While it is easy to think of fats and fatty acids as bad for your health, in the case of omega-3 fatty acids, the reverse is true. They are polyunsaturated fatty acids (PUFAs). Most people get PUFAs in their diet from vegetable oils. While there are two groups of PUFAs, omega-3 and omega-6 fatty acids, omega-3 fatty acids are more important for good health. Most vegetable oils have more omega-6 than omega-3 fatty acids. Omega-3s come from different sources, with fish being the best-known food rich in omega-3s.
The omega-3s include three fatty acids called alpha-linolenic acid (ALA), eicosa- pentaenoic acid (EPA), and docosahexaenoic acid (DHA). These have slightly different pathways and functions in the body. ALA is converted in small amounts to EPA and DHA. EPA may be more important for heart health, while DHA may be more critical to brain function, although both EPA and DHA contribute to good health.
ALA can be found in green leafy vegetables, as well as vegetable oil. EPA and DHA are found in fatty fish and fish oil. The omega-3s found in fish oil have probably received the most public attention, and they are found in a myriad of supplements. They are the only oils made as a pharmaceutical product that requires prescription.
The North American diet contains more omega-6 fatty acids than omega-3. It may be that more omega-3 fatty acids than omega-6 fatty acids need to be consumed to gain the full benefit from omega-3s.
Food Sources of Omega-3 Fatty Acids
| Food name | Serving Size | Omega-3 Fatty Acids (g) |
| Flax | 3oz (85g) | 11.4 |
| Hemp | 3oz (85g) | 11.0 |
| Sardines | 3oz (85g) | 2 |
| Mackerel | 3oz (85g) | 1.7 |
| Salmon | 3oz (85g) | 1.9 |
| Halibut | 3oz (85g) | 1.12 |
| Tuna | 3oz (85g) | 1.1 |
| Swordfish | 3oz (85g) | 0.97 |
| Greenshell/lipped mussels | 3oz (85g) | 0.95 |
| Tilefish | 3oz (85g) | 0.9 |
| Tuna | 3oz (85g) | 0.24 |
| Pollock | 3oz (85g) | 0.45 |
| Cod | 3oz (85g) | 0.24 |
| Catfish | 3oz (85g) | 0.3 |
| Flounder | 3oz (85g) | 0.48 |
| Grouper | 3oz (85g) | 0.23 |
| Mahi mahi | 3oz (85g) | 0.13 |
| Red snapper | 3oz (85g) | 0.29 |
| Shark | 3oz (85g) | 0.83 |
| King mackerel | 3oz (85g) | 0.36 |
Health Benefits of Omega-3 fatty acid
Omega-3 fatty acids have attracted interest as potential factors in reducing risk for vascular disease. Additional health benefits that have been associated with omega-3 fatty acids include the secondary prevention of chronic diseases such as inflammatory conditions, GI disorders, and type 2 diabetes. As a result of findings on infant growth and development, DHA (along with omega-6 arachidonic acid) is now being added to some infant formulas.
The American Heart Association recommend to consume fish (particularly fatty fish) at least two times a week to reduce the risk of cardiovascular disease. Fish is a great protein source and doesn’t have high saturated fat. Fatty fish like mackerel, herring, lake trout, albacore tuna, sardines, and salmon are high in two kinds of omega-3 fatty acids: EPA and DHA. Some people with high triglycerides and patients with cardiovascular disease may benefit from more omega-3 fatty acids than they can easily get from diet alone. These people should talk to their doctor about taking supplements to reduce heart disease risk. Because fish oil supplements can have potent effects, children, pregnant women, and nursing mothers should not take them without medical supervision.
- Prevention of Cancer
Consuming seafood that provides omega-3 fatty acids is associated with lower rates of some cancers, possibly because they suppress inflammation, a factor in cancer development, or through other mechanisms. After cancer develops, a significant reduction in cancer-related deaths has been associated with higher fish intakes. However, in a surprising twist, men with more DHA in their blood were more likely to have aggressive prostate cancer than men with lower levels. So little is known about the relationships between omega-3 fatty acids and cancers that people are wise to eat fish, not take supplements, to provide them.
