Friday, January 29, 2010

Paleo Diet Q & A - 29 January 2010 - Update on Eggs

Dear Readers,

Today's Paleo Diet Q & A is in response to a reader comment regarding eggs.

Here's the original reader question and Maelán's answer:

Q: Hello,

I heard Dr. Cordain speak twice in optometry meetings. He understood everything about his diet, but both times, I left with the same question in my head: what about eggs?

SO if you could please pass it on to him, I would appreciate it. Because eggs are a source of lutein which is very bioavailable and because lutein is extremely important in ocular health, I would like to know what his opinion is on that.


A: Dear Barbara,

Eggs are part of The Paleo Diet, as humans have consumed eggs during the paleolithic era, although not in a year round basis (because bird eggs appear only seasonally), hence Dr. Cordain has advocated eggs, specially those rich in omega-3 fatty acids, in his three books. One of the egg white functions is to protect the yolk against microbal attack using proteolytic enzymes, besides being storage of nutrients for the growing embryo and transport of nutrients into the growing embryo. Except for ovoalbumen, most of the proteins in egg white have antimicrobial, antibacterial or antiviral activity, some of these proteins are called ovomucoid, ovomucin and lysozyme, among others. These proteins may disrupt the integrity of the gut lining leading to increased intestinal permeability and lysozyme is the most harmful of these proteins in terms of membranolytic activity (breakdown of cell membranes). We recommend that patients suffering from autoimmune diseases to avoid egg white at the beginning as Lysozyme may increase intestinal permeability which is one of the contributing factors in autoimmune diseases. Another issue is egg allergy which is quite common.

On the other hand, eggs are rich in selenium, vitamin A, vitamin D and the B vitamins, and some minerals.

If the person does not suffer from autoimmune disease or egg allergy it shouldn't be a problem to eat eggs.

I hope this helps.

Here is our reader's comment:

January 27, 2010

Eric L said...

Please rewrite the the lysozyme section. Lysozyme is an enzyme that breaks down peptidoglycan. Humans obviously do not have peptidoglycan. It makes up the bacterial cell wall. I think some one got lost on this one.

Lysozyme has no eukaryotic membranolytic activity (btw membranolytic is not even a word.)

Please fix Loren.


Here is Dr. Cordain's response:

Dear Eric,

Many thanks for your response to Maelan’s answer to Barbara’s question about eggs in the Paleo Diet. Let me first address my feelings about egg consumption for the general population and then I will respond to your point, which is technically valid.

In all three of my books, I have advocated egg consumption, particularly eggs that are produced with high omega 3 fatty acid contents. Chicken eggs are generally a nutritious food and are a good source of selenium, vitamin A, vitamin D and the B vitamins, some minerals and lutein as Barbara indicated. Additionally, numerous recent experimental and epidemiological studies (reviewed in references 1, 2) indicate that regular egg consumption (7 per week) does not increase the risk for coronary heart disease (CHD). As I have previously noted, although eggs are one of the most concentrated sources of dietary cholesterol (212 mg per egg), dietary cholesterol has a minimal effect upon blood cholesterol concentrations in most people1, 3. Further, high cholesterol egg diets cause an increase in blood HDL particles (the good particles that remove cholesterol from the body)1 and reduce the highly atherogenic small dense LDL particles while simultaneously increasing the less atherogenic large, “fluffy” LDL particles4, 5.

So, should everybody include eggs in their diet on a daily basis? Not necessarily, particularly if we examine the evolutionary template. Without question our pre-agricultural ancestors would have collected and consumed eggs from birds’ nests whenever possible. However, in the wild, bird eggs only appear seasonally. Hence, pre-agricultural humans could have never consumed two eggs for breakfast every morning of the year similar to some westernized people, but rather only occasionally for a few brief weeks or months.

If we follow up on the clue from the evolutionary template and examine eggs more closely, they maintain certain nutritional shortcomings that may be problematic, particularly for people suffering from autoimmune diseases and allergies. Although eggs are classified as animal food sources and are lumped together with meats in the USDA My Pyramid, eggs are uniquely different from meats in that they represent the reproductive endpoints of adult birds which exist outside their mother’s body in a semi permeable, warm compartment. As such, all eggs are particularly vulnerable to invasion, attack and destruction by microorganisms such as fungi, bacteria and viruses present in their nesting environment.

The innermost yolk of a chicken egg represents the growing embryo which is anchored to the albumen or egg white by structures called chalazae. Outward from the egg white are the inner and outer membranes and then the shell, all of which provide physical barriers to infection from pathogens and microorganisms. The egg white makes up about 58% of the total egg volume and contains about 50% of the total egg protein and is composed of 88.5% water, 10.5% protein and 0.5% carbohydrate.6. The function of the egg white is threefold: 1) storage of nutrients for the growing embryo (yolk), 2) protection of the egg from microbial attack, and 3) transport of nutrients into the growing embryo.

As I have previously mentioned, a chicken egg is the reproductive endpoint for adult birds and survives by living outside its mother’s body in a semi permeable compartment that is essentially immovable. Accordingly, it has no means of protecting itself from microorganisms or predation by physical escape or avoidance. For this reason, the evolutionary strategy eggs have taken to protect themselves from microbial invaders is to select for toxic substances in the egg white; mainly in the form of antimicrobial proteins. Table 1 lists the major proteins in egg whites and their likely functions. Note that except for ovalbumen which comprises 54% of the total protein in egg white, virtually all the other major proteins (~33% of the total) maintain one form or another of antimicrobial activity.

