 |
 |
 |
|
History; Source
The practice of giving cod liver oil began when the smoke-filled skies of nineteenth-century England deprived youngsters of exposure to the sun. Without sun, their bodies couldn't make vitamin D, and they developed rickets. Because cod liver oil contains large amounts of vitamin D, it cured rickets and made a great contribution to public health. Today, however, other constituents of cod liver and other fish oils have become of interest: the omega-3 fatty acids.
Fish oil is obtained from the livers of fish or from the meat.
The most important omega-3 fatty acids found in fish oil are called EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). In order to match the dosage used in several major studies, one should probably take enough fish oil to supply about 1,800mg of EPA and 900mg of DHA daily. Certain conditions require a predominance of EPA while others require DHA. Since they compete with each other, careful attention must be paid to their ratio in those conditions which are discussed elsewhere.
Some manufacturers add vitamin E to fish oil capsules to keep the oil from becoming rancid. Another method is to remove all the oxygen from the capsule.
Function; Reasons For Use
The omega-3 fatty acids found in fish oil can lower blood triglyceride levels, thin the blood, and also decrease inflammation in various parts of the body. These effects, as well as others, may explain many of fish oil's apparent benefits.
There has been a great deal of excitement about the possibility of using fish oil to help prevent heart disease. According to some but not all studies, fish or fish oil appears to lower triglyceride levels, raise HDL ("good") cholesterol, "thin" the blood, reduce levels of homocysteine, slow down atherosclerosis, help prevent death from heart disease, and perhaps also treat hypertension.
Fish oil has also become recognized as an effective treatment for early stages of rheumatoid arthritis. It appears to significantly reduce symptoms without side-effects and may magnify the benefits of standard arthritis drugs. However, there appears to be no evidence that fish oil slows the progress of the disease.
Various essential fatty acids, including fish oil, flaxseed oil, and GLA (gamma-linolenic acid), are widely recommended for dysmenorrhea (menstrual pain), and two studies suggest that fish oil may indeed be effective.
According to one small study, fish oil may produce benefits in bipolar disorder (more commonly known as manic-depressive illness), reducing risk of relapse and improving emotional state.
Small studies also suggest that fish oil may be helpful in Raynaud's phenomenon (a condition in which a person's hands and feet show abnormal sensitivity to cold temperatures), psoriasis, sickle-cell anemia, the autoimmune disease lupus, and a form of kidney disease called IgA nephropathy. Preliminary double-blind trials suggest that EPA, but not DHA, might be helpful for schizophrenia.
Evidence is mixed on whether fish oil can help prevent flare-ups of Crohn's disease, a condition in which parts of the digestive tract are highly inflamed. A 1-year double-blind trial, involving 78 participants with Crohn's disease in remission who were at high risk for relapse, found that fish oil supplements helped keep the disease from flaring up. However, a double-blind placebo-controlled trial that followed 120 individuals for 1 year found that fish oil did not reduce the relapse rate as compared to placebo. Negative results were also seen in a smaller double-blind trial.
Small double-blind trials suggest that fish oil might be helpful for reducing symptoms of ulcerative colitis. However, another small double-blind placebo-controlled trial found no such benefit. Larger studies will be necessary to discover for certain whether fish oil helps or not. Regular use of fish oil does not appear to help prevent disease flare-ups.
A large observational study found evidence that higher consumption of fish and other sources of omega-3 essential fatty acids may reduce the risk of stroke. Interesting, but highly preliminary, evidence suggests that fish oil, or its constituents, might be helpful for treating depression, preventing premature birth, improving vision in premature babies, treating kidney stones, alleviating the symptoms of chronic fatigue syndrome, and reducing the risk of prostate cancer.
Fish oil has also been proposed as a treatment for many other conditions, including diabetic neuropathy, allergies, gout, and migraine headaches, but there has been little real scientific investigation of these uses.
Preliminary studies suggest fish oil may help symptoms of multiple sclerosis; however, one double-blind study found no difference between people taking fish oil and those taking olive oil (used as a placebo).
