive Decline: A Systematic Review and Meta-analysis. The Journals of Gerontology: Series A. 2017;73(11):1504-11.
- Xu W, Tan C-C, Zou J-J, Cao X-P, Tan L. Sleep problems and risk of all-cause cognitive decline or dementia: an updated systematic review and meta-analysis. Journal of Neurology, Neurosurgery & Psychiatry. 2019:jnnp-2019-321896.
- Spira AP, Chen-Edinboro LP, Wu MN, Yaffe K. Impact of sleep on the risk of cognitive decline and dementia. Current opinion in psychiatry. 2014;27(6):478-83.
- Opie RS, Ralston RA, Walker KZ. Adherence to a Mediterranean-style diet can slow the rate of cognitive decline and decrease the risk of dementia: a systematic review. Nutrition & Dietetics. 2013;70(3):206-17.
- Loef M, Walach H. Fruit, vegetables and prevention of cognitive decline or dementia: A systematic review of cohort studies. The journal of nutrition, health & aging. 2012;16(7):626-30.
- Harrison FE. A critical review of vitamin C for the prevention of age-related cognitive decline and Alzheimer's disease. Journal of Alzheimer's disease : JAD. 2012;29(4):711-26.
- Ghasemi Fard S, Wang F, Sinclair AJ, Elliott G, Turchini GM. How does high DHA fish oil affect health? A systematic review of evidence. Critical Reviews in Food Science and Nutrition. 2018:1-44.
- Jackson PA, Deary ME, Reay JL, Scholey AB, Kennedy DO. No effect of 12 weeks' supplementation with 1 g DHA-rich or EPA-rich fish oil on cognitive function or mood in healthy young adults aged 18–35 years. British Journal of Nutrition. 2012;107(8):1232-43.
- Lee LK, Shahar S, Chin A-V, Yusoff NAM. Docosahexaenoic acid-concentrated fish oil supplementation in subjects with mild cognitive impairment (MCI): a 12-month randomised, double-blind, placebo-controlled trial. Psychopharmacology. 2013;225(3):605-12.
- Daiello LA, Wellenius G, Ott BR, Buka SL. Role of supplemental docosahexaenoic acid (DHA) for cognition in Alzheimer's disease and mild cognitive impairment: A systematic review and meta-analysis of randomized controlled trials. Alzheimer's & Dementia: The Journal of the Alzheimer's Association. 2015;11(7):P611.
- O'Connor EM, Power SE, Fitzgerald GF, O'Toole PW. Fish-oil consumption is inversely correlated with depression and cognition decline in healthy Irish elderly adults. Proceedings of the Nutrition Society. 2012;71(OCE2):E151.
- Daiello LA, Gongvatana A, Dunsiger S, Cohen RA, Ott BR. Association of fish oil supplement use with preservation of brain volume and cognitive function. Alzheimer's & Dementia. 2015;11(2):226-35.
- Perez-Pardo P, Dodiya HB, Broersen LM, Douna H, van Wijk N, Lopes da Silva S, et al. Gut–brain and brain–gut axis in Parkinson's disease models: Effects of a uridine and fish oil diet. Nutritional neuroscience. 2017:1-12.
- Crawford C, Teo L, Lafferty L, Drake A, Bingham JJ, Gallon MD, et al. Caffeine to optimize cognitive function for military mission-readiness: a systematic review and recommendations for the field. Nutrition reviews. 2017;75(suppl_2):17-35.
- Irwin C, Khalesi S, Desbrow B, McCartney D. Effects of acute caffeine consumption following sleep loss on cognitive, physical, occupational and driving performance: A systematic review and meta-analysis. Neuroscience & Biobehavioral Reviews. 2020;108:877-88.
- Ruxton CHS. The impact of caffeine on mood, cognitive function, performance and hydration: a review of benefits and risks. Nutrition Bulletin. 2008;33(1):15-25.
