Natural Aids to Memory and Cognitive Performance

As the American population ages, quality-of-life issues often seem to surpass concerns for longevity. Whether it’s our joints, our hearing, or our mental performance, individuals throughout America—and the world—are rightly seeking to increase their quality of life, not merely the number of birthdays they celebrate. High on the list of performance concerns are those that relate to mental acuity.

The United States Centers for Disease Control and Prevention (CDC) reports that one in nine Americans (ages 45 or older) report experiences of confusion and memory loss. ¹ Clearly, you are not alone if you have been experiencing difficulty with your memory.

What to Do About Memory Difficulties

If you have noticed some deterioration in your recall, start by discussing your concerns with a physician or other expert. This may seem obvious, but a 2013 CDC study indicated that over two-thirds of those so affected will not consult a health professional. ²

Medical evaluation is extremely important. Although memory difficulties may be among the earliest signs of dementia, fearing the worst is no reason to defer a thorough diagnosis. Even if a dementing process is at work, some causes of dementia can be halted or reversed. However, the best news is that many cases of memory challenge are not due to Alzheimer’s or other forms of dementia. Medical evaluation can uncover treatable memory-robbers like depression, nutritional deficiency, or medication side-effects.

But what if you pass your physical exam with flying colors? If your memory is not suffering due to a diagnosable medical or mental health condition, that’s even better. Most people who struggle with less than optimal memory can significantly improve their recall by simple lifestyle practices. In this article we’ll cover eight key areas of lifestyle that can boost your memory—whether or not you have any cognitive limitations.

Physiology of Memory

A basic understanding of brain physiology can help us better understand the connection between lifestyle practices and improved memory. Critical to optimal memory are a pair of structures that lie deep in our brains, the hippocampi (plural for hippocampus). Known as part of the “limbic system” or emotional brain, the hippocampi lie in a region called the medial temporal lobe. They are involved in contextual and relational memory—those types of memory which are typically the domains in question when lay people evaluate their recall.³ (By contrast, learning to ride a bike or downhill ski would involve different brain regions).

The applications here are fairly straightforward: improve hippocampal function, improve memory; impair hippocampal function, impair memory. We should mention that neuroimaging studies indicate that the prefrontal cortex in the frontal lobes also plays an important role in memory.

Brain Cell Fertilizer

Although a multitude of factors can impact the hippocampi, one of the most interesting is something called “brain-derived neurotropic factor” (BDNF). This compound is, as its name indicates, a brain cell (neuron) growth (trophic) factor that is made by the brain itself. In addition to its memory benefits, BDNF has far-reaching health implications. For example, it appears to decrease one’s risk of Alzheimer’s and Parkinson’s diseases, enhance recovery from stroke, and help prevent depression.⁴ With respect to memory, BDNF works in the hippocampi to help develop stronger nerve connections which lie at the foundation of memory.⁵ Although other nerve growth factors play a role in remembrance, BDNF is the most abundant.

With this cursory introduction to some key aspects of the memory physiology, let’s turn our attention to those eight lifestyle factors. Medical research indicates that each of these can boost memory, often by raising BDNF levels, or directly stimulating the hippocampi, or both.

Dietary Memory Enhancers

Whole Plant Foods Are Winners!

Eating an abundance of whole foods from the plant kingdom is one way to give your memory a boost. Consuming a balanced diet primarily of whole foods and low in refined foods and animal protein sets up mechanisms within the body to reduce undesirable inflammation. Moreover, a plant-based diet, consisting of a variety of fruits, vegetables, legumes, nuts, and whole grains, contains many antioxidant and anti-inflammatory compounds that can enhance cognitive abilities. In animal models these nutrients and phytochemicals  have been shown to enhance the creation of new brain cells. Nutrients and phytochemicals also increase the number of synapses, improve their efficiency, and protect neurons from free radical damage and inflammation. ⁶ Additionally, cognitive decline might be slowed with diets having a low Dietary Inflammatory Index (DII) score, characterized by the presence of anti-inflammatory plant foods and phytonutrients. ⁷

Vegetarians and vegans should take extra care in getting adequate amounts of B12, vitamin D, and omega-3 fats. Deficiency in vitamin B-12 is prevalent among vegetarians and vegans, often causing mental decline and neurological and psychological symptoms if a deficiency persists. Deficient vitamin D levels have been linked to cognitive impairment.