Some, but not all, studies suggest that fish oil and GLA taken along with calcium may be helpful in preventing osteoporosis.
Directions
Typical dosages of fish oil are 3 to 9gm daily, but this is not the upper limit. In one study, participants ingested 60gm daily.
Side-Effects; Counter-Indicators and Warnings
Often there is a digestive disturbance that prevents some people from using fish oils. There are preparations which are coated to overcome this difficulty.
CAUTION: Do not confuse "fish oil" with "cod liver oil" as they are not the same thing. Cod liver oil contains high concentrations of vitamin A. Taking cod liver oil in the same amounts that are recommended for fish oil can be toxic, and even more so in people who have chronic renal failure (because vitamin A can build up to toxic levels).
|
|
 |
|
 |
Fish Oils can help with the following:
Fish Oils can help prevent the following: | | | | | Tumors, Malignant |  Prostate Cancer | Several studies have shown an inverse relationship between blood levels of fish oils (eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]) and the risk of prostate cancer. A study by medical researchers at the Karolinska Institute confirms this association. [The Lancet, Vol. 357, June 2, 2001, pp. 1764-66 (research letter), British Journal of Cancer, Vol. 81, No. 7, December 1999, pp. 1238-42] |
|
| | | | |
KEY | | Likely to help |  | | Avoid absolutely |
GLOSSARY
Allergy (Allergies)
Hypersensitivity caused by exposure to a particular antigen (allergen), resulting in an increased reactivity to that antigen on subsequent exposure, sometimes with harmful immunologic consequences.
Anemia (Anaemia, Anemias)
A condition resulting from an unusually low number of red blood cells or too little hemoglobin in the red blood cells. The most common type is iron-deficiency anemia in which the red blood cells are reduced in size and number, and hemoglobin levels are low. Clinical symptoms include shortness of breath, lethargy and heart palpitations.
Arthritis (Arthritic)
Inflammation of a joint, usually accompanied by pain, swelling, and stiffness, and resulting from infection, trauma, degenerative changes, metabolic disturbances, or other causes. It occurs in various forms, such as bacterial arthritis, osteoarthritis, or rheumatoid arthritis. Osteoarthritis, the most common form, is characterized by a gradual loss of cartilage and often an overgrowth of bone at the joints.
Atherosclerosis
Common form of arteriosclerosis associated with the formation of atheromas which are deposits of yellow plaques containing cholesterol, lipids, and lipophages within the intima and inner media of arteries. This results in a narrowing of the arteries, which reduces the blood and oxygen flow to the heart and brain as well as to other parts of the body and can lead to a heart attack, stroke, or loss of function or gangrene of other tissues.
Autoimmune Disease (Autoimmune, Autoimmunity)
One of a large group of diseases in which the immune system turns against the body's own cells, tissues and organs, leading to chronic and often deadly conditions. Examples include multiple sclerosis, rheumatoid arthritis, systemic lupus, Bright's disease and diabetes.
Bipolar Disorder (Manic Depression, Manic-Depression, Manic-Depressive)
A disorder is characterized by alternating periods of extreme moods, usually swinging from being overly elated or irritable (mania) to sad and hopeless (depression) and then back again, with periods of normal mood in between. The frequency of the swings between these two states, and the duration of the mood, varies from person to person.
Calcium
The body's most abundant mineral. Its primary function is to help build and maintain bones and teeth. The body also needs calcium to carry nerve signals, keep the heart functioning, contract muscles, clot blood and maintain healthy skin. Calcium helps control blood acid-alkaline balance, plays a role in cell division, muscle growth and iron utilization, activates certain enzymes, and helps transport nutrients through cell membranes. Calcium also forms a cellular cement called ground substance that helps hold cells and tissues together.
Cancer
Refers to the various types of malignant neoplasms that contain cells growing out of control and invading adjacent tissues, which may metastasize to distant tissues.
Cholesterol
A waxy, fat-like substance manufactured in the liver and found in all tissues, it facilitates the transport and absorption of fatty acids. In foods, only animal products contain cholesterol. An excess of cholesterol in the bloodstream can contribute to the development of atherosclerosis.
