The Neurobiology of Love

Love is a complex neurobiological phenomenon, relying on trust, belief, pleasure and reward activities within the brain, i.e., limbic processes. These processes critically involve oxytocin, vasopressin, dopamine, and serotonergic signaling. Moreover, endorphin and endogenous morphinergic mechanisms, coupled to nitric oxide autoregulatory pathways, play a role. Naturally rewarding or pleasurable activities are necessary for survival and appetitive motivation, usually governing beneficial biological behaviors like eating, sex, and reproduction. Yet, a broad basis of common signaling and beneficial neurobiological features exists with connection to the love concept, thereby combining physiological aspects related to maternal, romantic or sexual love and attachment with other healthy activities or neurobiological states. Medical practice can make use of this concept, i.e., mind/body or integrative medicine. Thus, love, pleasure, and lust have a stress-reducing and health-promoting potential, since they carry the ability to heal or facilitate beneficial motivation and behavior. In addition, love and pleasure ensure the survival of individuals and their species. After all, love is a joyful and useful activity that encompasses wellness and feelings of well-being.     

The neurobiology of pleasure, reward processes, addiction and their health implications

Modern science begins to understand pleasure as a potential component of salutogenesis. Thereby, pleasure is described as a state or feeling of happiness and satisfaction resulting from an experience that one enjoys. We examine the neurobiological factors underlying reward processes and pleasure phenomena. Further, health implications related to pleasurable activities are analyzed. With regard to possible negative effects of pleasure, we focus on addiction and motivational toxicity. Pleasure can serve cognition, productivity and health, but simultaneously promotes addiction and other negative behaviors, i.e., motivational toxicity. It is a complex neurobiological phenomenon, relying on reward circuitry or limbic activity. These processes involve dopaminergic signaling. Moreover, endorphin and endogenous morphinergic mechanisms may play a role. Natural rewarding activities are necessary for survival and appetitive motivation, usually governing beneficial biological behaviors like eating, sex and reproduction. Social contacts can further facilitate the positive effects exerted by pleasurable experiences. However, artificial stimulants can be detrimental, since flexibility and normal control of behavior are deteriorated. Additionally, addictive drugs are capable of directly acting on reward pathways. Thus, the concrete outcome of pleasant experiences may be a question of dose. Moderate pleasurable experiences are able to enhance biological flexibility and health. Hence, pleasure can be a resistance resource or may serve salutogenesis. Natural rewards are mediated by sensory organ stimulation, thereby exhibiting a potential association with complementary medical approaches. Trust and belief can be part of a self-healing potential connected with rewarding stimuli. Further, the placebo response physiologically resembles pleasure phenomena, since both involve brain's reward circuitry stimulation and subjective feelings of well-being. Pleasurable activities can stimulate personal growth and may help to induce healthy behavioral changes, including stress management. However, more research is needed to better understand the nature, neurobiology and maybe dangerous aspects of pleasure. Also, a possible involvement of endogenous morphinergic signaling has to be studied further.     

Climate Change and Health in Sub-Saharan Africa: A Case-Based Perspective

Over the coming decades, sub-Saharan Africa will face profound stresses and challenges from global climate change. Many of these will manifest as adverse health outcomes. This article uses a series of five hypothetical cases to review the climate impacts on the health and well-being of individuals and populations in sub-Saharan Africa. This approach fosters insights into the human dimensions of the risks to health, their interaction with local human ecology, and awareness of the diverse health ramifications of external environmental changes. Each case illustrates the health impact resulting from a specific environmental or social consequence of climate change, including impacts on agriculture and food security, droughts, floods, malaria, and population displacement. Whereas the article focuses on discrete manifestations of climate change, individuals will, in practice, face multiple stresses from climate change (i.e., floods and malaria) concomitant with other non-climate stressors (i.e., HIV/AIDS, globalization, etc.). These multiple sources of vulnerability must be considered when designing climate change and socioeconomic development interventions.     