Anthocyanin Boosters

Consider anthocyanins, a class of phytochemicals found in foods like red apples, berries, grapes, onion and garlic. These and related plant chemicals have been shown in animal models to improve memory. Anthocyanins provide these benefits by ramping up levels of brain-derived neurotrophic factor (BDNF) in the hippocampi, a brain region vital in memory processes.⁸

Green Leafy Vegetables

Regular consumption of green leafy vegetables may help to keep you mentally sharp. In one study researchers found the consumption of green leafy vegetables was associated with slower cognitive decline after adjusting for age, sex, education, participation in cognitive activities, physical activities, smoking, seafood, and alcohol consumption. In fact, in one study, those who ate them every day slowed their cognitive decline or had the equivalent of being 11 years younger in mental age that those who consumed them infrequently. ⁹

Dietary Memory Subtractors

These messages were underscored by two other recent studies. Australian researchers studied over 200 individuals between 65 and 90 years old. Those who ate the most processed foods (think canned, boxed, or in crinkly bags) were over twice as likely to have poorer mental performance than peers who chose an abundance of unrefined produce.¹⁰ Thousands of miles away, in the Middle East, Jordanian investigators used an animal model to demonstrate that one of the signatures of processed foods—high content of both fat and carbohydrates—was associated with adverse changes in the hippocampi and poorer memory performance.¹¹ A decade earlier, researchers documented a vital physiologic connection in an animal model: a diet rich in saturated fat (abundant in meats) and refined sugar decreased hippocampal BDNF levels.¹²

Temperance

In addition to moving away from animal products by opting for vegetarian sources of nutrition, you can also boost brain BDNF levels by simply eating less. Besides contributing to weight gain, overeating is associated with lower levels of this vital brain- and memory-enhancing compound. Research indicates cutting your caloric intake by as little as 30% can significantly raise brain BDNF content. In addition to caloric restriction in general, intermittent fasting specifically (skipping supper, for example) can boost BDNF levels and pay dividends in cognitive improvement.¹³

Indeed, the research is compelling: focus on unrefined vegetarian sources of nutrition—and curb your caloric intake— to reap the most memory gains.

Exercise Rejuvenates!

For optimal memory function, it is important to prioritize both exercise and rest. Exercise alone has been found to increase BDNF levels in the hippocampal region.¹⁴ A recent paper came to some especially fascinating conclusions using a rat model of Alzheimer’s disease. The investigators showed that while Alzheimer’s depressed hippocampal BDNF levels and impaired memory, thirty minutes of treadmill exercise daily for four weeks could prevent those changes from ever occurring. They concluded: “treadmill exercise may provide therapeutic value for alleviating the symptoms of Alzheimer’s disease.”¹⁵ These results extended the findings of a 2008 prestigious Cochrane review: “There is evidence that aerobic physical activities which improve cardiorespiratory fitness are beneficial for cognitive function in healthy older adults, with effects observed for motor function, cognitive speed, delayed memory functions, and auditory and visual attention.”¹⁶

Although more research is needed, some evidence suggests the venue for exercise makes a difference. Specifically, getting outdoors where you can not only exercise your muscles but make vitamin D may have memory- and other cognitive-boosting benefits. Data already indicates that vitamin D may have brain-health enhancing properties. However, of utmost interest to memory, vitamin D receptors are found in the hippocampus.¹⁷ It is not a great leap to wonder if the “sunshine vitamin” may aid our powers of recall.

