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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.

Regards,

Loren Cordain, Ph.D., Professor

REFERENCES:

1. Emanuel HA, Hassel CA, Addis PB, Bergmann SD, Zavoral JH. Plasma cholesterol oxidation products (oxysterols) in human subjects fed a meal rich in oxysterols. Journal of food science 1991; 56: 843-7.
Hubbard RW, Ono Y, Sanchez A. Atherogenic effect of oxidized products of cholesterol. Prog Food Nutr Sci. 1989;13(1):17-44.
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.
5. Otaegui-Arrazola A, Menéndez-Carreño M, Ansorena D, Astiasarán I. Oxysterols: A world to explore. Food Chem Toxicol. 2010 Dec;48(12):3289-303.
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.
9. Lordan S, Mackrill JJ, O’Brien NM. Oxysterols and mechanisms of apoptotic signaling: implications in the pathology of degenerative diseases. J Nutr Biochem. 2009 May;20(5):321-36.
10. Aubourg S., Gallardo J.M. and Medina, I. 1997. Changes in lipids during different sterilizing conditions in canning albacore (Thunnus alalunga) in oil. Int. J. Food Sci. Tech. 32, 427-431.
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.
12. Boran G., Karacam H. and Boran M. 2006. Changes in the quality of fish oils due to storage temperature and time. Food Chem. 98, 693-698.
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.
21. Zunin P, Boggia R, Evangelisti F. Identification and Quantification of Cholesterol Oxidation Products in Canned Tuna. JAOCS. 2001; 78: 1037–1040

To download this study, click on the link below:

Fruit – no adverse effects in Diabetics 2013

Hello there. I am sure you receive a generous amount of email, so I will not waste time with small talk and hope you actually get this email. Long story short: I earned my undergraduate in nutrition from University Nevada Reno in 2003. I left the world of academia with my general understanding of nutrition and felt ready to conquer the world of unhealthy eating ha! I have been doing a bit of research on the paleo diet as well as some others. I have been attempting to try out the paleo diet on myself as a sort of experiment. I had actually stopped eating grains for the most part about 5yrs ago, so it hasn’t been that difficult. What I am ultimately wondering is whether gluconeogenesis via the use of protein aka amino acids and efficient way to rebuild muscle glycogen (well liver glycogen and then to muscles). I just don’t want to be turning my wheels in the gym. It seems like maybe my body will adapt, but I have felt so fatigued at gym. I bonk within the 1st 15 20 min. Maybe I should add more carbs but it is difficult to know which carbohydrates I can eat. I’m not going to lie, I kind of want to just go eat a bowl of dairy filled ice cream and quickly revamp my glycogen. I am sure you are busy, but any help or resources would be greatly appreciated.

Sincerely,

Shilo

Dr. Cordain’s Response:

Hi,

Building glucose and then glycogen via gluconeogenesis is a very inefficient pathway. A better strategy is to obtain your carb stores as Joe Friel and I have outlined in our newly revised 2012, The Paleo Diet for Athletes. This book describes how Paleo foods such as sweet potatoes, yams, bananas, fresh fruit, fruit juices and dried fruit are both Paleo friendly and help to restore muscle glycogen. Additionally, we describe how to top off muscle glycogen before, during and after workouts and competition. Finally, by eliminating grains and refined carbs, you will force your body’s metabolic machinery to rely more upon stored intramuscular triglyceride (IMT) which will increase beta oxidation of IMT, which is a highly labile source of ATP during exercise. Higher muscle concentrations of IMT “spare” muscle glycogen and actually allow you additional time before muscle glycogen stores are depleted causing you to bonk. Many high level endurance athletes have successfully employed “Paleo” to improve performance. I will copy the co-author of my cookbook, Nell Stephenson (also a national caliber triathlete) with your message and she can point you in the direction of how to buy and prepare Paleo friendly and tasty foods.

Good luck,

Loren Cordain, Ph.D., Professor

Dear Prof. Cordain,

I am an orthopaedic surgeon specializing in hip and knee arthroplasty for the treatment of symptomatic arthritis. I am currently coming to the end of a clinical fellowship in Toronto and will be returning to the UK to take up a post as a consultant (attending) in a NHS hospital and I would be grateful if you could give me any information on the use of Paleo diet and evolutionary fitness principles in the treatment of my patients.
 
