Balancing Omega-3 and Omega-6? I don’t understand the difference between omega-3 and omega-6 fatty acids. I know we’re supposed to increase consumption of the omega-3s. What about omega-6? |  | ||
| A | Answer (Published 2/22/2007) | ||
| Omega-3 and omega-6 are types of essential fatty acids – meaning we cannot make them on our own and have to obtain them from our diet. Both are polyunsaturated fatty acids that differ from each other in their chemical structure. In modern diets, there are few sources of omega-3 fatty acids, mainly the fat of cold water fish such as salmon, sardines, herring, mackerel, black cod, and bluefish. There are two critical omega-3 fatty acids, (eicosapentaenoic acid, called EPA and docosahexaenoic or DHA), that the body needs. Vegetarian sources, such as walnuts and flaxseeds contain a precursor omega-3 (alpha-linolenic acid called ALA) that the body must convert to EPA and DHA. EPA and DHA are the building blocks for hormones that control immune function, blood clotting, and cell growth as well as components of cell membranes. By contrast, sources of omega-6 fatty acids are numerous in modern diets. They are found in seeds and nuts, and the oils extracted from them. Refined vegetable oils, such as soy oil, are used in most of the snack foods, cookies, crackers, and sweets in the American diet as well as in fast food. Soybean oil alone is now so ubiquitous in fast foods and processed foods that an astounding 20 percent of the calories in the American diet are estimated to come from this single source. The body also constructs hormones from omega 6 fatty acids. In general, hormones derived from the two classes of essential fatty acids have opposite effects. Those from omega-6 fatty acids tend to increase inflammation (an important component of the immune response), blood clotting, and cell proliferation, while those from omega-3 fatty acids decrease those functions. Both families of hormones must be in balance to maintain optimum health.
If you follow my anti-inflammatory diet, you should get a healthy ratio of these fatty acids. In general, however, you can cut down on omega-6 levels by reducing consumption of processed and fast foods and polyunsaturated vegetable oils (corn, sunflower, safflower, soy, and cottonseed, for example). At home, use extra virgin olive oil for cooking and in salad dressings. Eat more oily fish or take fish oil supplements, walnuts, flax seeds, and omega-3 fortified eggs. Your body and mind will thank you. Andrew Weil, M.D. | |||
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http://www.mind1st.co.uk/EPADHA.asp
Omega 3 fish oil EPA and DHA
Omega 3 fish oil contains two active ingredients: EPA (Eicosapentaenoic Acid) and DHA (Docosahexaenoic Acid).DHA
DHA is now thought to constitute the ‘building blocks’ of the brain, forming about 8% of the brain by weight - this is why it is important for pregnant mothers to ensure an adequate supply throughout pregnancy.
DHA is also added to some infant milk formulas by some leading manufacturers, as an infant requires a lot of DHA in the first two years of life to support the growth of the brain.
EPA
EPA however is different; this essential nutrient is now considered by some leading doctors and professors in the UK as being the single most vital nutrient in the functioning of the brain and nerve stimulation.
This was highlighted by the release of a very high profile book by a leading psychiatric professor, who is using a very strong form of ethyl EPA to help treat patients of his who suffer from depression and schizophrenia. Moreover, the ethyl EPA that the professor is using has had the DHA removed. In the book he explains that Ethyl EPA fish oil is not as potent, and does not give the same therapeutic effects when DHA is present.
According to the professor, this is backed up by two randomised controlled trials at the University of Baylor and Sheffield, where depressed people who were given DHA only fared slightly worse than the placebo-controlled group.
Conversion
So what happens if the body becomes deficient of DHA? The professor goes on to describe that the body can convert EPA into DHA, as it is only two steps down the chain of ecosanoids. This is a process the body can do relatively easily. The body can also convert DHA into EPA, but our bodies struggle to make this conversion and it is not a very efficient process.
A good example of this would be with flaxseed oil, that is high in the omega 3 parent fatty acid ALA (alphalinoic acid); to obtain roughly 1 gram of EPA, you would have to ingest 11 grams of flaxseed oil.