Exercise Caveat

When it comes to memory, not all that comes with physical exercise is beneficial. High-risk and extreme sports often carry with them undue risk of traumatic brain injury (TBI). There is growing consensus that as innocuous as a “mild concussion” once sounded, events that traumatize the brain typically take a toll on memory.¹⁸ Yet, the plot deepens. For there is a fascinating relationship between exercise and recovery from TBI. Some evidence suggests that physical exercise within the first seven days is detrimental to optimal recovery. On the other hand, exercise delayed for two weeks after the event offers the expected BDNF stimulation.¹⁹

Don’t Get Short Changed!

Adequate rest and sleep are not only important following a concussion. The vital commodity of rest must be balanced with activity even when we are in optimal health. Sleep, in particular, is necessary for short-term working memory as well as forming long-term memories.^20,21 Perhaps more importantly, chronic sleep deprivation may cause permanent damage to the brain. Recent data indicates that cutting oneself short on sleep (as occurs with typical shift work) may damage the locus ceruleus, the very region of the brain necessary for optimal wakefulness, attention, and thus “capturing” of memories.²²

How do you know if you’re getting enough sleep? Data suggests that for most people, optimal sleep duration is between 7 and 8 ½ hours. However, an arbitrary number of hours is not the best rule of thumb. Consider these two self-checks. First, if you are not able to wake up without an alarm clock and feel refreshed, you may be short-changing yourself when it comes to this vital commodity. Second, another tell-tale sign of sleep deprivation is short sleep latency. This refers to the time it takes to fall asleep after lying down. Falling asleep within five minutes of the time your head hits the pillow may be an indicator of sleep deprivation.

Mental Stimulation: Use It or Lose It

A growing body of evidence indicates just what you might expect: the more you challenge your brain and your memory, the better they get. This has been demonstrated in normal healthy individuals as well as in those with cognitive impairment.²³ The message is simple: engage in a variety of wholesome mental activities that stimulate different regions of your brain. Challenge yourself with mathematical puzzles, crosswords, or even a jigsaw puzzle. Learn a new skill or a language. Engage in-depth Bible study. Embrace a hands-on hobby like carpentry, gardening, knitting, or mechanics. The options are endless, but the message is clear: use your memory and it will improve.

Develop Social Connectedness

At all stages of the lifespan, social connectedness appears important for optimal cognitive health. Using animal models of brain development, researchers from Rome, Italy demonstrated that mice raised in an environment of strong maternal and peer interactions were primed for optimal memory throughout their lives. These socially integrated mice were found to have high BDNF levels in their hippocampi.²⁴

However, a rough childhood does not doom you to cognitive mediocrity. We can benefit from social support regardless of age or health status. In an animal model, mice that were socially isolated immediately after a stroke had greater amounts of brain damage and an increased risk of mortality when compared to mice housed with a healthy peer. These socially-supported mice also showed increased BDNF levels.²⁵ This data complements human data that show similar mortality and health benefits when people are more socially connected following a major health challenge.²⁶ The data suggests that higher BDNF levels may explain these benefits and present another on-topic reminder; namely, social support especially in disease states may help us to maintain or improve cognitive performance and memory.

Avoiding Toxins

A number of addictive compounds have been linked to memory deterioration and/or other forms of cognitive impairment. Let’s look at three of the most common: tobacco, marijuana, and alcohol.

Tobacco

In 2008, British researchers completed a comprehensive review of the literature to date connecting smoking with cognitive performance. Their meta-analysis concluded: “Current smoking increases risk of Alzheimer’s disease and may increase risk of other dementias.”²⁷

Marijuana

The hippocampus is also vulnerable to THC, the addictive agent in marijuana. Not surprisingly, research evidence suggests that marijuana use impairs a person’s ability to form new memories. Furthermore, these hippocampal effects have long term implications. For example, experimentation in rats has linked adolescent marijuana use with adverse changes in adult hippocampus structure and function.²⁸

Alcohol

While the data linking smoking and marijuana to cognitive impairment seem clear cut, relationships with alcohol consumption are more confusing. Earlier data suggested that even moderate alcohol impaired cognition in younger subjects. However, most researchers today feel moderate drinking is not detrimental to mental functioning at any age. And many proclaim it can stave off dementia later in life. Such conclusions should be met with considerable skepticism. There are at least two reasons for this.