Table 1. Major proteins and their properties found in egg whites (adapted from references 6-10).

Protein% total proteinsFunction(s)
Ovalbumen54Storage protein
Ovotransferrin12Iron binding with antimicrobial activity
Ovomucoid11Protease inhibitor/antimicrobial activity?
Ovomucin3.5Potent antiviral activity
Lysozyme3.4Antibacterial activity
G2 globulin4.0?Antibacterial activity
G3 globulin4.0?Antibacterial activity
Ovoinhibitor1.5Protease inhibitor/antimicrobial activity?
Thiamin binding protein1Thiamin transport
Ovoflavoprotein/Riboflavin binding
0.8Riboflavin transport
Ovomacroglobulin (Ovostatin)0.5Protease inhibitor/antimicrobial activity?
Cystatin0.05Protease inhibitor/antimicrobial activity?
Avidin0.05Antibacterial activity

Egg white allergy in the general population varies between 1.6 – 3.2 % and is the second most common cause of food allergy in children next to milk8. For both adults and children one or more of the following symptoms may occur: hives, atopic dermatitis (red, flaky itchy skin), asthma, runny nose, diarrhea, abdominal pain, rapid swelling of the skin and mucosa, and anaphylactic shock which may be life threatening. The major allergens in egg white are ovomucoid, ovalbumen, ovotransferrin and lysozyme8 (Table 1). So for the vast majority of children and adults (98.4 – 96.8% of the population), egg white allergy is not a problem, and except for anaphylactic shock is not a debilitating or life threatening condition.

The same conclusion may not be true for people suffering from an autoimmune disease (e.g. multiple sclerosis, rheumatoid arthritis, ankylosing spondylitis, lupus erythematosus and others), since egg white consumption may contribute to the origin and progression of these diseases via a process of molecular mimicry that I have previously outlined for dietary lectins found in wheat, peanuts and other grains and legumes 11.

You can see from Table 1 that egg white protein is no simple protein, but rather a conglomeration of multiple proteins which have been designed by natural selection to cause toxic and lethal effects in bacteria and microorganisms reminiscent of food lectins found in grains and legumes11. In order for any food proteins to potentially cause or promote an autoimmune disease, it must:
  1. Survive the human digestive processes intact
  2. Cross the gut barrier intact either alone or with other attached proteins
  3. Interact with the immune system in a manner suspected of causing an autoimmune disease.
A number of egg white proteins fulfill these necessary steps. Most problematic is the egg white protein, lysozyme which is actually an enzyme known as N-acetylhexosaminodase that is also found in many human tissues, including tears 12. The function of lysozyme in both egg whites and in human tears is to act as a potent bacterialcidal agent by binding and dissolving bacterial cell walls12.

Now let me answer Eric’s specific point. Bacterial cell walls are called the murein or peptidoglycan layer which is a gigantic polymer of (N-acetylglucosamine and N-acetylmuyramic acid) polysaccharide strands cross linked through short peptide bridges at the lactyl groups of the muramic acid residues. Lysozyme degrades bacterial cell walls by catalyzing hydrolysis of the beta (-1,4-) linkage between N-acetylglucosamine and N-acetylmuramic acid. As Eric correctly pointed out human cells do not maintain a murein (peptidoglycan) exterior lining. Consequently, dietary lysozyme from egg whites do no increase intestinal permeability by breakdown of intestinal cell membranes as suggested by Maelan, but rather lysozyme increases intestinal permeability by other means that I will explain. It is this increase in intestinal permeability or "leaky gut" that makes egg white consumption problematic for people with egg allergies or autoimmune disease.

Lysozyme is unusual among the major egg white proteins in that it has an alkaline isoelectric point, which means that it can form strong complexes with other egg white proteins including ovomucin, ovalbumen and ovotransferrin6, 12. Hence, even though lysozyme is a benign enzyme produced in our own bodies, when we eat egg white lysozyme, it comes as a compound attached to other egg white proteins or to gut borne bacterial proteins foreign to our bodies.

In the human digestive tract, enzymes called proteases normally break down proteins into their constituent amino acids so that the amino acids can be absorbed across the intestines. Because egg white protein contains high concentrations of protease inhibitors (ovomucoid, ovoinhibitor, ovostatin, cystatin) (Table 1), the human gut proteases (trypsin and chymotrypsin primarily) are less effective in degrading egg white proteins, and lysozyme/egg white protein complexes. Additionally lysozyme is stable in the acidic gut environment12 and therefore arrives intact in the lower gastrointestinal tract.

So what’s wrong if lysozyme/egg white protein/bacterial complexes aren’t dissolved by normal digestive processes? Normally, large multifaceted proteins such as these complexes don’t have a prayer of getting across the intestinal barrier and into the bloodstream where they can interact with the immune system. Once again, lysozyme is an unusual protein because it rapidly breeches the gut barrier and enters human circulation14, due to its unusual chemical properties (a positively charged isoelectric point)15. Because lysozyme maintains a positive charge, it results in an electrostatic attraction to the negatively charged proteoglycans (the glycocalyx) of intestinal epithelial cells which in turn allows lysozyme to be absorbed rapidly into circulation15.

