Labels on food and news stories mentioned the Omega 3 often (usually referring to fish oils for heart health). They are discussed extensively because of the many health benefits that are associated.
The Omega 3 are a type of polyunsaturated fatty acid that the body needs but can not by itself generate. That is why we need to obtain food through.
There are three omega-3 main. One, alpha-linolenic acid, found in some seeds and some plant oils such as linseed. The other two are EPA * and DHA *, and they appear almost exclusively in fish and shellfish. EPA and DHA are known as omega-3 "long chain" because its structure is longer than the alpha-linolenic acid. The body has a strong preference for the omega-3 long chain.
Can you hear you can get the same health benefits associated with the consumption of fish with food from plants, such as linseed. However, alpha-linolenic acid plant does not have the same properties as the omega-3 from fish. How important is the difference? Can be, depending on your needs.
Omega-3. The role of EPA and DHA.
The Omega-3 fish oil EPA and DHA have special functions in the body. DHA is highly concentrated in the brain, where it helps brain cells communicate with each other and protects them from harmful substances such as Alzheimer's disease. It focuses on the retina of the eye, where it is critical for visual function. The EPA is important for healthy blood vessels, for heart health and brain function. It also has anti-inflammatory and anticoagulant that favor a brain and a healthy heart.
The Omega-3 from plants.
Alpha-linolenic acid is the only omega-3 found in plants. It has some, but not all, the health benefits associated with EPA and DHA. Most of it is oxidized or "burned" for energy. A very small amount, less than 5%, is converted to EPA. Only a very small amount of EPA is converted to DHA. What creates a dilemma is our limited ability to convert ALA into EPA and DHA almost anything. The body needs DHA for brain structure and function and the retina of the eye. Without enough DHA available, substitutes, made of other fatty acids, not work as well. This is of key importance for pregnant women who must supply DHA to the developing fetus. If you do not obtain DHA from the foods they eat, DHA absorbs fetal tissues of the mother. After multiple pregnancies, This process is intended to provide the mother.
DHA is important in the retina for visual acuity, the ability to see clearly. Once exhausted, the retina can not fully recover, even be provided after much DHA. The DHA in the retina is also involved in the communication processes of the cells that eventually result in the ability to see. The retina is the highest concentration of DHA in the body, which is an indication of its importance.
DHA is important also for the protection of brain health. Recent studies have shown that DHA is the basis for the development of a substance called D1 neuroprotectin, which reduces the production of the protein responsible for Alzheimer's disease. Neuroprotectin protects brain cells against other harmful cellular products, prolongs the life of brain cells and reduces inflammation, processes that are occurring at the beginning of the development of Alzheimer's disease. It is also a key substance in communication between brain cells.
The preference of the body by the omega-3 fish rather than those of plants.
When you consume EPA and DHA from fish oil in the form of processed product, immediately absorbed into the tissues. Not used for energy. This means you are ready to go to work for us to stabilize the heart rhythm, curbing the overactive inflammatory responses, improving the flow of blood and participate in brain function. In pregnancy and in early childhood, the fetus and infant in the early readily incorporate DHA in your brain expanding and developing their visual system, whereas alpha-linolenic acid from plant has limited use because very little of it is converted into DHA.
Fish consumption is very low in most Western countries, even in the U.S., but the consumption of vegetable oils rich in linoleic acid, which is another type of polyunsaturated fatty acid, is high. Americans consume at least 10 times as much linoleic acid and alpha-linolenic acid. High levels of linoleic acid further reduce the conversion of alpha-linolenic acid to EPA. Other poly-unsaturated, including flaxseed and fish oils, also reduce the amounts converted. So taking flaxseed oil to increase consumption of omega 3, likely to reduce the amount converted to EPA rather than increase.
To his credit, omega-3 from plants help to offset the large amounts of linoleic acid containing Western diets. They also have some positive effects on heart health and immune function. However, the effects of omega-3 fish oils appear to be stronger, faster activity, and more diverse.
Foods rich in Omega-3.
EPA and DHA are found almost exclusively in fish and shellfish shellfish. They are most abundant in fatty fish like salmon, rainbow trout, Patagonian toothfish (cod), sardines, mackerel and herring. All seafoods have some EPA and DHA. Egg yolks from hens fed flaxseed have alpha-linolenic acid, EPA and DHA, because the chicken is better able to convert ALA into EPA and DHA than we do. The omega-3 eggs are usually marked as containing "omega-3". Small amounts of EPA and DHA are also found in poultry.
Sources of alpha-linolenic acid that originate in plants are the seeds and flaxseed oil, walnuts and canola oil and soy. New products such as yogurt, margarine, the spreads and snack bars may have omega-3, but may not have any indication that ones they have. These foods usually have alpha-linolenic acid from seeds or flaxseed oil. Unless the label specifically mentions omega-3 "long chain", or EPA, o DHA, tener will in the omega-3 fish oil. Be sure to read the label.
Written by Joyce A. Nettleton, DSc, RD, ScienceVoice Consulting, Denver, CO. 4/06 –
Other Resources
|
|
