INTRODUCTION
Mental health is a critical component of overall well-being and is particularly significant for athletes who must maintain optimal psychological and physical performance. Athletes encounter unique stressors, such as rigorous training schedule, high-performance expectation, and requirement of quick response of injuries to treatment, which can profoundly impact their mental health [1]. Mental health issues, including anxiety, depression, and exhaustion, are prevalent in athletic populations and can negatively influence both performance and quality of life [2,3].
Cortisol, a glucocorticoid hormone released in response to stress, is a key stress biomarker. Elevated cortisol levels are associated with adverse effects on cognitive function, mood, and overall mental health, emphasizing the need for effective interventions to modulate cortisol levels and improve mental health outcomes in athletes [4-6]. Given the significant role of nutrition in mental health, dietary intervention has emerged as a promising approach for supporting mental health and manage stress [7].
Finger millet (Eleusine coracana) is a cereal grain known for its high nutritional value and composition of essential amino acids, antioxidants, and micronutrients. These nutrients are recognized for their beneficial effects on brain health and stress response [8,9]. The amino acid composition found in finger millet, such as tryptophan, play a crucial role in serotonin synthesis, a neurotransmitter that regulates mood, and antioxidants present in finger millet help reduce oxidative stress, which is linked to cognitive decline and mental health disorders [10,11].
Previous studies have suggested that the intake of nutrient-dense food can enhance cognitive function, reduce symptoms of anxiety and depression, and improve overall mood [12-14]. Specifically, diets rich in antioxidants and micronutrients can reduce oxidative stress and inflammation, thereby potentially improving mental health outcomes [15,16]. Athletes are vulnerable to stress due to physical and psychological demands, which can negatively impact their performance and mental health. This study aimed to explore the potential of finger millet (E. coracana) in improving mental health among athletes by examining its role in modulating corti-sol levels via specific mechanisms, such as regulation of the gut-brain axis and blood sugar levels. Previous studies [8,9,15] have suggested that the unique nutritional profile of millet, including amino acids, vitamins, and dietary fiber, may play a critical role in stress reduction, which this review aims to substantiate.
Athlete and Mental Health
Athletes are frequently subjected to intense physical and psychological demands that can adversely impact their mental health. Mental health problems among athletes are not only detrimental to their well-being but also negatively affect their performance and overall quality of life [2,17,18]. Studies have shown that the prevalence of mental health issues in athletes is comparable to or even higher than that in the general population [3,19]. Demands to perform, maintain peak physical condition, and recover swiftly from injuries contribute to elevated levels of stress and susceptibility to mental health issues1. Colangelo et al. [20] offered an in-depth understanding of athletes’ mental health status, revealing significant incidence level of depression, anxiety, and eating disorders among various athletic populations, including swimmers, triathletes, endurance cyclists, ultramarathoners, and paddlers. Increased training volume is often correlated with higher levels of depression, anxiety, fatigue, exercise dependence, eating disorders, and mood disturbance across various athletic populations [21,17,18], emphasizing the need for careful monitoring and supporting athletes engaged in high-volume training [20].
Athletes, particularly those in traditionally male-dominated sports, face a higher risk of developing eating disorders due to cultural and psychological pressures to conform to masculine norms and achieve peak physical performance. These athletes often encounter unique challenges, such as muscle dissatisfaction, stringent dietary practices, and stigma around mental health, leading to underreporting and delayed treatment of eating disorders. These findings underscore the need for vigilant monitoring, early detection, and comprehensive care tailored to the specific needs of male athletes to address both physical and psychological aspects of eating disorders [22,23].
Athletes often face mental health challenges, including anxiety, depression, and substance abuse, which can significantly impact their lives both within and outside of sports. Leading male athletes face significant mental health challenges due to injuries, stress, and performance pressure, which are often exacerbated by their reluctance to seek help because of stigma [24]. Male athletes tended to report fewer psychological symptoms than that of female athletes, likely due to greater stigma associated with reporting mental health concerns. Despite their obsession with success and external validation, athletes struggle to express vulnerability, masking their mental health issues [25,26].
