Omega-3 fatty acids, fish oil, alpha-linolenic acid

Background

Taking cod liver oil as a source of vitamin D first became popular in 19th Century England. Fish oil has been studied for heart health since it was found that Greenland Inuit people may have a lower risk of heart disease despite eating a high-fat diet.

The main essential fatty acids in the human diet are omega-3 and omega-6 fatty acids. Foods that provide omega-3 fatty acids include fish oil and certain plant and nut oils, while omega-6 fatty acids can be found in palm, soybean, rapeseed, and sunflower oils. This is problematic because, despite being essential, these fats can become downright unhealthy when the ratio of omega-6 to omega-3 gets higher than 4:1.Sadly, most American and European diets put people well over this 4:1 ratio of omega-6 to omega-3 fats. When the ratio of omega-6 to omega-3 fats is closer to 1:1, the risk of these diseases is significantly decreased, and muscle growth and fat loss are enhanced.

Omega-9 fatty acids, which are not considered essential, can be found in animal fat and olive oil.Like the omega-3 and omega-6 fats, the omega-9 fats also provide health benefits, namely anti-inflammatory properties that enhance joint healing and may help prevent numerous diseases. But unlike omega-3 and omega-6, the omega-9 fatty acids are not essential fats. This means that your body can produce them on its own. Plus, the omega-9 fats are also found in olive oil and other vegetable oils. So, if you include olive oil in your diet, which you should, you are likely getting adequate amounts of omega-9 fats.

Fish oil contains two omega-3 fatty acids called docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Some nuts, seeds, and vegetable oils contain alpha-linolenic acid (ALA), which may be converted to DHA and EPA in the body.

In the United States, percentages of DHA and EPA have been found to be lower compared to other nations with lower heart disease rates, such as Japan. High levels of omega-6 fatty acids have been linked to an increased risk of some conditions such as heart disease and depression.

Omega-3 fatty acids are thought to provide a wide range of health benefits, including a lower risk of coronary heart disease and improvement in cholesterol. There have also been promising results from studies looking at omega-3 for cancer, depression, and attention-deficit hyperactivity disorder (ADHD). Due to these potential health benefits, fish oil, which is rich in omega-3 fatty acids, has become a popular supplement.

There is evidence that recommended amounts of DHA and EPA, taken as fish or fish oil supplements, may lower triglycerides and reduce the risk of heart attack, abnormal heartbeat, and stroke in people who have heart disorders. DHA and EPA may also benefit people who have hardening of the arteries or high blood pressure. Similar effects have been found for ALA, but more evidence is needed to support its potential benefits.

High doses may have harmful effects, such as increased bleeding risk, higher levels of low-density lipoprotein (LDL, or "bad") cholesterol, blood sugar control problems, and a "fishy" odor. In some at-risk populations, such as people who have had a heart transplant, omega-3 fatty acids may affect the heart rate. Omega-3 fatty acids should be used only under medical care in people who have heart disease. Some fish such as swordfish, king mackerel, tilefish, and albacore tuna may carry a higher risk of mercury poisoning, though fish oil has not been found to carry a significant risk.

SUPPLEMENT WHAT YOUR DIET LACKS

I understand the reasoning for a 3-6-9 supplement: Since the proper ratio is so important, why not supplement in that ratio? But the truth is that the only thing wrong with most people's omega fats ratio is too little omega-3s. Supplementing with omega-6 fats, even in a 3-6-9, will only further reinforce the bad ratio for them. After all, omega-3-6-9 supplements generally have only 10-20 percent the amount of omega-3 fats as omega-3 fish oil supplements. My advice is to skip the omega-9 supplements and focus on supplementing with an omega-3, like fish oil. In addition, regularly use olive oil for cooking and in salad dressings. If you do this, you'll get a proper ratio of omega-6 to omega-3 fats and still take in adequate amounts of omega-9s. Plus you'll get all the benefits that come with these fats.

Evidence

These uses have been tested in humans or animals.  Safety and effectiveness have not always been proven.  Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Key to grades

