Omega-3 Fatty Acids

I’m not seeking medical advice, just information.

I see more and more products with Omega-3 fatty acids (DHA and EPA) in them, and some people I know, including a pregnant woman, take them as dietary supplements, either as fish oil flaxseed oil. When I asked my general practitioner about it, he said “Just eat some fish”, which I do, but heavy metals, PCBs, etc. worry me. Even the most rigorous-sounding information I can find on the internet, from WebMD and such, seems pretty equivocal. Plus, I imagine that the maufacturers have some influence on the information out there. What is the straight dope on this stuff?

I’ve read the following, and would like to know if any of it is backed up with data:

It helps in the prevention of heart disease.

It should be consumed in a ratio of 3 parts Omega-6 to 1 part Omega-3. The average American gets more like 20 to 1.

It can cause bleeding problems if taken in unspecified large amounts with blood-thinning medications.

Products derived from fish body oils (as opposed to fish liver oils) are better than those derived from flaxseed, owing to better bioavailability or somesuch.

Algae-derived products and ‘molecularly distilled’ products made from fish body oils do not contain detectable amounts of heavy metals or PCBs, and are therefore safe to consume.

It contributes to fetal brain and eye development and is linked to better vision and psychomotor development in infants.

Some questions:

Is there a recognized upper limit on daily consumption?

What dangerous effects (if any) are there from overconsumption?

Is a 1-2 or closer ratio considered safe?

Is there any difference between getting Omega-3 from fish vs. oils?

Any journal articles I should read?

Sorry for the lengthy post, but I’ve been thinking about this for a while, and I’m more confused than when I started.

Sorry, no info to add, but I am interested in this too. I’ve tried taking omega-3 from two sources (fish oil and flaxseed) but both times it made my face very rough and the skin very sensitive. I tried to isolate the omega-3 pills- not adding anything else new to my diet- and checking the ingredients for added weird stuff, but couldn’t come up with another culprit. It’s puzzled me, since they are supposed to help with skin issues. . .

I’ve been taking four “triple-strength” Omega-3 capsules per day, for many years, and it’s really helped with my cholesterol. According to my doctor, any more than four have no additional benefit, and it doesn’t matter whether you take them all at once or spaced throughout the day. And I haven’t noticed any adverse side effects.

I don’t even worry about Omega-6, since it’s practically ubiquitous in our diets.

Michael Pollan, (of The Omnivore’s Dilemma: A Natural History of Four Meals) in In Defense of Food: An Eater’s Manifesto, suggests the O-3 fishoil, and this is the only specfic additive or food he suggests. His three rules “Eat Food, Mosty Fruits & Vegetables, and Not too much” are a marvel of simplicity.

So, I verified his claims through my own research, journal articles, Google Scholar and the like. Thus, I have also added them to my vitamins.

If you like, I’ll seach tomorrow on Google Scholar and come up with some cites. But in the meantime-

heeeeeere’s wiki :’"
*Health benefits

On September 8, 2004, the U.S. Food and Drug Administration gave “qualified health claim” status to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) n−3 fatty acids, stating that “supportive but not conclusive research shows that consumption of EPA and DHA [n−3] fatty acids may reduce the risk of coronary heart disease.”[2] This updated and modified their health risk advice letter of 2001 (see below).

People with certain circulatory problems, such as varicose veins, benefit from fish oil. Fish oil stimulates blood circulation, increases the breakdown of fibrin, a compound involved in clot and scar formation, and additionally has been shown to reduce blood pressure.[3][4] There is strong scientific evidence that n−3 fatty acids significantly reduce blood triglyceride levels[5][6][7][8] and regular intake reduces the risk of secondary and primary heart attack.[9][10][11][12]

Some benefits have been reported in conditions such as rheumatoid arthritis[13][14] and cardiac arrhythmias.[15][16][17]

There is a promising preliminary evidence that n-3 fatty acids supplementation might be helpful in cases of depression[18][19] and anxiety.[20][21] Studies report highly significant improvement from n-3 fatty acids supplementation alone and in conjunction with medication.[22]

Some research suggests that fish oil intake may reduce the risk of ischemic and thrombotic stroke.[23][24][25] However, very large amounts may actually increase the risk of hemorrhagic stroke (see below). Lower amounts are not related to this risk,[25] and many studies used substantially higher doses without major side effects (for example: 4.4 grams EPA/2.2 grams DHA in 2003 study).[18][26][27] No clear conclusion can be drawn at this time, however.