- Panza F, Solfrizzi V, Barulli MR, Bonfiglio C, Guerra V, Osella A, et al. Coffee, tea, and caffeine consumption and prevention of late-life cognitive decline and dementia: A systematic review. The journal of nutrition, health & aging. 2015;19(3):313-28.
- Prediger RD. Effects of caffeine in Parkinson's disease: from neuroprotection to the management of motor and non-motor symptoms. Journal of Alzheimer's Disease. 2010;20(s1):S205-S20.
- Ross GW, Petrovitch H. Current Evidence for Neuroprotective Effects of Nicotine and Caffeine Against Parkinson’s Disease. Drugs & Aging. 2001;18(11):797-806.
- Camfield DA, Stough C, Farrimond J, Scholey AB. Acute effects of tea constituents L-theanine, caffeine, and epigallocatechin gallate on cognitive function and mood: a systematic review and meta-analysis. Nutrition reviews. 2014;72(8):507-22.
- Health. Mo. New Zealand Health Survey. Wellington; 2013.
- University of Otago and Ministry of Health. A Focus on Nutrition: Key findings of the 2008/09 New Zealand Adult Nutrition Survey. Wellington; 2011.
- Vinod Kumar M, Rajagopalan S. Trial using multiple micronutrient food supplement and its effect on cognition. The Indian Journal of Pediatrics. 2008;75(7):671-8.
- Macpherson H, Rowsell R, Cox KHM, Scholey A, Pipingas A. Acute mood but not cognitive improvements following administration of a single multivitamin and mineral supplement in healthy women aged 50 and above: a randomised controlled trial. AGE. 2015;37(3):38.
- Reger MA, Henderson ST, Hale C, Cholerton B, Baker LD, Watson GS, et al. Effects of β-hydroxybutyrate on cognition in memory-impaired adults. Neurobiology of Aging. 2004;25(3):311-4.
- Cunnane SC, Courchesne-Loyer A, St-Pierre V, Vandenberghe C, Pierotti T, Fortier M, et al. Can ketones compensate for deteriorating brain glucose uptake during aging? Implications for the risk and treatment of Alzheimer's disease. Annals of the New York Academy of Sciences. 2016;1367(1):12-20.
- Matsuo J, Ashida K, Hattori K, Kunugi H, Ota M, Takahashi T, et al. PT599. Effect of single ketogenic diet containing medium chain triglycerides on cognitive functions in elderly adults. International Journal of Neuropsychopharmacology. 2016;19(Suppl 1):20-.
- Lai P-L, Naidu M, Sabaratnam V, Wong K-H, David RP, Kuppusamy UR, et al. Neurotrophic Properties of the Lion's Mane Medicinal Mushroom, Hericium erinaceus (Higher Basidiomycetes) from Malaysia. 2013;15(6):539-54.
- Park YS, Lee HS, Won MH, Lee JH, Lee SY, Lee HY. Effect of an exo-polysaccharide from the culture broth of Hericium erinaceus on enhancement of growth and differentiation of rat adrenal nerve cells. Cytotechnology. 2002;39(3):155.
- Nagano M, Shimizu K, Kondo R, Hayashi C, Sato D, Kitagawa K, et al. Reduction of depression and anxiety by 4 weeks Hericium erinaceus intake. Biomedical Research. 2010;31(4):231-7.
- Wong K-H, Vikineswary S, Naidu M, Keynes R. Activity of Aqueous Extracts of Lion's Mane Mushroom Hericium erinaceus (Bull.: Fr.) Pers. (Aphyllophoromycetideae) on the Neural Cell Line NG108-15. 2007;9(1):57-65.
- Wong K-H, Naidu M, David P, Abdulla MA, Abdullah N, Kuppusamy UR, et al. Peripheral Nerve Regeneration Following Crush Injury to Rat Peroneal Nerve by Aqueous Extract of Medicinal Mushroom Hericium erinaceus (Bull.: Fr) Pers. (Aphyllophoromycetideae). Evidence-Based Complementary and Alternative Medicine. 2011;2011:10.
