Herbs for stress may address the effects of stress as an undeniable factor in many illnesses, and growing evidence now suggests that stress can negatively impact memory and other neurocognitive functions while having lasting consequences on the brain, behavior, and physical fitness levels.
Stress and Physical Activity
When an individual’s capacity to adapt to stress (physical, mental, or emotional) is exceeded, this can result in cumulative wear and tear on the body and relate to declining physical function and performance over time.1 Strenuous physical exercise itself can act as a type of allostatic load for the hypothalamic-pituitary-adrenal (HPA) axis.
Athletes undergoing excessive training schedules can develop significant decreases in performance due to “overtraining syndrome,” a stress-related condition that consists of alterations of physiological functions, impairment of psychological processing, immunological dysfunction and other biochemical abnormalities.2 Delays in recovery from exercise including dampened muscular and neural adaptations have been observed with chronic stress, and can impact athletic performance both physically and cognitively.3
Stress and Cognition
Prolonged exposure to stress has been found to lead to neuronal losses, whereas a healthy termination of the stress response can promote memory storage and retrieval.4,5 Loss of memory and decline in cognitive processes becomes particularly concerning with aging, and research within the last several decades shows that those who experience persistent or high levels of stress are especially vulnerable. Chronic stress appears capable of causing atrophy of dendrites, suppression of neurogenesis, and impairment of hippocampal-dependent cognitive functions.6
Stress affects cognition in several ways, acting rapidly via catecholamines and more slowly by glucocorticoids such as cortisol, the body’s major stress hormone. Cortisol is produced by the adrenal glands, which can modulate synaptic plasticity and induce long-lasting influences on both cognitive and emotional processes.7
Basal corticosteroid levels are associated with memory formation by inducing patterns of synaptic activity that produce a sustained increase in signal transmission between neurons.8 As memories are thought to be encoded by modification of synaptic strength, this is considered to be one of the major cellular mechanisms underlying learning and memory, and cortisol appears to act as a key controller for the adaptation and maintenance of homeostasis in situations of acute, chronic, and repeated stress.9 Cortisol is also an essential adaptation hormone during exercise, and an inability to recover from stress can potentially have adverse effects on the cognitive processes related to peak physical performance such as reaction time, concentration, and muscle fatigue.10
A substantial contributor to stress-induced cognitive decline appears to be Hypothalamic-Pituitary-Adrenal (HPA) axis dysfunction. Providing the body with herbs for stress and the support it needs to better adapt to and recover from stress is of vital importance to help prevent the unregulated production of stress hormones which can impact neurocognitive health.
Herbs for Stress: Nutrition for Neurocognitive Health
Various nutritional and botanical therapies like herbs for stress have much to offer in regard to balancing HPA activity, while simultaneously providing neuroprotective effects and improving an array of metabolic functions.
American ginseng (Panax quinquefolium) is one of the most commonly used ginsengs and a member of the Araliaceae plant family. As opposed to Korean ginseng (Panax ginseng), American ginseng is native to the Eastern United States and Canada, and it has a long history of medicinal use by the Native peoples of these regions as a tonic for respiratory and digestive conditions and fatigue. Traditional Chinese Medicine (TCM) views American ginseng as a calming yin tonic useful for treating acute stress-related conditions, whereas Korean ginseng is regarded more as a heating or yang tonic best avoided in cases of acute stress.
American ginseng is a classic herbal adaptogen, a substance that enhances human health by restoring homeostasis especially while under stress. American ginseng has therapeutic potential in the treatment of stress-related disorders to increase physiological resistance to stress and to enhance immunity, physical, and cognitive performance.11 It is considered to have a calming role upon the HPA axis and aid in the regulation of cortisol, inflammatory cytokines, and brain monoamines. It has been shown to help reduce anxiety and improve learning and memory functions in animal models of Alzheimer-like syndromes and enhance cognitive performance in humans by improving working memory processes.12-15
Its most active compounds include triterpenoid saponins called ginsenosides (e.g. Rb1, Rb2, Rc, Rd, Re, Rg1). Ginsenoside Rb1 appears most abundantly and has greater sedative and hypotensive effects compared to Rg1, which is more predominantly found in Korean ginseng.