Conclusion
The simple truth is that you need both these essential nutrients. The evidence is increasingly pointing towards the two being important for various stages of life. DHA when compared against EPA in treating depression is faring no better than a placebo; however the DHA is important for pregnant mothers and children from birth to two years. Beyond that some leading doctors (Mercola, Stoll, Puri) are leaning towards EPA being very beneficial for the daily functioning of the brain.
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Note: (ref: nutrition action health letter)
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sandwiches.) That would supply 500 to 1,000 mg a day of DHA plus EPA.
Eat fatty fi sh like salmon twice a week. (Try canned salmon instead of tuna in ■
If you’re a vegetarian, look for foods or supplements with DHA from algal oil. ■
1,000 mg a day of DHA plus EPA from fi sh oil. If you have side effects like burping,
try taking them at bedtime or ask your doctor for a prescription for pure fi sh oil.
If you have heart disease, follow the American Heart Association’s advice to take■ Taking more than 3,000 mg a day of DHA plus EPA may cause bleeding. http://www.mind1st.co.uk/acne-fish-oil.asp
Acne and fish oil
Omega 3 fatty acids found in fish oil could help in the treatment of acne by alleviating some of the inflammation associated with acne, and by inhibiting the processes that lead to overproduction of sebum. If too much sebum is produced, pores can become blocked leading to a build up of bacteria, infection, and finally to a breakout of acne.EPA or Eicosapentaenoic acid, is an essential Omega 3 fatty acid that can help increase the level of anti-inflammatory Prostaglandins. Prostaglandins are hormone like substances that are found in every cell in the body. They are synthesised in the cells from Gamma-linolenic acid (GLA), Arachidonic acid (AA) and Eicosapentaenoic acid (EPA). Both GLA and AA are Omega 6 fatty acids, which are proinflammatory. EPA, an Omega 3 fatty acid that is anti-inflammatory, can only be found in any significant quantities in oily fish or fish oil.
One study has indicated that production of leukotriene B4, a prostaglandin that is proinflammatory, could be a contributory factor to developing acne. A diet too rich in Omega 6 and deficient in Omega 3, can lead to over production of leukotriene B4, so increasing consumption of Omega 3 fatty acids could help to re-dress this imbalance.
Omega 3 fatty acids can also help to keep the production of androgens under control. Androgens are hormones that influence sebum production and are particularly active during adolescence, which is possibly why many teenagers suffer from acne.
As Omega 3 can only be found in sufficient quantities in oily fish such as anchovies, herring, salmon, mackerel, tuna and sardines, it is difficult to get enough of these in the diet. Mounting concern over the amount of toxins in our fresh fish means that the current recommendation is to eat only 1 or 2 portions of oily fish a week but no more.
An excellent way of getting enough of the essential fatty acids in the diet to help treat acne is to supplement the diet with good quality fish oil containing high levels of EPA.
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http://www.dhaomega3.org/
Introduction to Omega-3
There has been a dramatic surge in interest recently, amongst the public and health professionals alike, of the health effects of omega-3 fatty acids derived from fish/fish oils - consisting of docosahexaenoic acid (DHA) plus eicosapentaenoic acid (EPA).
DHA is required in high levels in the brain and retina as a physiologically-essential nutrient to provide 1) for optimal neuronal functioning (learning ability, mental development) and visual acuity, in young and old alike. DHA plus EPA are both considered to have beneficial effects in the 2) prevention and management of cardiovascular disease plus associated risk factors as well as other chronic disorders. Whereas considerable amounts of the plant-derived omega-3 fatty acid known as a-linolenic acid (ALA) is consumed daily in North America (approximately 2 g/day), the physiologically-essential nutrient, DHA, is consumed at much smaller levels (approximately 80 mg/day) while EPA is consumed at the level of approximately 50 mg/day in a typical North American diet.
