Fish oil contains so-called omega-3 polyunsaturated fatty acids. They differ from omega-6 polyunsaturated fatty acids from vegetable oil and have a different effect. Fish do not produce these fat themselves, but take them from the plankton (their food). As water is colder, plankton contains more omega-3 fatty acids. The strongest effects have eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and large quantities are found in fish living in cold water – salmon, trout, mackerel and tuna. The third type of omega-3 acid is called a-linolenic acid (ALA) and is found in vegetable oils (flaxseed oil) and green parts of porslane. But it seems that ALA is not as effective as EPA and DHA; these issues are still being investigated.
How does it work?
Omega-3 fatty acids are important for a large number of important processes in the body, ranging from regulating blood pressure and blood clotting to strengthening immunity. They can be useful in preventing and treating many diseases and disorders.
PREVENTION: fish oil seems to reduce the risk of heart disease, and this happens in several ways. The most important of these is the action of omega-3 fatty acids on blood platelets, which are then less intractable for each other, meaning less clots that cause heart infarction. In addition, these fatty acids reduce triglyceride levels (fats that, like cholesterol, are in the blood) and blood pressure. Recent studies also show that omega-3 acids stabilize the conduction of electrical impulses through the heart, which reduces the incidence of cardiac rhythm disorders (arrhythmia). However, the strongest evidence for beneficial effects on the heart was obtained by studies in which subjects did not take fish oil as dietary supplements, but they ate fish.
In the artery walls omega-3 fatty acids alleviate the inflammation, which is one of the factors in plaque formation. Taking fish oil in therapeutic doses is one of the few successful methods to prevent re-occlusion of the arteries after angioplasty (a process during which a small balloon in induced through the artery to the obstruction, inflates and presses the plaque, this expands the blood vessels and increases blood flow to the heart). Because of this effect, fish oil is also useful for people with Raynaud’s disease.
ADDITIONAL USEFUL EFFECTS: omega-3 fatty acids are effective anti-inflammatory substances, useful in joint, lupus and psoriasis problems. Research has shown that they reduce swelling and relieve pain in people with rheumatoid arthritis, so they may even reduce the dose of anti-inflammatory drugs while taking fish oil preparations. A study on patients with Crohn’s disease (a painful form of inflammatory bowel disease) showed that the symptoms disappeared in 69% of people who took capsules with fish oil that dissolves in the intestine (about three grams a day), while in the group of those who took placebo symptoms disappeared in only 28%.
Fish oil can also alleviate menstrual cramps. There is also the possibility of beneficial effects of omega-3 fatty acids on mental health; some nutritionists believe there is a link between increasing the frequency of depression in Australia and reduced fish consumption. Initial research shows that omega-3 acids can relieve the weight of schizophrenia by 25% and help in children with dyslexia.
How to take it?
For heart diseases, Raynaud’s disease, lupus and psoriasis: take 3000 mg of fish oil per day.
For rheumatoid arthritis: take 6000 mg of fish oil per day.
For inflammatory bowel disease: the daily dose is 5000 mg.
USE GUIDELINES: if you eat blue fish at least twice a week, you do not need any nutrition supplements with fish oil. However, in rheumatoid arthritis and other inflammatory conditions, it is recommended to take them. Capsules are taken with meals. These dietary supplements are easier to tolerate if the daily dose is divided. For example, instead of taking 3000 mg at once, take 1000 mg three times. You should take many antioxidants with fish oil supplements – many fruits and vegetables or nutritional supplements with vitamin E.
Possible side effects
Capsules with fish oil can cause burping, flatulence, inflammation, nausea and diarrhea. Taking large doses can result in fish-like body odor. There is concern that large doses may cause internal bleeding, but studies on patients with heart diseases who took 8,000 mg of fish oil with Aspirin (which slows blood clotting) did not show this. Some research, however, suggests that high doses of fish oil hinder blood glucose control in people with diabetes mellitus; in other people this effect was not observed. Therefore, apart from the advice of doctors, diabetics should not take more than 2,000 mg of this oil per day.
People with elevated triglycerides and those with higher ”bad” (LDL) cholesterol levels must be careful: therapeutic doses of fish oil increase the value of LDL cholesterol. This effect can be prevented by using food supplements with garlic, as shown by one study. If you have rheumatoid arthritis and other inflammatory conditions, it is probably not enough to just eat fish, but also nutritional supplements.
IMPORTANT: since omega-3 fatty acids slow down blood clotting, you should consult your doctor if you are already taking any anti-clotting medication before using a fish oil.
Fish oil should not be taken two days before and two days after any surgery.
As large doses of fish oil can increase blood glucose levels, diabetics should consult their physician before taking these preparations.