Flexible Working Hours,Health, and Well-Being in Europe: Some Considerations from a SALTSA Project

The project brought together researchers from 9 EU-Countries and resulted in a number of actions, in particular the following: (a) There is an urgent need of defining the concept of flexible working hours, since it has been used in many different and even counterintuitive ways; the most obvious distinction is where the influence over the working hours lies, that is between the “company-based flexibility” and the “individual-oriented flexibility”; (b) The review of the Legislation in force in the 15 European countries shows that the regulation of working times is quite extensive and covers (Council Directive 93/104/EC) almost all the various arrangements of working hours (i.e., part-time, overtime, shift, and night work), but fails to provide for flexibility; (c) According to the data of the Third EU Survey on Working Conditions, longer and “irregular” working hours are in general linked to lower levels of health and well-being; moreover, low (individual) flexibility and high variability of working hours (i.e., company-based flexibility) were consistently associated with poor health and well-being, while low variability combined with high autonomy showed positive effects; (d) Six substudies from different countries demonstrated that flexible working hours vary according to country, economic sector, social status, and gender; overtime is the most frequent form of company-based flexibility but has negative effects on stress, sleep, and social and mental health; individual flexibility alleviates the negative effects of the company-based flexibility on subjective health, safety, and social well-being; (e) The literature review was able to list more than 1,000 references, but it was striking that most of these documents were mainly argumentative with very little empirical data. Thus, one may conclude that there is a large-scale intervention ongoing in our society with almost completely unknown and uncontrolled effects. Consequently, there is a strong need for systematic research and well-controlled actions in order to examine in detail what flexible working hours are considered, what and where are their positive effects, in particular, as concerns autonomy, and what regulation seem most reasonable.     

Neurobiological implications of eating healthy

Over the last decades, the importance of food in the development of chronic diseases has been examined, as well as the medical value of eating healthy. The contribution of the eating process itself to health and well-being, however, has not been questioned until most recently. Biology has linked eating to appetitive motivational processes with their underlying neurophysiology, including CNS reward circuitries: Eating uses the pleasure-reward physiology to motivate us to eat. Endogenous opiates, such as morphine, insure our survival by helping us to make eating motivational via pleasure induction. After taking in enough food, we become satisfied, i.e., tolerant to food. Our appetite, and so is our appetence, are then low and need a certain time span to reach their former levels for then inducing food-seeking behaviors, food intake, etc. again. When tolerance passes, we once more engage in this pleasurable process related to positive behavioral motivation. Opioid receptor agonists, however, may induce energy intake even beyond an actual need. This interesting potential of opioidergic signaling may have its roots in biological mechanisms that insured the intake and storage of high energy foods, hence preparing for future famines. In our world of today, however, such neurobiological pathways may pose a threat on our health. Thus, feedback mechanisms, such as tolerance, aversion and satiety, have to be finely tuned. Therefore central autoregulation that involves, for example, limbic mu receptor signaling and other endogenous signaling compounds comes into the focus of modern science. The time where research recognizes the importance of neurobiological pathways such as endogenous opiate autoregulation or CNS reward circuitries for examining the physiology of food intake has yet begun. Many questions remain open and have to be answered through future scientific inquiry.     

The broaden-and-build theory of positive emotions

The broaden-and-build theory describes the form and function of a subset of positive emotions, including joy, interest, contentment and love. A key proposition is that these positive emotions broaden an individual's momentary thought-action repertoire: joy sparks the urge to play, interest sparks the urge to explore, contentment sparks the urge to savour and integrate, and love sparks a recurring cycle of each of these urges within safe, close relationships. The broadened mindsets arising from these positive emotions are contrasted to the narrowed mindsets sparked by many negative emotions (i.e. specific action tendencies, such as attack or flee). A second key proposition concerns the consequences of these broadened mindsets: by broadening an individual's momentary thought-action repertoire--whether through play, exploration or similar activities--positive emotions promote discovery of novel and creative actions, ideas and social bonds, which in turn build that individual's personal resources; ranging from physical and intellectual resources, to social and psychological resources. Importantly, these resources function as reserves that can be drawn on later to improve the odds of successful coping and survival. This chapter reviews the latest empirical evidence supporting the broaden-and-build theory and draws out implications the theory holds for optimizing health and well-being.     

The interference of flexible working times with the circadian temperature rhythm--a predictor of impairment to health and well-being?

In order to analyze whether impairments to health and well-being under flexible working hours can be predicted from specific characteristics of the work schedules, periodic components in flexible working hours and their interference with the circadian temperature rhythm were analyzed applying univariate and bivariate spectrum analyses to both time series. The resulting indicators of spectral power and phase shift of these components were then related to reported health impairments using regression analysis. The results show that a suppression of both the 24 and the 168 h components in the work schedules (i.e., a lack of periodicity) can be used to predict reported health impairments, and that if there are relatively strong 24 and 168 h components left in the work schedules, their phase difference with the temperature rhythm (as an indicator of the interference between working time and the circadian rhythm) further predicts impairment. The results indicate that the periodicity of working hours and the amount of (circadian) desynchronization induced by flexible work schedules can be used for predicting the impairing effects of flexible work schedules on health and well-being. The results can thus be used for evaluating and designing flexible shift rosters.     