A

Strong scientific evidence for this use

A	Coronary heart disease Evidence suggests that people who have low levels of EPA and DHA may have a higher risk of coronary heart disease and heart failure. Clinical trials suggest that omega-3 fatty acids may have benefits in terms of reducing total and heart disease mortality (death). It is believed that omega-3 fatty acids may help lower triglycerides and inflammation. Daily intake has been linked to a reduced risk of sudden heart failure.
A	High blood pressure Many studies report that omega-3 fatty acids may help reduce blood pressure. However, effects have generally been small, and other trials reported no benefit. Effects may be greater in people who have higher blood pressure and may depend on the dose. DHA may have greater benefits than EPA.
A	Hyperlipidemia (triglyceride lowering) There is strong scientific evidence that omega-3 fatty acids from fish or fish oil supplements can significantly reduce triglyceride levels. Higher doses have been found to have greater effects, and a dose of four grams daily may lower triglyceride levels by up to 40%. Effects may be increased when taken with statin drugs such as simvastatin and atorvastatin.It is unclear how fish oil therapy compares to other agents used to lower triglycerides. Some studies suggest that fish oil may increase LDL levels.
A	Rheumatoid arthritis Many studies report improvements in morning stiffness and joint tenderness with regular intake of fish oil supplements for up to three months. Benefits may increase with use of anti-inflammatory medications such as ibuprofen or aspirin. Benefits have also been seen with fish oil given through an intravenous tube. Fish oil has been found to have effects on the immune system and on fats in the blood in people with rheumatoid arthritis. However, effects beyond three months of treatment are unclear. More research is needed before a firm conclusion may be made.
A	Secondary cardiovascular disease prevention (fish oil / EPA plus DHA) Fish oil has been studied for use in protecting people who have had past heart problems from new ones, such as heart attack or sudden death.Many studies report that regularly eating oily fish or taking fish oil supplements may help reduce the risk of nonfatal and fatal heart attack, sudden death, and mortality in people with a history of heart attack. There is evidence that an increased intake of fish or omega-3 may be linked to a lower risk of heart failure. These therapies may add to the effects of other treatments, and benefits have been reported after three months of use.

Dosing

Adults (18 years and older)

The average American consumes about 1.6 grams of omega-3 fatty acids daily. About 1.4 grams of this comes from ALA, while 0.1-0.2 grams from EPA and DHA. In Western diets, people eat about 10 times more omega-6 fatty acids than omega-3 fatty acids. These large amounts of omega-6 fatty acids come from vegetable oils such as corn oil, sesame oil, sunflower oil, and walnut oil. Because omega-6 and omega-3 fatty acids compete in the body, benefits may be reached either by decreasing omega-6 intake or increasing omega-3 intake.

The American Heart Association recommends that healthy adults eat fish at least twice weekly. Fatty fish such as catfish, halibut, salmon, striped sea bass, and albacore tuna are particularly recommended. Plant-based sources of ALA such as tofu, walnuts, and canola oil are also recommended. The World Health Organization recommends a daily EPA and DHA intake of 0.3-0.5 grams and a daily ALA intake of 0.8-1.1 grams.

Safety

Side Effects and Warnings

Omega-3 is considered likely safe when taken as a supplement in recommended doses for up to 2-3.5 years, or when included in the diet (1-2 fish meals per week). The U.S. Food and Drug Administration (FDA) has ruled that the use of EPA and DHA, the primary omega-3 fatty acids found in fish, as dietary supplements is safe and lawful, as long as daily intakes do not exceed three grams per person daily from food and supplement sources.

Omega-3 is considered possibly safe when taken by mouth in amounts found in foods during pregnancy and breastfeeding. There is not enough information at this time regarding the safety of fish oils when used in amounts greater than those found in foods during pregnancy and breastfeeding. Up to 20 grams of fish may be well tolerated by most adults, although some experts warn that high doses may cause bleeding complications.

Omega-3 may increase the risk of bleeding, particularly at doses of three grams daily or greater. Caution is advised in people with bleeding disorders or those taking drugs that may increase the risk of bleeding. Dosing adjustments may be necessary.

Omega-3 may affect blood sugar levels. Caution is advised in people with diabetes or hypoglycemia and in those taking drugs, herbs, or supplements that affect blood sugar. Blood glucose levels may need to be monitored by a qualified healthcare professional, including a pharmacist, and medication adjustments may be necessary.

Omega-3 may cause low blood pressure. Caution is advised in people taking drugs or herbs and supplements that lower blood pressure.

Use cautiously in all people, as omega-3 may affect levels of cholesterol and may cause vitamin E deficiency.

Use cautiously in people who are at risk for hormone imbalance or those undergoing hormone replacement therapy.

Use cautiously in people who have abnormal heart rhythms, asthma, and inflammatory bowel disease, as worsened outcomes have been reported with omega-3 use.

Use cautiously in people with liver disease or those using agents that may be toxic to the liver. Changes in liver function tests have been reported with omega-3 use.

Interactions with Herbs and Dietary Supplements

Omega-3 may increase the risk of bleeding when taken with herbs and supplements that are believed to increase the risk of bleeding. Multiple cases of bleeding have been reported with the use of Ginkgo biloba, and fewer cases with garlic and saw palmetto. Numerous other agents may theoretically increase the risk of bleeding, although this has not been proven in most cases.

Omega-3 may affect blood sugar levels. Caution is advised when using herbs or supplements that may also affect blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.

Omega-3 may cause low blood pressure. Caution is advised in people taking herbs or supplements that lower blood pressure.