I first read about the Paleo diet on Art de Vaney’s website, then read Rob Wolff’s ‘The Paleo Solution’ and am now reading through your book ‘The Paleo Diet.’ I already give many of the patients I see dietary advice because very often they are overweight (in fact, more often than not) and have radiographically mild disease but considerable pain. It is an observation many surgeons have made anecdotally that patients who are of normal weight and are active seem to be able to tolerate far more severe disease (in terms of joint destruction observable on X-radiographs) than those who are overweight and sedentary. Many patients can be educated that weight loss may improve their symptoms and are willing to try but conventional diets are difficult to follow, so I advise them to follow Paleo principles because I think it is a much easier diet to follow consistently. However, I wonder if there is anything specific I should be advising that may help their symptoms. Also, exercise is important for joint function, symptom control and general health, but of course it is very difficult to exercise when one has a painful joint. Do you have any advice that I can pass on to them, or do you know of anyone doing clinical work in this field who I could get in contact with?

Many thanks for your time in reading this. Kind regards,

Julian Gilbody MSc, FRCS (Tr & Orth)
Lower limb arthroplasty fellow, Toronto Western Hospital

Dr. Cordain’s Response:

Hi Julian,

Thanks for your support of the Paleo diet. I believe that arthritis, particularly RA (rheumatoid arthritis) is driven by inflammation emanating from the gut. See our group’s paper “Modulation of immune function by dietary lectins in rheumatoid arthritis.” Hence, inflammation of the gut and inflammation of the joints (particularly in RA) appear to be linked by a number of dietary mechanisms we have proposed in this paper. Clearly arthritis can result from purely mechanical factors independent of the gut immune response. Nevertheless, arthritis of mechanical origin is also driven via systemic inflammation, and any environmental factor (pharmaceutical, dietary or otherwise) that reduces inflammation will also tend to reduce symptoms of arthritis (mechanical or otherwise). This therapeutic response in all arthritis patients who adopt the Paleo Diet may help to explain your anecdotal observations why contemporary Paleo diets are therapeutic for your arthritis patients. Keep up the good work, and keep me posted on any case studies you may encounter.

Regards,

Loren

Hi Loren,

Here I go again with the question of the week. I love my job!

What do you think about carnitine found in high levels in red meat ( and in other products- other meats,  sports drinks, etc) and its potential association with the formation of coronary plaque?

I appreciate your response to my questions.  Feel free to answer when you have time.  No rush.

Thanks for your time and expertise. — Pam

Dr. Cordain’s Response:

Hi Pam,

Good to hear from you.  General practitioners such as yourself are responsible to your patients for giving them proper dietary advice, particularly whether or not they should avoid red meat to protect against heart disease.  The most recent commotion about red meat, carnitine and formation of coronary plaque (atherosclerosis) comes from the paper (1) listed below from Stanley Hazen’s group at the Cleveland Clinic.

My colleague, Chris Masterjohn, has done a superb job of critiquing this paper and it’s scientific shortcomings.  See his write-up here:

http://www.westonaprice.org/blogs/cmasterjohn/2013/04/10/does-carnitine-from-red-meat-contribute-to-heart-disease-through-intestinal-bacterial-metabolism-to-tmao/

I am in complete agreement with Chris’s conclusion that,  “The bottom line here is that the popular interpretation of this study as an indictment of red meat makes no sense”.  I have a few additional comments that corroborate Chris’s conclusion.

Although intriguing, Hazen’s model doesn’t fit well with the bigger picture of atherosclerosis etiology, particularly the two large meta analyses by Key’s group (2, 3) showing cardiovascular disease (CVD) mortality in vegans and vegetarians to be no better than the general population.  Vegans/vegetarian data from India actually show high mortality from CVD and an earlier disease progression/mortality (4).

Another point worth considering are the well studied polymorphisms disrupting FMO3 activity in trimethylaminuria patients causing inefficient conversion of TMA to TMAO.  Hence in these patients tissue concentrations of TMAO are severely reduced.  Given this metabolic scenario, one would expect that any of the polymorphisms disrupting the FMO3 gene would be highly protective for CVD (if the Hazen hypothesis is correct).  No CVD epidemiologic evidence supports this evidence.  In fact, a recent study (5) shows that heterozygote genotypes (158Glu/Lys and 308Glu/Gly) increase the risk of stroke six times in hypertensives.

