Increased focus on role of omega-3/omega-6 imbalance in promoting cancer would help public health
by Craig Weatherby and Randy Hartnell
We were sorry to hear today about the recurrence of cancer in Elizabeth Edwards, wife of Democratic presidential candidate John Edwards.
And we’d like to make positive use of this difficult news by revisiting the cancer-promotion risks posed by a dangerously overlooked aspect of the standard American diet.
There is no way of knowing whether diet will be decisive in preventing or halting a cancer in any given case or genetic group.
But there's strong evidence that American's typically excessive intake of omega-6 fatty acids and lack of adequate omega-3 fatty acids promotes the growth and spread of cancers.
Elizabeth Edwards’ all-too-familiar travail
Mrs. Edwards was first diagnosed with breast cancer toward the end of her husband’s 2004 vice-presidential campaign.
Last year, she published what Publisher’s Weekly called a “disarmingly moving” memoir about her experience, title Saving Graces.
Diet matters: Where are the omega-6 and omega-3 fatty acids?America's omega-6 overload stems from three sources: 1) omega-6-rich vegetable oils—corn, safflower, sunflower, canola, soybean, and cottonseed oil—2) dressings and packaged or prepared foods made with these same oils, and 3) factory-farmed meats and poultry raised on omega-6-rich grains instead of omega-3-rich pasture grasses and plants.
Worse yet, most of the omega-6-rich oils used in processed foods are hydrogenated: a process that destroys their omega-3s and turns their omega-6s into heart-attacking trans fatty acids.
Americans eat few foods in which omega-3s predominate. These include seafood (especially oily fish like salmon)—which provides the most beneficial kind of omega-3s in abundance—and, in descending order, flaxseed, hemp seed, green vegetables, and beans.
Canola oil, soybean oil, and walnuts have omega-3s but contain many more omega-6s.
Unlike wild salmon, farmed salmon is high in omega-6s as well as omega-3s.
Fish oil supplements can dramatically boost daily intake of the most beneficial kind of omega-3s: the long-chain "marine" omega-3s called DHA and EPA.
The recent discovery of a small tumor in a rib bone occurred, fortuitously, when she suffered a fractured rib and doctors saw signs of cancer on the X-rays.
Her doctors say that Mrs. Edwards has meta-static (stage four) breast cancer, which means that it has spread beyond the breast and lymph nodes. The cancer remains treatable because the bone tumor is small and little cancer was found in other places.
Sadly, while 98 percent of patients whose cancer is confined to the breast survive for five-years or more, only one in four patients with Mrs. Edward’s current diagnosis live for five years.
The Edwards’ personal challenge is very tough. But we feel sure that they would want us to use the attention attracted by their public roles to stress the importance of a better (higher) omega-3/omega-6 ratio to curbing cancer risks and optimizing patient outcomes.
We’ll start with a personal account from Randy Hartnell, co-founder and president of Vital Choice Seafood.
Omega science versus actual practice:
The deadly disconnect
A few years back, I visited a conference of the American Institute for Cancer Research (AICR), attended mostly by physicians, where multiple researchers described the dramatic impact of manipulating dietary omega 3/omega-6 ratios on cancer tumors.
Some of the studies were presented by W. Elaine Hardman, Ph.D. who we heard and spoke with at the Seafood & Health Conference 2005.
In a nutshell, all of these presenters found that raising the omega 3/omega-6 ratio in animals and in isolated human cancer cells -- i.e., more omega-3 fatty acids and fewer omega-6 fatty acids -- stopped the growth of the tumors.
In contrast, lowering the omega 3/omega-6 ratio -- i.e., fewer omega-3s and more omega-6s -- “rescued” dying tumors.
To read our coverage of research by Dr. Hardman and others, see:
You may also be interested in a concise summary of the supporting science, penned by leading omega-3 researcher Artemis Simopoulos. M.D.. Her book, The Omega-3 Diet, is a valuable addition any home health and cooking library.
I'll never forget the frustration felt by me and others in the audience when doctors at the AICR conference said they could not recommend dietary therapy to patients due to a lack of controlled clinical studies on these key food factors.
Animal, test tube, and human population studies offer ample evidence of this connection between cancer and American's omega-3/omega-6 intake imbalance, but controlled clinical studies testing the effects of higher omega-3 intake and lower omega-6 intake remain lacking.
This data gap persists for four main reasons:
- Controlled clinical studies would need to be long term (hence costly), and it would be hard to get people to stick to diets providing specific omega-3/omega-6 ratios over many months, and to hide the differences between “active” and “placebo” diets.
- Drug companies have no interest in funding studies on non-patentable—hence, relatively unprofitable—diets or food factors.
- Drug companies exert enormous influence over US government agencies' research-funding decisions, thanks to their political and economic power. Their obvious incentive is to discourage Federal funding of nutrition-disease studies that might make drugs less necessary or profitable.
- Big food companies don’t want their finances impacted by nutrition research, and they, too, exert great influence on federal agencies. Vegetable oils high in omega-6s and the many products made with omega-6-rich oils are unhealthful when consumed in excess, but they are cheap and shelf-stable.
We speak as informed-by-insiders realists, not conspiracy theorists. Public corporations are naturally disinclined to spend shareholder dollars on self-defeating ventures. And they try to ensure that Federal agencies, which are run by political appointees, act accordingly. They succeed, to a dismaying degree, in derailing nutrition research dollars at NIH and elsewhere.
