Adiponectin. Also known as apM1, AdipoQ, Acrp30, and GBP-28. Adiponectin is encoded by the ADIPOQ gene and is secreted by fat cells. It regulates glucose levels and fat burning.
Adrenal glands. Endocrine glands that produce hormones, such as sex hormones and cortisol, which help you respond to stress and have many other functions. You have an adrenal, or suprarenal, gland at the top of each kidney.
Adrenocorticotropic hormone (ACTH). Also known as corticotropin. A hormone released from the anterior pituitary gland in the brain, ACTH is an important component of the hypothalamic-pituitary-adrenal axis because it increases production of cortisol in the adrenal gland. Produced in response to stress, ACTH levels in the blood are measured to help detect, diagnose, and monitor conditions associated with excessive or deficient cortisol in the body.
Allele. An allele is a variant form of a gene. For each genetic locus in your chromosome, you have two alleles. You inherit one allele (copy of a gene) from your mother and one copy from your father. If the alleles you inherit are the same, you are homozygous for that gene. If the alleles are different, you are heterozygous for that gene.
Amyloid beta. Sticky peptides, or groups of amino acids, that can aggregate together and form amyloid plaques. The peptides come from a larger precursor protein (amyloid precursor protein, or APP), which is cleaved to yield amyloid beta. It impairs the structure and function of your tissues, collects in the brain, and is toxic to nerve cells, increasing the risk for Alzheimer’s disease.
Beta amyloid. See amyloid beta.
Brain-derived neurotrophic factor (BDNF). Part of the family of proteins known as neurotrophic factors that contribute to the growth and survival of nerve cells. BDNF is found in the brain and spinal cord and is active at the connections between nerve cells, known as synapses. BDNF promotes synaptic plasticity, facilitates neural repair, and enhances learning and memory.
Collagen. An easily digested form of protein that improves skin, hair, and nails. As you age, you break down more internal collagen than you make, leading to saggy skin, cracking fingernails, dull hair, and wrinkles.
Corticotropin-releasing hormone (CRH). A hormone involved in the stress response system. It is secreted by the hypothalamus and stimulates the pituitary gland to make adrenocorticotropic hormone (ACTH). Excess stress and over exercising raise CRH levels, which can increase the permeability of the intestinal walls as well as the permeability of the lungs, skin, and blood-brain barrier. CRH can also be released outside of the central nervous system, such as in the skin, where it may cause inflammation.
Deoxyribonucleic acid (DNA). A repeating pattern of four chemical bases: adenine (A), cytosine (C), guanine (G), and thymine (T). These bases are the alphabet in which your genetic code is written. The bases pair up with each other—A with T, and C with G—to form a base pair. Your DNA is like a ladder, with the base pairs forming the ladder’s rungs. (The sides of the ladder are composed of sugar and phosphate.) You have three billion bases in your genome, and 99.5 percent of them are the same from human to human.
Epigenetics. Refers to the changes in gene expression caused by mechanisms other than the DNA sequence. Certain triggers may override your gene expression, silencing a bad gene or promoting a good gene.
Epinephrine. A hormone with neurotransmitters made in the inner core of the adrenals that help you focus and problem-solve. It creates amounts of glucose and fatty acids that can be used by the body as fuel in times of stress or danger when increased alertness or exertion is required.
Gene. Your genes are collections of base pairs that give the recipes to make specific proteins, such as enzymes. Each gene makes about three proteins. The sequence of the bases tells your body how to build, repair, and maintain itself. You inherit one copy of a gene from your mother and one copy from your father. The single copies are called alleles. If you inherit the normal copy of the gene from each parent, you are normal, or wild type. If you inherit one copy of the normal gene and one copy of the polymorphism, you are heterozygous. If you inherit two copies of the same polymorphism, you are homozygous. Problems arise mostly when you are heterozygous or homozygous.
Genetics. Refers to the function and composition of specific genes.
Genomics. Refers to how all your genes are expressed in your body.
Gene regulation. Refers to the mechanisms used by the cell to control which genes are expressed and to increase or decrease the production of RNA and proteins.
Glucocorticoids. Made in the outside portion (the cortex) of the adrenal gland, glucocorticoids regulate the metabolism of glucose and are chemically classed as steroids. Cortisol is the major natural glucocorticoid.
Hypothalamic-pituitary-adrenal (HPA) axis. A feedback loop by which signals from the brain trigger the release of hormones needed to respond to stress. Because of its function, the HPA axis is also sometimes called the stress circuit.
