A psychoactive drug, commonly known as Ecstasy or Molly. MDMA exerts both stimulant and hallucinogenic effects, altering mood and perception. It may induce feelings of increased energy, pleasure, emotional warmth, and distorted sensory and time perception.

A chemical byproduct of tryptophan obtained in the diet. 5-HTP is a precursor of serotonin, a neurotransmitter that plays important roles in mood, sleep, appetite, and many other physiological processes.

An energy-carrying molecule present in all cells. ATP fuels cellular processes, including biosynthetic reactions, motility, and cell division by transferring one or more of its phosphate groups to another molecule (a process called phosphorylation).

A catecholamine hormone produced by the adrenal glands and some neurons. Adrenaline, also known as epinephrine, exerts many effects in the body, the most notable being those associated with the “fight or flight” response to stressors. The effects of epinephrine and norepinephrine (a related catecholamine) are mediated by adrenergic receptors, which act as the interface between the sympathetic nervous system and the cardiovascular system.

The death rate from all causes of death for a population in a given time period.

An omega-3 fatty acid found mostly in plants. ALA can be converted into the omega-3 fatty acids EPA or DHA, but this conversion process is very inefficient in humans. When ALA is not converted to EPA or DHA, it remains inactive and is simply stored or used as energy, like other fats. Some evidence suggests an association between a diet rich in ALA and reduced risk of heart disease. Dietary sources of ALA include kale, spinach, soybeans, walnuts, seeds, and plant-based oils.

An area of the brain located close to the hippocampus, in the frontal portion of the temporal lobe. The amygdala governs our responses to fear, arousal, and emotional stimulation. Poor sleep increases activity within the amygdala.

A molecule that inhibits oxidative damage to DNA, proteins, and lipids in cells. Oxidative damage plays a role in the aging process, cancer, and neurodegeneration. Many vitamins and plant-based compounds are antioxidants.

A type of omega-6 polyunsaturated fat. Arachidonic acid is found in the phospholipid components of cell membranes, especially those in the brain, muscles, and liver. It plays key roles in the body’s inflammatory process. In particular, it promotes the formation of eicosanoids, a class of proinflammatory compounds, following injury or irritation.

A test used in laboratory medicine, pharmacology, environmental biology, and molecular biology to determine the content or quality of specific components.

A medicinal herb commonly used in traditional Chinese medicine. More than 200 distinct components of the dried roots of AM have been identified, the majority of which are polysacharrides, flavonoids, and saponins. In 2000, cycloastragenol, a small molecule extract of the herb, was found to exhibit telomerase activating properties.[1] Extracts of the plant have also demonstrated immunomodulatory, anti-oxidative stress, and anti-aging effects, the latter of which are associated with the lengthening of telomeres. AM is purportedly a prominent component of an "anti-aging" supplement known as TA-65.[2, 3, 4]

[1] Salvador, Laura, et al. "A natural product telomerase activator lengthens telomeres in humans: a randomized, double blind, and placebo-controlled study." Rejuvenation research 19.6 (2016): 478-484. [2] Liu, Ping, Haiping Zhao, and Yumin Luo. "Anti-aging implications of Astragalus Membranaceus (Huangqi): a well-known Chinese tonic." Aging and disease 8.6 (2017): 868.( https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5758356/) [3] Blackburn, Elizabeth H., Elissa S. Epel, and Jue Lin. "Human telomere biology: a contributory and interactive factor in aging, disease risks, and protection." Science 350.6265 (2015): 1193-1198.( http://science.sciencemag.org/content/350/6265/1193) [4] Shahzad, Muhammad, et al. "The antioxidant effects of Radix Astragali (Astragalus membranaceus and related species) in protecting tissues from injury and disease." Current drug targets 17.12 (2016): 1331-1340.

A developmental disorder characterized by impaired social interaction, behavioral problems, and poor communication. Autism typically manifests in early childhood and is slightly more common among boys than girls. In clinical trials, sulforaphane, a compound derived from broccoli and broccoli sprouts, reduces the characteristic behaviors associated with autism.

An entheogenic brew made out of Banisteriopsis caapi vine and the Psychotria viridis leaf. The brew is used as a traditional spiritual medicine in ceremonies among the indigenous peoples of Amazonia. People who have consumed ayahuasca report having spiritual revelations regarding their purpose on earth, the true nature of the universe as well as deep insight into how to be the best person they possibly can.

A hormone produced in the brain that blocks the sensation of pain. Beta-endorphin is released in response to a wide range of painful stimuli and stressors, including heat.^[1] Beta-endorphin exhibits morphine-like activity, but its effects are up to 33-times more potent than morphine.^[2] Both morphine and beta-endorphin act on the μ-opioid receptor.

