The benefits of consuming foods high in omega-3s and limiting those with omega-6s is a hot topic these days. A lot of this talk is focused on how the good fat, omega-3, is beneficial. However, this has been indirectly known for quite some time, as nearly 2,000 years ago Galen used fish for both nutrition and medicinally. Galen is one of the most famous physicians ever, and he treated some of the most influential people in the history of the world, including my favorite, Marcus Aurelius. While Caveman Doctor doesn’t watch much TV, except for mostly the nature channel to remind him of the “good old days”, when the series “Rome” came out, you couldn’t tear him away from the TV. However, why have fish been recommended for good health for thousands of years, from Ancient Rome to present day?
Maximizing Your Omega-3 Intake: Tipping the Ratio Back to Health
Essential fatty acids are those that the body cannot make from other fats, proteins, or carbohydrates, thus they are “essential” in our diet. Omega-3 and omega-6 are two the main essential fatty acids. Omega-3s are made from the precursor alpha-linolenic acid (ALA), and consist of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), while omega-6s are composed of linoleic acid.
ALA is found in green leafy vegetables and even vegetable oils have a little, (which may be the only thing going for them), but a large amount can be found in the meat of free-ranging animals and wild cold-water fish. Linoleic acid is found in much larger amounts in vegetable oils, seeds, and grains, which is often why vegetarian diets are very high in linoleic acid and deficient in ALA (i.e. high in omega-6 and low in omega-3).
Just as we explored in cooking oils, the addition of a double bond in a saturated fat can reduce its stability, and greatly affects how our body deals with them. You have likely heard the term omega-3 or omega-6 fatty acids. This number refers to the distance of the double bond from the end of the fatty acids, with omega-3 being three carbon atoms away and omega-6 is six away. While omega-6s have the double bond only 3 small places away at the 6 location, the changes on our body appear to be very important.
Our modern diet has swayed from the proportions of omega-3 and 6 fatty acids that our bodies are programed to process. For millions of years, as we wandered the earth hunting and gathering foods, we consumed a near 1:1 ratio of omega-6 to omega-3 fats1. However, in less than .00008% of this time, our ratio has increased to an astonishing 30:12!!!, as modern unhealthy foods contain a large amount of omega-6s. At the same time, chronic disease, obesity, and inflammation have vastly increased.
Omega-3 and Omega-6 in the Diet
Eating a higher amount of omega-6 relative to omega-3 leads to many health issues, and most are likely related to increased inflammation. Linoleic acid (omega-6) leads to inflammation and cancer, and is even used to promote cancer in laboratory experiments, as described in several posts including one on CLA and vegetable oil. Population studies have shown that omega-3s appear to counteract the negative effects of omega-6s by lowering inflammatory markers like IL-63 and may even reduce the risk of prostate cancer.4,5
On the other hand, DHA and EPA from omega-3s contain anti-inflammatory elements that quiet inflammation (aptly called resolvins and protectins).6 The scientists who discovered these healing properties of DHA and EPA obviously wanted the world to recognize their ability to resolve inflammation.
Omega-3 and even omega-6 fats are extremely important for many physiologic functions, including our immune system, inflammatory response, and blood clotting. As fats, they are both incorporated into our cell membranes as part of the cell wall. However, the body has a preference: omega-6 fatty acids in our cell membranes are actually replaced by DHA and EPA (made from omega-3) when available from your diet7. So, when given the choice, your body kicks out omega-6 in favor of omega-3. That says a lot to me, as I believe our bodies are smarter than we are in knowing what it needs.
After an insult to the body, both omega fats produce inflammatory mediators. However, arachidonic acid (from omega-6s) is significantly more inflammatory than EPA (from omega-3s), resulting in increased swelling, temperature rise, inflammation, and damage after trauma. For example, if you sprain your ankle, arachidonic acid is one of the main chemicals responsible for the swelling that occurs afterwards. Of note, aspirin blocks this pathway, which Hippocrates was using even before Galen, some 2,400 years ago. A key theme of this website is avoiding inflammation; therefore I try to minimize my intake of omega-6 food sources.
Omega-6 Quick Facts:
- Omega-6 sources are found heavily in the western diet (grains, grain-fed animals, vegetable oils).
- Omega-6 is composed of linoleic acid.
- Linoleic acid is converted to arachidonic acid.
- Arachidonic acid is a potent mediator of inflammation.
- High omega-6 foods should be limited in an effort to keep your omega-6/omega-3 ratio under 4, and to reduce inflammation in your body.
- Omega-6s increase blood vessel constriction and spasms (vasospasms), blood viscosity, and are prothrombotic and proaggretory, i.e. pro blood clots.
- A high ratio of omega-6 to omega-3 is associated with an increased risk of high-grade prostate cancer8.