First, no one has done any randomized controlled trials on alcohol consumption and cognition. In other words, researchers haven’t conducted rigid scientific studies, giving alcoholic beverages to lifetime non-drinkers and studying the impact on their brain functioning over time. Instead, they merely study people who drink and compare them with those who do not. Such data is subject to something called confounding, where associations can be due to factors other than the one in question. For example, since moderate alcoholic beverage consumption is associated with more education and higher social class,²⁹ these subject characteristics may be what decrease dementia risk rather than the fermented beverages themselves.

Alcohol disrupts hippocampal function directly³⁰ and has been demonstrated to decrease BDNF levels in this key memory region.³¹ This helps to explain something we have known for years: alcohol impairs both learning and recall of new information.³²

In short, don’t buy the hype that moderate drinking ultimately may be good for your brain. Stick with practices of proven benefit to your brain as a whole and especially with regards to the hippocampus and BDNF levels.

Controlling Stress

For years scientists have connected chronic stress, with its hallmark of elevated levels of the hormone cortisol, to deterioration of the hippocampi and consequent memory impairment.^33,34 The data indicates that any serious attempt to improve memory must come to grips with significant stressors in one’s life. Both authors have found particular stress-management benefits from the study of the Bible and the God there revealed.

 

1. https://www.cdc.gov/aging/data/infographic/cognitive-decline.html↩
2. Centers for Disease Control and Prevention.  Self-Reported Increased Confusion or Memory Loss and Associated Functional Difficulties Among Adults Aged ≥60 Years — 21 States, 2011. MMWR  62(18);347-350 (May 10, 2013). https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6218a1.htm ↩
3. McGaugh JL. Searching for Memory in the Brain: Confronting the Collusion of Cells and Systems (Chapter 1 of Neural Plasticity and Memory: From Genes to Brain Imaging Bermúdez-Rattoni F, editor.) Boca Raton (FL): CRC Press; 2007.↩
4. Lee BH, Kim YK. The roles of BDNF in the pathophysiology of major depression and in antidepressant treatment. Psychiatry Investig. 2010 Dec;7(4):231-5.↩
5. Minichiello L. TrkB signalling pathways in LTP and learning. Nature reviews Neuroscience. 2009;10:850–860.↩
6. Rajaram S. Plant-Based Dietary Patterns, Plant Foods, and Age-Related Cognitive Decline. Adv Nutr. 2019 Nov; 10(Suppl 4): S422–S436.↩
7. Frith E.Dietary inflammatory index and memory function: population-based national sample of elderly Americans. Br J Nutr. 2018;119(5):552–8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5839966/ ↩
8. Rendeiro C, Vauzour D, et al. Dietary levels of pure flavonoids improve spatial memory performance and increase hippocampal brain-derived neurotrophic factor. PLoS One. 2013 May 28;8(5):e63535.↩
9. Morris MC. Nutrients and bioactives in green leafy vegetables and cognitive decline. Neurology. 2018 Jan 16; 90(3): e214–e222.↩
10. Torres SJ, Lautenschlager NT, et al. Dietary patterns are associated with cognition among older people with mild cognitive impairment. Nutrients. 2012 Oct 25;4(11):1542- 51.↩
11. Alzoubi KH, Khabour OF, et al. Vitamin E prevents high-fat high-carbohydrates diet- induced memory impairment: The role of oxidative stress. Physiol Behav. 2013 Jun 12. pii: S0031-9384(13)00197-2.↩