Chronic Fatigue Syndrome (CFS, Chronic Fatigue)
A disorder of unknown cause that lasts for prolonged periods and causes extreme and debilitating exhaustion as well as a wide range of other symptoms such as fever, headache, muscle ache and joint pain, often resembling flu and other viral infections. Also known as Chronic Fatigue and Immune Dysfunction Syndrome (CFIDS), Chronic Epstein-Barr Virus (CEBV), Myalgic Encephalomyelitis (ME), "Yuppy Flu" and other names, it is frequently misdiagnosed as hypochondria, psychosomatic illness, or depression, because routine medical tests do not detect any problems.
Chronic Renal Failure (Chronic Renal Insufficiency, Kidney Failure, Renal Insufficiency)
(CRF) Irreversible, progressive impaired kidney function. The early stage, when the kidneys no longer function properly but do not yet require dialysis, is known as Chronic Renal Insufficiency (CRI). CRI can be difficult to diagnose, as symptoms are not usually apparent until kidney disease has progressed significantly. Common symptoms include a frequent need to urinate and swelling, as well as possible anemia, fatigue, weakness, headaches and loss of appetite. As the disease progresses, other symptoms such as nausea, vomiting, bad breath and itchy skin may develop as toxic metabolites, normally filtered out of the blood by the kidneys, build up to harmful levels. Over time (up to 10 or 20 years), CRF generally progresses from CRI to End-Stage Renal Disease (ESRD, also known as Kidney Failure). Patients with ESRD no longer have kidney function adequate to sustain life and require dialysis or kidney transplantation. Without proper treatment, ESRD is fatal.
Crohn's Disease (Crohn's)
Chronic inflammatory disease of the gastrointestinal tract. The most common symptoms are abdominal pain, often in the lower right area, and diarrhea. Rectal bleeding, weight loss, and fever may also occur. Bleeding may be serious and persistent, leading to anemia.
DHA
Docosahexanoic Acid. A metabolite of the omega-3 fatty acid alpha-linolenic acid.
Diabetes Mellitus (Diabetes, Diabetic, Diabetics)
A disease with increased blood glucose levels due to lack or ineffectiveness of insulin. Diabetes is found in two forms; insulin-dependent diabetes (juvenile-onset) and non-insulin-dependent (adult-onset). Symptoms include increased thirst; increased urination; weight loss in spite of increased appetite; fatigue; nausea; vomiting; frequent infections including bladder, vaginal, and skin; blurred vision; impotence in men; bad breath; cessation of menses; diminished skin fullness. Other symptoms include bleeding gums; ear noise/buzzing; diarrhea; depression; confusion.
Dysmenorrhea
Difficult or painful menstruation.
EPA
Environmental Protection Agency. Also: Eicosapentanoic Acid. A metabolite of the omega-3 fatty acid alpha-linolenic acid.
Essential Fatty Acid (EFA, EFAs, Essential Fatty Acids)
A substance that the human body cannot manufacture and therefore must be supplied in the diet.
Fatty Acids (Fatty Acid)
Chemical chains of carbon, hydrogen, and oxygen atoms that are part of a fat (lipid) and are the major component of triglycerides. Depending on the number and arrangement of these atoms, fatty acids are classified as either saturated, polyunsaturated, or monounsaturated. They are nutritional substances found in nature which include cholesterol, prostaglandins, and stearic, palmitic, linoleic, linolenic, eicosapentanoic (EPA), and decohexanoic acids. Important nutritional lipids include lecithin, choline, gamma-linoleic acid, and inositol.
Gamma-Linolenic Acid (GLA)
A downline metabolite of linoleic acid, an Omega-6 oil.
Gout
A disease characterized by an increased blood uric acid level and sudden onset of episodes of acute arthritis.
Gram (gm, gms, Gramme, Grammes, Grams)
A metric unit of weight, there being approximately 28 grams in one ounce.
High-Density Lipoprotein (HDL)
Also known as "good" cholesterol, HDLs are large, dense, protein-fat particles that circulate in the blood picking up already used and unused cholesterol and taking them back to the liver as part of a recycling process. Higher levels of HDLs are associated with a lower risk of cardiovascular disease because the cholesterol is cleared more readily from the blood.
