Nutrient Physiology
Disease
Oxidative Stress and Free Radicals
Oxidative stress occurs when an oxygen molecule splits into single atoms with unpaired electrons, which are called free radicals. The body is under constant attack from oxidative stress. Oxygen in the body splits into single atoms with unpaired electrons. Electrons prefer to be in pairs, so these atoms, called free radicals, scavenge the body to seek out other electrons to pair with, causing damage to cells, proteins, and DNA.
Impact on Human Health
Free radicals are associated with human diseases, including cancer, atherosclerosis, Alzheimer's disease, Parkinson's disease, and many others. They may also be linked to aging, defined as a gradual accumulation of free-radical damage. Substances that generate free radicals can be found in the food we eat, the medicines we take, the air we breathe, and the water we drink. These substances include fried foods, alcohol, tobacco smoke, pesticides, and air pollutants.
The Danger of Free Radicals
According to Rice University, once free radicals are formed, a chain reaction can occur. The first free radical pulls an electron from a molecule, destabilizing it and turning it into a free radical. This molecule then takes an electron from another molecule, destabilizing it and turning it into a free radical. This domino effect can eventually disrupt and damage the whole cell.
The free radical chain reaction may lead to broken cell membranes, which can alter what enters and exits the cell. The chain reaction may change the structure of a lipid, making it more likely to become trapped in an artery. The damaged molecules may mutate and grow tumors, or the cascading damage may change the DNA code.
Oxidative Stress and Associated Diseases
Oxidative stress occurs when there are too many free radicals and too much cellular damage. Oxidative stress is associated with the damage of proteins, lipids, and nucleic acids. Several studies over the last few decades have suggested that oxidative stress plays a role in developing many conditions, including macular degeneration, cardiovascular disease, certain cancers, emphysema, alcoholism, Alzheimer's disease, Parkinson's disease, ulcers, and all inflammatory diseases, such as arthritis and lupus.
Free Radicals and Aging
Free radicals are also associated with aging. The free radical theory of aging states that we age because of free radical damage over time. Free radicals can damage DNA's instructional code, causing our new cells to grow incorrectly, leading to aging.
Antioxidants and Free Radicals
Antioxidants keep free radicals in check. Antioxidants are molecules in cells that prevent free radicals from taking electrons and causing damage. Antioxidants can give an electron to a free radical without becoming destabilized themselves, thus stopping the free radical chain reaction. "Antioxidants are natural substances whose job is to clean up free radicals. Just like fiber cleans up waste products in the intestines, antioxidants clean up the free radical waste in the cells." Well-known antioxidants include beta-carotene and other carotenoids, lutein, resveratrol, vitamin C, vitamin E, lycopene, and other phytonutrients.
Example: Taurine, Oxidative Stress, and Cancer
It has become increasingly apparent that oxidative stress plays a major role in a broad range of human diseases. The overproduction of reactive oxygen species and the body’s inability to stem the accumulation of highly reactive free radicals have been implicated in cardiovascular disease, diabetes-induced renal injury, inflammatory disease, and several major disorders of the central nervous system (CNS), which includes the brain and spinal cord. In each case, taurine, by virtue of its antioxidant activity, has been shown to play a crucial role as a cryoprotectant and in the attenuation of apoptosis.
When cells die, they generate toxic substances. These toxins can pass through gap junctions to kill their neighbors, a process referred to as "bystander" cell death, which rids the body of unhealthy cells. Cancer tumors lack this cell death from what's called apoptosis.
Taurine's Role in Preventing Apoptosis
Taurine inhibits apoptosis by preventing the formation of a key stage in the mitochondrial pathway to cell death. Apoptosis is a type of cell death in which a series of molecular steps in a cell lead to its death. This is one method the body uses to get rid of unneeded or abnormal cells. The process of apoptosis may be blocked in cancer cells. Taurine also improves mitochondrial function by stabilizing the electron transport chain and inhibiting the generation of reactive oxygen species.
