Tag Archives: fatty acids

Prostate Cancer Omega-3 | The Paleo Diet

By now you’re all familiar with the study published online by Brasky et al. in the Journal of the National Cancer Institute entitled, “Plasma Phospholipid Fatty Acids and Prostate Cancer Risk in the SELECT Trial.” It was widely publicized in the mass media, showing an increased risk of prostate cancer for men with higher vs lower omega-3 blood levels. Dr. James H O’Keefe, world renowned cardiologist and Director of the Preventive Cardiology Program at Saint Luke’s, colleague, and co-author on a number of my scientific papers, has given this study exceptional thought and attention. I share with you his insightful response to why it is largely irrelevant clinically below.

Dr. Hector Lopez, board-certified specialist in physical medicine and rehabilitation, with a concentration in spine, sports and musculoskeletal medicine with post-graduate training in nutritional biochemistry has also provided an in-depth analysis examining in objective detail what risks, if any, long chain fatty acid present to the prostate in Long-Chain Omega-3 Fatty Acids: Friend or Foe to Prostate? More than meets the eye to recent controversy over omega-3 levels and prostate cancer risk.

Coridally,

Loren Cordain, Ph.D., Professor Emeritus

This was a retrospective case-control study that showed miniscule differences in omega-3 blood levels: 3.62% in the no-cancer control group, 3.66% in the prostate cancer group. For example, a headline in the Huffington Post read: “Omega-3 supplement taken by millions linked to aggressive prostate cancer.” This is blatantly untrue. To have an omega-3 blood level of 3.6 to 3.7% range is compatible with little to no fish consumption, and no fish oil capsule intake in BOTH arms of the study.

Japanese men consume about 8 times more fish than American men, and on average have an omega-3 index of 8 to 10% (over twice as high as either group in this study). Japanese men have a prostate cancer level that is less than one-sixth that is noted in American men. Prior studies from other investigators have suggested if anything lowers rates of prostate cancer, it is with higher intake of fish and omega-3 fatty acids.

Higher omega-3 levels have been consistently and strongly correlated with lower risks for cardiovascular mortality, sudden cardiac death, all-cause mortality and genetic aging at a cellular level (slowing telomere attrition). William Harris PhD, the ‘CodFather’ of omega-3, and I are looking at the GISSI trials to see if we can shed light on this issue with randomized trial data. Stay tuned, we will let you know what it shows. In the meantime, here is Dr. Harris’s in-depth analysis.

Bottom line: In my opinion, this study is largely irrelevant clinically. And on a personal note, I will continue to emulate the Japanese and keep my omega-3 levels at or above 8%.

James H O’Keefe, MD
Director, Preventive Cardiology Program

Canned Tuna | The Paleo Diet

Hi Dr. Cordain,

I read your book The Paleo Diet several years ago and on page 122 you mention that “Canning also increases the level of oxidized cholesterol in fish, specifically increasing a molecule called 25 hydroxycholesterol that is extremely destructive to the linings of arterial blood vessels. This is so destructive, in fact, that oxidized cholesterol is routinely fed to laboratory animals to accelerate the artery-clogging atherosclerotic process in order to test theories of heart disease. In animal models of atherosclerosis and heart disease, only 0.3 % of the total ingested cholesterol needs to be in the form of oxidized cholesterol to cause premature damage to arterial linings.”

Many health-conscious people eat canned fish for the supposed health benefits and are not aware of the book’s claims. Also noticed you only mention canned tuna but no other species of fish.

Is consuming canned fish really a serious danger to people’s arterial blood vessels and should we avoid eating these products? Appreciate if you could refer me to research studies that confirm the above and if you aware of any recent studies?

Your thoughts are appreciated and I look forward to your reply.

Sincerely,

Dan

Dr. Cordain’s Response:

Hi Dan,

Good to hear from you and good question. The bottom line is that we should steer clear from oxidized cholesterol derived from any and all foods in our diet (see references 1-9). Clearly it is an impossible task to completely remove oxidized cholesterol from our diets, given that we are no longer hunter gatherers and that we enjoy cooked meats and fish in 21st century contemporary “Paleo Diets.” In references (10-21) you can see how the canning, smoking and preservation process of fish dilutes its nutritional characteristics and increases the production of oxidized cholesterol which is frequently referred to as oxysterols.