Flexible working hours, health, and well-being in Europe: some considerations from a SALTSA project

The project brought together researchers from 9 EU-Countries and resulted in a number of actions, in particular the following: (a) There is an urgent need of defining the concept of flexible working hours, since it has been used in many different and even counterintuitive ways; the most obvious distinction is where the influence over the working hours lies, that is between the “company-based flexibility” and the “individual-oriented flexibility”; (b) The review of the Legislation in force in the 15 European countries shows that the regulation of working times is quite extensive and covers (Council Directive 93/104/EC) almost all the various arrangements of working hours (i.e., part-time, overtime, shift, and night work), but fails to provide for flexibility; (c) According to the data of the Third EU Survey on Working Conditions, longer and “irregular” working hours are in general linked to lower levels of health and well-being; moreover, low (individual) flexibility and high variability of working hours (i.e., company-based flexibility) were consistently associated with poor health and well-being, while low variability combined with high autonomy showed positive effects; (d) Six substudies from different countries demonstrated that flexible working hours vary according to country, economic sector, social status, and gender; overtime is the most frequent form of company-based flexibility but has negative effects on stress, sleep, and social and mental health; individual flexibility alleviates the negative effects of the company-based flexibility on subjective health, safety, and social well-being; (e) The literature review was able to list more than 1,000 references, but it was striking that most of these documents were mainly argumentative with very little empirical data. Thus, one may conclude that there is a large-scale intervention ongoing in our society with almost completely unknown and uncontrolled effects. Consequently, there is a strong need for systematic research and well-controlled actions in order to examine in detail what flexible working hours are considered, what and where are their positive effects, in particular, as concerns autonomy, and what regulation seem most reasonable.     

Neuroimaging of children following prenatal drug exposure

Recent advances in MR-based brain imaging methods have provided unprecedented capabilities to visualize the brain. Application of these methods has allowed identification of brain structures and patterns of functional activation altered in offspring of mothers who used licit (e.g., alcohol and tobacco) and illicit (e.g., cocaine, methamphetamine, and marijuana) drugs during pregnancy. Here we review that literature, which though somewhat limited by the complexities of separating the specific effects of each drug from other confounding variables, points to sets of interconnected brain structures as being altered following prenatal exposure to drugs of abuse. In particular, dopamine-rich cortical (e.g., frontal cortex) and subcortical (e.g., basal ganglia) fetal brain structures show evidence of vulnerability to intrauterine drug exposure suggesting that during brain development drugs of abuse share a specific profile of developmental neurotoxicity. Such brain malformations may shed light on mechanisms underlying prenatal drug-induced brain injury, may serve as bio-markers of significant intrauterine drug exposure, and may additionally be predictors of subsequent neuro-developmental compromise. Wider clinical use of these research-based non-invasive methods will allow for improved diagnosis and allocation of therapeutic resources for affected infants, children, and young adults.     

Stress-associated impacts of short-term holding on fishes

Most sources of stress in aquaculture, fish salvage, stocking programs, and commercial and sport fisheries may be unavoidable. Collecting, handling, sorting, holding, and transporting are routine practices that can have significant effects on fish physiology and survival. Nevertheless, an understanding of the stressors affecting fish holding can lead to practices that reduce stress and its detrimental effects. The stress-related effects of short-term holding are influenced by water quality, confinement density, holding container design, and agonistic and predation-associated behaviors. Physiological demands (e.g., resulting from confinement-related stresses) exceeding a threshold level where the fish can no longer compensate may lead to debilitating effects. These effects can be manifested as suppressed immune systems; decreased growth, swimming performance, or reproductive capacity; even death. Furthermore, holding tolerance may depend upon the species, life stage, previous exposure to stress, and behavior of the held fish. Water quality is one of the most important contributors to fish health and stress level. Fish may be able to tolerate adverse water quality conditions; however, when combined with other stressors, fish may be quickly overcome by the resulting physiological challenges. Temperature, dissolved oxygen, ammonia, nitrite, nitrate, salinity, pH, carbon dioxide, alkalinity, and hardness are the most common water quality parameters affecting physiological stress. Secondly, high fish densities in holding containers are the most common problem throughout aquaculture facilities, live-fish transfers, and fish salvage operations. Furthermore, the holding container design may also compromise the survival and immune function by affecting water quality, density and confinement, and aggressive interactions. Lastly, fishes held for relatively short durations are also influenced by negative interactions, associated with intraspecific and interspecific competition, cannibalism, predation, and determining nascent hierarchies. These interactions can be lethal (i.e., predation) or may act as a vector for pathogens to enter (i.e., bites and wounds). Predation may be a significant source of mortality for fisheries practices that do not sort by size or species while holding. Stress associated with short-term holding of fishes can have negative effects on overall health and well-being. These four aspects are major factors contributing to the physiology, behavior, and survival of fishes held for a relatively short time period.     

Brain proteome response following whole body exposure of mice to mobile phone or wireless DECT base radiation

The objective of this study was to investigate the effects of two sources of electromagnetic fields (EMFs) on the proteome of cerebellum, hippocampus, and frontal lobe in Balb/c mice following long-term whole body irradiation. Three equally divided groups of animals (6 animals/group) were used; the first group was exposed to a typical mobile phone, at a SAR level range of 0.17–0.37 W/kg for 3 h daily for 8 months, the second group was exposed to a wireless DECT base (Digital Enhanced Cordless Telecommunications/Telephone) at a SAR level range of 0.012–0.028 W/kg for 8 h/day also for 8 months and the third group comprised the sham-exposed animals. Comparative proteomics analysis revealed that long-term irradiation from both EMF sources altered significantly (p < 0.05) the expression of 143 proteins in total (as low as 0.003 fold downregulation up to 114 fold overexpression). Several neural function related proteins (i.e., Glial Fibrillary Acidic Protein (GFAP), Alpha-synuclein, Glia Maturation Factor beta (GMF), and apolipoprotein E (apoE)), heat shock proteins, and cytoskeletal proteins (i.e., Neurofilaments and tropomodulin) are included in this list as well as proteins of the brain metabolism (i.e., Aspartate aminotransferase, Glutamate dehydrogenase) to nearly all brain regions studied. Western blot analysis on selected proteins confirmed the proteomics data. The observed protein expression changes may be related to brain plasticity alterations, indicative of oxidative stress in the nervous system or involved in apoptosis and might potentially explain human health hazards reported so far, such as headaches, sleep disturbance, fatigue, memory deficits, and brain tumor long-term induction under similar exposure conditions.     

Autoradiographic localization of subcomponents of the macromolecular GABA receptor complex

The autoradiographic localization of subcomponents of the gamma-aminobutyric acid (GABA) receptor-chloride ionophore complex has provided insight into the distribution of this macromolecular system. GABA inhibits neurons by preferentially increasing the permeability of the affected membrane to chloride ions. This inhibition can be modified by the presence of other substances which bind to the GABA receptor complex. Autoradiographic localization of specific receptor subtypes associated with this complex has been accomplished in the central nervous system. This type of analysis has been performed on high and low affinity GABAA, benzodiazepine (BZ; both BZ1 and BZ2) and convulsant sites. These receptor sites are situated in distinct brain regions and co-exist in several areas. Other receptor subtypes, which may be influenced by the presence of GABA, can be analyzed for comparison in order to define regions of the brain where GABA may be exerting independent effects (i.e., those not associated with chloride channels). Microscopic localization of receptor sites indicates specific areas to investigate in further studies concerning the characterization of subcomponents of the macromolecular GABA complex associated with chloride ion channels.     

Health Consequences of Drought on the Canadian Prairies

Population pressures and expanding agricultural and industrial development, with their resulting environmental degradation and demand for water, are likely to increase drought vulnerability on the Canadian Prairies. Coupled with increases in drought expected under climate change, the health and well-being of prairie populations may be compromised. However, little is known about the health effects of drought in this region or of possible adaptation strategies. This article assesses the available information on the health effects associated with drought and uses this information to develop an ecosystem health framework for outlining how drought may affect the prairie ecosystem and the health and well-being of Canadian Prairie populations. The article identifies multisector mitigation and adaptation strategies for reducing the harmful effects of drought on the prairie ecosystem and its populations. The literature review revealed that drought is associated with crop failure, increased atmospheric dust, and intensifying forest fire frequency, with health effects ranging from respiratory illnesses from inhaling dust or smoke, to mental health concerns arising from economic stress, particularly among farmers. Future research is needed on: the health effects associated with drought more specific to the Prairie region; the mental well-being of farmers and agricultural communities; the health effects from exposure to forest fire haze; and the health effects of reduced water supply and quality. Reducing drought vulnerability requires multisectoral collaboration, starting at the community level, to identify more sustainable water use, diverse health risks of drought, and ways of adapting to drought conditions.     