DHA plus EPA are absent from plant food sources rich in ALA (such as flax, canola oil, and walnuts). Since the metabolic conversion of ALA to DHA/EPA (combined) by metabolism is very limited in humans, the most direct way of providing DHA plus EPA for the body is via their direct consumption. Current intakes of DHA are approximately 20% of the target (300 mg/day) suggested by an expert scientific group during pregnancy and lactation. The extremely low intake of DHA in young children (e.g., approximately 19 mg DHA/day on average for 3-yr. olds in North America ) is also of particular concern. Current intakes of DHA/EPA (combined) of 130 mg/day are approximately 15% of the target (900 mg/day) officially recommended by the American Heart Association for those with coronary heart disease and 20% of the 650 mg/day advised by an expert scientific group for healthy individuals. In view of the widespread reluctance of the public to consume sufficient amounts of fish, functional foods containing DHA plus EPA will become increasingly important sources of these important nutrients in the coming years to support optimal brain/visual performance, for cardio care, and other health conditions for young and old alike. DHA is required in high levels in the brain and retina as a physiologically-essential nutrient to provide 1) for optimal neuronal functioning (learning ability, mental development) and visual acuity, in young and old alike. DHA plus EPA are both considered to have beneficial effects in the 2) prevention and management of cardiovascular disease plus associated risk factors as well as other chronic disorders. Whereas considerable amounts of the plant-derived omega-3 fatty acid known as a-linolenic acid (ALA) is consumed daily in North America (approximately 2 g/day), the physiologically-essential nutrient, DHA, is consumed at much smaller levels (approximately 80 mg/day) while EPA is consumed at the level of approximately 50 mg/day in a typical North American diet.
In summary and conclusion, DHA is the physiologically-essential nutrient needed in the brain and retina for cognitive functioning and visual acuity, respectively. DHA supplementation of infant formula (containing ALA ) has been found to enhance cognitive performance in term infants. Conversion efficiencies of ALA to DHA in human trials have been determined to range from 0-9%. Higher dietary intakes of ALA (increasing intakes by 1,200 mg/day) have been associated with an approximate 20% lower risk of fatal heart disease whereas higher fish intakes (up to and including 5 servings/week providing approximately 650 mg DHA/EPA combined/day) have been associated with an approximate 40% lowering of CHD mortality based on epidemiological studies. In general, stronger inverse relations between blood levels of EPA plus DHA and fatal cardiac events have been found than for ALA. Most of the favorable effects of DHA/EPA ingestion on various risk factors for cardiovascular disease (via controlled interventional trials) including blood triglyceride-lowering are not found or matched by equivalent intakes of ALA. In contrast to ALA intakes, current dietary intakes of DHA/EPA in North America appear to be very much below target intakes for optimal human health and the prevention/management of cardiovascular disease and associated risk factors.
Dietary Sources of Omega-3 Fatty Acids
As for saturated and monounsaturated fatty acids, the omega-6 and omega-3 polyunsaturated fatty acids (PUFA) are chemically linked to fat structures known as triglycerides in the various foods and oils that are consumed. The natural triglyceride or fat structure consists of a 3-carbon glycerol backbone onto which 3 long-chain fatty acids of varying types and structures are linked or 'esterified'. These are hydrolyzed by enzymes and digested in the small intestine thereby providing for their absorption, transport in the blood, and assimilation into cells and body tissues. Table 1 lists some common food sources of both the omega-6 and omega-3 fatty acids as found in a typical North American diet.