Absorption of pure egg white lysozyme by itself into circulation is likely not problematic because lysozyme is an enzyme that the body naturally produces. Rather it is the complexes that lysozyme forms with other egg white proteins, gut borne bacterial peptides and food peptides that may adversely stimulate the immune system. When these chimeric (monster) molecules breech the gut barrier via their net positive charge and enter circulation, they have the capacity to promote allergy and autoimmune disease.

Just how autoimmune diseases are triggered by gut borne antigens from egg white lysozyme and other common foods (cereal grains, legumes, dairy and certain saponin containing foods) is another good story that our research group has been working on for the past decade. We hope to publish this seminal paper in 2010.


Loren Cordain, Ph.D.

  1. Fernandez ML. Dietary cholesterol provided by eggs and plasma lipoproteins in healthy populations. Curr Opin Clin Nutr Metab Care. 2006 Jan;9(1):8-12.
  2. Kritchevsky SB. A review of scientific research and recommendations regarding eggs. J Am Coll Nutr. 2004 Dec;23(6 Suppl):596S-600S.
  3. Howell WH, McNamara DJ, Tosca MA, Smith BT, Gaines JA. Plasma lipid and lipoprotein responses to dietary fat and cholesterol: a meta-analysis. Am J Clin Nutr. 1997 Jun;65(6):1747-64.
  4. Herron KL, Lofgren IE, Sharman M, Volek JS, Fernandez ML.High intake of cholesterol results in less atherogenic low-density lipoprotein particles in men and women independent of response classification. Metabolism. 2004 Jun;53(6):823-30.
  5. Maki KC, Van Elswyk ME, McCarthy D, Seeley MA, Veith PE, Hess SP, Ingram KA, Halvorson JJ, Calaguas EM, Davidson MH.Lipid responses in mildly hypertriglyceridemic men and women to consumption of docosahexaenoic acid-enriched eggs. Int J Vitam Nutr Res. 2003 Oct;73(5):357-68.
  6. Stevens L. Egg white proteins. Comp Biochem Physiol B 1991;100:1-9.
  7. Szxena I, Tayyab S. Protein proteinases inhibitors from avian egg whites. Cell Mol Life Sci 1997;53:13-23.
  8. Mine Y, Yang M. Recent advances in the understanding of egg allergens: basic, industrial and clinical perspectives. J Agric Food Chem 2008;56:4874-4900.
  9. Wellman-Labadie O, Picman J, Hincke MT. Comparative antibacterial activity of avian egg white protein extracts. Br Poult Sci. 2008 Mar;49(2):125-32.
  10. Takahashi K.G., Nakamura A., Mori K. Inhibitory effects of ovoglobulins on bacillary necrosis in larvae of the pacific oyster, Crassostrea gigas. J Invert Pathol 2000;75:212-217.
  11. Cordain L, Toohey L, Smith MJ, Hickey MS. Modulation of immune function by dietary lectins in rheumatoid arthritis. Br J Nutr. 2000 Mar;83(3):207-17.
  12. Proctor VA, Cunningham FE. The chemistry of lysozyme and its use as a food preservative and a pharmaceutical. Crit Rev Food Sci Nutr 1988;26:359-395.
  13. Holtje JV. Lysozyme substrates. EXS 1996;75:105-10.
  14. Hashida S, Ishikawa E, Nakamichi N, Sekino H. Concentration of egg white lysozyme in the serum of healthy subjects after oral administration. Clin Exp Pharmacol Physiol. 2002 Jan-Feb;29(1-2):79-83.
  15. Nishikawa M, Hasegawa S, Yamashita F, Takakura Y, Hashida M. Electrical charge on protein regulates its absorption from the rat small intestine. Am J Physiol Gastrointest Liver Physiol. 2002 Apr;282(4):G711-9.

Monday, January 25, 2010

Paleo Diet Q & A - 25 January 2010

Dear Readers,

Today's edition of Paleo Diet Q & A on rheumatoid arthritis.

Q: The article, "Modulation of immune function by dietary lectins in rheumatoid arthritis" is of interest to me, but is 10 years old. Can you suggest any more recent scientifically valid articles on the same topic?

Many thanks,

A: Hi Allena,

To my knowledge, there are no reviews or studies addressing the role of a paleolithic diet and it's implications in rheumatoid arthritis, except from that of Dr. Cordain. In his MS (Multiple Sclerosis) DVD Dr. Cordain thoroughly explains the dietary mechanisms of autoimmunity in MS, which are almost the same for all autoimmune diseases--including RA. Those are: increased intestinal permeability, increased passage of luminal antigens into peripheral circulation, molecular mimicry and genetic susceptibility (genes encoding for the HLA system), among other factors.

In recent years, new substances have been discovered which might be responsible for increased intestinal permeability, namely saponins (found in legumes), potatoes, soya, quinoa, amaranth, alfalfa sprouts or tomatoes. If you've seen Dr. Cordain's scientific paper entitled "Modulation of immune function by dietary lectins in rheumatoid arthritis", I am sure you are aware of the role lectins play in autoimmunity.

Adjuvants are used by immunologists in order to boost the immune system and induce immunization. It turns out that certain foods have bioactive compounds that have adjuvant-like activity, this is the case for tomatoes or quillaja (a foaming agent used in beers and soft drinks).