Functional salutogenic mechanisms of the brain

Neuroscientists are typically interested in the brain in relation to disease, but much could also be learned by studying the brain in relation to health. The brain has processes, functional salutogenic mechanisms, that contribute to health by enabling one's outlook on life to benefit one's health. For example, the belief that things will work out as well as can reasonably be expected is a key aspect of the outlook of people who tend to stay well even when in potentially stressful situations. Believing in God, feeling happy, being mutually in love, and expecting things to change for the better are also outlooks that can be salutogenic. Beliefs need not even be rational or realistic in order for them to be salutogenic, as shown by phenomena such as faith healing and the placebo effect. Thus, the brain responds to stimuli and interprets them, mainly without one's awareness, in ways that can enhance one's well-being. Although little is presently known concerning neuropathways of functional salutogenic mechanisms, further research on relations between salutogenesis and brain function can be expected to provide new strategies for improving health worldwide.     

Most Synaptic Vesicles Isolated from Rat Brain Carry Three Membrane Proteins, SV2, Synaptophysin, and p65

We have prepared highly purified synaptic vesicles from rat brain by subjecting vesicles purified by our previous method to a further fractionation step, i.e., equilibrium centrifugation on a Ficoll gradient. Monoclonal antibodies to three membrane proteins enriched in synaptic vesicles--SV2, synaptophysin, and p65--each were able to immunoprecipitate specifically approximately 90% of the total membrane protein from Ficoll-purified synaptic vesicle preparations. Anti-SV2 precipitated 96% of protein, anti-synaptophysin 92%, and anti-p65 83%. These results demonstrate two points: (1) Ficoll-purified synaptic vesicles appear to be greater than 90% pure, i.e., less than 10% of membranes in the preparation do not carry synaptic vesicle-associated proteins. These very pure synaptic vesicles may be useful for direct biochemical analyses of mammalian synaptic vesicle composition and function. (2) SV2, synaptophysin, and p65 coexist on most rat brain synaptic vesicles. This result suggests that the functions of these proteins are common to most brain synaptic vesicles. However, if SV2, synaptophysin, or p65 is involved in synaptic vesicle dynamics, e.g., in vesicle trafficking or exocytosis, separate cellular systems are very likely required to modulate the activity of such proteins in a temporally or spatially specific manner.     

结合生态系统服务供需和人类福祉的区域规划

生态系统服务与人类福祉的和谐关系是区域规划的基石。现有的区域规划较少同时考虑生态系统服务的供需和流域居民的福祉差异。以城市化流域——官厅水库流域为例,应用改进后的CASA模型、IPCC清单法、SolVES模型和问卷调查量化食物供给、碳固持和文化服务以及人类福祉,再结合服务的供需关系及人类福祉水平开展聚类分区,并针对各区情况提出规划建议。结果显示,官厅水库流域内食物供给和文化服务供大于求,而碳固持服务供不应求。流域福祉位于中等水平,分值为3.44(满分5分)。其中,居民的基本物质需求分值最高(3.64),收入分值(3.00)明显低于流域整体水平。除此之外,居民认为供水、医疗条件和收入这些福祉要素仍有待改善。流域可分为城市发展区、城郊休闲区、生态涵养区和文化建设区。在各区需采用因地制宜的方式,通过增大植被覆盖面、开展文旅产业和推动冰雪项目等形式,提高居民生活质量和维持区域可持续性。     

The osmotic/calcium stress theory of brain damage: Are free radicals involved?