The extent and rate at which drugs or other substances, such as plant-based dietary compounds, enter the body’s circulation. Bioavailability is influenced by a variety of factors, including dose, the presence of other foods or substances, and interindividual differences in metabolism due to gut absorptive surface and commensal microbial populations.

A highly selective semi-permeable barrier in the brain made up of endothelial cells connected by tight junctions. The blood-brain barrier separates the circulating blood from the brain's extracellular fluid in the central nervous system. Whereas water, lipid-soluble molecules, and some gases can pass through the blood-brain barrier via passive diffusion, molecules such as glucose and amino acids that are crucial to neural function enter via selective transport. The barrier prevents the entry of lipophilic substances that may be neurotoxic via an active transport mechanism.

A type of protein that acts on neurons in the central and peripheral nervous systems. BDNF is a type of neurotrophin – or growth factor – that controls and promotes the growth of new neurons. It is active in the hippocampus, cortex, cerebellum, and basal forebrain – areas involved in learning, long term memory, and executive function. Rodent studies suggest that lactate, one of many so-called exerkines, mediates some of the benefits of exercise on learning and memory via inducing neuronal BDNF expression.^[1] Exercise in combination with heat stress increases BDNF more effectively than exercise alone.^[2] BDNF is a profoundly universal point of convergence for mechanistically explaining essentially all known activities that promote brain health.

An amino acid having aliphatic side-chains with a branch (a central carbon atom bound to three or more carbon atoms). Among the proteinogenic amino acids, there are three BCAAs: leucine, isoleucine and valine.

A person who is 100 or more years old.

A waxy lipid produced primarily in the liver and intestines. Cholesterol can be synthesized endogenously and is present in all the body's cells, where it participates in many physiological functions, including fat metabolism, hormone production, vitamin D synthesis, and cell membrane integrity. Dietary sources of cholesterol include egg yolks, meat, and cheese.

A tightly coiled molecule of DNA found in the nucleus of a cell. Chromosomes contain the genes and other genetic material for an organism. Humans have 46 chromosomes arranged in 23 pairs. Each chromosome is comprised of long stretches of DNA wrapped around proteins called histones, which provide structural support. At the end of each chromosome is a repetitive nucleotide sequence called a telomere. Telomeres form a protective “cap” – a sort of disposable buffer that gradually shortens with age – that prevents chromosomes from losing genes or sticking to other chromosomes during cell division.

A substance whose presence is essential for the activity of an enzyme. Many minerals and vitamins are cofactors for enzymes.

A steroid hormone that participates in the body’s stress response. Cortisol is a glucocorticoid hormone produced in humans by the adrenal gland. It is released in response to stress and low blood glucose. Chronic elevated cortisol is associated with accelerated aging. It may damage the hippocampus and impair hippocampus-dependent learning and memory in humans.

A ring-shaped protein found in blood plasma. CRP levels rise in response to inflammation and infection or following a heart attack, surgery, or trauma. CRP is one of several proteins often referred to as acute phase reactants. Binding to phosphocholine expressed on the surface of dead or dying cells and some bacteria, CRP activates the complement system and promotes phagocytosis by macrophages, resulting in the clearance of apoptotic cells and bacteria. The high-sensitivity CRP test (hsCRP) measures very precise levels in the blood to identify low levels of inflammation associated with the risk of developing cardiovascular disease.

A broad category of small proteins (~5-20 kDa) that are important in cell signaling. Cytokines are short-lived proteins that are released by cells to regulate the function of other cells. Sources of cytokines include macrophages, B lymphocytes, mast cells, endothelial cells, fibroblasts, and various stromal cells. Types of cytokines include chemokines, interferons, interleukins, lymphokines, and tumor necrosis factor.

A general term referring to cognitive decline that interferes with normal daily living. Dementia commonly occurs in older age and is characterized by progressive loss of memory, executive function, and reasoning. Approximately 70 percent of all dementia cases are due to Alzheimer’s disease.

The biological process in which a cell matures and specializes. Differentiation is essential for the development, growth, reproduction, and lifespan of multicellular organisms. Differentiated cells can only express genes that characterize a certain type of cell, such as a liver cell, for example.

A powerful hallucinogenic substance that is widespread in nature. DMT is a derivative of tryptamine. It is structurally similar to serotonin and functions in much the same way as psilocybin drugs. Well-known for its relatively short duration of action, intense effects, and rapid onset, it is one of the major psychoactive compounds used in religious practices in South America for centuries and, more recently, as a recreational drug in the US and Europe.