Previous studies have confirmed that taurine shows an anti-cancer effect on a variety of human tumors by inhibiting cell proliferation and inducing apoptosis.
Body Physiology
Vitamins, Minerals, and Amino Acids
Vitamins, minerals, and amino acids are involved in everything from mobilizing energy from the food you eat to allowing your blood to carry oxygen. They help you build bones and fight the harmful effects of oxidation throughout your body.
13 Vitamins
Fat-Soluble Vitamins
The body stores fat-soluble vitamins in fatty tissue and the liver, and reserves of these vitamins can stay in the body for days and sometimes months. Dietary fats help the body absorb fat-soluble vitamins through the intestinal tract.
- Vitamin A: Retinol, retinal, and "the four carotenoids," including beta carotene.
Function: Essential for eye health.
Deficiency: May cause night blindness and keratomalacia, which causes the clear front layer of the eye to grow dry and cloudy. - Vitamin D: Ergocalciferol, cholecalciferol.
Function: Necessary for the healthy mineralization of bone.
Deficiency: May cause rickets and osteomalacia, or softening of the bones. - Vitamin E: Tocopherol, tocotrienol.
Function: Antioxidant activity helps prevent oxidative stress, an issue that increases the risk of widespread inflammation and various diseases.
Deficiency: Rare, but may cause hemolytic anemia in newborns. This condition destroys blood cells. - Vitamin K: Phylloquinone, menaquinone.
Function: Necessary for blood clotting.
Deficiency: Low levels may cause an unusual susceptibility to bleeding, or bleeding diathesis.
Water-Soluble Vitamins
Water-soluble vitamins do not stay in the body for long and cannot be stored. They leave the body via the urine. Because of this, people need a more regular supply of water-soluble vitamins than fat-soluble ones.
- Vitamin B1: Thiamine.
Function: Essential for producing various enzymes that help break down blood sugar.
Deficiency: May cause beriberi and Wernicke-Korsakoff syndrome. - Vitamin B2: Riboflavin.
Function: Essential for the growth and development of body cells and helps metabolize food.
Deficiency: Symptoms include inflammation of the lips and fissures in the mouth. - Vitamin B3: Niacin, niacinamide.
Function: Needed for the cells to grow and work correctly.
Deficiency: Low levels result in pellagra, which causes diarrhea, skin changes, and intestinal upset. - Vitamin B5: Pantothenic acid.
Function: Necessary for producing energy and hormones.
Deficiency: Symptoms include paresthesia, or "pins and needles." - Vitamin B6: Pyridoxine, pyridoxamine, pyridoxal.
Function: Vital for the formation of red blood cells.
Deficiency: Low levels may lead to anemia and peripheral neuropathy. - Vitamin B7: Biotin.
Function: Enables the body to metabolize proteins, fats, and carbohydrates. Also contributes to keratin, a structural protein in the skin, hair, and nails.
Deficiency: Rare but can lead to skin rash, hair loss, and brittle nails. - Vitamin B9: Folic acid, folinic acid.
Function: Essential for making DNA and RNA.
Deficiency: During pregnancy, this can affect the fetus’s nervous system. Doctors recommend folic acid supplements before and during pregnancy. - Vitamin B12: Cyanocobalamin, hydroxocobalamin, methylcobalamin.
Function: Essential for a healthy nervous system.
Deficiency: Low levels may lead to neurological problems and some types of anemia. - Vitamin C: Ascorbic acid.
Function: Contributes to collagen production, wound healing, and bone formation. Strengthens blood vessels, supports the immune system, helps the body absorb iron, and acts as an antioxidant.
Deficiency: May result in scurvy, which causes bleeding gums, loss of teeth, and poor tissue growth and wound healing.
Vitamin Effects on Organs
Brain
That think tank doesn’t just fill itself — it needs sustenance. And that comes through the nutrients in your food.