Ginsenosides exert a wide range of different biological activities, resulting in hypoglycemic and anti-inflammatory effects. They also diminish the risk of several cardiovascular and neurodegenerative diseases.16-18 Evidence of enhanced neurocognitive function demonstrated by an improvement in working memory performance was shown in an acute, randomized, placebo-controlled, cross-over study, and beneficial effects were attributed primarily to ginsenoside Rb1 by improving cholinergic metabolism.19 Ginsenoside Rb1 has also demonstrated in vitro neuroprotective potential through antioxidant effects, increasing the activity of the glutathione system, superoxide dismutases (SOD), and activation of the Nrf2 pathway. Moreover, a protective effect against mitochondrial dysfunction was observed, suggesting a potential influence on the pathogenesis of neurodegenerative diseases and mitochondria-dependent aging processes in general.20,21
Cordyceps sinensis is a fungus belonging to the Clavicipitaceae family that has been used as a medicinal food in TCM for centuries. Cordyceps is renowned for its nutritional benefits and ability to promote health and longevity. It is sometimes referred to as “caterpillar fungus,” as its growth involves parasitizing moth and butterfly larvae, depositing its spores, and subsequently growing through the insect. The fungus will then rupture from the host and form a fruiting body which is then harvested for its wide variety of bioactive compounds, including:
- Nucleosides (e.g. adenosine and cordycepin)
- Vitamins (E, K, B1, B2, and B12)
- A variety of minerals (K, Na, Ca, Mg, Fe, Cu, Mn, Zn, Se)22
Many of the bioactive components found in Cordyceps engage in a multitude of functions, with protein fragments and polysaccharides appearing to be the most biologically relevant. Specifically, the nucleoside cordycepin can participate in various cellular activities due to its structural similarity with adenosine, exhibiting significant therapeutic potential on many intracellular targets including nucleic acid, apoptosis, and cell cycle programming. This wide spectrum of protection towards cells can help prevent tissue damage and lends toward its significant anti-inflammatory properties.
An increasing number of in vitro and in vivo studies have demonstrated Cordyceps’s potential as a therapeutic agent for the effective treatment of a range of metabolic-related disorders, having immunoregulatory, hypoglycemic, renoprotective, and cardiovascular-protective effects. Additionally, a remarkable performance by female Chinese athletes at the Chinese National Games in Beijing in 1993 attracted international attention to Cordyceps’ effects.23
Neuroprotective effects of Cordyceps have also been demonstrated in animals, showing an ability to improve memory impairment caused by cerebral ischemia and induced memory deterioration.24-25 In one animal study, amyloid-beta protein-induced models found that Cordyceps had a protective role against cognitive impairment and the progression of Alzheimer’s, improving learning and memory function when compared with the control group as well as inhibiting nitric oxide production and lipid peroxidation in the brain, liver, and kidneys.26 Animal studies have also shown beneficial effects on stress, aging, and blood glucose metabolism, suggesting a potential use in the recovery of vascular dementia and other neuroinflammatory disorders.27-29 Its adaptogenic effects have been attributed mainly to an ability to reduce fatigue, boost physical stamina, and improve recovery in stress-induced animal models and effect corticosterone production in adrenal cells.30-31
Other edible fungi such as Turkey Tail (Trametes versicolor), Maitake (Grifola frondosa), and Shitake (Lentinula edodes) have also been shown to have beneficial effects on neurocognitive health. One study concluded that increasing mushroom consumption could possibly promote cognitive health, and that a deficiency in key bioactives could be a risk factor for neurodegeneration and cognitive decline.32
Specifically, a team at the National University of Singapore recently found that seniors who consumed more than two standard portions (defined as ¾ cup of cooked mushrooms with an average weight of around 150 grams) of mushrooms weekly may have 50 percent reduced odds of developing mild cognitive impairment (MCI). The six-year study showed that even one small portion of mushrooms a week may still be beneficial to reduce chances of MCI. The researchers suspected specific antioxidant and anti-inflammatory compounds found in mushrooms (e.g. ergothioneine, hericenones, erinacines) were responsible for the beneficial effects. These compounds may promote the synthesis of nerve growth factors and protect the brain from neurodegeneration by inhibiting production of beta amyloid and phosphorylated tau (a major protein component of neurofibrillary tangles).32
Herbs for Stress: Key Nutrients and Lifestyle for Neurocognitive Health
Preserving cognitive function and the repair of damaged brain cells affected by aging is a complex process, but the role of nutritional and herbs for stress to help stimulate neurogenesis and combat neurodegenerative disease and cognitive decline is becoming clearer. A high stress lifestyle that includes alcohol, high-fat, and high-sugar diet can negatively affect adult neurogenesis, while diets enriched with key phytonutrients and polyphenols along with physical exercise can help to induce neurogenesis in adult brains.33 Key antioxidants such as vitamins C and E, carotenoids, curcumin, CoQ10, and B vitamins may all play a role in helping to reduce neuroinflammation and oxidative stress. Consumption of these antioxidants can be increased through diet or supplementation to support both cognition and nervous system health at any age.