Donohue et al. [27] indicated that collegiate athletes’ mental health service utilization varies depending upon factors, such as class standing and symptom severity, with newcomers being less likely to seek help despite being at a greater risk for mental health issues. This highlights the importance of targeted interventions and the influential role of coaches and teammates in promoting mental health service engagement among athletes. Sports clubs can significantly support young male athletes’ mental health by providing emotional support and fostering open communication. However, the challenge remains in addressing and transforming traditional masculine norms within these environments to promote mental health literacy, tolerance, and overall well-being [28]. Higher levels of mindfulness were associated with lower frequency of symptoms of anxiety and depression, highlighting the potential protective effects of mindfulness skills in elite athletes [29]. In addition, mindfulness practice in sports contributes to enhanced concentration and reduced performance anxiety. Integrating physical and psychological approaches in sports is crucial to promote overall mental well-being across diverse populations [30].
Athlete, Mental Health, and Cortisol
Cortisol, a glucocorticoid hormone released in response to stress, is a critical indicator of stress in the body. Elevated cortisol levels are linked to various negative health effects, such as diminished cognitive function, mood disorders, and decreased athletic performance [6]. Chronic stress and sustained high cortisol levels can lead to significant health issues such as cardiovascular disease and metabolic disorders, making it crucial to find effective ways to manage stress and cortisol levels in athletes [5].
Chronic stress and low energy availability (LEA) in athletes can lead to elevated cortisol levels, which are linked with an increased risk of anxiety and depression, highlighting the complex relationship between physical health, stress, and mental well-being [31]. Figure 1 shows the possible effects of chronic stress and LEA on mental health.
A 20-min professional diving session increased response time and salivary cortisol levels, suggesting reduced cognitive function and mental health after diving. Mental fatigue increases and the attention span decreases post-diving. Diving temporarily impairs cognitive function, cautioning against engaging in tasks that require high attention immediately after diving [32]. There was a significant improvement in Total Mood Disturbance (TMD) and various mood components following morning and evening exercise in male athletes.
Moderate aerobic training increases cortisol, free testosterone, and lactate dehydrogenase (LDH) levels in male athletes [33]. Cortisol levels tend to increase as athletes progress through competition preparation periods, likely because of prolonged energy deficits and increased physical activity. This increase in cortisol levels may result from elevated lipolysis and muscle tissue proteolysis due to caloric deficits and increased exercise [34].
A meta-analysis by Paridon et al. [35] revealed a significant anticipatory cortisol response in athletes before sports competitions, with a greater response observed closer to the start of the competition. Sex differences were observed, with males showing a stronger anticipatory cortisol response than that of females, potentially owing to differences in the interpretation of psychological stressors. In addition, cortisol reactivity varied based on the level of competition and time of sample collection for cortisol measurement before competition, emphasizing the importance of timing in assessing anticipatory stress responses in athletes.
Pearlmutter et al. [36] suggested that the cortisol response to exercise may be influenced by the intensity and timing of the workout. Athletes’ salivary cortisol levels vary with the time of day and exercise intensity, showing lower changes in the morning compared with the afternoon. This suggests that cortisol levels can be effectively used to assess exercise-induced stress, aiding in preventing overtraining syndrome by tailoring training programs to individual circadian rhythms [37]. Athletes maintain stable cortisol levels post-exercise unlike non-athletes whose cortisol levels decrease. This suggests that athletes’ cortisol levels are more resilient to exercise-induced changes, potentially due to higher workout intensity and dietary factors [38].
Cortisol and testosterone levels in athletes vary according to competition setting, with higher stress indicated by increased cortisol levels during indoor races. In addition, high cortisol levels inhibit testosterone response. The testosterone/cortisol ratio varies with competition settings and stressors, suggesting its potential as a performance predictor in young athletes [39]. Variations in insulin-like growth factor-1 (IGF-1)/cortisol ratio in young boxers have been linked to changes in performance and training load. High-intensity training increases cortisol levels, indicating a catabolic state and reduced performance. During tapering, cortisol decreases and IGF-1 increases, reflecting an anabolic state and improved performance. This suggests that the IGF-1/cortisol ratio is a potential marker for monitoring training and performance in athletes [40].