Vitamin E and the Brain
Antioxidant and neuroprotector vitamin E boosts brain health by reducing oxidative stress. It also helps combat inflammation and may help lower cholesterol, both of which are important for your little gray cells. People with Alzheimer’s have been found to have lower levels of vitamin E than those who don’t have the disease.
B-Vitamins and the Brain
Being the most metabolically active organ in the body, your brain benefits from B vitamins that help produce the energy required to create new brain cells. Vitamins B6, B9 (folate), and B12 also help break down homocysteine, an amino acid associated with a greater risk of dementia or Alzheimer’s disease.
Heart
Vitamins and minerals play a huge role in heart health.
Magnesium
Low magnesium can be a predictor of heart disease — it’s been linked with cardiovascular risk factors like high blood pressure, high cholesterol, and hardening of the arteries.
Folic Acid
Folic acid may help reduce your risk of stroke and cardiovascular disease by lowering the concentration of homocysteine in your blood.
Potassium
Potassium helps regulate blood pressure levels and reduces a person’s risk of stroke and cardiovascular disease.
Vitamin D
Studies show that getting enough of the sunshine vitamin may help reduce the formation of plaque and hardening of your arteries — both of which may help you avoid cardiovascular disease.
Skin
To keep your skin supple and healthy, make sure you’re getting enough of antioxidant vitamins C and E, wound healing vitamin K, and sunny vitamin D.
Vitamin C
Protects against the oxidative effects of harmful UV rays and helps build collagen, which helps keep your skin firm.
Vitamin E
Is another antioxidant powerhouse that protects your skin from sun damage.
Vitamin K
Helps your blood clot and has been shown to help heal wounds and help with rosacea, spider veins, and stretch marks.
Vitamin D
Ironically, while the sun’s rays are a major cause of skin damage, the vitamin D you largely get from the sun is important for healthy skin, helping reduce psoriasis symptoms, atopic dermatitis, and other skin disorders.
Minerals
Essential Minerals for Human Health
There are 102 minerals that the human body needs, but thirteen are essential for proper health. Their deficiency leads to critical health conditions.
Macro-Minerals
These are required in greater amounts and include calcium, potassium, sodium, phosphorus, magnesium, chloride, and sulfur.
Trace Minerals
These are needed in smaller amounts and include iron, zinc, selenium, manganese, copper, iodine, and cobalt.
Both types of minerals support a wide variety of bodily functions, ranging from building and maintaining healthy bones and teeth to keeping your muscles, heart, and brain working properly.
Key Minerals and Their Functions
- Calcium: Builds strong bones and teeth and helps in muscle contraction, blood clotting, nerve transmission, cell signaling, and regulation of metabolism. Deficiency makes bones fragile and easy to fracture. Sources include milk and dairy products, cashews, dates, broccoli, parsley, and greens.
- Sodium: Helps in muscle contraction, conducts nerve impulses, and controls fluid balance in the body. The primary source is table salt, which should be taken in moderation.
- Potassium: Plays a crucial role in maintaining fluid balance, muscle contraction, and nerve impulse conduction. It supports brain health and reduces the risk of stroke. Sources include bananas, sweet potatoes, avocados, beets, and dates.
- Chloride: Maintains normal fluid balance in the body and is used in the formation of hydrochloric acid for digestion. Sources include table salt, tomatoes, celery, and lettuce.
- Magnesium: Acts as a cofactor in several enzymatic reactions and is required for DNA synthesis and as an antioxidant. Sources include green leafy vegetables, legumes, nuts, seeds, and whole grains.
- Phosphorus: Builds and repairs bones and teeth, helps nerves function, and makes muscles contract. Sources include meats, poultry, beans, nuts, seeds, and dairy products.
- Iodine: Used to produce thyroid hormones necessary for metabolism and physical and mental development. Sources include seafood, dairy products, and iodized salt.
- Iron: Used in hemoglobin formation, which carries oxygen in the blood. Deficiency can lead to cellular hypoxia and cell death. Sources include green leafy vegetables and meats.