Insulin. Drives glucose into cells as fuel and deposits fat. Chronically high insulin increases estrogen, and estrone, specifically, increases the cells’ resistance to insulin.
Irisin. A hormone secreted from muscles in response to exercise. It tricks white fat into behaving like brown fat, builds muscle, activates weight loss, and blocks diabetes.
Leptin. A hormone that controls hunger, metabolism, and the utilization of food as fuel or fat.
Maximal heart rate. The highest heart rate you can achieve during maximum physical exertion. To calculate, subtract your age from 220. This is the maximum number of times your heart should beat per minute while you are exercising.
Melatonin. A hormone secreted by the pineal gland in the brain that helps regulate other hormones and maintains the body’s circadian rhythm. Melatonin also helps control the timing and release of female reproductive hormones.
Methylfolate. The enzyme methylenetetrahydrofolate reductase (MTHFR) takes folate (vitamin B9) and converts it into methylfolate (L5MTHF). Activated methylfolate plays a key role in the biochemical process of methylation. Methylation is the powerhouse detoxification, production, and DNA protection system that almost every cell of your body depends on.
Mitochondrial dysfunction. Occurs when the mitochondria are not able to perform their job and is one of the cellular signs of aging. Causes include nutritional deficiencies and excesses, toxin exposure, oxidative stress, and microbial infection (or dysbiosis). Tired mitochondria may make you feel more fatigued during and after exercise or cause muscle pain.
Myokines. Small proteins released when your muscles are contracting. These proteins enter the bloodstream and their levels increase before and after exercise. Higher levels of myokines in skin cells have been associated with younger-looking skin.
Myostatin. A growth factor that regulates muscle size and prevents them from growing too large. A lack of myostatin results in excessive muscle growth. It may also control loss of muscle mass in aging women.
Nerve growth factor. A neurotrophic factor (part of the same family of proteins as BDNF) and neuropeptide. It regulates the growth, maintenance, proliferation, and survival of certain neurons. Yoga is associated with higher levels of nerve growth factor.
Norepinephrine. A neurotransmitter made in the inner core of the adrenals that helps with focus and problem solving. It acts as a neuromodulator in the nervous system and as a hormone in the blood.
Oxidative stress. Refers to an imbalance between the production of reactive oxygen species (free radicals) and antioxidants. Free radicals are oxygen-containing molecules with one or more unpaired electrons that can interfere with and destabilize DNA, proteins, fats, and other cell components. Antioxidants neutralize and counteract the harmful effects of free radicals.
Oxytocin. Both a hormone and a neurotransmitter, which means it acts as a brain chemical that transmits information from nerve to nerve; called by some “the love hormone” because it increases in the blood with orgasm in both men and women. Oxytocin is also released when the cervix dilates, thereby augmenting labor, and when a woman’s nipples are stimulated, which facilitates breast-feeding and promotes bonding between mother and baby.
Single-nucleotide polymorphism (SNP, pronounced “snip”). SNPs are slight variations in genes. The variation refers to the sequence in which a single nucleotide—building block of DNA—is changed.
Synaptoporosis. Refers to the problem Alzheimer’s patients have with maintaining the balance between actively remembering and forgetting memory inputs. Amyloid precursor protein (APP) manages this process in the brain, and the delicate balance is completely impaired in Alzheimer’s patients.
Thyroid. A gland that keeps the metabolism balanced, giving you energy, comfortable warmth, and manageable weight.
Transcription factors. Proteins involved in the process of converting, or transcribing, DNA into RNA. They bind to specific sequences of DNA, thereby controlling the rate of transcription.
Vagal tone. Refers to the responsiveness of the vagus nerve. Lower vagal tone means the vagus nerve is not fully performing its functions and can lead to a variety of problems. Meditation can enhance vagal tone.
Vagus nerve. The most important nerve and the portal to the parasympathetic nervous system. If your vagus nerve is impaired, you won’t be healthy and are more likely to age faster.
Vasopressin (AVP). A hormone released by the hypothalamus in response to a stressful threat. It retains water in the body and constricts blood vessels.
Vitamin D. Synthesized from cholesterol and exposure to sunlight. It can also be ingested from food, but it is not officially an essential vitamin because it can be made by mammals exposed to the sun. It is considered a vitamin and a hormone. Present in eggs and fish, it is added to other foods such as milk; available as a dietary supplement.