Table 1: Dietary Sources of Omega-3 and Omega-3 Fatty Acids
Fatty Acid | Food Sources |
(i) Omega-6 Types | |
| LA, linoleic acid (18:2 n-6) | Vegetable oils (corn, safflower, sunflower, soybean), animal meats |
| AA, arachidonic acid (20:4 n-6) | Animal sources only (meat, eggs) |
(ii) Omega-3 Types | |
| ALA , (LNA) alpha-linolenic acid (18:3 n-3) | Flaxseed, canola oil, English walnuts, specialty eggs |
| EPA, eicosapentaenoic acid (20:5 n-3) | Fish, fish oils, marine sources |
| DHA, docosahexaenoic acid (22:6 n-3) | Fish, fish oils, specialty egg/dairy products |
In view of the high intake of vegetable oils containing n-6 PUFA directly and via various processed food products including meats, a typical diet contains 8-15 g/day of LA (omega-6) but much lower intakes of the omega-3 types. ALA consumption ranges from approximately 1.3-2.0 g/day or approximately 0.6% of total energy intake. In contrast to the considerable intake of ALA from plant sources, the intake of fish/fish oil-derived DHA/EPA (combined) represents approximately 0.13-0.15 g/day (130-150 mg/day) which is 0.05% of total energy intake or about 1/10 of the intake of ALA. The vast majority of the DHA plus EPA as consumed in the North American diet is from fish/fish oils with much smaller amounts from selected animal sources (e.g., eggs, some meat sources) and none from plant food/oils regardless of their ALA levels. The overall ratio of omega-6:omega-3 fatty acids in the current North American diet ranges from 6:1 to approximately 10:1.
Selected food sources of a-linolenic acid (ALA) are given in Table 2. Some of the common plant oils have significant levels of ALA - e.g., 7% by weight in soybean oil, 10% in canola oil, and approximately 20% in hemp oil. Much higher amounts are found in the oils from flax, perilla (Japan and elsewhere), and chia (Argentina and elsewhere) with approximately 50-60% of the fatty acids being in the form of ALA.
Table 2: Alpha-Linolenic Acid Content of Various Foods and Oils
Source (100 g raw edible portion) | ALA (g) | Source (100 g raw edible portion) | ALA (g) |
Nuts and Seeds | Legumes | ||
| Almonds | 0.4 | Beans, common (dry) | 0.6 |
| Beechnuts (dried) | 1.7 | Chickpeas (dry) | 0.1 |
| Butternuts (dried) | 8.7 | Cowpeas (dry) | 0.3 |
| Chia seeds (dried) | 3.9 | Lentils (dry) | 0.1 |
| Flaxseed | 22.8 | Lima beans (dry) | 0.2 |
| Hickory nuts (dried) | 1.0 | Peas, garden (dry) | 0.2 |
| Mixed nuts | 0.2 | Soybeans (dry) | 1.6 |
| Peanuts | 0.003 | ||
| Pecans | 0.7 | Grains | |
| Soybean kernels | 1.5 | Barley, bran | 0.3 |
| Walnuts, black | 3.3 | Corn, germ | 0.3 |
| Walnuts, English and Persian | 6.8 | Oats, germ | 1.4 |
| Rice, bran | 0.2 | ||
Vegetables | Wheat, bran | 0.2 | |
| Beans, navy, sprouted (cooked) | 0.3 | Wheat, germ | 0.7 |
| Beans, pinto, sprouted (cooked) | 0.3 | Wheat, hard red Winter | 0.1 |
| Broccoli (raw) | 0.1 | ||
| Cauliflower (raw) | 0.1 | Fruit | |
| Kale (raw) | 0.2 | Avocados, California (raw) | 0.1 |
| Leeks (freeze-dried) | 0.7 | Raspberries (raw) | 0.1 |
| Lettuce, butterhead | 0.1 | Strawberries (raw) | 0.1 |
| Lettuce, red leaf | 0.1 | ||
| Mustard | 0.1 | ||
| Purslane | 0.4 | ||
| Radish seeds, sprouted (raw) | 0.7 | ||
| Seaweed, Spirulina (dried) | 0.8 | ||
| Soybeans, green (raw) | 3.2 | ||
| Soybeans, mature seeds, sprouted (cooked) | 2.1 | ||
| Spinach (raw) | 0.1 | ||
Data from Kris-Etherton et al. (2000)
