Posted on 03/12/2008 6:29:03 PM PDT by blam
Cardiovascular Benefits Of Omega-3 Fatty Acids Reviewed
ScienceDaily (Mar. 12, 2008) — Thousands of research studies have documented how the oils known as omega-3 fatty acids can benefit the cardiovascular system, particularly among people diagnosed with coronary artery disease. The incredible volume of research on this topic creates difficulty for many physicians and patients to stay current with findings and recommendations related to these oils. In the March issue of Mayo Clinic Proceedings, contributors briefly summarize current scientific data on omega-3 fatty acids and cardiovascular health, focusing on who benefits most from their protective effects, recommended guidelines for administration and dosing, and possible adverse effects associated with their use.
Two omega-3 fatty acids that have been associated with cardiovascular benefit, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), are found in fish oils. The best source for DHA and EPA are fatty coldwater fish such as herring, mackerel, salmon and tuna. Fish oil supplements or algae supplements also can provide omega-3 fatty acids.
Author James O'Keefe, M.D., a cardiologist from the Mid America Heart Institute in Kansas City, Mo., cites the results of several large trials that demonstrated the positive benefits associated with omega-3 fatty acids, either from oily fish or fish oil capsules.
"The most compelling evidence for the cardiovascular benefit provided by omega-3 fatty acids comes from three large controlled trials of 32,000 participants randomized to receive omega-3 fatty acid supplements containing DHA and EPA or to act as controls," explains Dr. O'Keefe. "These trials showed reductions in cardiovascular events of 19 percent to 45 percent. Overall, these findings suggest that intake of omega-3 fatty acids, whether from dietary sources or fish oil supplements, should be increased, especially in those with or at risk for coronary artery disease."
How much fish oil should people attempt to incorporate into their diets? According to Dr. O'Keefe, people with known coronary artery disease should consume about 1 gram per day, while people without disease should consume at least 500 milligrams (mg) per day.
"Patients with high triglyceride levels can benefit from treatment with 3 to 4 grams daily of DHA and EPA," says Dr. O'Keefe. "Research shows that this dosage lowers triglyceride levels by 20 to 50 percent."
About two meals of oily fish can provide 400 to 500 mg of DHA and EPA, so patients who need to consume higher levels of these fatty-acids may choose to use fish oil supplements to reach these targets.
Dr. O'Keefe also notes that research supports the effectiveness of combining the consumption of fish oil with the use of cholesterol-lowering medications called statins. Combination therapy with omega-3 fatty acids and a statin is a safe and effective way to improve lipid levels and cardiovascular health beyond the benefits provided by statin therapy alone. Blood DHA and EPA levels could one day be used to identify patients with deficient levels and to individualize therapeutic recommendations.
Dr. O'Keefe found little evidence of serious adverse effects associated with fish oil consumption. "In prospective placebo-controlled trials, no adverse effects were observed to occur at a frequency of more than 5 percent, and no difference in frequency was noted between the placebo and omega-3 fatty acid groups," he says.
The most commonly observed side effects include nausea, upset stomach and a "fishy burp." Taking the supplement at bedtime or with meals, keeping fish oil capsules in the freezer or using enteric-coated supplements may help reduce burping and upset stomach symptoms.
Adapted from materials provided by Mayo Clinic.
Burp
Flax is ALA Omega-3, only.
Hemp oil does contain linoleic (LA) and alpha-linolenic (LNA) acids, which are the two essential oils in the human diet. The LNA in hemp oil is a precursor to DHA and EPA, however the conversion of LNA to DHA or EPA can be inhibited by bad fats (margarines, shortenings, trans-fatty acids, hard fats, sugar and cholesterol), lack of minerals (magnesium, selenium, zinc) and vitamins (B3, B6, C, E), viruses, obesity, diabetes, aging, and rare genetic mutations.
Also hemp oil, like most light plant oils, is quite perishable, so requires careful processing and handling. This is one reason why seeds, as is or freshly ground, are better than the extracted oils -- less chance of the oils going rancid. Chia seeds (aka Salba or salvia) and flax seeds are two excellent sources of these essential oils, and other nutrients.