Hypertension
High blood pressure. Hypertension increases the risk of heart attack, stroke, and kidney failure because it adds to the workload of the heart, causing it to enlarge and, over time, to weaken; in addition, it may damage the walls of the arteries.
Immunoglobulin A (IgA)
Supports mucosal immunity.
Kidney Stone (Kidney Gravel, Kidney Stones)
A stone (concretion) in the kidney. If the stone is large enough to block the tube (ureter) and stop the flow of urine from the kidney, it must be removed by surgery or other methods. Also called Renal Calculus. Symptoms usually begin with intense waves of pain as a stone moves in the urinary tract. Typically, a person feels a sharp, cramping pain in the back and side in the area of the kidney or in the lower abdomen. Sometimes nausea and vomiting occur. Later, pain may spread to the groin. The pain may continue if the stone is too large to pass; blood may appear in the urine and there may be the need to urinate more often or a burning sensation during urination. If fever and chills accompany any of these symptoms, an infection may be present and a doctor should be seen immediately.
Kidneys (Kidney, Renal)
Bean-shaped organs, each about the size of a fist. They are located near the middle of the back, just below the rib cage. The kidneys are sophisticated reprocessing machines, each day handling about 50 gallons of blood to sift out about half a gallon of waste products and extra water. The waste and extra water become urine, which flows to the bladder through tubes called ureters. The actual filtering occurs in tiny units inside the kidneys called nephrons. Every kidney has about a million nephrons. In a nephron, a glomerulus -- which is a tiny blood vessel, or capillary -- intertwines with a tiny urine-collecting tube called a tubule. A complicated chemical exchange takes place, as waste materials and water leave your blood and enter your urinary system. The kidneys recycle chemicals such as sodium, phosphorus, and potassium and thus regulate their levels. Renal: Pertaining to the kidneys.
Liver (Hepatic)
The largest and one of the most complex organs of the body, the liver is responsible for much of the metabolism of fats, proteins and carbohydrates. It is the site of much of the body's detoxification. It is connected very closely with digestion and the regulation of blood sugar, among many other functions. Found behind the ribs on the right side of the abdomen, it has many important functions such as removing harmful material from the blood, making enzymes and bile that help digest food, and converting food into substances needed for life and growth. Hepatic: Pertaining to the liver.
Menstruation (Menses, Menstrual, Menstrual Cycle, Menstrual Cycles, Menstrual Flow, Menstrual Phase, Monthly Cycle)
The periodic discharge of blood, tissue fluid and mucus from the endometrium (lining of the uterus) that usually lasts from 3 - 5 days. It is caused by a sudden reduction in estrogens and progesterone.
Migraine (Migraine Headache, Migraine Headaches, Migraines)
Not just a headache, but a disorder affecting the whole body, characterized by clearly defined attacks lasting from about 4 to 72 hours, separated by headache-free periods; progresses through five distinct phases. Prodrome: experienced by about 50% of migraineurs and starting up to 24 hours before the headache - changes in mood, sensory perception, food craving, excessive yawning, or speech or memory problems. Aura: experienced by about 15% and starting within an hour before the headache - disruption of vision (flashing lights, shimmering zigzag lines, blind spot) or sensation (numbness or 'pins and needles' around the lips or hand), or difficulty speaking. Headache: usually pulsating and occurring on one side of the head, it may occur on both sides of the head and alternate from side to side. Muscles in the neck and scalp may be tender; there may be nausea and the desire not to eat, move, see or hear. Resolution: the headache disappears and the body returns to normal. Resolution may occur over several hours during sleep or rest; an intense emotional experience or vomiting may also end the headache. Postdrome: After the headache stops, the sufferer feels drained, fatigued and tired. Muscles ache, emotions are volatile and thinking is slow.
Milligram (mg, Milligrams)
0.001 or a thousandth of a gram.