Gliadin is a prolamine found in wheat which has been shown to increase intestinal permeability and hence the risk of suffering an autoimmune disease.

On the other hand, several clinical trials have been conducted with promising results. However, they have used a gluten-free diet or vegan diet instead of a whole paleolithic diet, which we think is the superior diet.

In vegan diets, authors often claim that the effects might be due to the lack of meat, but we think the positive effect relies on the lack of diary proteins and gluten. Meat has historically been seen as the "bad guy" in inflammation, but the data to support that notion is not sufficient to support this view.

Below are some references that could be useful.

Gluten-free vegan diet induces decreased LDL and oxidized LDL levels and raised atheroprotective natural antibodies against phosphorylcholine in patients with rheumatoid arthritis: a randomized study. Elkan AC, Sjöberg B, Kolsrud B, Ringertz B, Hafström I, Frostegård J. Arthritis Res Ther. 2008;10(2):R34. Epub 2008 Mar 18.

A vegan diet free of gluten improves the signs and symptoms of rheumatoid arthritis: the effects on arthritis correlate with a reduction in antibodies to food antigens. Hafström I, Ringertz B, Spångberg A, von Zweigbergk L, Brannemark S, Nylander I, Rönnelid J, Laasonen L, Klareskog L. Rheumatology (Oxford). 2001 Oct;40(10):1175-9.

I hope this helps.

Friday, January 22, 2010

Paleo Diet Q & A - 22 January 2010

Dear Readers,

Today's edition of Paleo Diet Q & A discussing flax seed and flax seed oil consumption.

Q: Dear Dr. Cordain,

I recently visited family over the holidays and my brother is a new advocate of the Paleo Diet. For breakfast he made us "fakecakes" which had about 1-2 tablespoons of flax seed in them that he ground in a coffee grinder. I had few a questions regarding the use of flax seed in the Paleo Diet.

Firstly why are flax seeds ok in the Paleo Diet but other grains (seeds) are not? My understanding for eliminating grains from the diet is the toxins that they contain but flax seed contains large amounts of cyanogenic glycosides producing up to 139 mg/kg of hydrogen cyanide in raw human-grade flax seed. I am sure flax seeds are processed somehow before selling them but I don't know what process that is or what effect it has on the HCN concentration.

So, you know of any studies on the amount of HCN in meals containing ground flax seed and the chronic oral exposure of those amounts on humans? My understanding here is the HCN that isn't hydrolysed to formic acid in the stomach and doesn't bind to hemoglobin is converted to thiocyanate which hinders thyroid function.

Thank you for your time and any information you can supply.


A: Hi Tim,

We think your thoughts are on the right track.

When Dr. Cordain wrote The Paleo Diet, the advice to consume flax seed oil was an attempt to balance the increased omega-6/omega-3 fatty acid ratio due to the exaggerated intake of omega-6 vegetable oils, especially linoleic acid, in the typical western diet.

Nevertheless, animal foods (fish, muscle meat and organs from wild animals) are good sources of w3 fatty acids. As so, when people eat these foods regularly along with vegetables and nuts, and avoid vegetable oils (especially oils rich in Linoleic Acid – Omega 6), they get a balanced intake of omega 3, omega 6, monounsaturated and saturated fatty acids. In this context, there is no need for flax seeds to provide Omega 3 fatty acids and balance the Omega 3/Omega 6 ratio.

Here are some facts that support the notion that animal foods, vegetables and nuts provide the necessary Omega 6 and Omega 3 fatty acids in the right proportion:

  1. Hunter-gatherers do not eat ALA from seeds or vegetable oils.

  2. Nuts, green leafy vegetables and animal foods contain ALA.

  3. The conversion of ALA to EPA+DHA is limited, due to low delta-6 and delta-5 activity, although ALA is highly oxidized (twice as much as LA) (Freemantle et al.). Therefore, this means that at some pointing history we included preformed sources of EPA and DHA and still need to do so. Animal foods (especially brain from wild ruminants and fish) are very good sources of these fatty acids.

  4. The essentiality of LA & ALA in human metabolism has been questioned (Le et al.), as we relied almost on LCPUFA (Arachidonic Acid, EPA and DHA) during the Paleolithic era (see Dr. Cordain’s papers on that here and here). Moreover, there is already some evidence showing that human metabolism could re-convert AA and DHA into LA and ALA respectively, hence AA and DHA would be the true essential fatty acids.

  5. The possible toxicity from seeds and vegetable oils (HCN, saponins, lectins).

  6. They are not used by current HG societies, and these populations show no signs of western disease, so this means that flax seeds are not necessary.

  7. The well known positive health effects of fish oil supplementation (among other factors to improve omega-6/omega-3 ratio) in contrasts with some possible adverse effects of flax seed oil (like the epidemiological evidence that points towards increased risk of prostate cancer with flax oil consumption – see paper by Brouwer et al).
The bottom line from an evolutionary perspective is that flax seeds and/or flax seed oil would not have been consumed by pre-agricultural humans. However, having said that, hunter gatherers always would have preferentially sought high oil plant foods as per optimal foraging theory. But, most high fat plant foods contain high MUFA (with the exception of coconut and palm).

In addition, we will continue to explore the broader impact to health of modern vegetable oils, including flax.

Hope this helps.

Wednesday, January 20, 2010

Paleo Diet Q & A - 20 January 2010

Dear Readers,

Today's edition of Paleo Diet Q & A on salt.