- Zinc: Aids in cell division, immunity, and wound healing. Sources include oysters, red meat, poultry, beans, nuts, and whole grains.
- Copper: Helps in energy production and facilitates iron uptake from the gut. Sources include chocolate, liver, shellfish, and wheat bran cereals.
- Manganese: Plays a role in protein, carbohydrate, and cholesterol breakdown and cell division. Sources include whole grains, nuts, and rice.
- Sulfur: Has antibacterial properties and helps fight acne-causing bacteria in the skin. Sources include seafood and legumes.
- Selenium: Helps prevent oxidative damage to the cells and is important for thyroid hormone metabolism. Sources include Brazil nuts, seafood, and organ meats.
- Chromium: Though this trace mineral might enhance insulin activity and the breakdown of dietary sugars, it is only needed in small amounts and is not considered "essential" in the same way as other minerals.
Mineral Effects on Organs
Bone and Tooth Health
Your skeleton provides motility, protection and support for the body. It also stores minerals and other nutrients. Though they appear hard and unyielding, your bones are actually constantly being reabsorbed and reformed by your body. Several minerals make up the lattice architecture of your bones. Calcium is the most abundant mineral in your body and is found in your bones and blood.
Along with the minerals phosphorus and magnesium, calcium gives your bones strength and density. This mineral also builds and maintains strong, healthy teeth. Calcium deficiency due to poor nutrition or illness can lead to osteoporosis, a condition in which the bones become brittle and less dense, increasing the risk of fractures. KidsHealth notes that foods that are rich in calcium include milk and other dairy products, green, leafy vegetables and canned fish with bones.
Energy Production
You require oxygen to produce energy that is necessary for every bodily function and process. Red blood cells -- or erythrocytes -- carry oxygen to each of your infinite cells, where it is used to generate energy. Red blood cells contain a heme or iron component that binds to oxygen so that it can be transported. Without the iron molecules, oxygen could not be attached to the blood cells and the body would not be able to produce the energy necessary for life. Iron is an essential mineral, and failing to get enough from your diet can lead to a condition called anemia, which causes weakness and fatigue. This mineral is primarily found in the blood, and it is also stored in your liver, spleen, bone marrow and muscles.
Nerve and Muscle Function
Potassium is found in bananas, dates, tomatoes, green leafy vegetables, citrus fruits and legumes such as peas and lentils. This nutrient is important to keep muscles and the nervous system functioning normally. Potassium helps to maintain the correct water balance in the cells of your nerves and muscles. Without this essential mineral, your nerves could not generate an impulse to signal your body to move, and the muscles in your heart, organs and body would not be able to contract and flex.
Immune Health
Some minerals such as calcium are needed in large quantities, while others such as zinc are only needed in trace amounts. Zinc is an essential mineral that is important for keeping your immune system strong and helps your body fight infections, heal wounds and repair cells. KidsHealth notes that eating meat and legumes such as beans, peas and lentils will give you sufficient amounts of zinc. Selenium is also needed in small amounts for immune health. A deficiency of selenium has been linked to an increased risk of heart disease and even some types of cancers.
Amino Acids
Amino acids are organic compounds composed mainly of nitrogen, carbon, hydrogen, and oxygen. Your body needs 20 different amino acids to grow and function properly. While all 20 of these are important for your health, only 9 are classified as essential, 11 nonessential, and 8 conditional.
Essential Amino Acids
Although your body can make nonessential amino acids, it cannot make essential amino acids, so you have to get them from your diet.
- Histidine
- Isoleucine
- Leucine
- Lysine
- Methionine
- Phenylalanine
- Threonine
- Tryptophan
- Valine
Nonessential Amino Acids
Nonessential means that our bodies can produce the amino acid, even if we do not get it from the food we eat.
- Alanine
- Arginine
- Asparagine
- Aspartic acid
- Cysteine
- Glutamic acid
- Glutamine
- Glycine
- Proline
- Serine
- Tyrosine
Conditional Amino Acids
Conditional amino acids are usually not essential, except in times of illness and stress.