A 2006 report in the Journal of the American Medical Association concluded that their review of literature covering cohorts from many countries with a wide variety of demographic characteristics demonstrating a link between n−3 fatty acids and cancer prevention gave mixed results.[28] This is similar to the findings of a review by the British Medical Journal of studies up to February 2002 that failed to find clear effects of long and shorter chain n−3 fats on total mortality, combined cardiovascular events and cancer.[29]

In 1999, the GISSI-Prevenzione Investigators reported in the Lancet, the results of major clinical study in 11,324 patients with a recent myocardial infarction. Treatment 1 gram per day of n−3 fatty acids reduced the occurrence of death, cardiovascular death and sudden cardiac death by 20%, 30% and 45% respectively.[30] These beneficial effects were seen already from three months onwards.[31]

In April 2006, a team led by Lee Hooper at the University of East Anglia in Norwich, UK, published a review of almost 100 separate studies into n−3 fatty acids, found in abundance in oily fish. It concluded that they do not have a significant protective effect against cardiovascular disease.[32] This meta-analysis was controversial and stands in stark contrast with two different reviews also performed in 2006 by the American Journal of Clinical Nutrition[33] and a second JAMA review[34] that both indicated decreases in total mortality and cardiovascular incidents (i.e. myocardial infarctions) associated with the regular consumption of fish and fish oil supplements. In addition n−3 has shown to aid in other mental disorders such as aggression and ADHD (Attention-deficit hyperactivity disorder).[35]

Several studies published in 2007 have been more positive. In the March 2007 edition of the journal Atherosclerosis, 81 Japanese men with unhealthy blood sugar levels were randomly assigned to receive 1800 mg daily of eicosapentaenoic acid (EPA - an n−3 essential fatty acid from fish oil) with the other half being a control group. The thickness of the carotid arteries and certain measures of blood flow were measured before and after supplementation. This went on for approximately two years. A total of 60 patients (30 in the EPA group and 30 in the control group) completed the study. Those given the EPA had a statistically significant decrease in the thickness of the carotid arteries along with improvement in blood flow. The authors indicated that this was the first demonstration that administration of purified EPA improves the thickness of carotid arteries along with improving blood flow in patients with unhealthy blood sugar levels.[36]

In another study published in the American Journal of Health System Pharmacy March 2007, patients with high triglycerides and poor coronary artery health were given 4 grams a day of a combination of EPA and DHA along with some monounsaturated fatty acids. Those patients with very unhealthy triglyceride levels (above 500 mg/dl) reduced their triglycerides on average 45% and their VLDL cholesterol by more than 50%. VLDL is a bad type of cholesterol and elevated triglycerides can also be deleterious for cardiovascular health.[37]

There was another study published on the benefits of EPA in The Lancet in March 2007. This study involved over 18,000 patients with unhealthy cholesterol levels. The patients were randomly assigned to receive either 1,800 mg a day of EPA with a statin drug or a statin drug alone. The trial went on for a total of five years. It was found at the end of the study those patients in the EPA group had superior cardiovascular function. Non-fatal coronary events were also significantly reduced in the EPA group. The authors concluded that EPA is a promising treatment for prevention of major coronary events, especially non-fatal coronary events.[38]

Another study regarding fish oil was published in the Journal of Nutrition in April 2007. Sixty four healthy Danish infants from nine to twelve months of age received either cow’s milk or infant formula alone or with fish oil. It was found that those infants supplemented with fish oil had improvement in immune function maturation with no apparent reduction in immune activation.[39]

There was yet another study on n−3 fatty acids published in the April 2007 Journal of Neuroscience. A group of mice were genetically modified to develop accumulation of amyloid and tau proteins in the brain similar to that seen in people with poor memory. The mice were divided into four groups with one group receiving a typical American diet (with high ratio of n−6 to n−3 fatty acids being 10 to 1). The other three groups were given food with a balanced 1 to 1 n−6 to n−3 ratio and two additional groups supplemented with DHA plus long chain n−6 fatty acids. After three months of feeding, all the DHA supplemented groups were noted to have a lower accumulation of beta amyloid and tau protein. Some research suggests that these abnormal proteins may contribute to the development of memory loss in later years.[40]