Q: Hi there! I bought my book and started my diet a couple of days ago. My husband told me that sea salt as opposed to table salt is okay to use. - Is this correct? Can I use sea salt while on the Paleo Diet? Please let me know. Thanks! Sincerely, Lani

A: Hi Lani,

Salt was not part of the hunter-gatherers' diet, hence, our metabolism can not handle salt very well, specially in a context of high fructose intake and high blood pressure sufferers. Nevertheless, a small amount of salt probably won't be an issue for you. But use it in moderation.

On the other hand, conditions such as insomnia or exercise induced asthma may improve on a low-salt diet.


Dr. Cordain's Latest Paper

Dear Readers,

Dr. Cordain, et al, have published a new paper entitled "Diet-dependent acid load, Paleolithic nutrition, and evolutionary health promotion,"available for download on our web site.

Tuesday, January 19, 2010

Paleo Diet Q & A - 19 January 2010

Dear Readers,

Today's Paleo Diet Q & A on MS.

Q: As a MS patient for 5 years, I have been following the Swank diet (or the Judy Graham's approach to the Swank diet) since the beginning. Meaning that I am in a low fat diet with a high intake of Omega 6 (2-3 gr. of Primrose Oil daily) and Omega 3 (1 gr. of Fish Oil daily). As a Spanish person, I also take lots of Extra Virgin Olive Oil (as salad dressing or cooking oil). I did not take milk or dairy in all these years. I swim half hour every week. The result is that my lesions are inactive, I have had just one MS episode in the last three years but, on the other side, I suffer of great fatigue and I get very tired after walking short distances. And I hardly can stand stressing situations.

Your conference in Youtube made me buy your book and I have started following the Paleo diet. My question is if I am doing the right thing taking that amount of vegetable oils. I understood (in the video part 3) that lots of Omega 6 and few Omega 3 could be inflammatory and is not recommended for autoinmune diseases. But in my case I think that is helping to feel better (I have felt worse when I have stopped taking it for several weeks).

Do you have any recommendation for me?


A: Hi Andrés,

Yes, you are right. We think that a high intake of vegetable oils (specially omega-6 linoleic acid), probably, is not the best approach for inflammatory conditions. However, Primrose Oil is a good source of GLA, a precursor of anti-inflammatory substances namely PGE1.

Perhaps 2-3 grams of Primrose Oil is too much and 1 gram of Fish Oil is not enough. For an inflammatory disease we recommend to take 2 grams EPA+DHA/day.

Regarding your fatigue symptoms, you don't necessarily have to stick to a low-fat diet when treating MS, and muscles should be well adapted to burn fat. One of the causes of chronic fatigue is fatty acid deficiency, so we encourage you to eat good fat sources such as oily fish, olive oil, coconut oil (a good source of Medium Chain Triglycerides for your muscles and keeps harmful bacteria under control) and nuts (macadamia and walnuts).

A paleolithic-type diet will provide you the adequate amount and balance between the different fatty acids.

On the other side, you may be aware of the importance of gut permeability on MS patients, so the paleo diet will help you treating this part of the story.

I hope this is helpful,

Best wishes,

Thursday, January 14, 2010

The Dietary Cure for Acne Eating Guide

Dear Readers,

The Dietary Cure for Acne Eating Guide is now available for purchase as a stand-alone product (PDF) for $29.95. The Dietary Cure for Acne Eating Guide contains 63 easy to follow recipes, meal ideas, shopping, food prep, and dining tips, recommended foods, and much more. Please visit our web store for more information.

Wednesday, January 13, 2010

Autographed Copies of The Paleo Diet for Athletes Now Available

Dear Readers,

Dr. Cordain's hard cover edition of The Paleo Diet for Athletes (available exclusively from our web store) may now be purchased as an autographed edition signed by Dr. Cordain! Please visit our web store to obtain your copy.

Tuesday, January 12, 2010

Paleo Diet Q & A - 12 January 2010

Dear Readers,

Here's today's edition of Paleo Diet Q & A.

Q: Have you had any results in curbing the symptoms of Crohn's Disease with the Paleo Diet. As I am a sufferer, I would love to know.

Thank you,

A: Dear Shannon,

Indeed, inflammatory bowel disease (Ulcerative Colitis & Crohn's Disease) patients usually do very well with The Paleo Diet, as nutrients are one of the main environmental triggers of this condition.

Crohn's disease is an autoimmune disease where the immune system mounts an attack against its own tissues, in this case the cells lining the intestine.

For an autoimmune disease to occur we need a genetic predisposition and an environmental trigger. The genetic predisposition depends on genes coding for the HLA system. On the other side, one of the environmental triggers may be nutrition, besides infections, geography (vitamin D deficiency), physical trauma or vaccination.

One of the key points in this process is increased intestinal permeability. This means that the gut barrier allows increased passage of bacterial or food proteins (antigens) into peripheral circulation, skipping a process known as oral tolerance. Once antigens get in contact with the immune system located in the gut associated lymphoid tissue, they may elicit a T-cell mediated immune response against those antigens.

If the molecular structure of the dietary or bacterial antigens is similar to that of the HLA system (part of the immune system presenting cells machinery), chances are that a cross reaction between foreign antigens and self antigens (produced by T-cells) occur. This is termed molecular mimicry and leads to self injury by the adaptive immune system.