Runners training at higher altitudes have significantly higher basal salivary cortisol levels and greater cortisol responses to exercise than those training at lower altitudes. This finding suggests that altitude training increases stress levels in athletes [41]. During periods of intense training, young endurance athletes exhibit higher salivary cortisol levels and lower heart rate variability, indicating increased stress and fatigue as competition approaches. Reduced sleep duration is correlated with elevated cortisol levels, suggesting that sleep loss contributes to weekly strain. Despite high training loads, athletes manage stress better when hard training volume is minimized [42].
Testosterone levels are found higher in winning teams, but cortisol concentrations do not vary with the match outcome. Competition level influences the cortisol response, with novice players showing greater reactivity than that of high-level players. During recovery, cortisol levels increased up to 48 h post-match, suggesting an extended recovery period between matches for high-level players. Psychological factors, such as mood state and cognitive anxiety, influence hormonal changes during and after matches, highlighting the importance of monitoring physiological and psychological stress in athletes [43].
Elite female volleyball players exhibit higher serum levels of testosterone, cortisol, human growth hormone, and IGF-1 than those of healthy female individuals, suggesting that long-term physical exercise induces hormonal changes in highly trained athletes. These findings emphasize the importance of establishing tailored laboratory reference ranges for hormone levels in athletes to ensure accurate clinical assessment and management of health status, particularly in sports medicine services [44].
Nutritional Intervention and Mental Health
The relationship between nutrition and mental health of athletes is complex and multifaceted. Nutritional intake plays a critical role in brain function and psychological well-being by influencing cognitive processes, mood regulation, and stress responses. For instance, a balanced diet abundant in omega-3 fatty acids, vitamins, minerals, and antioxidants is linked to enhanced mood and decreased symptoms of anxiety and depression [45,7,16]. These nutrients are crucial for brain function, aiding in the regulation of neurotransmitters and reducing inflammation, which can positively influence mood and cognitive performance [46]. Probiotic supplementation may positively impact mental health outcomes in athletes, potentially influencing mood-related measures such as vigor and cognitive functions [47]. Conversely, deficiencies in essential nutrients such as vitamin D, vitamin B, and iron can contribute to mental health issues, including fatigue, mood swings, and cognitive decline [48]. The high physical and psychological demands on athletes necessitate optimal nutrition to support their performance and mental health.
Although physical activity benefits athletes, competitive sports induce significant stress, which can be measured through salivary α-amylase and cortisol levels. Ergogenic aids, including caffeine and β-alanine, impact stress and performance, but their effects vary, and maintaining gastrointestinal health and consumption of a balanced diet is crucial for overall well-being and stress management in athletes [49]. Conversely, another study [50] suggests that high dietary quality does not always equate to better mental health outcomes in athletes. Christensen et al. [50] reported that female collegiate athletes who consumed a high-quality diet during the COVID-19 pandemic experienced higher levels of stress and psychological strain. This paradox may be due to the athletes’ keen focus on maintaining a socially acceptable body image and optimal performance, which leads to restrictive eating patterns and associated mental health issues. These findings indicate the necessity for a holistic approach that combines nutritional guidance with psychological support to enhance athletes’ mental health effectively. Figure 2 illustrates the effects of various foods and nutrients on mental health.
Cortisol Modulation through Nutritional Interventions
The management of cortisol levels through dietary interventions is an area of growing interest. Foods rich in essential nutrients and antioxidants can help modulate stress responses and cortisol levels. Previous studies have demonstrated that diets with high antioxidant levels can reduce cortisol levels and improve stress resilience [7]. For example, consumption of whole grains, which are rich in fiber and nutrients, has been associated with lower cortisol levels and better stress management [14]. Given the nutritional profile of finger millet, it is plausible that its supplementation could similarly benefit athletes by modulating cortisol levels and enhancing stress resilience.
A previous study [51] demonstrated that 4-week tangeretin (TG) supplementation significantly decreased serum cortisol levels in athletes undergoing high-intensity resistance exercise, supporting its role in modulating cortisol stress response. Moreover, TG supplementation reduced adrenocorticotropin hormone (ACTH) and white blood cell levels while increasing superoxide dismutase (SOD) activity, suggesting its potential to attenuate inflammation and improve resilience against oxidative stress during exercise. These findings highlight the regulatory effect of TG on cortisol synthesis and secretion, supporting its potential use as a nutritional supplement to enhance recovery and mitigate adverse effects of high-intensity exercise-induced stress [51]. Figure 3 shows cortisol modulation through nutritional intervention.