- Wong K-H, Naidu M, David RP, Abdulla MA, Kuppusamy UR. Functional Recovery Enhancement Following Injury to Rodent Peroneal Nerve by Lion's Mane Mushroom, Hericium erinaceus (Bull.: Fr.) Pers. (Aphyllophoromycetideae). 2009;11(3):225-36.
- Moldavan M, Grygansky AP, Kolotushkina OV, Kirchhoff B, Skibo GG, Pedarzani P. Neurotropic and Trophic Action of Lion's Mane Mushroom Hericium erinaceus (Bull.: Fr.) Pers. (Aphyllophoromycetideae) Extracts on Nerve Cells in Vitro. 2007;9(1):15-28.
- Mizuno T. Bioactive Substances in Hericium erinaceus (Bull.: Fr.) Pers. (Yamabushitake), and Its Medicinal Utilization. 1999;1(2):105-19.
- Mori K, Obara Y, Moriya T, Inatomi S, Nakahata N. Effects of Hericium erinaceus on amyloid β(25-35) peptide-induced learning and memory deficits in mice. Biomedical Research. 2011;32(1):67-72.
- Mori K, Inatomi S, Ouchi K, Azumi Y, Tuchida T. Improving effects of the mushroom Yamabushitake (Hericium erinaceus) on mild cognitive impairment: a double-blind placebo-controlled clinical trial. Phytotherapy Research. 2009;23(3):367-72.
- Colucci L, Bosco M, Rosario Ziello A, Rea R, Amenta F, Fasanaro AM. Effectiveness of nootropic drugs with cholinergic activity in treatment of cognitive deficit: a review. J Exp Pharmacol. 2012;4:163-72.
- Neuropharmacological Review of the Nootropic Herb Bacopa monnieri. Rejuvenation Research. 2013;16(4):313-26.
- Stough C, Downey LA, Lloyd J, Silber B, Redman S, Hutchison C, et al. Examining the nootropic effects of a special extract of Bacopa monniera on human cognitive functioning: 90 day double-blind placebo-controlled randomized trial. Phytotherapy Research. 2008;22(12):1629-34.
- Kongkeaw C, Dilokthornsakul P, Thanarangsarit P, Limpeanchob N, Norman Scholfield C. Meta-analysis of randomized controlled trials on cognitive effects of Bacopa monnieri extract. Journal of Ethnopharmacology. 2014;151(1):528-35.
- Tan M-S, Yu J-T, Tan C-C, Wang H-F, Meng X-F, Wang C, et al. Efficacy and adverse effects of ginkgo biloba for cognitive impairment and dementia: a systematic review and meta-analysis. Journal of Alzheimer's Disease. 2015;43(2):589-603.
- Lopresti AL. Salvia (Sage): A Review of its Potential Cognitive-Enhancing and Protective Effects. Drugs in R&D. 2017;17(1):53-64.
- Miroddi M, Navarra M, Quattropani MC, Calapai F, Gangemi S, Calapai G. Systematic Review of Clinical Trials Assessing Pharmacological Properties of Salvia Species on Memory, Cognitive Impairment and Alzheimer's Disease. CNS Neuroscience & Therapeutics. 2014;20(6):485-95.
- Burgum C, Lee D, McGrath K, O'Hare K, Morrin A. The effect of sage (Salvia officinalis) on cognitive and vascular function in healthy young adults.. 2014.
- Lally T. The effects of sage (Salvia officinalis) supplementation on vascular health, cognitive function and menopausal symptoms in peri-and post-menopausal women 2018.
- Falcone PH, Tribby AC, Vogel RM, Joy JM, Moon JR, Slayton CA, et al. Efficacy of a nootropic spearmint extract on reactive agility: a randomized, double-blind, placebo-controlled, parallel trial. Journal of the International Society of Sports Nutrition. 2018;15(1):58.