A major contributing factor to aging, cellular senescence, and the development of cancer. Byproducts of both mitochondrial energy production and immune activity are major sources of DNA damage. Additionally, environmental stressors can increase this base level of damage. DNA damage can be mitigated by cellular repair processes; however, the effectiveness of these processes may be influenced by the availability of dietary minerals, such as magnesium, and other dietary components, which are needed for proper function of repair enzymes.

An omega-3 fatty acid found in the human brain and the meat of fatty fish. DHA plays a key role in the development of eye and nerve tissues, and is essential for normal brain function in humans. DHA may also reduce the risk of Alzheimer’s disease1 and cardiovascular disease, and may be useful in treating certain inflammatory conditions, such as rheumatoid arthritis. Dietary sources of DHA include krill oil and the meat and roe of salmon, flying fish, and pollock. [1] Patrick, Rhonda P. "Role of phosphatidylcholine-DHA in preventing APOE4-associated Alzheimer’s disease." The FASEB Journal (2018): fj-201801412R.

A neurotransmitter best known for its role in motor, motivation, and pleasure control. Dopamine also functions as a paracrine (cell-to-cell) hormone in other parts of the body. It is derived from tyrosine and is the precursor to norepinephrine and epinephrine. Some evidence suggests that dopamine may also be involved in pain modulation.

A potent endogenous opioid peptide. Dynorphin acts on the kappa-opioid receptor and is associated with a transient feeling of dysphoria. It has many different physiological actions, depending upon its site of production, and is involved in addiction, temperature regulation, appetite, circadian rhythm, pain, stress, and depression. Dynorphin may also be involved in the body’s thermoregulatory response to hyperthermia.^[1]

An omega-3 fatty acid found in the meat of fatty fish. EPA reduces inflammation in the body and helps counter oxidative stress in cells. It is crucial for modulating behavior and mood and has demonstrated beneficial effects in managing anxiety and depression. EPA may reduce risk of developing certain chronic diseases such as cancer or cardiovascular disease. Dietary sources of EPA include herring, salmon, eel, shrimp and sturgeon.

Any of a group of complex proteins or conjugated proteins that are produced by living cells and act as catalyst in specific biochemical reactions.

A bioactive compound found in green tea. EGCG is a type of catechin. It is a potent scavenger of reactive oxygen species and has demonstrated antioxidant, anti-inflammatory, and anticarcinogenic properties in both clinical and in vitro studies.

Genetic control elicited by factors other than modification of the genetic code found in the sequence of DNA. Epigenetic changes determine which genes are being expressed, which in turn may influence disease risk. Some epigenetic changes are heritable.

The ability to store and retrieve specific episodes from personal experiences in the past. Episodic memory involves times, places, feelings, and other contexts. It occurs in the medial temporal lobe of the brain, especially the hippocampus.

A vitamin that is readily dissolved in fats or oils. Fat-soluble vitamins are absorbed along with fats in the diet and can be stored in the body’s fatty tissue. Vitamins A, D, E, and K are fat-soluble. Dietary sources of fat-soluble vitamins include fatty fish (such as salmon), nuts, oils, and avocados, among others.

A molecule composed of carboxylic acid with a long hydrocarbon chain that is either saturated or unsaturated. Fatty acids are important components of cell membranes and are key sources of fuel because they yield large quantities of ATP when metabolized. Most cells can use either glucose or fatty acids for this purpose.

A type of spindle-shaped cell that produces connective tissue, such as collagen. During inflammation, fibroblasts produce cytokines, chemokines, and other inflammatory proteins to promote tissue rearrangement and subsequent repair. The failure to switch off fibroblasts may be a mechanism leading to chronic inflammation.

Flavonoid are widely distributed in plants, fulfilling many functions. Flavonoids have been shown to have a wide range of biological and pharmacological activities in animal, human, and in-vitro studies. Examples include anti-allergic, anti-inflammatory, antioxidant, antimicrobial, anti-cancer, and anti-diarrheal activities.

The process in which information stored in DNA is converted into instructions for making proteins or other molecules. Gene expression is highly regulated. It allows a cell to respond to factors in its environment and involves two processes: transcription and translation. Gene expression can be turned on or off, or it can simply be increased or decreased.

Plant secondary metabolites found primarily in cruciferous vegetables. Glucosinolates give rise to a variety of compounds that have been identified as potent chemoprotective agents in humans against the pathogenesis of many chronic diseases such as cancer, cardiovascular disease, and neurodegenerative disease, among others. These products are responsible for the pungent aroma, sharp flavor, and the “heat” commonly associated with some cruciferous vegetables such as wasabi and horseradish.