Donald et al. [52] found that athletes exhibited higher cortisol concentrations, particularly after aerobic exercise. Sleep deprivation further increases cortisol levels, with caffeine consumption showing a potential blunting effect on cortisol increase. Overall, these findings suggest that stress responses in athletes may be cumulative, with higher cortisol responses being observed in sleep-deprived states, potentially affecting performance and recovery. Another study [53] found that adherence to a low-carbohydrate high-fat (LCHF) diet led to an increased exercise-induced cortisol response after two days, which was likely due to low carbohydrate availability. However, this cortisol response was attenuated after two weeks of adherence to the LCHF diet. Additionally, metabolic changes, such as lower respiratory exchange ratio (RER), lower glucose, higher free fatty acid (FFA), and increased ketone levels, were observed after both short-term and prolonged adherence to the LCHF diet [53]. Low-dose iron supplementation (3.6 mg/day) over four weeks helped maintain normal levels of salivary cortisol, indicating a reduction in exercise-associated stress among athletes. Although no significant increase in hemoglobin was observed, iron supplementation was associated with improved fatigue relief, reduced exercise burden, and elevated mood state, particularly in male athletes [54].
Finger Millet: Nutritional Profile and Health Benefits
Finger millet (E. coracana) is traditionally consumed in various parts of Asia and Africa. It is valued for its rich nutritional profile, including high levels of essential amino acids, fiber, and minerals [8]. Finger millet is particularly notable for its high content of tryptophan, an amino acid that acts as a precursor to serotonin, a neurotransmitter involved in mood regulation [55]. In addition, finger millet is a good source of antioxidants, which help decrease oxidative stress and inflammation, aspects that are related to cognitive decline and mental health disorders [8].
Being rich in vital nutrients, such as calcium, iron, and dietary fiber, finger millet contributes significantly to nutritional security and health improvement. Studies have shown that high calcium content of finger millet (approximately 344 mg per 100 g) surpasses that of many other cereals, making it an excellent food for bone health and prevention of osteoporosis [8]. Moreover, its iron content is beneficial for combating anemia, particularly in populations with a high prevalence of iron-deficiency anemia [56]. The nutritional composition of finger millet, rice, and wheat (cereals commonly consumed by athletes) is shown in Table 1.
In addition to its high nutrient density, finger millet pos-sesses significant health-promoting properties owing to its unique biochemical composition. The grain contains bioactive compounds, such as phytates, tannins, and phenolic acids, which exhibit antimicrobial and anti-inflammatory effects and contribute to overall health maintenance and disease prevention [57]. These compounds have been shown to enhance immune function and reduce inflammation, thereby lowering the risk of various chronic diseases, including cancer and cardiovascular diseases [58]. Moreover, high levels of dietary fiber in finger millet support digestive health by preventing constipation, promoting regular bowel movements, and fostering a healthy gut microbiome, which is progressively recognized for its role in overall health and disease prevention [59].
Finger millet is also notable for its high polyphenol and antioxidant contents, which play a crucial role in managing oxidative stress and lowering the risk of chronic diseases like diabetes and cardiovascular diseases. Dietary fiber in finger millet aids in maintaining healthy blood sugar levels by slowing down the digestion and absorption of carbohydrates, thus preventing sudden spikes in blood glucose levels [60,15]. Furthermore, finger millet has been found to exhibit hypoglycemic effects owing to its low glycemic index (GI), which makes it an essential food for managing and preventing metabolic disorders, particularly type 2 diabetes. Low GI foods are digested and absorbed more slowly, leading to a gradual increase in blood sugar levels, which helps maintain steady energy levels and improves insulin sensitivity [10]. The inclusion of finger millet in the diet can thus aid in weight management, as its high fiber content induces satiety and cuts down overall calorie intake. Given its wide array of health benefits, finger millet is increasingly being recognized as a functional food that can significantly contribute to better health outcomes when incorporated into a balanced diet [61]. Therefore, the incorporation of finger millet into the diet can enhance overall health by providing essential nutrients and helping to prevent and manage various chronic conditions.
