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.

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