There is also a study published regarding n−3 supplementation in children with learning and behavioral problems. This study was published in the April 2007 edition of the Journal of the Developmental and Behavioral Pediatrics (5), where 132 children, between the ages of seven to twelve years old, with poor learning, participated in a randomized, placebo-controlled, double-blinded interventional trial. A total of 104 children completed the trial. For the first fifteen weeks of this study, the children were given polyunsaturated fatty acids (n−3 and n−6, 3000 mg a day), polyunsaturated fatty acids plus multi-vitamins and minerals or placebo. After fifteen weeks, all groups crossed over to the polyunsaturated fatty acids (PUFA) plus vitamins and mineral supplement. Parents were asked to rate their children’s condition after fifteen and thirty weeks. After thirty weeks, parental ratings of behavior improved significantly in nine out of fourteen scales. The lead author of the study, Dr. Sinn, indicated the present study is the largest PUFA trial to date with children falling in the poor learning and focus range. The results support those of other studies that have found improvement in poor developmental health with essential fatty acid supplementation.[37][38][39][40][41][42]

Research in 2005 and 2006 has suggested that the in-vitro anti-inflammatory activity of n−3 acids translates into clinical benefits. Cohorts of neck pain patients and of rheumatoid arthritis sufferers have demonstrated benefits comparable to those receiving standard NSAIDs.[citation needed] Those who follow a Mediterranean-style diet tend to have less heart disease, higher HDL (“good”) cholesterol levels[43] and higher proportions of n−3 in tissue highly unsaturated fatty acids.[44] Similar to those who follow a Mediterranean diet, Arctic-dwelling Inuit - who consume high amounts of n−3 fatty acids from fatty fish - also tend to have higher proportions of n−3, increased HDL cholesterol and decreased triglycerides (fatty material that circulates in the blood) and less heart disease. Eating walnuts (the ratio of n−3 to n−6 is circa 1:4 respectively[45]) was reported to lower total cholesterol by 4% relative to controls when people also ate 27% less cholesterol.[46]

A study[47] examining whether omega-3 exerts neuroprotective action in Parkinson’s disease found that it did, using an experimental model, exhibit a protective effect (much like it did for Alzheimer’s disease as well). The scientists exposed mice to either a control or a high omega-3 diet from two to twelve months of age and then treated them with a neurotoxin commonly used as an experimental model for Parkinson’s. The scientists found that high doses of omega-3 given to the experimental group completely prevented the neurotoxin-induced decrease of dopamine that ordinarily occurs. Since Parkinson’s is a disease caused by disruption of the dopamine system, this protective effect exhibited could show promise for future research in the prevention of Parkinson’s disease.

A study carried out involving 465 women showed serum levels of eicosapentaenoic acid is inversely related to the levels of anti-oxidized-LDL antibodies. Oxidative modification of LDL is thought to play an important role in the development of atherosclerosis.[48]

In 2008 a German study suggested that Omega-3 fatty acids have a positive effect on atopic dermatitis[49]

[edit] Health risks

In a letter published October 31, 2000,[50] the United States Food and Drug Administration Center for Food Safety and Applied Nutrition, Office of Nutritional Products, Labeling, and Dietary Supplements noted that known or suspected risks of EPA and DHA n−3 fatty acids may include the possibility of:

* Increased bleeding if overused (normally over 3 grams per day) by a patient who is also taking aspirin or warfarin. However, this is disputed.[51]
* Hemorrhagic stroke (only in case of very large doses, called "Eskimo amounts").[52]
* Oxidation of n−3 fatty acids forming biologically active oxidation products.
* Reduced glycemic control among diabetics.
* Suppression of immune and inflammation responses, and consequently, decreased resistance to infections and increased susceptibility to opportunistic bacteria.
* An increase in concentration of LDL cholesterol in some individuals.

Subsequent advices from the FDA and national counterparts have permitted health claims associated with heart health.

[edit] Cardiac risk

Persons with congestive heart failure, chronic recurrent angina or evidence that their heart is receiving insufficient blood flow are advised to talk to their doctor before taking n−3 fatty acids. It may be prudent for such persons to avoid taking n−3 fatty acids or eating foods that contain them in substantial amounts*"

None of this is out of line from what I found myself. I didn’t know a few of these things.

I have had heart attacks in the past and bad cholesterol numbers,I now take the Omega 3 fish oil supplement every day.My cholesterol is perfect.If you decide to use it be sure and read the ingredients because oil from cold water fish is best,at least that is what my heart specialist told me.One other note I think I would look for another M.D. maybe a younger one. :wink: