by: Samuel “Jody” Stagg, M.D., F.A.C.C., F.A.C.P.
What are Omega-3 FA?1
What’s the big deal about Omega-3 FA, in particular fish oil? Omega-3 FA are carboxyl acids derived from outside food sources important in human metabolism and physiology. They are essential for normal growth in children and are crucial in multiple metabolic pathways. They are important to healthy growth and function.
Omega-3 FA are considered essential fatty acids because they cannot be synthesized by the human body. They need to be consumed from outside food sources.
Three Types of Omega-3 FA Involved in Human Physiology
- ALA (alpha-linolenic acid) found in plant oils
- EPA (eicosapentaenoic acid)
- DHA (docosahexaenoic acid)
EPA and DHA are both commonly found in marine oils. Common sources of ALA are plant oils including walnut, sea-buckthorn, chia seeds, berry oils, clary sage seed oil, algal oil, flaxseed oil, Sacha Inchi oil, Echium oil, and hemp oil.
ALA is a shorter-chain fatty acid, and humans have a limited ability to synthesize the more important long-chain fatty acids EPA and DHA from ALA.
Common sources of EPA/DHA include fish oils, egg oil, squid oils, and krill oil.
Mechanism of Action of Essential Fatty Acids
Essential fatty acids were first given their name when they were found to be essential to normal growth in children and animals. The modern definition has evolved to mean that they aren’t metabolized by the human body and require an external food source for their presence in the human body.
Omega-6 FA (gamma linolenic acid and arachidonic acid) are also necessary for normal growth, in particular in dental development, kidney function and development, and normal childbirth. Omega-6 FA are converted into eicosanoids (thromboxanes, prostacyclins, and leukotrienes) which are often pro-inflammatory.2 If the synthesis of eicosanoids from Omega-6 FA is higher than the metabolism and breakdown, then there is an increased inflammatory effect in the body which has a negative effect on many organ systems.
Omega-3 FA and Omega-6 FA can both be converted to eicosanoids but the ones synthesized from Omega-3 FA are significantly less inflammatory.
Omega-3 FA and Omega-6 FA compete for the same metabolic enzymes so the ratio of consumed Omega-6 to Omega-3 FAs has a significant impact on the production of different types of eicosanoids (more or less inflammatory). Altering this ratio can influence the body’s inflammatory state.3
Also, if there is an excess of Omega-6 FA available, it will negatively influence the conversion of short-chain plant ALA to the more beneficial long-chain EPA and DHA.
The recommended levels of Omega-6 FA to Omega-3 FA ranges depend on authors but can be 4:1 all the way to 1:4, but the typical Western diet which has a ratio of 10:1 to 30:1 has a much higher level than even the most minimal recommendations.4
The ratio of Omega-6:Omega-3 in vegetable oils is as follows:
Flaxseed oil 1:3
Canola oil 2:1
Soybean Oil 7:1
Olive oil 3-13:1
Corn oil 46:1
Sunflower, cottonseed, peanut, and grapeseed oil have almost no Omega-3 fatty acids.5
Fish – Coldwater oily fish (salmon, mackerel, herring, anchovies, and sardines) have an Omega-6:Omega-3 ratio of a very beneficial 1:7 and are the most widely available sources of EPA and DHA. Tuna is also a valuable source but with a less beneficial ratio. Interestingly, fish which are such a valuable source of Omega-3 FA don’t actually synthesize the fatty acid but actually get them from algae or plankton in their diets.6
Fish oil – Supplementation with coldwater fish oil provides a very valuable source of EPA and DHA. It’s especially important in people that require daily supplementation of Omega-3 FA.
Krill oil – This is a relatively recently discovered source of EPA and DHA; however, routinely the amount of DHA and EPA in krill oil supplements is significantly less than in fish oil supplements.
Calamari oil – This is another potentially valuable source of Omega-3 FA.
Eggs – Eggs are a source of Omega-3 FA, and the diet of the chickens producing the eggs can affect the content of Omega-3’s.
Elevated egg levels of Omega-3’s can be induced by giving chickens a diet rich in:
1) Greens and insects7
2) Fish oils8
3) Flaxseed and canola seeds9]
4) Green algae or seaweed10
Apparently chickens aren’t particularly picky eaters.
Meat – Grass-fed beef can have twice the amount of beneficial Omega-3s compared to Omega-6 FA than grain-fed beef has.11 In fact, when cattle are taken off pasture and shipped to the feed lot for fattening on grain prior to their slaughter, their ratio of Omega-3 FA to Omega-6 FA significantly worsens. The beef from grass-fed cattle has multiple potential benefits compared to grain-fed cattle beef, and an increased ratio of Omega-3 FA is one of them.
Mammalian brains and eyes and seal oil are other meats high in EPA and DHA.
What are the health benefits of consumption of Omega-3 FA?
There is currently no conclusive data on the beneficial effects of Omega-3 FA on the development or treatment of malignancies. There is data, however, that shows that consumption of marine Omega-3 FA may reduce the risk of breast cancer12 and currently the effect of Omega-3 consumption on prostate carcinoma is inconclusive.13
2. Inflammatory disorders
There appears to be a significant anti-inflammatory effect associated with consumption of long-chain Omega-3 FA. The clinical benefit of this is not completely known but there appears to be clinical improvement in patients with rheumatoid arthritis with consumption of Omega-3 FA with symptomatic improvement in joint pain and swelling and also a decrease in the necessity of using non-steroidal anti-inflammatory medications for treatment.14
3. Developmental disorders
There is currently a lot of interest in the potential for utilization of Omega-3 FA to assist with the treatment of autism and ADHD. There are multiple studies and reviews looking at using Omega-3 FA to treat these disorders but there are currently no consistent findings. They are being used by many healthcare providers for their potential benefit here.