12. Molteni R, et al. A high-fat, refined sugar diet reduces hippocampal brain-derived neurotrophic factor, neuronal plasticity, and learning. Neuroscience. 2002;112(4):803-14.↩
13. Mattson MP, Wan R. Beneficial effects of intermittent fasting and caloric restriction on the cardiovascular and cerebrovascular systems. J Nutr Biochem. 2005 Mar;16(3):129- 37↩
14. Gomez-Pinilla F et al. Brain-derived neurotrophic factor functions as a metabotrophin to mediate the effects of exercise on cognition. Eur J Neurosci. 2008 Dec;28(11):2278-87.↩
15. Kim BK et al. Treadmill exercise improves short-term memory by enhancing neurogenesis in amyloid beta-induced Alzheimer disease rats. J Exerc Rehabil. 2014 Feb 28;10(1):2-8.↩
16. Angevaren M, et al. Physical activity and enhanced fitness to improve cognitive function in older people without known cognitive impairment. Cochrane Database Syst Rev. 2008 Apr 16;(2):CD005381.↩
17. Annweiler C, et al. Vitamin D and cognitive performance in adults: a systematic review. Eur J Neurol. 2009 Oct;16(10):1083-9.↩
18. Flynn FG. Memory impairment after mild traumatic brain injury. Continuum (Minneap Minn). 2010 Dec;16(6 Traumatic Brain Injury):79-109.↩
19. Griesbach GS, et al. Voluntary exercise following traumatic brain injury: brain-derived neurotrophic factor upregulation and recovery of function. Neuroscience. 2004;125(1):129-39.↩
20. Alhola P, Polo-Kantola P. Sleep deprivation: Impact on cognitive performance. Neuropsychiatr Dis Treat. 2007;3(5):553-67.↩
21. Stickgold R. Sleep-dependent memory consolidation. Nature. 2005 Oct 27;437(7063):1272-8.↩
22. Zhang J, et al. Extended wakefulness: compromised metabolics in and degeneration of locus ceruleus neurons. J Neurosci. 2014 Mar 19;34(12):4418-31.19↩
23. Alves J, et al. Non-pharmacological cognitive intervention for aging and dementia: Current perspectives. World J Clin Cases. 2013 Nov 16;1(8):233-241.↩
24. Branchi I, et al. Early interactions with mother and peers independently build adult social skills and shape BDNF and oxytocin receptor brain levels. Psychoneuroendocrinology. 2013 Apr;38(4):522-32↩
25. Venna VR, et al. Social interaction plays a critical role in neurogenesis and recovery after stroke. Transl Psychiatry. 2014 Jan 28;4:e351.↩
26. Glass TA, et al. Impact of social support on outcome in first stroke. Stroke. 1993 Jan;24(1):64-70.↩
27. Peters R, et al. Smoking, dementia and cognitive decline in the elderly, a systematic review. BMC Geriatr. 2008 Dec 23;8:36.↩
28. National Institute on Drug Abuse. Marijuana, Memory, and the Hippocampus. Accessed 2 April 2014 at www.drugabuse.gov/publications/research-reports/marijuana/how- does-marijuana-use-affect-your-brain-body↩
29. Lee SJ et al. Functional limitations, socioeconomic status, and all-cause mortality in moderate alcohol drinkers. J Am Geriatr Soc. 2009 Jun;57(6):955-62.↩
30. White AM, et al. Ethanol, memory, and hippocampal function: a review of recent findings. Hippocampus. 2000;10(1):88-93.↩
31. Miller MW, Mooney SM. Chronic exposure to ethanol alters neurotrophin content in the basal forebrain-cortex system in the mature rat: effects on autocrine-paracrine mechanisms. J Neurobiol. 2004 Sep 15;60(4):490-8.↩
32. Lister RG, et al. Ethanol intoxication and memory. Recent developments and new directions. Recent Dev Alcohol. 1987;5:111-26.↩
33. Lupien SJ, et al. Cortisol levels during human aging predict hippocampal atrophy and memory deficits. Nat Neurosci. 1998 May;1(1):69-73.↩
34. Bremner JD, Narayan M. The effects of stress on memory and the hippocampus throughout the life cycle: implications for childhood development and aging. Dev Psychopathol. 1998 Fall;10(4):871-85.↩