Top US government researchers have told us that they are actively warned against sharing evidence that puts dietary therapy in a good light. We bore witness to the fact that non-scientist “minders” from the National Institutes of Health enforced censorship on NIH employees who spoke at the 2005 Seafood & Health Conference in Washington D.C, which forced these top scientists to share their findings with us in a furtive fashion.
Certainly, people with or at high risk of cancer should be informed of the mountains of persuasive non-clinical evidence concerning the cancer implications of imbalanced fatty acid intake, especially since there no drawbacks—and multiple benefits—associated with consuming fewer omega-6 fatty acids and more omega-3s.
Cancer and America’s insidious fatty acid imbalance
Americans consume loads of vegetable oils high in omega-6 fatty acids—corn, safflower, sunflower, canola, soybean, and cottonseed oil—processed foods made with these oils, and mass-produced meats and poultry raised on omega-6-rich grains instead of traditional grass-fed throwbacks raised on the omega-3-rich plants of natural green pasture.
(Note: olive, macadamia, and “hi-oleic” versions of sunflower oil are low in omega-6 fatty acids.)
The consequence of this radical shift from our prehistoric predecessors’ dietary pattern is a corresponding shift in the ratio of fatty acids in our diets.
Early and pre-humans ate diets high in fruits, leafy greens and aquatic plants and animals, which contained three or four omega-6s to every omega-3: the same ratio found in modern populations that enjoy cancer rates lower than those in America (e.g., Japan).
In contrast, today’s diets provide 15 to 30 units of omega-6s for every omega-3. Leafy greens and aquatic plants and animals are rich in omega-3 fats, while omega-6 fats are concentrated in the seed oils and grains that form the basis of processed foods and the diets of most livestock.
Among other things, this radical shift in the ratio of fatty acids in the American diet has dire implications, both for the risk of developing cancer and for the ability of tumors to resist attacks by the body’s immune system and from medical drug or radiation therapies.
Research findings remain unused
The failure of most doctors to advise cancer patients of the importance of fatty acid intake is equaled only by their failure to do the same for healthy patients with known cancer risk factors, such as a family history of breast cancer.
And this disconnect persists despite acknowledgement of the importance of the omega-3/omega-6 ratio by even the most conservative authorities.
For example, we had no difficulty finding articles on this topic at the website of the American Institute for Cancer Research (AICR): the nation's leading non-profit focused on the field of diet, nutrition and cancer.
These selected excerpts highlight the role of people's omega-3/omega-6 intake ratio to the growth or inhibition of cancer.
AICR press release (AICR 2004)
- “Cancer experts said today that even though many Americans have cut back on fat, the relative amount of two specific kinds of fat in the typical diet remains ‘out of whack’—and unhealthy.”
- “…American diets are overloaded with omega-6 fats and deficient in omega-3 fats, a state of affairs that has been linked to increased cancer risk.”
- “Studies that have compared the diets and disease rates of large populations show that when the ‘omega’ fats are in better balance, the risk for breast cancer, prostate cancer and colon cancer is lower.”
- “The molecules that arise when omega-3 fatty acids get metabolized provide a range of potential anti-cancer benefits… research funded by AICR has shown that adding omega-3 fatty acids to the diet of mice can actually reduce the occurrence of tumors and slow tumor growth."
- “…omega-3s also have a potential role in helping chemotherapy drugs work more effectively and in reducing side effects from cancer treatment."
AICR Nutrition Notes newsletter (Collins K 2006)
- “A wide range of laboratory studies shows that our bodies convert omega-3 fats to hormone-like substances [prostaglandins] that decrease the growth of cancer cells and limit their ability to spread. Laboratory studies also suggest that the converted substances enhance the self-destruction of cancer cells and contribute to normal immune function.”
- “Another type of polyunsaturated fat—omega-6—is converted by our bodies into hormone-like compounds [prostaglandins] that have the opposite effects of compounds from omega-3 fat. These compounds from omega-6 fat can initiate reactions that could lead to cell changes linked with cancer development."
- “The omega-3 fats known as EPA and DHA, which are found in seafood, are converted to active compounds at about ten times greater rates as the form of omega-3 fat (alpha-linolenic acid) found in plant foods, like walnuts and canola oil.”
- “To benefit from omega-3 fat, many researchers say that we need to avoid overeating sources of omega-6 fat like corn, safflower and other vegetable oils… Studies that fail to look at people's overall fat intake may miss differences that strongly affect cancer risk.”
- “Especially if we choose fish high in omega-3 fat, fish is also a good bet for lowering the risks of both heart disease and cancer.”
We can only hope that everyone becomes more aware of this researchwhich applies to cancers that afflict both sexes— and acts on its health implications.
- Broder JM, Hauser C. Edwards to Continue ’08 Bid Despite Wife’s Cancer. The New York Times. March 22, 2007. Accessed online March 22, 2007 at http://www.nytimes.com/2007/03/22/us/politics/22cnd-edwards.html?hp
- AICR (American Institute for Cancer Research). Experts Concerned Over Unhealthy "Fat Ratio" in American Diets. May 13, 2004. Accessed online March 22, 2007 at http://www.aicr.org/site/News2?abbr=pr_&page=NewsArticle&id=7620
- Collins K. Fish for Lower Cancer Risk. American Institute for Cancer Research. Nutrition Notes: Week of April 10, 2006. Accessed online March 22, 2007 at http://www.aicr.org/site/News2?abbr=pr_hf_&page=NewsArticle&id=9585