4. Mental health
There is evidence that Omega-3 FA are potentially related to mental health issues, in particular bipolar disease and depression.
There is currently some limited evidence that utility of Omega-3 FA supplementation can be helpful with treating depression.15, 16
5. *Cognitive function
There are multiple studies that have looked at Omega-3 FA consumption and risk of dementia, and there appears to be significant promise here. Clinical benefits have been seen in particular in patients with early decline in cognitive function before the development of true Alzheimer’s disease.17
A very recent study in the journal Alzheimer’s and Dementia showed that fish oil supplementation used during the study was associated with both improved cognitive function as well as less cerebral atrophy in older adults. 18
“VERY SIGNIFICANT FINDING” Taking omega-3 fatty acid oral supplements helps prevent one of our deepest fears, and that’s the development of dementia and Alzheimer’s disease. This, as much as any health benefit, should make us strongly consider taking oral omega-3 supplements.
6. Cardiovascular disease
I will discuss the many potential benefits of Omega-3 FA in prevention and treatment of cardiovascular disease in the second part of this discussion, but beginning as early as September 8, 2004, the Food and Drug Administration (FDA) reported that supportive but not conclusive research showed that consumption of EPA and DHA fatty acids may reduce the risk of coronary heart disease. There are multiple potential benefits clinically and physiologically that range from lowering of atherogenic lipid levels to significant improvement in the intravascular inflammatory state. This is certainly one of the most promising healthcare benefits of Omega-3 FA supplementation and the one that will have the most widespread application.
Omega-3 FA are critical food nutrients that can only be obtained from outside food sources, and supplementation with coldwater fish oil has a large potential application. There are still many studies ongoing concerning the potential clinical benefits of Omega-3 FA, and appropriate dosing to achieve those benefits. And more and more data will continue to be forthcoming. At this point the current recommendations from the American Heart Association for supplementation with EPA/DHA are as follows:
- People with no history of coronary artery disease should consume oily fish or fish oils two times per week.
- People with coronary artery disease and a history of a myocardial infarction should consume 1 gram EPA and DHA per day.
- People with elevated triglycerides should consume 2 to 4 grams per day of EPA and DHA for maximum benefit in lowering the elevated triglyceride levels.
- Wikipedia 2014 “Omega-3 FA”.
- Lands, WE FASEB J 1992:6(8):2530-2536.
- Tribole, EF et al. “Risks and benefits for omega-3, fats for mortality, cardiovascular disease, and cancer: systematic review. BMJ 2006:332(7544)752-760.
- Hibbeln, JR et al. “Healthy intakes of N-3 and N-6 fatty acids: estimations considering worldwide diversity” Am. J. Clin. Nutr. 2006:83(6 Supp)1483S-1493S.
- Oil:USDA Nutrient Data: Condé Nast SR-21.
- Falk-Peterson, S et al. “Lipids and fatty acids in ice algae and phytoplankton from the marginal ice zone in the Barents Sea” 1998 Polar Biology:20(1):41-47.
- “How Omega-6s usurped Omega-3s in U.S. diet” medicalnewstoday.com 51575.
- Trebunova, A et al. Deutsche tierarztliche Wochenschrift 2007:114(7):275-279.
- Cherian, G et al. “Effect of feeding full fat flax and canola seeds to laying hens on the fatty acids composition of eggs” http://agris.fao.org\agris-search\.
- Sterling, Colin “Washington Post egg taste test says homegrown and factory eggs taste the same.” Huffington Post.com.
- Duckett, SK et al. “Effects of winter stocker growth rate and finishing system on: III.Tissue proximate, fatty acid, vitamin and cholesterol content” Journal of Animal Science 2009:87(9):2961-70.
- Zheng, J et al. “Intake of fish and marine N-3 polyunsaturated fatty acids and risk of breast cancer, meta-analysis of data from 21 independent prospective cohort studies” BMJ 2013 346 3706.
- Heinze, VM et al. “Dietary conjugated linoleic acid and long-chain N-3 fatty acids in mammary and prostate cancer protection: A review International Journal of Food Sciences and Nutrition 2012:63(1):66-78.
- Miles, EA et al. “Influence of marine N-3 polyunsaturated fatty acids on immune function and a systematic review of their effects on clinical outcomes in rheumatoid arthritis” The British Journal of Nutrition 2012:107(supplemental 2):S171-84.
- Perica, MM et al. “Essential fatty acids in psychiatric disorders” Nutrition In Clinical Practice 2011:26(4):409-25.
- Hegarty, B et al. “Fish oil as a management component for mood disorders – an evolving signal” Current Opinion in Psychiatry 2013:26(1):33-40.
- Mazereeuw, G et al. “Effects of Omega-3 FA on cognitive performance:a meta-analysis” Neurobiology Aging 2012:33(7):E17-29.
- Daiello, Lori et al. “Association of fish oil supplement used with preservation of brain volume and cognitive function” Alzheimer’s and Dementia:2014:published on line June 20, 2014.