- Cardiovascular Health
From epidemiologic evidence plus clinical trials, it seems very clear that both DHA and EPA provide cardioprotective benefits by lowering triglycerides, lowering blood pressure, and decreasing inflammatory chemicals involved in heart dis- ease. They also lower the risk of irregular heart rhythms (arrhythmias) and sudden cardiac death. Studies have been done with fish, fish oil, and specific omega-3s. Most have shown that increased fish intake and supplementation with fish oil or its components can be beneficial.
Evidence continues to be gathered about the positive effects of omega-3s on heart health. The GISSI-HF is a large, double-blind, multicenter trial in Italy, which evaluated the effect of omega n-3s on heart failure. It followed 7,000 patients for four years. A 2008 report indicated that there was a definite benefit to supplementation, with lowered risk of mortality and hospital admission. Although the benefit was small, it was statistically significant. The omega n-3 supplementation was free of serious side effects, which makes it a good addition to the treatment of patients with heart failure.
- Coronary Heart Disease
As stated, DHA and EPA lower a number of cardiovascular risk factors. In addition to decreasing blood pressure and triglycerides, they have been shown to improve arterial and endothelial function (the workings of the artery walls and their linings) and decrease platelet clumping.
Large scale trials-have proved the usefulness of the omega-3s for both primary and secondary prevention of coronary heart disease as well as advanced heart failure. The American Heart Association recommends 1 g per day of a combination of DHA and EPA for individuals with coronary heart disease. It recommends at least 500 mg a day of the same as primary prevention, to prevent cardiovascular disease.
Elevated triglycerides, especially after meals, are a risk factor for CHD independent of cholesterol and other factors. DHA and EPA have large effects on elevated triglycerides. This has been demonstrated in multiple clinical trials. Studies indicate that omega-3 fatty acids can help lower triglycerides by themselves, or along with commonly used statins. A lot more omega-3 needs to be taken to reduce very high triglyceride levels, some 3 to 4 g of EPA plus DHA.
- Cure for Asthma
As noted in “Mechanism of Action,” omega-3 fatty acids, especially EPA and DHA, are metabolized into a number of chemical mediators of inflammation. Asthma is a disease of airway inflammation; substances like omega-3s involved in inflammation might help asthma. The AHRQ report reviewed a large amount of data and many studies. There was not adequate information to say that omega-3 fatty acids are of any benefit for asthma. Studies were either flawed or inconclusive. There has also been very little research done on North American populations.
It was suggested that more, well-designed, and well-controlled studies are needed. Omega-3 fatty acids do seem to be very safe when used for asthma. There was also a suggestion that a lowering of dietary omega-6 fatty acids might need to take place along with supplements of omega-3 fatty acids for benefits to occur.
- Neurological health
There have been epidemiologic studies as well as lab studies indicating that DHA may protect against Alzheimer’s disease as well as ensure the proper development of the brain. For example, one population study of a group (called the Framingham group) showed that the highest levels of measurable DHA were associated with the lowest risk for developing Alzheimer’s disease over the course of approximately nine years.
The AHRQ report also noted that there is not enough data yet to reach definite conclusions. There is data that indicate a reduction in the risk of Alzheimer’s or cognitive decline with fish or fish oil consumption, but there are not yet definitive results from clinical trials using omega-3s.
Clinical trials need to be done examining the effect of taking fish oil or omega-3 fatty acids on the risk of developing a number of neurological diseases, as well as the possibility that omega-3s may help treat these diseases. There is currently a large clinical trial in progress evaluating the effect of DHA on Alzheimer’s disease.
- Combat anxiety and depression
Depression is the common mental disorder in the world. It shows the symptoms such as lethargy, sadness and general loss of interest in life. In addition, anxiety is also a common problem which characterizes constant worry and nervousness. Study shows that people with regular intake of omega 3s are less prone to depression. Depression or anxiety patients should take omega-3 supplements to improve the symptoms. Omega-3 fatty acids are of three types such as ALA, EPA and DHA.
- Enhance eyesight
DHA is a type of omega-3 which is a major structural component of retina of eye. Vision problems arise when one does not get adequate DHA. Adequate amount of omega-3 is associated to lowering chances of macular degeneration which is the leading cause of permanent eye damage or blindness.