Omega-3 Quick Facts:
- Grass-fed beef, free-roaming animals, and those fed non-grain diets have markedly higher ratios of omega-3 to omega-6.
- Omega-3 fatty acids exhibit anti-tumorigenic effects (likely via their anti-inflammatory effects).
- They decrease potent inflammatory factors like TNF and arachidonic acid (increased from stress and chronic inflammation which may lead to cancer)
- Unlike omega-6, omega-3 is antithrombotic and anti-inflammatory.
- Omega-3s are important in the prevention and treatment of high blood pressure, diabetes, heart disease, arthritis, autoimmune disease, cancer2, and even in macular degeneration.
- Again, aim for a 1:1 ratio of omega-6 to omega-3, but be happy with anything less than 4:1.
- Omega-3s may fight inflammation and cancer merely by counter-acting arachidonic acid.
OK, so I want more Omega-3s over 6s. Where can I get them?!
As is often the case, Nature paved the way for us to health by providing delicious sources of omega-3s. Natural sources include most of the food that modern cavemen are already eating: eggs, grass-fed beef, vegetables, and wild-caught fish.
Like I’ve said before, not all meat is created equal. Grass-fed beef has 4-times the omega-3s than confined/grain-fed/unethically-raised cattle, and cream and cheese from these ruminants have more as well.9 However, what most people don’t realize is that the same is true for fish10 and eggs.11 Wild salmon is full of omega-3s, while farmed salmon has nearly none. Nearly none! It’s ironic that many people pass up red meat for the health benefits of fish, but if you are eating farmed fish it is less nutrient-dense than red meat. Make sure the salmon you buy at the store is wild and look for the country in which it is from, as much of the world’s farmed fish supply comes from Southeast Asia. Unlike farm-raised and hence less healthy salmon, DHA is increased in the cell membranes of cold-water fish (nature has to keep them warm with good fats), so aiming for them may be your best bet. Unfortunately, it doesn’t end there, as cultured vegetable are no different and contain significantly less omega-3s than wild plants.2 In general, if the food you eat is healthier, hardier, and happier, you will be too!
Healthy wild salmon may be tough to get at times, but worth it…
However, many (including myself) choose to take fish oil in pill form to supplement their diet. There is no set official dose, though most people recommend 2-4 grams/day, which has been shown to be safe in studies addressing triglyceride control.12 Doses at 4g/day may increase bleeding time and decrease platelet count (so if you have issues with this, talk to your doctor), but in large human studies, these doses caused no known adverse effects.13 Fish oil tablets are one of the few supplements that I take, especially if I am in a situation where I cannot consume adequate omega-3s. However, if I’m eating my normal diet of salmon, fatty fish, grass-fed beef and free-ranging animals, as well as leafy greens, I usually take roughly 2-3 grams per day. One more quick note on fish oil: when you first start to take them, they may cause a little stomach upset. This can be moderated by taking them with food.
Caveman Doctor’s Favorite Studies Showing the Benefits of Omega-3 and Cancer:
- A recent mouse study at Wake Forest University showed that DHA (a type of omega-3) blocked survival pathways in breast cancer cells, causing these cancer cells to commit suicide (apoptosis)14.
Speaking of Wake Forest, anyone remember when Randolph Childress apoptosed North Carolina in the 1995 ACC Tournament??
- Omega-3s have been shown to decrease the incidence of colon cancer and enhance the treatment of colon cancer15.
- Omega-3s stop prostate cancer progression by blocking proliferation pathways like mTOR (just like in autophagy , whereas omega-6 arachidonic acid actually promoted tumor progression16.
- My favorite: High levels of omega-3 fatty acids in actual breast tissue obtained through biopsy or lumpectomy were significantly associated with a lower risk of breast cancer, and the amount of DHA in the breasts of patients with breast cancer correlated with their response to chemotherapy17.
- We have eaten a ratio of roughly a 1:1 omega-6 to omega-3 fats for several million years.
- Increasing this ratio, as seen in the modern Western diet, leads to inflammation, obesity and disease as omega-6 is an inflammatory fat.
- Maximizing your intake of omega-3 and even supplementing with fish or krill oil may lead to significant health benefits.
- Avoid vegetable oils, grains, and other high omega-6 and linoleic acid foods.
- Make sure to buy wild and grass-fed meat sources, and avoid farm-raised salmon which has few omega-3s.
- Continue eating those caveman foods that are chock full of omega-3s.
Both omega-3 and omega-6 fatty acids are necessary in our diet and provide us with many benefits and aid our physiologic and metabolic function. Even the increases in inflammation that occur from omega-6s are necessary to fight infection and other insults on the body. Unfortunately, modern foods and techniques of industrially raising animals has brought upon an abundance of omega-6s. This disruption of the near 1:1 ratio that we consumed for several million years while hunting and gathering the foods that nature laid out for us has led to an attack on our health. Luckily, many of the foods that are high in omega-3 fatty acids are those that we are already eating by following a caveman diet. Once again, nature made it easy for us: continue eating the same natural foods that we have been hunting and gathering for millions of years to optimize your health.
1. Eaton SB: The ancestral human diet: what was it and should it be a paradigm for contemporary nutrition? The Proceedings of the Nutrition Society 65:1-6, 2006, http://www.ncbi.nlm.nih.gov/pubmed/16441938
2. Simopoulos AP: Essential fatty acids in health and chronic disease. The American Journal of Clinical Nutrition 70:560S-569S, 1999, http://www.ajcn.org/content/70/3/560S.abstract
3. Vedin I, Cederholm T, Freund Levi Y, et al: Effects of docosahexaenoic acid–rich n–3 fatty acid supplementation on cytokine release from blood mononuclear leukocytes: the OmegAD study. The American journal of clinical nutrition 87:1616-1622, 2008, http://www.ajcn.org/content/87/6/1616.abstract
4. Norrish AE, Skeaff CM, Arribas GL, et al: Prostate cancer risk and consumption of fish oils: a dietary biomarker-based case-control study. British journal of cancer 81:1238-42, 1999, http://ukpmc.ac.uk/abstract/MED/10584888
5. Terry P, Lichtenstein P, Feychting M, et al: Fatty fish consumption and risk of prostate cancer. Lancet 357:1764-6, 2001, http://ukpmc.ac.uk/abstract/MED/11403817
6. Greene ER, Huang S, Serhan CN, et al: Regulation of inflammation in cancer by eicosanoids. Prostaglandins & other lipid mediators 96:27-36, 2011, http://www.ncbi.nlm.nih.gov/pubmed/21864702
7. Simopoulos AP: Omega-3 Fatty Acids in Inflammation and Autoimmune Diseases. Journal of the American College of Nutrition 21:495-505, 2002, http://www.jacn.org/content/21/6/495.abstract
8. Williams CD, Whitley BM, Hoyo C, et al: A high ratio of dietary n-6/n-3 polyunsaturated fatty acids is associated with increased risk of prostate cancer. Nutrition research 31:1-8, 2011, http://www.ncbi.nlm.nih.gov/pubmed/21310299
9. Nuernberg K, Nuernberg G, Ender K, et al: N-3 fatty acids and conjugated linoleic acids of longissimus muscle in beef cattle. European Journal of Lipid Science and Technology 104:463-471, 2002, http://www.ncbi.nlm.nih.gov/pubmed/2296923
11. Simopoulos AP, Salem N, Jr.: n-3 fatty acids in eggs from range-fed Greek chickens. The New England journal of medicine 321:1412, 1989, http://www.ncbi.nlm.nih.gov/pubmed/2811950
12. Kris-Etherton PM, Harris WS, Appel LJ: Fish consumption, fish oil, omega-3 fatty acids, and cardiovascular disease. Circulation 106:2747-57, 2002, http://www.ncbi.nlm.nih.gov/pubmed/12438303
13. von Schacky C, Fischer S, Weber PC: Long-term effects of dietary marine omega-3 fatty acids upon plasma and cellular lipids, platelet function, and eicosanoid formation in humans. The Journal of clinical investigation 76:1626-31, 1985, http://www.ncbi.nlm.nih.gov/pubmed/2997286
14. Sun H, Hu Y, Gu Z, et al: Omega-3 fatty acids induce apoptosis in human breast cancer cells and mouse mammary tissue through syndecan-1 inhibition of the MEK-Erk pathway. Carcinogenesis 32:1518-24, 2011, http://www.ncbi.nlm.nih.gov/pubmed/21771724
15. Cockbain AJ, Toogood GJ, Hull MA: Omega-3 polyunsaturated fatty acids for the treatment and prevention of colorectal cancer. Gut 61:135-49, 2012, http://www.ncbi.nlm.nih.gov/pubmed/21490374
16. Friedrichs W, Ruparel SB, Marciniak RA, et al: Omega-3 fatty acid inhibition of prostate cancer progression to hormone independence is associated with suppression of mTOR signaling and androgen receptor expression. Nutrition and cancer 63:771-7, 2011, http://www.ncbi.nlm.nih.gov/pubmed/21667400
17. Bougnoux P, Germain E, Chajes V, et al: Cytotoxic drugs efficacy correlates with adipose tissue docosahexaenoic acid level in locally advanced breast carcinoma. British journal of cancer 79:1765-9, 1999, http://www.ncbi.nlm.nih.gov/pubmed/10206290
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