One of the most abundant non-essential amino acids in the human body. Glutamine plays key roles in several metabolic functions, including protein and glutathione synthesis, energy production, antioxidant status, and immune function. In addition, it regulates the expression of several genes. Although the body can typically produce all the glutamine it needs, during periods of metabolic stress it must rely on dietary sources of glutamine such as meats, fish, legumes, fruits, and vegetables.

An antioxidant compound produced by the body’s cells. Glutathione helps prevent damage from oxidative stress caused by the production of reactive oxygen species.

An antioxidant produced within cells that enzymatically reduces hydrogen peroxide to water to limit its harmful effects. Glutathione peroxidase's primary role is to protect cells from oxidative damage, a key factor in many diseases.

A series of enzyme-dependent reactions that breaks down glucose. Glycolysis converts glucose into pyruvate, releasing energy and producing ATP and NADH. In humans, glycolysis occurs in the cytosol and does not require oxygen.

A naturally occurring substance capable of stimulating cellular growth, proliferation, healing, and differentiation. Growth factors typically act as signaling molecules between cells. Examples include cytokines and hormones that bind to specific receptors on the surface of their target cells.

A bidirectional signaling pathway between the gastrointestinal tract and the nervous system, often involving intestinal microbiota. Several studies have shown that the gut microbiota is involved in the regulation of anxiety, pain, cognition, and mood.

An iron-containing molecule that carries oxygen in the blood. Heme is acquired in the diet from meat, poultry, seafood, and fish and is readily absorbed in the human gut. Although iron is an essential nutrient, high intake of heme iron is associated with increased risk of several cancers, type 2 diabetes, and coronary heart disease. Biliverdin, one of the byproducts of heme degradation, is responsible for the yellow color associated with bruises and urine, and the brown color of feces.

The chief protein components of chromatin found in eukaryotic cell nuclei that package and order the DNA into structural units called nucleosomes acting as spools around which DNA winds, and playing a role in gene regulation.

An alternative medicine practice based on the concept that the body can cure itself. Homeopathic remedies are made from substances derived from plants, animals, or minerals that have been diluted in water and shaken until there is little, if any, of the original substance left. Homeopaths believe that the original substance leaves a “molecular blueprint” in the water that triggers the body's healing mechanisms.

Biological responses to low-dose exposures to toxins or other stressors such as exercise, heat, cold, fasting, and xenohormetics. Hormetic responses are generally favorable and elicit a wide array of protective mechanisms. Examples of xenohormetic substances include plant polyphenols – molecules that plants produce in response to stress. Some evidence suggests plant polyphenols may have longevity-conferring effects when consumed in the diet.

A critical element of the body’s immune response. Inflammation occurs when the body is exposed to harmful stimuli, such as pathogens, damaged cells, or irritants. It is a protective response that involves immune cells, cell-signaling proteins, and pro-inflammatory factors. Acute inflammation occurs after minor injuries or infections and is characterized by local redness, swelling, or fever. Chronic inflammation occurs on the cellular level in response to toxins or other stressors and is often “invisible.” It plays a key role in the development of many chronic diseases, including cancer, cardiovascular disease, and diabetes.

A peptide hormone secreted by the beta cells of the pancreatic islets cells. Insulin maintains normal blood glucose levels by facilitating the uptake of glucose into cells; regulating carbohydrate, lipid, and protein metabolism; and promoting cell division and growth. Insulin resistance, a characteristic of type 2 diabetes, is a condition in which normal insulin levels do not produce a biological response, which can lead to high blood glucose levels.

One of the most potent natural activators of the AKT signaling pathway. IGF-1 stimulates cell growth and proliferation, inhibits programmed cell death, mediates the effects of growth hormone, and may contribute to aging and enhancing the growth of cancer after it has been initiated. Similar in molecular structure to insulin, IGF-1 plays a role in growth during childhood and continues later in life to have anabolic, as well as neurotrophic effects. Protein intake increases IGF-1 levels in humans, independent of total caloric consumption.

Experiments that are performed using cells or microorganisms outside of their normal biological context and are often done in a test tube or petri dish.

A trace mineral that is essential for human health. Iodine is necessary for normal thyroid and immune function.

Byproduct of a reaction between two compounds (glucosinolates and myrosinase) that are found in cruciferous vegetables. Isothiocyanates inhibit phase I biotransformation enzymes, a class of enzymes that transform procarcinogens into their active carcinogenic state. Isothiocyanates activate phase II detoxification enzymes, a class of enzymes that play a protective role against DNA damage caused by reactive oxygen species and carcinogens. Examples of phase II enzymes include UDP-glucuronosyltransferases, sulfotransferases, N-acetyltransferases, glutathione S-transferases, and methyltransferases.