- Arginine
- Cysteine
- Glutamine
- Tyrosine
- Glycine
- Ornithine
- Proline
- Serine
Essential Amino Acids
Phenylalanine
Your body turns this amino acid into the neurotransmitters tyrosine, dopamine, epinephrine, and norepinephrine. It plays an integral role in the structure and function of proteins and enzymes and the production of other amino acids.
Valine
This is one of three branched-chain amino acids (BCAAs) on this list. That means it has a chain branching off from one side of its molecular structure. Valine helps stimulate muscle growth and regeneration and is involved in energy production.
Threonine
This is a principal part of structural proteins, such as collagen and elastin, which are important components of your skin and connective tissue. It also plays a role in fat metabolism and immune function.
Tryptophan
Often associated with drowsiness, tryptophan is a precursor to serotonin, a neurotransmitter that regulates your appetite, sleep, and mood.
Methionine
This amino acid plays an important role in metabolism and detoxification. It’s also necessary for tissue growth and the absorption of zinc and selenium, minerals that are vital to your health.
Leucine
Like valine, leucine is a BCAA that is critical for protein synthesis and muscle repair. It also helps regulate blood sugar levels, stimulates wound healing, and produces growth hormones.
Isoleucine
The last of the three BCAAs, isoleucine is involved in muscle metabolism and is heavily concentrated in muscle tissue. It’s also important for immune function, hemoglobin production, and energy regulation.
Lysine
Lysine plays major roles in protein synthesis, calcium absorption, and the production of hormones and enzymes. It’s also important for energy production, immune function, and the production of collagen and elastin.
Histidine
Your body uses this amino acid to produce histamine, a neurotransmitter that is vital to immune response, digestion, sexual function, and sleep-wake cycles. It’s critical for maintaining the myelin sheath, a protective barrier that surrounds your nerve cells.
Taurine
Taurine, a sulfur-containing amino acid, rather than a carbonic amino acid is the most abundant intracellular amino acid in humans, and is implicated in numerous biological and physiological functions. Taurine is considered a “conditionally” essential amino acid, due to its lack of involvement in protein synthesis. However, given its significant role in many biological processes including bile salt formation, osmoregulation, antioxidation, retinal development, and the central nervous and cardiovascular systems, its presence in the body appears very much essential.
Nonessential Amino Acids
Alanine
Purpose: Alanine is essential for the glucose-alanine cycle. It acts as a carrier of nitrogen from peripheral tissues to the liver, where it is involved in gluconeogenesis, the process of forming glucose from non-carbohydrate sources. This cycle helps regulate blood sugar levels and supports energy production during fasting or intense exercise.
Arginine
Purpose: Arginine has several important functions. It is a precursor for nitric oxide (NO) synthesis, a molecule that plays a crucial role in vasodilation, improving blood flow and cardiovascular health. Additionally, arginine is involved in the urea cycle, contributing to the detoxification of ammonia, a byproduct of protein metabolism.
Asparagine
Purpose: Asparagine is primarily involved in protein synthesis. It provides a crucial component for the formation of peptide bonds between amino acids, supporting the building and repair of tissues, enzymes, and other proteins.
Aspartic Acid
Purpose: Aspartic acid participates in the urea cycle, aiding in the removal of ammonia from the body. Additionally, it plays a role in the citric acid cycle (Krebs cycle), contributing to energy production by facilitating the conversion of citrate to isocitrate.
Cysteine
Purpose: Cysteine is a key component for the synthesis of glutathione, a potent antioxidant. Glutathione helps neutralize free radicals, protecting cells from oxidative stress. Cysteine's involvement in protein structure is crucial for the formation of disulfide bonds, which contribute to the stability of various proteins.
Glutamic Acid
Purpose: Glutamic acid serves as a precursor for the synthesis of the neurotransmitter glutamate. This amino acid is essential for excitatory signaling in the central nervous system, playing a vital role in neuronal communication and brain function.