Flax has more omega 3's and hemp more omega 6's. While an ideal diet would probably have somewhat more omega 6's than 3's (which is why hemp oil is marketed as having the ideal 3:1 ratio of 6's to 3's), our typical diets all have a great excess of omega 6's, so the focus can reasonably be more on getting more omega 3's than 6's (as can be found in flax oil), to bring things closer to a healthy balance.
Many common fish sources risk being contaminated with heavy metals, especially from the larger fish higher in the food chain such as shark or swordfish. Farm raised salmon, as opposed to wild caught, are likely to be much less healthy, in what they do, and do not, contain. The smaller fish, such as sardines, don't have the heavy metal problems. Krill, which is a main source of food for whales, is an excellent source of such oils, and does not risk heavy metal contamination, and is abundantly available, especially from near Antarctica.
Really fresh, carefully processed and handled fish oils should have little or no fishy taste.
Really fresh cod liver oil actually tastes pretty good, and mild.
“Egg yolks, both chicken and duck, are a good source of omega 3 fatty acids.”
Farm-raised eggs don’t normally have adequate levels of omega-3 unless the chickens are fed a diet which is unlike a standard chicken diet.
Animals can’t make Omega-3 from a diet of grain sources. It has to be grass feed for them to process it to Omega-3.
This is true for farm-raised fish, also. Most farm-raised fish don’t have much Omega-3, because they are fed a grain-based diet, unlike wild-caught fish, which eat sea grasses.
The only problem with cod liver oil is the nearly toxic amount of vitamin A in it.
Even when it is chemically reduced, it is considered far too high for what recent tests say we should supplement.
there are 3 omega3 molecules. Our body needs some of each for health. one is the uniquely plant derived one found in flax, walnuts, purslane, etc. The other 2 are from animal sources, not plants. The plant one can be used by the body to manufacture the second, and the second can be converted to the third, but many people are very poor converters. We need all 3. The plant one has been hyped by some as being awesomely good with cancer, as much as 94% cure rate on prostate cancer. I have to assume we would be better off to take all 3, not focus on one and ignore the others.
thanks
bump for later read.
Most light plant oils are not suited for cooking; they don't hold up to the heat. Olive oil does a little better, macadamia (if I recall correctly) a little better, and coconut oil pretty good.
If you can find it, and your religion allows it, you can't beat lard (pig fat) for cooking.
All this hoopla over “19 to 45% reduction” and the vitamin b6 crowd is reporting 76% reduction. Wonder what you get if you take both?
Use it quickly, because it becomes rancid if exposed to any light at all.
From http://www.westonaprice.org/men/vitaminabodybuilding.html:
Many health conscious individuals avoid cod liver oil and other foods rich in vitamin A because of concerns about vitamin A toxicity. Yet, according to the Merck Manual, vitamin A poisoning is rare. In adults, vitamin A toxicity has been reported in Arctic explorers who developed drowsiness, irritability, headaches and vomiting, with subsequent peeling of the skin, within a few hours of ingesting several million units of vitamin A from polar bear or seal liver. These symptoms cleared up with discontinuation of the vitamin A rich food.Other than this unusual example, however, only vitamin A from "megavitamin tablets containing vitamin A. . . when taken for a long time" has induced acute toxicity, that is, 100,000 IU synthetic vitamin A per day taken for many months.
Unless you are an Arctic explorer, it is very difficult to develop vitamin A toxicity from food. The putative toxic dose of 100,000 IU per day would be contained in 3 tablespoons of high vitamin cod liver oil, 6 tablespoons of regular cod liver oil, two-and-one-half 100-gram servings of duck liver, 150 grams of beef liver, seven pounds of butter or 309 egg yolks. Bodybuilders undergoing strenuous exercise can consume even higher amounts without adverse effects. For further information see "Vitamin A Saga."
I’m not against using cod liver oil, but the reality is that its form of vitamin A is stored in our fat cells, making a large daily dose over time a real hazard:
http://en.wikipedia.org/wiki/Hypervitaminosis_A
http://en.wikipedia.org/wiki/Cod_liver_oil
bump
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