Saturday, December 5, 2009

Paleo Diet Q & A - 5 December 2009

Dear Readers,

Thank you for continuing to post your comments and questions. Here's today's edition of Paleo Diet Q & A.



Q: Dear Dr. Cordain,

I am a PhD student, and I am starting to study how our instinct should lead us to enjoy the foods best suited for us, as it seems it does for any known animal.

Some of the first things I have found are your works. The point I am trying to get at is that we should have in us this instinct. So just one question. Do you know about, or have you read works of any authors that have made research on this point?

Best regards and many thanks.
Alfis.

A: Hi Alfis,

Off the top of my head, I can't remember any specific papers on the topic. However, there are thousands of papers on taste & humans have a proclivity towards sweet, salty and fatty. Under stone age conditions in which these tastes were associated with foods that limited and difficult to procure these tastes led us to foods that conferred survival value. In the modern world in which we have completely dissociated energy expenditure from energy intake we can eat anything that our taste guides us to in virtually unlimited quantity. Hence our hard wired tastes which once conferred survival value in a Stone Age environment now represent a liability in our western world of food abundance.

Best wishes,
Loren Cordain, Ph.D., Professor



Q: I understand the Paleo Diet to be primarily a removal from the diet of all grains, dairy products, and man-processed sugars. But what about potatoes, corn, and legumes (all of which cannot be digested raw and are high in starch), and natural sugars like maple syrup and honey? Do they fit into the Paleo Diet?

I bought and read the book years ago, but cannot remember the exact teachings on these particular foods, and cannot find clear teachings about them on the website. Perhaps I am looking in the wrong place?

A: Potatoes are not part of The Paleo Diet because they contain some harmful substances, namely saponins (solanine and chaconine) which can't be degraded by digestion or cooking. They can contribute to an increase in intestinal permeability which is associated to many chronic diseases.

Regarding legumes, they are also sources of saponins as well as lectins. Lectins are also toxic substances for the intestinal barrier, and they can adversely stimulate the immune system.

Corn is a cereal grain which is also a source of lectins (see Dr. Cordain paper entitled "Cereal grains: Humanity's double edged sword" in our published research section).

Sugars were part of our Hunter-gatherers ancestors' diet but not year round. So, use them in moderation.

6 comments:

  1. Dear Dr Cordain,
    I have a couple of questions...
    1) How to do you see/rate seeds in the diets of athletes - specifically quinoa and buckwheat. Can they or do they lead to potential leaky gut/gut permeability, and/or lead to issues with iron/zinc malabsorption.
    I am not aware they are high-phytate foods? Are they sources of lectins?

    2)What sort of cow's milk alternatives do you recommend?

    I would very much appreciate your comments with regard to these queries. Thank you for all your great newsletters and your book "Paleo Diet for Athletes" is excellent - in case anyone wants to know!!

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  2. Celiacs consume "alternative" grains such as quinoa, buckwheat, tapioca, sorghum. Are these allowable on the Paleo Diet?

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  3. Posted on behalf of Dr. Cordain:

    Lucy-Ann,

    Quinoa, when it is not milled (e.g. whole quinoa) is a concentrated source of antinutrients known as saponins which increase intestinal permeability and lead to a "leaky gut" which in turn may promote low level chronic, systemic inflammation. This inflammation is caused by leakage of substances (lipopolysaccharide or LPS) derived from resident gram negative gut bacteria that pass through the gut barrier and enter circulation. Chronic low level inflammation in the bloodstream is suspected to fundamentally underlie cardiovascular disease, cancer and autoimmune disease. Quinoa saponins also exhibit immunological adjuvant properties in animal models (meaning that they may increase the immune response when bound to other proteins (antigens) foreign to the body.

    Refined or milled Quinoa (which generally is the product available commercially) contains significantly lower concentrations of saponins. Quinoa also contains phytates which inhibit the absorption of its endogenous divalent ions such as iron and zinc. The anti-nutritional effects of Buckwheat have been poorly studied in humans. We advocate that Paleo Athletes obtain their carbs from non-grain sources such as yams, sweet potatoes, fruits, fresh fruit juices, dried fruit and vegetables. Less active people should be careful with fruit juices and dried fruits and consume these foods sparingly.

    Loren Cordain, Ph.D., Professor

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  4. Dear Dr. Cordain,

    I suffer from allergies to mould, pollen and numerous other allergies that I haven't properly been tested for. After moving from California to the UK, I have also developed asthma. I am 31 and otherwise a reasonably active person (yoga and Pilates teacher), and my ill health has really bothered me. I found out about the Paleo diet during my research on low-sugar diets and also the anti-candida diet, which in its purest form seems to be almost identical to the Paleo diet. I have been eating this way for two weeks now, and I do see improvement in symptoms. However, I have noticed that when I wake up in the morning, my "allergy shiners" (dark circles around my eyes) are darker than before and I look a bit scary! I have lost quite a bit of weight... is it perhaps a side-effect of ketosis?

    Also, can you please tell me if I have a chance of completely clearing my allergies with time?
    Thank you very much for your help!

    Barbara

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  6. Posted on behalf of Maelán:

    Hi Barbara,

    Allergies are associated to increased intestinal permeability, which means that your intestinal barrier is Leaky and allows increased passage of intestinal bacteria or food proteins into peripheral circulation. This fact sensitizes the immune system against several proteins (antigens) because immune tolerance is broken. Increased intestinal permeability allows paracellular transport of antigens which means that antigens pass between two cells and not through M-cells. M-cells are responsible for what is known as immune tolerance. If then any other part of your immune system, for example, mucous associated lymphoid tissue (nose), is challenged with proteins similar (molecular mimicry) to those of bacterial or food antigens your immune system will develop hyper reactivity producing normally a high amount of antibodies (IgE). This is due to the fact that the immune system, usually, is sensitized in the gut, although symptoms appear in the nose or eyes. IgE stimulate some immune cells, namely Mast cells, to release histamine. Histamine is one of the substances responsible for many of the allergy symptoms.

    In summary, you should avoid all the foods known to increase intestinal permeability such as gluten containing grains, legumes, potatoes, tomatoes, alcohol, quinoa, amaranth and chili peppers.

    Furthermore, allergy is characterized by an increased (and unbalanced) Th2 immune response which could be regulated using probiotics (6-9 billion/d), omega-3 fatty acids (2-3 grams/d), vitamin D (2000IU/D) and Zinc (25mg/d).

    We can not guarantee 100% certainty of success because there are a lot of factors (hygiene hypothesis, metabolic programming or stress) known to increase the risk of allergy besides nutrition.

    I hope this helps.
    Maelán

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