One of four related receptors that bind opioid-like compounds in the brain. Opioid receptors are responsible for mediating the effects of these compounds, which including altering pain, consciousness, motor control, mood, stress, and addiction. Agonism of this receptor produces a transient feeling of dysphoria but also causes an upregulation and sensitization of mu opioid receptors, which interact with beta-endorphin.

A type of white blood cell. Macrophages engulf and digest cellular debris, foreign substances, microbes, cancer cells, and oxidized LDL in a process called phagocytosis. After phagocytizing oxidized LDL, macrophages are referred to as foam cells.

An enzyme that participates in genetic pathways that sense amino acid concentrations and regulate cell growth, cell proliferation, cell motility, cell survival, protein synthesis, autophagy, and transcription. mTOR integrates other pathways including insulin, growth factors (such as IGF-1), and amino acids. It plays key roles in mammalian metabolism and physiology, with important roles in the function of tissues including liver, muscle, white and brown adipose tissue, and the brain. It is dysregulated in many human diseases, such as diabetes, obesity, depression, and certain cancers. mTOR has two subunits, mTORC1 and mTORC2. Also referred to as “mammalian” target of rapamycin.

Rapamycin, the drug for which this pathway is named (and the anti-aging properties of which are the subject of many studies), was discovered in the 1970s and is used as an immunosuppressant in organ donor recipients.

A hormone that regulates the sleep-wake cycle in mammals. Melatonin is produced in the pineal gland of the brain and is involved in the expression of more than 500 genes. The greatest influence on melatonin secretion is light: Generally, melatonin levels are low during the day and high during the night. Interestingly, melatonin levels are elevated in blind people, potentially contributing to their decreased cancer risk.^[1]

The thousands of biochemical processes that run all of the various cellular processes that produce energy. Since energy generation is so fundamental to all other processes, in some cases the word metabolism may refer more broadly to the sum of all chemical reactions in the cell.

A biochemical process involving the addition or subtraction of a methyl group (CH3) to another chemical group. In epigenetics, a methyl group is added to an amino acid in a histone tail on DNA, altering the activity of the DNA segment without changing its sequence. Under- and over-methylation are referred to as hypomethylation and hypermethylation, respectively.

Single-celled microorganisms that live in marine or freshwater environments. Microalgae use the process of photosynthesis to convert sunlight, water, and carbon dioxide to oxygen and microalgal biomass, the latter of which is rich in omega-3 fatty acids.

Vitamins and minerals that are required by organisms throughout life in small quantities to orchestrate a range of physiological functions. The term micronutrients encompasses vitamins, minerals, essential amino acids, essential fatty acids.

Tiny organelles inside cells that produce energy in the presence of oxygen. Mitochondria are referred to as the "powerhouses of the cell" because of their role in the production of ATP (adenosine triphosphate). Mitochondria are continuously undergoing a process of self-renewal known as mitophagy in order to repair damage that occurs during their energy-generating activities.

A family of enzymes whose sole known substrates are glucosinolates. Myrosinase is located in specialized cells within the leaves, stems, and flowers of cruciferous plants. When the plant is damaged by insects or eaten by humans, the myrosinase is released and subsequently hydrolyzes nearby glucosinolate compounds to form isothiocyanates (see definition), which demonstrate many beneficial health effects in humans. Microbes in the human gut also produce myrosinase and can convert non-hydrolyzed glucosinolates to isothiocyanates.

The process of forming new neurons. Neurogenesis is essential during embryonic development, but also continues in certain brain regions throughout human lifespan.

A type of white blood cell, also known as a granulocyte. Neutrophils are the most abundant form of blood cell, comprising approximately 60 percent of total cells. They ingest, kill, and digest microbial pathogens, and are the first cells recruited to acute sites of injury. Neutrophils can infiltrate brain structures, driving inflammation and increasing the risk for neurodegenerative disorders, such as Parkinson's disease and Alzheimer's disease.

A rapid-acting transcription factor that responds to harmful cellular stimuli, such as reactive oxygen species, IL-1B, bacterial endotoxin (lipopolysaccharide or "LPS"), ionizing radiation, and oxidized LDL. Incorrect regulation of NF-kB has been linked to cancer, inflammatory and autoimmune diseases, septic shock, viral infection, and improper immune development. Several viruses, including the AIDS virus HIV, have binding sites for NF-kB. In the case of HIV, the presence of NF-kB is believed to be involved in switching the virus from a latent to an active state.