Finger Millet and Mental Health
Effect of tryptophan on mental health and cortisol levels
Studies have indicated that diets rich in tryptophan can enhance serotonin production, potentially improving mood and cognitive function [62,63]. One of the key components of finger millet is tryptophan, which is an essential amino acid that serves as a precursor of serotonin, a neurotransmitter critical for regulating mood, sleep, and anxiety [9]. A diet rich in tryptophan can help enhance serotonin production, substantially eliminating the risk of depression and anxiety disorders [62,63]. Tryptophan metabolism occurs through three pathways: kynurenine (KYN), 5-hydroxytryptamine (serotonin, 5-HT), and gut microbiota (indole) pathways. The KYN pathway occurs in the liver and epithelial cells and helps reduce depression by producing KYN metabolites [64]. In the 5-HT pathway occurring in the central nervous system, tryptophan hydroxylase (TRP) catalyzes the conversion of tryptophan into 5-hydroxytryptophan (5-HTP) and further metabolizes it into 5-HT. The 5-HT form of tryptophan regulates appetite, emotions, anxiety, behavior, melatonin production, sleep-wake cycle, cognition, mental disorders, nutrient absorption in the intestine, and immunity by regulating cytokine secretion [65,66]. The gut microbiota have a key function in metabolizing tryptophan through the indole pathway that takes place in the intestine to regulate nutrient absorption, inflammation, neurotransmission, and immune responses through the gut-brain axis [65,64,67]. Tryptophan 5-HT helps reduce stress by reducing plasma cortisol levels66 and is also effective in reducing stress-induced hunger and appetite [68]. Figure 4 presents a pictorial representation of the effects of tryptophan on mental health.
Effect of calcium on mental health
Finger millet is rich in calcium (364 mg/100 g) and dietary fiber (11.18 g/100 g). Calcium improves mental health, anxiety, and mood by playing an important role in the synthesis and release of neurotransmitters. Calcium is essential for the production of serotonin, an important neurotransmitter that improves mental and cognitive health. Serotonin is also a precursor of melatonin that regulates sleep health, sleep-wake cycle, and emotional health. Therefore, calcium indirectly helps regulate sleep and emotional and overall mental health. Calcium deficiency may lead to anxiety, aggression, depression, negative mood, and stress [69].
Effect of magnesium on stress and cortisol levels
Finger millet is rich in magnesium that helps in the production of melatonin and improves sleep quality and overall brain function via the hypothalamic-pituitary-adrenal (HPA) axis [70]. It also reduces free radicals and oxidative stress and exhibits antidepressant and neuroprotective properties by upregulating the expression of brain-derived neurotrophic factor (BDNF) in the brain [71]. Magnesium acts as a cofactor in the serotoninergic system and aids tryptophan metabolism, which in turn improves mental health by producing serotonin [70,71]. Modulating neurotransmission pathways reduces the release of ACTH as well as decreases cortisol levels [71]. Magnesium deficiency can increase cortisol levels, stress, and inflammation. Magnesium supplementation can improve glucocorticoid metabolism and reduce cortisol, plasma prolactin, and stress levels by functioning as an antagonist of N-methyl-D-aspartate (NMDA) receptors [70,72].
Effect of antioxidants on mental health and cortisol levels
High antioxidant content in finger millet, such as polyphenols, plays a significant role in reducing oxidative stress, which has been implicated in the pathophysiology of various mental health conditions [73,14,74]. Oxidative DNA damage, inflammation, low gamma-aminobutyric acid (GABA) levels, and high glutamate levels are biomarkers of depression, neurotoxicity, cognitive decline, and mental health disorders. Antioxidants cross the blood-brain barrier, regulate neurotransmitters, suppress inflammatory pathways, such as IL-6 and TNF, and regulate BDNF to manage and improve mental and cognitive health status [75,76]. High cortisol levels are marked by the production of free radicals that cause oxidative stress and inflammation. Antioxidants effectively regulate cortisol levels by neutralizing free radicals and reducing oxidative stress and inflammation [77]. Empirical evidence on other whole grains has shown similar benefits, indicating that finger millet could be a valuable addition to the diet for those looking to improve their mental health [13,12].