- Lower ADHD symptoms
Attention deficit hyperactivity disorder (ADHD) is a behavioral disorder indicated by inattention, hyperactivity and impulsivity. Study shows that children having ADHD have low blood levels of omega-3 fatty acids than healthy ones. Study shows that omega-3 supplements could lower ADHD symptoms of ADHD. Omega 3s improves inattention and completion of tasks. It lowers hyperactivity, restlessness, impulsiveness and aggression. Recent research shows that fish oil supplements are effective treatment for ADHD.
- Combat inflammation
Inflammation is the response to damage and infections in the body. It is crucial for health. Sometimes inflammations prevail for long time even without injury or infection, it is known as long term or chronic inflammation which contributes to cancer and heart disease. Omega-3 fatty acids could lower production of molecules or substances associated to inflammation such as cytokines and inflammatory eicosanoids. The observation of study showed a connection between high intake of omega-3 and low inflammation.
- Ease menstrual pain
Menstrual pain takes place in lower abdomen and pelvis and scatter to lower back and thighs. It affects the quality of life. Study have shown that women who intake most omega 3s have mild menstrual pain. One study shows that supplement of Omega-3 was found to be more effective when compared to ibuprofen in treating severe pain during menstruation.
- High blood pressure
Omega-3 fatty acids can lower blood pressure in hypertension.
- High blood lipids
Omega-3 fatty acids lower levels of triglycerides (and, to a lesser extent, total cholesterol), while increasing HDL cholesterol.
- Bronchial asthma
Omega-3 fatty acids can reduce chronic inflammation and the frequency and severity of asthma.
- Diabetes
Omega-3 fatty acids can reduce high levels of triglycerides, reduce blood pressure, and reduce leakage of proteins from small blood vessels. However, in some diabetics, omega-3 fatty acids may also have adverse effects, such as reducing insulin action and increasing blood sugar.
- Osteoarthritis
Omega-3 fatty acids may reduce pain and ease movement.
- Migraine headache
Omega-3 fatty acids can reduce migraine frequency and intensity.
- Autoimmune, rheumatic, and inflammatory disorders
In rheumatoid arthritis supplemental omega-3 fatty acids may reduce pain, inflammation, and joint stiffness. Other disorders, such as Crohn disease and ulcerative colitis can also benefit from omega-3 fatty acids.
- Skin disorders
Omega-3 fatty acids may reduce skin inflammation, redness, and scaling in patients with psoriasis and/or atopic eczema.
Side effects
People might experience gastrointestinal complaints such as belching, dyspepsia and belching a fishy odor or flavor. Also eructation, flu syndrome, infection and dyspepsia were observed.
Dietary Intake
Currently, Americans are eating about 33 percent of their total calories each day from fat. Recall that the acceptable range for total fat intake for adults is between 20 and 35 percent. Fat intake as a percentage of calories is down from 36 percent in the early 1970s, and down markedly from 45 percent in 1965.
Although the percentage of calories from fat dropped, average calorie intake increased, which means Americans are actually consuming more total grams of fat. Current intake of saturated fat is about 11 percent of calories, a little higher than recommended. Major sources of saturated fatty acids in the U.S. diet include regular cheese; pizza; grain-based desserts; chicken and chicken mixed dishes; and sausage, franks, bacon, and ribs. Cholesterol intake averages 341 milligrams per day for adult men and 242 milligrams per day for adult women. Intake of linoleic acid is estimated to be 6 percent of calories, with alpha-linolenic acid providing 0.75 percent of calories and EPA plus DHA another 0.1 percent of calories. By keeping total fat intake within the AMDR and getting most of our fat from vegetable oils, fish, and nuts, we can move closer to meeting recommendations. The amount of trans fat in the U.S. diet has been declining over the past decades; however, it still appears to be in the range of 2 to 7 percent of total energy intake, significantly higher than the AHA recommendations to limit trans-fat to less than 1 percent of energy.
References:
https://en.wikipedia.org/wiki/Omega-3_fatty_acid
https://www.healthline.com/nutrition/17-health-benefits-of-omega-3#section1
https://ods.od.nih.gov/factsheets/Omega3FattyAcids-Consumer/
http://pennstatehershey.adam.com/content.aspx?productId=107&pid=33&gid=000316