Hence, decreasing intestinal permeability is one of the treatment targets. There are several nutrients known to increase intestinal permeability that you may want to avoid, at least until symptoms subside. Here you have a list of them and the noxious substance in parentheses:

  • Cereal grains (lectins and gliadin)
  • Legumes, including soya and peanuts (lectins and saponins)
  • Tomato (tomato lectin and alpha-tomatin)
  • Potato (lectins and saponins)
  • Chili (capsaicin)
  • Quillaja (foaming substance)
  • Quinoa (saponins)
  • Egg white (lisozyme)
  • Alfalfa sprouts (saponins)
  • Amaranth (saponins)
  • Alcohol
Moreover, some nutrients exert an adjuvant-like activity (they stimulate the immune system), which is something you don't want to if you are suffering from an autoimmune disease. Nutrients containing adjuvants:
  • Quillaja extract, found in root beer
  • Tomato alpha-tomatine
Dairy products and vegetable oils also have deleterious effects upon your immune system.

I hope this helps.

Q: Good Morning,

I've recently started on the Paleo Diet. I've read through your site and others to make sure I'm going about it the right way. What a revelation! It's fantastic in its simplicity.

My concern is that when I was about 18 I developed an allergy to fish. I have no idea how this happened. I ate two or three nights a week growing up at home. Curiously, this allergy seems to only apply to scaled fish, as I can still eat shellfish. I am 23 years old.

When I eat fish I get terrible heartburn/indigestion, and the last time I tried it, about two years ago, my face started swelling and itching. I saw an allergist who told me to avoid fish because of the potential of a very serious reaction.

What do you recommend I do? It seems like eating seafood is a big part of the Paleo Diet. I'm happy to eat shellfish, but aside from shrimp it's often prohibitively expensive. Obviously I'm not going to eat fish unless I can "outgrow" the allergy. I was once allergic to eggs, but I've gotten over that now.


A: Dear Harrison,

From an evolutionary standpoint fish allergy is nonsense, as it has been part of the human nutrition since, probably, 2-2.5 million years ago.

Allergy is an exaggerated reaction of the body's immune system against foreign proteins, where the body's common mucosal immune system (located in the gut, nose, eyes, lungs, etc) increases the production of cell (eosinophils) and/or antibody (IgE) mediated immune response. This leads to histamine release throughout the CMIS and signs and symptoms related to allergy, such as inflammation, redness, itching, sneezing, or anaphylactic shock if acute vasodilatation occurs.

But how or why do fish proteins trigger an allergy reaction?
  1. An early exposure to food proteins, lets say before 3-6 months of life, when the gut associated lymphoid tissue is immature increases the risk of allergy later in life.

  2. An increased intestinal permeability allows food proteins to pass through the gut barrier and skip M-cells mediated oral tolerance, inducing hyper-sensitivity to those proteins.

  3. In the last years a wide body of scientific papers has shed light to what is known as the "hygiene hypothesis". A correlative association has been shown between increased use of antibiotics and vaccines and inflammatory conditions such as multiple sclerosis, type 1 diabetes and allergy, during the last 50 years. Human beings are less exposed to microorganisms, such as intestinal bacteria, than they used to. This leads to lack of immune regulation mediated, in part, by gut and environmental microorganisms.
How can the Paleo Diet help you?

Of course we can not address point 1 but we can do something regarding points 2 and 3.

The Paleo Diet is free of some food known to increase intestinal permeability such as cereal grains, legumes (soya and peanuts), alcohol, tomato, potato, quinoa, amaranth, egg white, alfalfa sprouts and root beer (quillaja extract). By eliminating those foods and eating a diet based on lean meats, shellfish, vegetables, fruits and nuts your intestinal permeability will decrease and your immune system will be less challenged by those food proteins (fish) and perhaps we can restore immune tolerance to a normal food as fish. For more information about intestinal permeability and nutrition we recommend you to check out our published newsletters section.

Regarding point 3 we suggest you to take a probiotic supplement (6-9 billion/day) for several months.

Other supplements that can help you improve intestinal permeability:
  • Pre-biotic 2-4grs/day
  • L-glutamine 0.2grs/kg body weight one month, then 0.1gr/kg
  • Zinc 25mg/day
  • Vitamin D 2000 IU
  • Omega-3 fatty acids EPA+DHA=2.6grs/day
I hope this is useful.

Thursday, January 7, 2010

Paleo Diet Q & A - 7 January 2010

Dear Readers,

Here is today's edition of Paleo Diet Q & A.

Q: Hello,

I heard Dr. Cordain speak twice in optometry meetings. He understood everything about his diet, but both times, I left with the same question in my head: what about eggs?

SO if you could please pass it on to him, I would appreciate it. Because eggs are a source of lutein which is very bioavailable and because lutein is extremely important in ocular health, I would like to know what his opinion is on that.