Recently, strains of flaxseed oils have become available which contain approximately 70% by weight of the oil as ALA which is significantly higher than the 50-55% found in conventional flax oil varieties. Table 3 gives the levels of EPA plus DHA in a few selected fish and seafood. Table 3: Fish and Seafood Sources of DHA plus EPA
Source (100 g portion) | DHA + EPA (g) |
Fish | |
| Anchovy, European, raw | 1.449 |
| Carp, cooked, dry heat | 0.451 |
| Catfish, channel, farmed, cooked, dry heat | 0.177 |
| Cod, Atlantic , cooked, dry heat | 0.158 |
| Eel, mixed species, cooked, dry heat | 0.189 |
| Flatfish (flounder and sole), cooked, dry heat | 0.501 |
| Haddock, cooked, dry heat | 0.238 |
| Halibut, Atlantic and Pacific, cooked, dry heat | 0.465 |
| Herring, Atlantic , cooked, dry heat | 2.014 |
| Mackerel, Pacific and jack, mixed species, cooked, dry heat | 1.848 |
| Mullet, striped, cooked, dry heat | 0.328 |
| Perch, mixed species, cooked, dry heat | 0.324 |
| Pike, northern, cooked, dry heat | 0.137 |
| Pollock, Atlantic , cooked, dry heat | 0.542 |
| Salmon, Atlantic , farmed, cooked, dry heat | 2.147 |
| Sardine, Atlantic , canned in oil, drained solids with bone | 0.982 |
| Sea bass, mixed species, cooked, dry heat | 0.762 |
| Shark, mixed species, raw | 0.843 |
| Snapper, mixed species, cooked, dry heat | 0.321 |
| Swordfish, cooked, dry heat | 0.819 |
| Trout, mixed species, cooked, dry heat | 0.936 |
| Tuna, skipjack, fresh, cooked, dry heat | 0.328 |
| Whiting, mixed species, cooked, dry heat | 0.518 |
Crustaceans | |
| Crab, Alaska king, cooked, moist heat | 0.413 |
| Shrimp, mixed species, cooked, moist heat | 0.315 |
| Spiny lobster, mixed species, cooked, moist heat | 0.480 |
Mollusks | |
| Clam, mixed species, cooked, moist heat | 0.284 |
| Conch, baked or broiled | 0.120 |
| Mussel, blue, cooked, moist heat | 0.782 |
| Octopus, common, cooked, moist heat | 0.314 |
| Oyster, eastern, farmed, cooked, dry heat | 0.440 |
| Scallop, mixed species, cooked, breaded and fried | 0.180 |
It should be noted that algal oils have recently become available as a source of DHA (free of EPA) for infant formulas and other functional food fortification. There has been a marked increase in the use of high quality liquid fish oils containing DHA plus EPA as ingredients in a wide variety of functional foods (e.g., liquid eggs). Furthermore, stable and microencapsulated forms of DHA plus EPA (with varying amounts and ratios of DHA:EPA) have been utilized in a whole plethora of processed food formulations (breads, yogurts, snack foods, etc). In view of the resistance of the North American and other populations to increase fish consumption as a source of DHA plus EPA for health despite recommendations by health care agencies and professionals, it is apparent that functional foods will became an ever-increasing source of these important nutrients in the omega-3 family.
Denomme, J., et al ., Directly Quantitated Dietary (n-3) Fatty Acid Intakes of Pregnant Canadian Women are Lower than Current Dietary Recommendations. Human Nutrition and Metabolism. 135(2): 206-211, 2005.
Kris-Etherton, P.M., et al. Polyunsaturated fatty acids in the food chain in the United States . AJCN. 71: 179-188, 2000.
Raper, N.R., et al . Omega-3 fatty acid content of the US food supply. J. Am. Coll. Nutr. 11: 304-308, 1992.
Williams, C. M., and Burdge, G. Long-chain n-3 PUFA: plant v. marine sources. Proceedings of the Nutrition Society. 65:42-50, 2006.
So far, there’s decent evidence that DHA and EPA—the omega-3 fats in fi sh
oil—can reduce your risk of a heart attack, but not your risk of cancer, memory
loss, or macular degeneration.
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