Multiple Sclerosis (MS)
Demyelinating disorder of the central nervous system, causing patches of sclerosis (plaques) in the brain and spinal cord, manifested by loss of normal neurological functions, e.g. muscle weakness, loss of vision, and mood alterations.
Neuropathy
A group of symptoms caused by abnormalities in motor or sensory nerves. Symptoms include tingling or numbness in hands or feet followed by gradual, progressive muscular weakness.
Osteoporosis
A disease in which bone tissue becomes porous and brittle. The disease primarily affects postmenopausal women.
Placebo (Placebos)
A pharmacologically inactive substance. Often used to compare clinical responses against the effects of pharmacologically active substances in experiments.
Prostate
The prostate gland in men that surrounds the neck of the bladder and the urethra and produces a secretion that liquefies coagulated semen.
Psoriasis
An inherited skin disorder in which there are red patches with thick, dry silvery scales. It is caused by the body making too-many skin cells. Sores may be anywhere on the body but are more common on the arms, scalp, ears, and the pubic area. A swelling of small joints may go along with the skin disease.
Raynaud's Phenomenon (Raynaud's, Raynauds Disease, Raynaud's Disease, Raynauds Phenomenon, Raynauds Syndrome, Raynaud's Syndrome)
Raynaud's disease or syndrome is a disorder of blood circulation, mainly in the fingers and toes. It is of unknown cause and characterized by changes of the skin that are aggravated by exposure to cold: first, becoming white with numbness and pain as a result of inadequate oxygenation of the blood, then red/purple with a burning sensation. The sudden constriction of blood vessels causes decreased blood flow to the extremities and can, in extreme cases, lead to gangrene. Also called "white finger", "wax finger" or "dead finger".
Rheumatoid Arthritis
A long-term, destructive connective tissue disease that results from the body rejecting its own tissue cells (autoimmune reaction).
Rickets
Vitamin-D deficiency characterized by abnormal calcification of bone tissues.
Schizophrenia
Any of a group of psychotic disorders usually characterized by withdrawal from reality, illogical patterns of thinking, delusions, and hallucinations, and accompanied in varying degrees by other emotional, behavioral, or intellectual disturbances. Schizophrenia is associated with dopamine imbalances in the brain and defects of the frontal lobe and is caused by genetic, other biological, and psychosocial factors.
Stroke (Stroke-Type Event)
A sudden loss of brain function caused by a blockage or rupture of a blood vessel that supplies the brain, characterized by loss of muscular control, complete or partial loss of sensation or consciousness, dizziness, slurred speech, or other symptoms that vary with the extent and severity of the damage to the brain. The most common manifestation is some degree of paralysis, but small strokes may occur without symptoms. Usually caused by arteriosclerosis, it often results in brain damage.
Triglyceride (Triglycerides)
The main form of fat found in foods and the human body. Containing three fatty acids and one unit of glycerol, triglycerides are stored in adipose cells in the body, which, when broken down, release fatty acids into the blood. Triglycerides are fat storage molecules and are the major lipid component of the diet.
Ulcerative Colitis (Colitis Ulcerosa)
Ulceration of the colon and rectum, usually long-term and characterized by rectal bleeding or blood in the stool, frequent urgent diarrhea/bowel movements each day, abdominal pain.
Vitamin A
A fat-soluble vitamin essential to one's health. Plays an important part in the growth and repair of body tissue, protects epithelial tissue, helps maintain the skin and is necessary for night vision. It is also necessary for normal growth and formation of bones and teeth. For Vitamin A only, 1mg translates to 833 IU.
Vitamin D
A fat-soluble vitamin essential to one's health. Regulates the amount of calcium and phosphorus in the blood by improving their absorption and utilization. Necessary for normal growth and formation of bones and teeth. For Vitamin D only, 1mcg translates to 40 IU.
Vitamin E
An essential fat-soluble vitamin. As an antioxidant, helps protect cell membranes, lipoproteins, fats and vitamin A from destructive oxidation. It helps protect red blood cells and is important for the proper function of nerves and muscles. For Vitamin E only, 1mg translates to 1 IU.
Last updated: May 18, 2008
|
 |
|
|