A: Dear Barbara,

Eggs are part of The Paleo Diet, as humans have consumed eggs during the paleolithic era, although not in a year round basis (because bird eggs appear only seasonally), hence Dr. Cordain has advocated eggs, specially those rich in omega-3 fatty acids, in his three books. One of the egg white functions is to protect the yolk against microbal attack using proteolytic enzymes, besides being storage of nutrients for the growing embryo and transport of nutrients into the growing embryo. Except for ovoalbumen, most of the proteins in egg white have antimicrobial, antibacterial or antiviral activity, some of these proteins are called ovomucoid, ovomucin and lysozyme, among others. These proteins may disrupt the integrity of the gut lining leading to increased intestinal permeability and lysozyme is the most harmful of these proteins in terms of membranolytic activity (breakdown of cell membranes). We recommend that patients suffering from autoimmune diseases to avoid egg white at the beginning as Lysozyme may increase intestinal permeability which is one of the contributing factors in autoimmune diseases. Another issue is egg allergy which is quite common.

On the other hand, eggs are rich in selenium, vitamin A, vitamin D and the B vitamins, and some minerals.

If the person does not suffer from autoimmune disease or egg allergy it shouldn't be a problem to eat eggs.

I hope this helps.

Q: Is The Paleo Diet an option for someone with Type 1 Diabetes being treated with Coumadin?

A: Yes, The Paleo Diet will work good for you. Indeed, in our previous newsletter (v_5#36 2009) we reported how The Paleo Diet influences the different pathways involved in the disorder.

There are several known factors of the western diet contributing to triggering Type 1 Diabetes:
  • Proteins found in cow's milk: Beta-Lactoglobulin, Bovine Insulin, Bovine Serum Albumin and Beta Casomorphin-7.
  • Proteins found in cereal grains: Gluten is a well known trigger of an autoimmune disease associated with T1D called Celiac Disease. A gluten-free diet led to improvement in insulin response during a glucose tolerance test.
  • Another factor at the root of almost all autoimmune diseases is increased intestinal permeability. Certain substances found in the typical western diet (lectins, saponins, gliadin, alcohol and capsaicin) may increase intestinal permeability.
  • Other factors such as diet's fatty acid composition or vitamin D deficiency contribute to the pathogenesis of T1D.
The Paleo Diet is free of all those harmful substances, being based on lean meats, seafood, fruits, vegetables and nuts.

Finally, a low glycemic load diet will help you to better control your blood glucose levels in the long run.

On the other hand, if you are taking Coumadin it shouldn't be a problem with The Paleo Diet unless you are consuming high amount of omega-3 or vitamin E supplements.

I hope this helps.

Wednesday, January 6, 2010

Paleo Diet Q & A - 6 January 2010

Dear Readers,

Here's today's edition of Paleo Diet Q & A. Thank you again for your questions, comments, and your interest in the Paleo Diet.

Q: Recent tests have revealed that I have Polycystic Ovary Syndrome, which is something I have long suspected. I am 34, and have suffered with acne since the age of 11, and I barely ovulate. We would love to have children, and I am thoroughly sick of waiting to 'grow out' of acne. I have recently seen a fantastic doctor about my fertility issues, who has recommended the Paleo Diet. I am really keen to keep to the diet, see the benefits, and have bought the book, but have a few questions about particular foods.

Can smoked salmon (or any other smoked fish/meat) be included in this diet?

Also, you mention that pickled/preserved foods are a bad idea, and I really enjoy sun dried tomatoes, roast peppers in oil, and olives. Could I include any of these in the diet, if they are they are well rinsed of all excess oil etc?

How about decaf coffee?

I struggle a bit to find foods to eat for breakfast and lunch (evening meal no problem), and am REALLY missing cereals such as porridge (I don't know if you have any suggestions for substitutes)?

A: Polycystic Ovary Syndrome (PCOS) and Acne are both conditions associated to insulin resistance. Anovulation and infertility, are also added problems to PCOS and insulin resistance as insulin affects overall hormonal balance and particularly sex hormones through Sex Hormone Binding Globulin (SHBG) down-regulation. Insulin decreases SHBG production in the liver and at the same time increases male sex hormones availability (androgens), leading to an increased ratio of androgens/estrogens.

As thoroughly described by Dr. Cordain in his book The Dietary Cure for Acne and several scientific papers available in the published research section of our web site, diet is linked to the above mentioned hormonal imbalance.

Regarding your questions:
  • Smoked salmon could be part of your diet but don't use it as a staple food as it contains certain toxic substances.
  • Pickled tomatoes and/or peppers should be cut down as they may increase intestinal permeability. Intestinal hyperpermeability allows increased passage of intestinal food or bacterial antigens into peripheral circulation. Specially, certain bacterial cell wall antigens namely Lipopolysaccharide (LPS), are potent immune stimulators leading to chronic low grade inflammation which is at the root of many diseases and particularly insulin resistance (IR). IR is something you may want to correct in order to regulate your hormones.
  • Olives are part of The Paleo Diet.
  • Coffee shouldn't be a problem for you.
  • In the nutritional tools section of our web site you can find tons of recipes for your meals.
  • Cereal grains are all sources of harmful substances called lectins. You should avoid lectin containing foods as they contribute to low-grade chronic inflammation. Almond flour could be an option to substitute cereal grains.
I hope this helps.

Q: Are baked sweet potatoes allowed? I thought not!

A: Yes, sweet potatoes are allowed, specially in the post-workout period if you are an athlete. Sweet potatoes are different from potatoes in that they do not contain several harmful substances such as saponins and lectins, which may increase your intestinal permeability (if consumed regularly) and rev-up your immune system. But on the other hand, sweet potatoes are high glycemic index foods and should be restricted if you are struggling with overweight, at least until your body weight normalizes.