This overview presents data showing that glucose use increases and that excitatory amino acids (i.e., glutamate, aspartate), taurine and ascorbate increase in the extracellular fluid during seizures. During the cellular hyperactive state taurine appears to serve as an osmoregulator and ascorbate may serve as either an antioxidant or as a pro-oxidant. Finally, a unifying hypothesis is given for seizure-induced brain damage. This unifying hypothesis states that during seizures there is a release of excitatory amino acids which act on glutamatergic receptors, increasing neuronal activity and thereby increasing glucose use. This hyperactivity of cells causes an influx, of calcium (i.e. calcium stress) and water movements (i.e., osmotic stress) into the cells that culminate in brain damage mediated by reactive oxygen species.Special issue dedicated to Dr. Frederick E. Samson     

World Health Organization's low-intensity psychosocial interventions: a systematic review and meta-analysis of the effects of Problem Management Plus and Step-by-Step

Many societies have been recently exposed to humanitarian and health emergencies, which have resulted in a large number of people experiencing significant distress and being at risk to develop mental disorders such as depression, anxiety and post-traumatic stress disorder. The World Health Organization has released a series of scalable psychosocial interventions for people impaired by distress in communities exposed to adversities. Prominent among these is a low-intensity transdiagnostic psychosocial intervention, Problem Management Plus (PM+), and its digital adaptation Step-by-Step (SbS). This systematic review is the first to summarize the available evidence on the effects of PM+ and SbS. Up to March 8, 2023, five databases were searched for randomized controlled trials examining the effects of PM+ or SbS on distress indicators (i.e., general distress; anxiety, depressive or post-traumatic stress disorder symptoms; functional impairment, self-identified problems) and positive mental health outcomes (i.e., well-being, quality of life, social support/relationships). We performed random-effects multilevel meta-analyses on standardized mean differences (SMDs) at post-intervention and short-term follow-up assessments. Our search yielded 23 eligible studies, including 5,298 participants. We found a small to medium favorable effect on distress indicators (SMD=–0.45, 95% CI: –0.56 to –0.34) and a small beneficial effect on positive mental health outcomes (SMD=0.31, 95% CI: 0.14-0.47), which both remained significant at follow-up assessment and were robust in sensitivity analyses. However, our analyses pointed to substantial between-study heterogeneity, which was only partially explained by moderators, and the certainty of evidence was very low across all outcomes. These results provide evidence for the effectiveness of PM+ and SbS in reducing distress indicators and promoting positive mental health in populations exposed to adversities, but a larger high-quality evidence base is needed, as well as research on participant-level moderators of the effects of these interventions, their suitability for stepped-care programs, and their cost-effectiveness.     

A Bioluminescence Method for the Measurement of l-Glutamate: Applications to the Study of Changes in the Release of l-Glutamate from Lateral Geniculate Nucleus and Superior Colliculus After Visual Cortex Ablation in Rats

We have developed a rapid, simple, specific, and very sensitive bioluminescence method for the measurement of L-glutamate (L-Glu). Oxidation of L-Glu by glutamate dehydrogenase has been coupled with bacterial FMN reductase and luciferase. Light production (i.e., peak height or integral) was linear from less than 0.5 to 500 pmol of L-Glu. Potential interfering substances that may be encountered in brain tissue have been identified. The most potent inhibitors were ascorbate and the biogenic amines. Procedures that conferred long-term stability of the reagent mixture (greater than 8 h) were established. Bioluminescence analysis of L-Glu content in brain tissue extracts, fractions from release experiments, and human CSF corroborated respective results obtained by HPLC analysis. In this study, we have applied the method to monitor changes in the KCl-evoked release of endogenous L-Glu from milligram amounts of brain tissue, i.e., from lateral geniculate nucleus and superior colliculus after visual cortex ablation.     

Biodiversity and human health: evidence for causality?

The Millennium Ecosystem Assessment and other commentators have warned about the impacts that biodiversity decline will have on human health. There is no doubting that the natural world provides mankind with the majority of the resources required to sustain life and health. Many species provide food, fuel, medicines; with the potential for many more (as of yet) undiscovered uses for various species. Despite this, there have been very few attempts to actually investigate relationships between biodiversity (i.e. number of species, rather than the ability of specific species to provide health benefits) and human health. This paper reviews the available evidence and demonstrates that while the links between biodiversity and health seem intuitive, they are very difficult to prove. Socio-economics has a huge influence on health status and the exploitation of natural resources (leading to eventual biodiversity loss) tends to have a positive economic effects. More direct effects of biodiversity on health include the diversity of the internal microbiome, the effect of natural diversity on our mental health and well-being (although this has large social aspects with many people feeling fearful in very diverse environments). Still to be elucidated are the tipping points where the level of global biodiversity loss is such that human health can no longer be sustained.