One of four nitrogen-containing molecules that comprise DNA. A nucleotide consists of one of four chemicals, called a “base,” plus one molecule of sugar and one molecule of phosphoric acid. Nucleotides are typically identified by the first letter of their base names: adenine (A), cytosine (C), guanine (G), and thymine (T). They form specific pairs (A with T, and G with C), and their bonds provide the helical structure of the DNA strand.

A type of polyunsaturated fat that is essential for human health. Omega-3 fatty acids influence cell membrane integrity and affect the function of membrane-bound cellular receptors. They participate in pathways involved in the biosynthesis of hormones that regulate blood clotting, contraction and relaxation of artery walls, and inflammation. They have been shown to help prevent heart disease and stroke, may help control lupus, eczema, and rheumatoid arthritis, and may play protective roles in cancer and other conditions. Omega-3 fatty acids include alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). ALA is found mainly in plant oils such as flaxseed, soybean, and canola oils. DHA and EPA are found in fish and other seafood. The human body can convert some ALA into EPA and then to DHA, but the efficiency of the process varies between individuals.

A naturally-occurring substance found in many foods. Oxalate binds to calcium in the gut and is eliminated in the feces. Any unbound oxalate passes through the kidneys and is excreted in the urine. High levels of oxalate in the kidneys can contribute to the risk of developing kidney stones. Dietary sources of oxalate include dark green leafy vegetables, beans, potatoes, and bran, among others.

Highly reactive molecules that have the ability to oxidize other molecules and cause them to lose electrons. Common oxidants are oxygen, hydrogen peroxide, and superoxide anion.

A chemical reaction in which an atom, molecule, or ion loses one or more electrons. Oxidation of biological molecules is associated with oxidative stress, a key driver of many chronic diseases.

The process of generating energy that occurs when mitochondria couple oxygen with electrons that have been derived from different food sources including glucose, fatty acids, and amino acids.

A result of oxidative metabolism, which causes damage to DNA, lipids, proteins, mitochondria, and the cell. Oxidative stress occurs through the process of oxidative phosphorylation (the generation of energy) in mitochondria. It can also result from the generation of hypochlorite during immune activation.

A neurodegenerative disorder that affects the central nervous system. Parkinson’s disease is caused by destruction of nerve cells in the part of the brain called the substantia nigra. It typically manifests later in life and is characterized by tremors and a shuffling gait.

A small endocrine gland found in the brain of mammals. The pineal gland secretes melatonin, a hormone that regulates the sleep-wake cycle as well as other metabolic processes.

Capable of developing into any type of cell or tissue except those that form a placenta or embryo.

A class of chemical compounds produced in plants in response to stressors. Polyphenols contribute to the bitterness, astringency, color, flavor, and fragrance of many fruits and vegetables. They often serve as deterrents to insect or herbivore consumption. When consumed in the human diet, polyphenols exert many health benefits and may offer protection against development of cancers, cardiovascular diseases, diabetes, osteoporosis, and neurodegenerative diseases. Dietary sources of polyphenols include grapes, apples, pears, cherries, and berries, which provide as much as 200 to 300 mg polyphenols per 100 grams fresh weight.

An extremely rare genetic disorder in which symptoms resembling aspects of aging are manifested at a very early age. People born with progeria typically live to their mid teens to early twenties. Although the term progeria applies strictly speaking to all diseases characterized by premature aging symptoms, it is often applied specifically in reference to Hutchinson–Gilford progeria syndrome (HGPS).

A group of lipid-signaling molecules that have diverse hormone-like effects. Prostaglandins play roles in inflammation, vasoconstriction or vasodilation, aggregation or disaggregation of platelets, calcium movement, cell growth, and thermoregulation. Prostaglandins are produced in many places throughout the human body.

A class of hallucinogenic substances whose primary action is to alter cognition and perception, typically as serotonin receptor agonists, causing thought and visual/auditory changes, and "heightened state of consciousness." Major psychedelic drugs include mescaline, LSD, psilocybin, and DMT. Psychedelics have a long history of traditional use in medicine and religion, for their perceived ability to promote physical and mental healing.

A class of bacteria involved in the decomposition of living matter. Putrefying bacteria utilize essential amino acids (e.g., histidine, tryptophan, etc.) present in the gut to perform putrefaction, disrupting gut homeostasis. Some of the byproducts of putrefaction, such as ammonia, putrescine, cresol, indole, and phenol have been implicated in the pathogenesis of colon cancer.

A study in which people are randomly allocated to receive one of several clinical interventions. One of these interventions is the standard of comparison or control. The control may be a standard practice, a placebo, or no intervention at all.