So, I recommend to reduce oxidized cholesterol in your diet. Try to eat meat, fish, poultry and eggs that have been slowly cooked under low heat like steaming, slow cooking crock pots, low heat baking, poaching, and other low temperature cooking techniques, including microwave. Try to avoid foods that have been cooked under high temperatures like frying, broiling, high temperature barbecuing, and searing. Additionally, canned meats and fish are almost always cooked at high heats to prevent botulism, which increases their oxidized cholesterol content. Clearly, canned tuna contains many healthful elements (high protein, high omega 3 long chain fatty acids) and should be part of contemporary Paleo Diets, but fresh tuna and fish is a better option if it is available and you can afford it.

Cordially,

Loren Cordain, Ph.D., Professor Emeritus

References

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2. Jacobson MS. Cholesterol oxides in Indian ghee: possible cause of unexplained high risk of atherosclerosis in Indian immigrant populations. Lancet 1987;2:656-58.

3. Kumar, N., and O.P. Singhal, Cholesterol Oxides and Atherosclerosis: A Review, J. Sci. Food Agric. 55:497–510 (1991).

4. Kummerow FA. Interaction between sphingomyelin and oxysterols contributes to atherosclerosis and sudden death. Am J Cardiovasc Dis. 2013;3(1):17-26.

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6. Pohjantahti-Maaroos H, Palomaki A, Kankkunen P, Laitinen R, Husgafvel S, Oksanen K. Circulating oxidized low-density lipoproteins and arterial elasticity: comparison between men with metabolic syndrome and physically active counterparts. Cardiovasc Diabetol 2010 Aug 20; 9: 41.

7. Staprans I, Pan XM, Rapp JH, Feingold KR. Oxidized Cholesterol in the Diet Accelerates the Development of Aortic Atherosclerosis in Cholesterol- Fed Rabbits. Arterioscler Thromb Vasc Biol 1998 Jun; 18: 977-83.

8. Otaegui-Arrazola A, Menéndez-Carreño M, Ansorena D, Astiasarán I. Oxysterols: A world to explore. Food Chem Toxicol. 2010 Dec;48(12):3289-303.

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11. Aubourg S., Medina I. and Pérez-Martin R. 1996. Polyunsaturated fatty acids in tuna phospholipids: distribution in the sn-2 location and changes during cooking. J. Agr. Food Chem. 44, 585-589.

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13. Maruf F.W., Ledward D.A., Neale R.J. and Poulter R.G. 1990. Chemical and nutritional quality of Indonesian dried-salted mackerel. Int. J. Food Sci. Tech. 25, 66-77.

14. Ohshima, T., N. Li, and C. Koizumi, Oxidative Decomposition of Cholesterol in Fish Products, J. Am. Oil Chem. Soc. 70:595–600 (1993).

15. Oshima T. Formation and Content of Cholesterol Oxidation Products in Seafood and Seafood Products. In: Cholesterol and Phytosterol Oxidation Products Analysis, Occurrence, and Biological Effects, (Eds.), Codony R, Savage GP, Dutta PC , Cuardiola F. AOCS Publishing, 2002.

16. Osada, K., T. Kodama, L. Cui, K. Yamada, and M. Sugano, Levels and Formation of Oxidized Cholesterols in Processed Marine Foods, J. Agric. Food. Chem. 41:1893–1898 (1993).

17. Sebedio J.L., Ratnayake W.M.N. Ackman R.G., and Prevost J. 1993. Stability of polyunsaturated n-3 fatty acids during deep fat frying of Atlantic mackerel (Scomber scombrus L.). Food Res. Int. 26, 163-172.

18. Selmi S, Sadok S. Change in lipids quality and fatty acids profile of two small pelagic fish: sardinella aurita and sardina pilchardus during canning process in olive oil and tomato sauce respectively. Bull. Inst. Natn. Scien. Tech. Mer de Salammbô, Vol. 34, 2007.

19. Stołyhwo A., Kołodziejska I. and Sikorski Z.E. 2006. Long chain polyunsaturated fatty acids in smoked Atlantic mackerel and Baltic sprats. Food Chem. 94, 589-595

20. Tarley R.T.C. Visentainer V.J., Matsushita M. and De-Souza N.E. 2004. Proximate composition, cholesterol and fatty acids profile of canned sardines (Sardinella brasiliensis) in soybean oil and tomato sauce. Food Chem. 88, 1-6.

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