Effect of fiber on blood sugar levels
Finger millet has a low GI, which aids in stabilizing blood sugar levels, thereby preventing mood swings and promoting mental stability [78]. Finger millet is also rich in dietary fiber, which produces enzymes, gut hormones, bile acids, amino acids, and adipokines upon digestion in the gut, resulting in improved insulin sensitivity, reduced HbA1C levels, and reduced risk of type 2 diabetes mellitus [79]. Dietary fiber, particularly soluble fiber, helps reduce blood sugar levels by increasing the viscosity of stomach contents, which slows gastric emptying and reduces the rates of starch digestion and glucose absorption. Delayed digestion results in the formation of a protective layer around the food bolus, hindering digestive enzymes and limiting the release of glucose into the bloodstream. In contrast, insoluble fiber may improve early insulin response, promote satiety, and regulate body weight, further contributing to improved blood sugar management and a minimized risk of type 2 diabetes [80].
Gut-brain axis
Further, dietary fiber present in finger millet supports gut health by fostering an optimal gut microbiome, which is progressively recognized for its benefits on brain function and mental health through the gut-brain axis [81]. The gutbrain axis is composed of the following components. (a) The enteric nervous system (ENS), which regulates gastrointestinal functions such as peristalsis, motility, and nutrient absorption. (b) The vagus nerve (VN), which is a primary bidirectional communication pathway transmitting sensory signals such as satiety, nutrient availability, and gastrointestinal discomfort to the brain and motor instructions such as motility and gastric secretions in the gut [82]. The VN is composed of 80% afferent and 20% efferent fibers that function as a “neurometabolic sensor” and transmit gut-derived signals to the brain. The VN senses gut metabolites and modulates responses via afferent and efferent fibers, and plays role in inflammation reduction, neurotransmitter regulation, and stress response. Through its afferent fibers, the VN senses nutrients and gut peptides, whereas its efferent fibers activate the cholinergic anti-inflammatory pathway to suppress inflammatory cytokines. Natural therapies, such as probiotics, polyphenols, and psychobiotics, have shown promise for enhancing VN function, improving gut and brain health, reducing inflammation, and managing disorders such as depression, anxiety, and neurodegeneration. These effects are mediated by antioxidant pathways, neurotransmitter modulation, and gut microbiota balance. Disruptions in vagal function due to oxidative stress can lead to dysbiosis, gastrointestinal disorders, and brain damage, highlighting its critical role in gut-brain communication [83]. (c) The gut microbiota is a diverse microbial population that plays a pivotal role in metabolism, modulation of immune system, and neurotransmitter and short-chain fatty acid (SCFA) production, influencing gastrointestinal and neurological functions through the gut-brain axis communication [82].
Effect of dietary fiber on mental health and cortisol levels
The gut microbiota communicates with the central nervous system and generates various neurotransmitters, including serotonin, dopamine, GABA, and tryptophan, which can affect brain function and behavior [84]. Digestion and fermentation of dietary fiber by the gut microbiota improves cognition, anxiety, depression, and behavior by enhancing the levels of BDNF that supports neuronal growth and cognitive functions, and by promoting the production of neurotransmitters such as serotonin and dopamine, which are crucial hormones for regulating mood [85]. Soluble dietary fibers boost the gut microbiota population and produce SCFA, such as butyrate, acetate, and propionate, upon fermentation in the colon. These gut microbiota produced metabolites SCFA help in improving cognition, sleep [86], and immunity, reduce systemic inflammation by suppressing the activity of pro-inflammatory cytokines (IL-6 and TNF) [87], reduce cholesterol, reduce cortisol response by regulating the HPA axis [83], improve insulin response, enhance gut barrier integrity, strengthen gut-brain axis transmission, stimulate the vagus nerve, modulate the immune and endocrine systems, and regulate the HPA axis pathway to reduce stress and anxiety [85,87]. Additionally, butyrate, a product of intestinal fermentation, can cross the blood-brain barrier and has neuroprotective properties, contributing to brain health and potentially affecting mood and behavior [84]. Taken together, these processes create a bidirectional communication pathway that positively affects the mental and cognitive health. Therefore, incorporating finger millet into diet may provide a holistic approach to enhance mental well-being. Figure 5 depicts the effect of finger millet on mental health through the gut-brain axis.