An antibody that plays key roles in immunity. Secretory IgA is the most abundant antibody in the mucosal immune system, accounting for nearly 20 percent of serum immunoglobulin. It is crucial in protecting the intestinal epithelium from toxins and pathogenic microorganisms.

Senescence is a response to stress in which damaged cells suspend normal growth and metabolism. While senescence is vital for embryonic development, wound healing, and cancer immunity, accumulation of senescent cells causes increases inflammation and participates in the phenotype of aging.

A small molecule that functions as both a neurotransmitter and a hormone. Serotonin is produced in the brain and gut and facilitates the bidirectional communication between the two. It regulates many physiological functions, including sleep, appetite, mood, thermoregulation, and others. Many antidepressants are selective serotonin reuptake inhibitors (SSRIs), which work by preventing the reabsorption of serotonin, thereby increasing extracellular levels of the hormone.

A constellation of symptoms induced by the use of serotonergic drugs. Serotonin syndrome is characterized by the overactivation of serotonin receptors and is potentially life-threatening. Symptoms include changes in mental status, increased reflexes, muscle spasms, sweating, dilated pupils, and diarrhea.

A molecule that allows cells to perceive and correctly respond to their microenvironment, which enables normal cellular function, tissue repair, immunity, cognition, and more. Hormones and neurotransmitters are examples of signaling molecules. There are many types of signaling molecules, however, including cAMP, nitric oxide, estrogen, norepinephrine, and even reactive oxygen species (ROS).

A class of drugs that are typically used as antidepressants in the treatment of major depressive disorder and anxiety disorders. Some of the drugs that fall under this classification include: Citalopram (Celexa), Escitalopram (Lexapro), Fluoxetine (Prozac), Paroxetine (Paxil, Pexeva), Sertraline (Zoloft).

A class of drugs that lower blood cholesterol levels by blocking the production of an enzyme in the liver called hydroxy-methylglutaryl-coenzyme A reductase (HMG-CoA reductase). Taking statins may reduce the risk of cardiovascular disease in some people. Although statins are generally well tolerated, as many as 10 – 20 percent of people taking the drugs experience complications, including myopathy (muscle damage), liver damage, and cognitive problems, including issues with forgetfulness, memory loss, and confusion.

A cell that has the potential to develop into different types of cells in the body. Stem cells are undifferentiated, so they cannot do specific functions in the body. Instead, they have the potential to become specialized cells, such as muscle cells, blood cells, and brain cells. As such, they serve as a repair system for the body. Stem cells can divide and renew themselves over a long time. In 2006, scientists reverted somatic cells into stem cells by introducing Oct4, Sox2, Klf4, and cMyc (OSKM), known as Yamanaka factors.^[1]

The junction between one neuron and another or a gland or muscle cell. Synapses are critical elements in the transmission of nerve signals. Their formation is necessary for the establishment and maintenance of the brain’s neuronal network and the precision of its circuitry.

A microtubule-bound protein that forms the neurofibrillary "tau tangles" associated with Alzheimer's disease. Tau tangles disrupt transport of metabolites, lipids, and mitochondria across a neuron to the synapse where neurotransmission occurs. Diminished slow-wave sleep is associated with higher levels of tau in the brain. Elevated tau is a sign of Alzheimer's disease and has been linked to cognitive decline.

An enzyme that extends the telomeres of chromosomes. Telomerase adds specific nucleotide sequences to the ends of existing chromosomes. Telomerase activity is highly regulated during development, and its activity is at an almost undetectable level of activity in fully developed cells. This lack of activity causes the cell to age. If telomerase is activated in a cell, the cell will continue to grow and divide, or become "immortal," which is important to both aging and cancer. Telomerase enzyme activity has been detected in more than 90 percent of human cancers.

Distinctive structures comprised of short, repetitive sequences of DNA located on the ends of chromosomes. Telomeres form a protective “cap” – a sort of disposable buffer that gradually shortens with age – that prevents chromosomes from losing genes or sticking to other chromosomes during cell division. When the telomeres on a cell’s chromosomes get too short, the chromosome reaches a “critical length,” and the cell stops dividing (senescence) or dies (apoptosis). Telomeres are replenished by the enzyme telomerase, a reverse transcriptase.

A protein that binds to specific DNA sequences, thereby controlling the rate of transcription of genetic information from DNA to messenger RNA. A defining feature of transcription factors is that they contain one or more DNA-binding domains, which attach to specific sequences of DNA adjacent to the genes that they regulate.