Glutamine
Purpose: Glutamine is essential for maintaining the integrity of the intestinal mucosa. It serves as a primary fuel source for rapidly dividing cells, including those in the immune system. Glutamine supports immune function, intestinal health, and overall cellular metabolism.
Glycine
Purpose: Glycine is involved in the synthesis of creatine, a compound crucial for energy metabolism, particularly during short bursts of intense physical activity. As an inhibitory neurotransmitter, glycine helps regulate neuronal activity, promoting a balanced nervous system.
Proline
Purpose: Proline is essential for the structure and stability of collagen, a major protein in connective tissues. Collagen provides structural support to skin, tendons, ligaments, and blood vessels, contributing to the overall integrity of the body's structural framework.
Serine
Purpose: Serine serves as a precursor for the synthesis of other amino acids, including glycine and cysteine. Additionally, serine is crucial for the formation of phospholipids, essential components of cell membranes. It plays a role in maintaining cellular structure and function.
Tyrosine
Purpose: Tyrosine is a precursor for the synthesis of catecholamines (such as dopamine, norepinephrine, and epinephrine), important neurotransmitters that regulate mood and stress response. Tyrosine also contributes to the production of thyroid hormones, influencing metabolism, and plays a role in the synthesis of melanin, contributing to skin and hair pigmentation.
Taurine
Taurine has also been shown to have a protective effect on the microbiome, which could help address over-reliance on antibiotics. One study found that taurine levels influence pathogen colonization in the gut, and that a mild infection can prompt the liver and gallbladder to draw on taurine-conjugated bile acids to strengthen the microbiome and promote resistance to further infection.
Antioxidant: Taurine also acts as an antioxidant: concentration is particularly high in cells exposed to oxidative stress, and deficiency is linked with cell death (Jong et al., 2013). However, taurine is not a scavenger of free radicals, and the precise mechanism of antioxidant action is unclear. One known process involves a toxicity-suppressing reaction with halogenating agents such as hypochlorous acid, but taurine has demonstrated a protective effect in cells where these agents are absent.
Taurine, Oxidative Stress, and Cancer
It has become increasingly apparent that oxidative stress plays a major role in a broad range of human diseases. The overproduction of reactive oxygen species and the body’s inability to stem the accumulation of highly reactive free radicals have been implicated in cardiovascular disease, diabetes-induced renal injury, inflammatory disease, and several of the major disorders of the CNS (central nervous system that includes the brain and spinal cord). In each case, taurine, by virtue of its antioxidant activity, has been shown to play a crucial role as a cryoprotectant and in the attenuation of apoptosis.
When cells die, they tend to generate toxic substances. These toxins can pass through gap junctions to kill their neighbors, a process referred to as “bystander” cell death, which rids the body of unhealthy cells. Cancer tumors lack this cell death from what's called apoptosis. Taurine inhibits apoptosis by preventing the formation of a key stage in the mitochondrial pathway to cell death. (Apoptosis: A type of cell death in which a series of molecular steps in a cell lead to its death. This is one method the body uses to get rid of unneeded or abnormal cells. The process of apoptosis may be blocked in cancer cells.) as well as its ability to improve mitochondrial function by stabilizing the electron transport chain and inhibiting the generation of reactive oxygen species.
Previous studies have confirmed that taurine shows an anti-cancer effect on a variety of human tumors by inhibiting cell proliferation and inducing apoptosis.
Taurine, Bile Salts, and Microbiota
Taurine’s main function is the conjugation of cholesterol into bile acids. Bile acids are conjugated with taurine or glycine at a ratio of about 1:3, to form bile salts, which in turn form mixed micelles with phospholipids and cholesterol (Chiang, 2013). These are stored in the gallbladder and secreted to ease digestion and nutrient absorption.
In summary, each nonessential amino acid has specific roles in various biochemical processes, contributing to the body's overall function, structure, and health. Their diverse functions collectively support vital physiological processes, ensuring the proper functioning and well-being of the body.
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