Finger Millet for Athletes
Cortisol plays a vital role in the regulation of energy, metabolism, and stress response in athletes. However, prolonged elevated cortisol levels due to intense training, competition pressure, or inadequate recovery can impair performance, suppress immune function, and hinder muscle repair and growth [4,5]. Chronic stress can lead to overtraining syndrome, fatigue, and mental health challenges, such as anxiety and depression [6]. Dietary interventions, such as finger millet, can help mitigate these cortisol-related effects owing to its rich nutritional profile.
Exercise-induced oxidative stress due to free radicals, such as reactive oxygen species (ROS) and reactive oxygen and nitrogen species (RONS), can lead to fatigue and reduced performance. Antioxidants neutralize free radicals and reduce oxidative stress and inflammation, thereby improving performance, endurance, and strength. Antioxidants also have a key function in modulating and boosting the gut microbiota, which affects mental health through the gutbrain axis [88].
A large population (30-50%) of endurance athletes experience gastrointestinal issues due to high oxidative stress and high cortisol levels, which lead to reduced blood flow to the gastrointestinal tract and inflammation due to increase in the levels of inflammatory cytokines [89]. The high dietary fiber content of finger millet supports the gut-brain axis health by nourishing the gut microbiota, which regulates cortisol production, reduces systemic inflammation, and promotes mental well-being [82,87]. Fibers also help maintain stable blood glucose levels and prevent hypoglycemia-triggered cortisol spikes [85,87]. Fermented dietary fibers in the gut produce SCFA that improve exercise performance in athletes [89].
SCFA produced by the gut microbiota enhance calcium absorption and bioavailability by lowering the pH of the colon and regulating signaling pathways [89]. Calcium is an important mineral for maintaining bone health, recovery, and strength in athletes [90]. Calcium has also been associated with reduction in stress response by supporting the nervous system [69]. Therefore, finger millet, a rich source of calcium among grains, showing enhanced calcium bioavailability through its fiber and gut microbiota association, is an ideal option for athletes.
Hence, the presence of nutrients, such as calcium, magnesium, essential amino acids, antioxidants, and fiber) in finger millet reduces cortisol levels, enhancing stress resilience, supporting recovery by promoting muscle relaxation, reducing oxidative stress, and improving sleep quality and mental health [83,85-87]. Thus, integrating finger millet into an athlete’s diet could serve as a natural, holistic approach to manage the impact of cortisol on performance, recovery, and mental health.
Research Gaps in the Literature
Despite the promising potential of finger millet, there is a notable lack of research specifically examining its effects on mental health and cortisol levels in athletes. Most existing studies have focused on the general population or specific subgroups, leaving a gap in the literature regarding their impact on athletic populations. Additionally, although the benefits of dietary interventions on mental health are well-documented, there is a need for more targeted research to explore the specific mechanisms through which finger millet influences stress and mental health outcomes in athletes.
CONCLUSION
Athletes are subjected to intense physical and psychological demands that can elevate cortisol levels, leading to detrimental health outcomes such as anxiety, depression, and decreased performance. Chronic stress and LEA exacerbate these issues, highlighting the need for effective stress management strategies. Although studies have shown that physical exercise can help manage cortisol levels and mitigate the effects of stress, individualized exercise protocols are essential for optimal mental health benefits. The role of nutrition in modulating cortisol levels is well documented, with diets rich in antioxidants and essential nutrients helping to manage stress responses. Finger millet, with its high fiber content and low GI, aids in stabilizing blood sugar levels, which can prevent mood swings and promote mental health. This is particularly relevant for athletes who often experience fluctuations in cortisol levels owing to intense training and competition.
In summary, the incorporation of finger millet into athletes’ diet offers a multifaceted approach for improving mental health and managing cortisol levels. Its rich nutritional profile, combined with its ability to stabilize blood sugar levels and support healthy gut microbiome, makes it a valuable supplement to the dietary regimen of athletes. Future research should focus on clinical trials to further validate these findings and establish dietary guidelines for the optimal use of finger millet in sports nutrition.