An essential amino acid. Tryptophan plays key roles in the biosynthesis of proteins and is a precursor to several molecules with physiological significance, including melatonin, niacin, and the neurotransmitter serotonin. Inflammation causes tryptophan to be reallocated from serotonin synthesis to that of kynurenine, which then converts to the neurotoxin quinolinic acid, leading to depression. Dietary sources of tryptophan include most protein-based foods, such as meat, beans, or nuts.

An enzyme required for the synthesis of serotonin. Tryptophan hydroxylase catalyzes the formation of 5-hydroxytryptophan (5-HTP) from the dietary precursor tryptophan.

Genes that suppress cell division or growth. Tumor suppressor genes encode proteins involved in aspects of cell growth regulation such as cell cycle arrest and apoptosis. Loss of tumor suppressor gene function promotes uncontrolled cell division and growth, which are hallmarks of cancer.

A fat-soluble vitamin. Vitamin A is a collective term that includes retinol, retinal, and retinyl esters. Vitamin A plays key roles in immune function, reproduction, and cellular communication. It is best known for its role in supporting eye health and the processes involved in vision. Vitamin A also supports cell growth and differentiation and participates in the normal formation and maintenance of the heart, lungs, kidneys, and other organs. Dietary sources of vitamin A include liver, fish oils, milk, eggs, leafy green vegetables, orange and yellow vegetables, tomato products, fruits, and some vegetable oils.

A potent water-soluble antioxidant found in citrus fruits. Vitamin C is an essential nutrient involved in tissue repair, neurotransmission, and immune system function. Also known as ascorbic acid.

A fat-soluble vitamin stored in the liver and fatty tissues. Vitamin D plays key roles in several physiological processes, such as the regulation of blood pressure, calcium homeostasis, immune function, and the regulation of cell growth. In the skin, vitamin D decreases proliferation and enhances differentiation. Vitamin D synthesis begins when 7-dehydrocholesterol, which is found primarily in the skin’s epidermal layer, reacts to ultraviolet light and converts to vitamin D. Subsequent processes convert D to calcitriol, the active form of the vitamin. Vitamin D can be obtained from dietary sources, too, such as salmon, mushrooms, and many fortified foods.

A specific sequence of DNA located in the promoter region of genes regulated by vitamin D.

A fat-soluble vitamin. Vitamin E is the collective name for a group of eight fat-soluble compounds (alpha-, beta-, gamma-, & delta-tocopherol and alpha-, beta-, gamma-, & delta-tocotrienol) with distinctive antioxidant activities. Of these eight, only alpha- (α-) tocopherol meets human requirements. Vitamin E serves as an antioxidant that breaks the chain reaction formation of reactive free radicals. In doing so it becomes oxidized and loses its antioxidant capacity. Vitamin E also protects LDL from oxidation and maintains the integrity of cell membranes throughout the body. Dietary sources of vitamin E include nuts, seeds, eggs, and fatty fish, such as salmon.

A type of fat-soluble vitamin. Vitamin K is critical for blood clotting, bone metabolism, prevention of blood vessel mineralization, and regulation of various cellular functions. Naturally occurring forms of vitamin K include phylloquinone (vitamin K1) and a family of molecules called menaquinones (vitamin K2). Vitamin K1 is synthesized by plants and is the major form in the diet. Vitamin K2 molecules are synthesized by the gut microbiota and found in fermented foods and some animal products (especially liver). The body has limited vitamin K storage capacity, so the body recycles it in a vitamin K redox cycle and reuses it multiple times.

A type of fat-soluble vitamin that participates in blood clotting and bone metabolism. Naturally occurring forms of vitamin K include phylloquinone (vitamin K1) and a family of molecules called menaquinones (vitamin K2). Vitamin K1 is synthesized by plants and is the major form present in the diet. Vitamin K2 molecules are synthesized by the gut microbiota and found in fermented foods and some animal products (especially liver). The body has limited vitamin K storage capacity, so the body recycles it in a vitamin K redox cycle and reuses it multiple times.

A type of fat-soluble vitamins that participate in blood clotting and bone metabolism. Naturally occurring forms of vitamin K include phylloquinone (vitamin K1) and a family of molecules called menaquinones (vitamin K2). Vitamin K1 is synthesized by plants and is the major form in the diet. Vitamin K2 molecules are synthesized by the gut microbiota and found in fermented foods and some animal products (especially liver). The body has limited vitamin K storage capacity, so the body recycles it in a vitamin K redox cycle and reuses it multiple times.

A vitamin that is readily dissolved in water. Water-soluble vitamins are not stored in the body. Vitamin C and members of the vitamin B family are water-soluble. Dietary sources of water-soluble vitamins include fruits, vegetables, meats, and legumes, among others.