I hope this helps.

Q: I wanted to ask you why it is that you discourage saturated fats in the paleo diet? From what I have read their are healthy saturated fats from coconuts that are used for around 17% of the Kitavan diet. Also, what about tubers such as sweet potato and yam, do you think that consuming these in moderate portions (small enough to keep a low glycemic load) could be detrimental?

A: Here you have replies to similar questions posted before:

Regarding saturated fats:

Saturated fatty acids intake and the risk of developing cardiovascular disease (CVD) is a topic with a lot of controversy. In recent years a wide body of research has suggested that increased consumption of certain saturated fatty acids (Lauric acid, myristic acid and palmitic acid)
down-regulate LDL receptor and thereby increase LDL plasma levels, and this has been associated to increased risk of CVD. On the other hand, stearic acid (a 18 carbon saturated fatty acid) has been shown to decrease LDL plasma levels. However, this view is too simplistic as they are several other factors contributing to CVD, such as smoking, exercise, trans-fatty acids, increased omega-6/omega-3 ratio, free-radicals, nutrient deficiency, homocysteine, alcohol intake and low-grade chronic inflammation among others.

Moreover, some studies have suggested that there’s not enough scientific data to support the view that increased total or LDL cholesterol is an independent risk factor for CVD, but rather oxidized LDL. Plaque production is mediated by oxidized LDL but not LDL. Oxidized LDL can produce shedding of the inner layer of the artery namely glycocalix. Then oxidized LDL infiltrates in the intima of the artery. Oxidized LDL is eaten by macrophagues, a process known as phagocytosis, and therefore macrophagues are transformed into foam cells which produce the fibrous cap.

Once the fibrous cap has been produced we need to break it down in order to produce an ischemic event. Lectins and low-grade chronic inflammation are involved in the activation of matrix metalloproteinases which break down the fibrous cap.

In summary, high total cholesterol or LDL levels do not increase CVD risk but rather oxidized LDL. To produce oxidized LDL we need the factors mentioned above. Hence, consumption of saturated fatty acids is not an issue if we control several other factors such as those mentioned before.

Dr. Cordain wrote a book chapter where he shows that saturated fat consumption in ancient hunter-gatherer populations were usually above recommended 10% (American Heart Association) of energy from saturated fats yet non atherogenic.

The bottom line is that we do not recommend cutting down saturated fatty acid intake but rather decrease high-glycemic load foods, vegetable oils, refined sugars, grains, legumes and dairy.

Regarding sweet potatoes and The Paleo Diet:

Yes, early hominids probably ate large amounts of sweet potatoes as some hunter-gatherers do in Kitava-Papua New Guinea. Our ancestors didn't have an universal diet because it depended on climate, season, latitude, culture, etc. This means that the amount of carbohydrates they ate varied substantially. So, for instance in Kitava they eat a lot of carbohydrates and still have no obesity, so it seems as if some bioactive substances of neolithic foods are responsible for hormonal disruption.

However, there's a big different between potatoes and sweet potatoes. Potatoes are a good source of some known harmful substances namely saponins and lectins. They have the ability to increase intestinal permeability and hence increase the risk of autoimmune diseases (in genetically predisposed individuals), and induce low-grade chronic inflammation which is at the root of many chronic degenerative diseases. On the other hand, there's some preliminary data suggesting that some bioactive substances, such as lectins and saponins, contained in potatoes, grains, legumes, etc. can bind hormonal receptors impairing their function. This could be the case of leptin receptor leading to leptin resistance and some metabolic disorders.

I hope this helps.

Tuesday, January 5, 2010

More on Coconut Oil

Dear Readers,

The question of using coconut oil has been raised in previous blog questions and emails. Presented in this post are comments from Dr. Cordain and Paleo Diet team member Pedro Bastos on the use of coconut oil as part of the Paleo Diet.

Q: Is there a good reason to avoid using coconut oil?

A: This is not a clear cut issue as it once was. Coconut oil contains high concentrations of a saturated fatty acid called lauric acid (12:0) as well as other medium chain fatty acids (8:0, 10:0) which may have therapeutic effects. Coconut oil also contains other saturated fatty acids which elevate blood cholesterol. However, elevations in blood cholesterol without chronic low level inflammation may not necessarily increase the risk for CHD. My feeling is that coconut oil in the backdrop of a modern day Paleo Diet probably has few negative health implications.

Loren Cordain, Ph.D., Professor

A: I agree with Loren. Lauric acid has a more favorable effect on total HDL cholesterol than any other fatty acid, either saturated or unsaturated.

And, coconut oil appears to decrease Lipoprotein(a). Moreover, in primitive populations living close to water and where coconuts are available, these were probably consumed. I can think of at least 2 populations that eat a high amount of coconuts and exhibit a low incidence of CHD disease (Kitava and Tokelau), although we can't exclude the possibility that they could be even healthier if they didn't eat coconuts.

Hence, I believe coconut oil in the context of a 90% Paleo Diet (+ sun exposure + adequate sleep + regular exercise) may be neutral or even positive.

I hope this helps.

Sunday, January 3, 2010

Paleo Diet Article in The Washington Post

Dear Readers,

The Paleo Diet, Dr. Cordain, and Chris LaLanne are cited in a January 2, 2010 article in The Washington Post entitled "Paleolithic diet is so easy, cavemen actually did it."