1. Koeth RA, Wang Z, Levison BS, Buffa JA, Org E, Sheehy BT, Britt EB, Fu X, Wu Y, Li L, Smith JD, Didonato JA, Chen J, Li H, Wu GD, Lewis JD, Warrier M, Brown JM, Krauss RM, Tang WH, Bushman FD, Lusis AJ, Hazen SL. Intestinal microbiota metabolism of l-carnitine, a nutrient in red meat, promotes atherosclerosis. Nat Med. 2013 May;19(5):576-85

2. Key TJ, Fraser GE, Thorogood M, Appleby PN, Beral V, Reeves G, Burr ML, Chang-Claude J, Frentzel-Beyme R, Kuzma JW, Mann J, McPherson K. Mortality in vegetarians and nonvegetarians: detailed findings from a collaborative analysis of 5 prospective studies. Am J Clin Nutr. 1999 Sep;70(3 Suppl):516S-524S.

3. Key TJ, Appleby PN, Spencer EA, Travis RC, Roddam AW, Allen NE. Mortality in British vegetarians: results from the European Prospective Investigation into Cancer and Nutrition (EPIC-Oxford).  Am J Clin Nutr. 2009 May;89(5):1613S-1619S

4. Kumar J, Garg G, Sundaramoorthy E, Prasad PV, Karthikeyan G, Ramakrishnan L, Ghosh S, Sengupta S. Vitamin B12 deficiency is associated with coronary artery disease in an Indian population. Clin Chem Lab Med. 2009;47(3):334-8.

5. Türkanoğlu Özçelik A, Can Demirdöğen B, Demirkaya S, Adalı O. Flavin containing monooxygenase 3 genetic polymorphisms Glu158Lys and Glu308Gly and their relation to ischemic stroke. Gene. 2013 Mar 17. pii: S0378-1119(13)00244-8. doi: 10.1016/j.gene.2013.03.010. [Epub ahead of print]

The reason for writing to you is I read an interesting article by you about pre historical diet and grains ((The Evolutionary Discordance of Grains and Legumes in the Human Diet).

Background : I am not an academic. Until 3 years ago I lived in Asia and had a BMI of 24. On returning to the UK I have increased my body weight by about a kilo a month for 20 months. I am now doing something about it by changing my diet. My observation about my previous diet in Asia was that it contained only about 1 cup of rice per day, and no other grains; and no other processed foods with hidden grains or sugars.

It is my view based on common sense and a little reading, that grains are not natural to us. Yet, professional nutritionist friends insist that on the food pyramid we should be eating about 1/3 of our calorie intake through grains. I have contacted several academic nutritionists, and while in their academic articles they accept the pre-historical evidence that we did not eat grains, they all want to insist on the paradigm that we should be eating large amounts of grains.

Firstly, would you agree that grains are not natural in any more than marginal quantities, and have you any idea why nutritionists think we should be eating them in industrial quantities?

Thanks for your time,

Best Regards

Russell

Dr. Cordain’s Response:

Hi Russell,

Good to hear from you, and I wish you success as you adopt the Paleo diet to help  weight.  Indeed our Stone Age ancestors did not consume cereal grains, except infrequently as starvation foods.  As a species, human have no cereal grain requirement for proper nutrition, as we can obtain all required nutrients from meats, fish, seafood, poultry, fresh fruits, vegetables and nuts.  In fact  consumption of cereal grains  actually reduces the overall vitamin and mineral content of the diet because cereal grains on average are less nutrient dense for the 13 vitamins and minerals most lacking in the US diet when compared to fish, seafood, lean meat, fresh vegetables and fruits.  I have pointed this fact out in a paper I published in the American Journal of Clinical Nutrition in 2005 (1).  Further, cereal grains contain a variety of “antinutrients” which actually adversely affect health.  I have described these effects in a paper I wrote called “Cereal Grains: Humanity’s Double Edged Sword” (2).  You can download and read both of these papers at the links I have provided below:

(1)          Cordain L, Eaton SB, Sebastian A, Mann N, Lindeberg S, Watkins BA, O’Keefe JH, Brand-Miller J. Origins and evolution of the western diet: Health implications for the 21st century. Am J Clin Nutr 2005;81:341-54. http://thepaleodiet.com/published-research-about-the-paleo-diet/#2005

(2)          Cordain L, (1999). Cereal grains: humanity’s double edged sword. World Review of Nutrition and Dietetics, 84: 19-73. http://thepaleodiet.com/published-research-about-the-paleo-diet/#1999

Best wishes,

Loren Cordain, Ph.D., Professor