Monday, December 9, 2013

Phytates: Antinutrient or Essential Nutrient?

'Paleo' and low-carbohydrate diet advocates often claim that humans can't obtain adequate nutrition from a plant-based diet because plants have too many so-called antinutrients. For example, in their paper "Man The Fat Hunter" Ben-Dor et al write:

"Nuts, or other high-quality foods of decent size appear only seasonally above ground in the savanna and such is the case in the Levant, too. But not only are they seasonal, they also require laborious collection and most of them contain phytic acid [phytate] that inhibits the absorption of contained minerals. These foods also contain anti-nutrients and toxins such as trypsin, amylase and protease inhibitors as well as tannins, oxalate, and alkaloids the elimination of which can only be achieved (sometimes only partially) by pre-consumption processing like drying, soaking, sprouting, pounding, roasting, baking, boiling and fermentation."

As I wrote in Powered By Plants: Natural Selection & Human Nutrition:

"Whether any of the so-called anti-nutrients has any harmful effects in humans depends entirely on whether humans have specific metabolic adaptations to these compounds."
In Powered By Plants: Natural Selection & Human Nutrition I have a section devoted to one of these "antinutrients": tannins. Animals naturally adapted to plant-based diets produce salivary proline-rich proteins, which neutralize the anti-nutritive effects of tannins. About 70% of the proteins in human saliva consist of proline-rich proteins. Moreover, humans seem to have a 'taste' or preference for tannin-rich foods such as tea, herbs, spices, chocolate, beer, and smoked foods. Thus we have clear evidence that humans have an evolved adaptation to tannins, which negates their claimed antinutrient effects.

Read more....

Monday, December 2, 2013

Powered By Plants: Natural Selection & Human Nutrition: NOW AVAILABLE

Well, more than two years of work has come to fruition.  I have finished Powered By Plants: Natural Selection & Human Nutrition.

In this extensively documented, 321 page e-book, including a 20 page bibliography and more than 800 footnotes, many including live links to the references, I present evidence supporting the hypothesis that a plant-based diet powered human evolution.

The first two chapters discuss the logical errors involved in taking fossil evidence, evolutionary hypotheses, and the fact that many humans do eat animals as "evidence" that humans are adapted to an animal-based diet and must eat animal flesh to maintain health and fitness.  The second chapter discusses in-depth the scientific meanings of the terms "carnivore" and "omnivore," and the logical errors involved in taking carnivorous behavior as evidence of biological adaptation to flesh-eating. This chapter also covers the nature of nutritional adaptations, using various illustrative examples from plant and animal evolution. 

Each of the Chapters 3 through 18 discusses one or more specific aspect of modern human anatomy, physiology, or metabolism in light of Darwinian evolutionary theory.  I present evidence that humans have heritable features primarily and specifically adapted to a plant-based diet, and lack the heritable features we would expect to find as evidence of specific adaptation to consumption of animal flesh.  I thoroughly discuss evidence casting doubt on claims that the features of our teeth and intestines provide evidence that our proposed stone-age African ancestors could not have obtained adequate energy, protein, or essential fatty acid intake from wild plants without eating flesh- and fat- rich diets.

The key Darwinian measure of adaptation consists of reproductive fitness.  Carnivores produce more viable offspring when eating animal-based diets than when eating plant-based diets; and animals biologically adapted to plant-based diets have their greatest fertility when eating plant-based diets.  Hence, the hypothesis that an animal-based diet powered human evolution predicts that animal-based diets promote and plant-based diets harm human fertility; while the hypothesis that a plant-based diet powered human evolution predicts that plant-based diets promote and animal-based diets impair human fertility.  Chapter 11 discusses extensively the evidence of the effect of animal- and plant- based diets on human reproductive function and Darwinian fitness.

The power of a hypothesis lies in its ability to explain or accommodate facts.  Given two hypotheses, the one that can explain and accommodate the largest body of evidence is the superior theory.  The two competing hypotheses concerning the role of foods in human evolution–the animal-based/hunting hypothesis, and the plant-based/cooking hypothesis–differ markedly in explanatory power.

For example, the hunting hypothesis predicts that humans will display a high tolerance for dietary cholesterol and saturated fats and that these promote health, not disease.  Hence,  this hypothesis can not easily explain the large body of independently accumulated evidence indicating that dietary cholesterol and saturated fats promote cardiovascular disease in humans, nor the evidence that the disease rarely occurs in populations eating plant-based diets.  Consequently, adherents get involved in trying to deny that body of evidence, or using ad hoc adjunct hypotheses (e.g. discussed in Chapter 18 of the book) to shore up the hunting hypothesis.  When a theory entails denying evidence independently accumulated in other relevant fields or requires ad hoc hypotheses for support, this usually means the theory is in crisis, as explained by Thomas Kuhn in The Structure of Scientific Revolutions.  In contrast, the plant-based/cooking hypothesis predicts that humans do not have a high tolerance for dietary cholesterol and saturated fats, despite having the ability to hunt, so it easily accommodates the independently produced evidence supporting the lipid hypothesis.

I have in this book presented what I believe to constitute convincing evidence that humans have a physiology primarily adapted by natural selection to a whole foods plant-based diet.  This evidence also indicates that humans lack many heritable adaptations to acquisition and chronic consumption of animal flesh that we find in other carnivores and omnivores.  Further, I also cite evidence that we have heritable characteristics specifically maladapted to flesh consumption.  I have spent more than two years gathering and organizing the literature in this one document.  I invite you to read the literature and judge for yourself.

Click on the cover to purchase your copy.  Table of contents below the image.

Table of Contents

Chapter 1:  The Stone Age Red Herring
Chapter 2:  The Nature of Nutritional Adaptations
Chapter 3:  Our Sensory Approach to Food
Chapter 4:  Locomotion
Chapter 5:  Manual endowments
Chapter 6:  Face, mouth, and throat
Chapter 7:  Stomach
Chapter 8:  Small Intestine
Chapter 9:  Cecum & Appendix
Chapter 10:  Colon
Chapter 11: Reproductive System
Chapter 12:  Protein Requirements
Chapter 13:  Vitamin C, Uricase, and Uric Acid
Chapter 14:  Complexion Preference
Chapter 15:  Carotenoids, Retinol, Cobalamin
Chapter 16:  Carbohydrate and Lipid Metabolism
Chapter 17:  Brain Size and Metabolism
Chapter 18:  Meat-Adaptive Genes?
Chapter 19:  Science, or Science Fiction?

Appendix A: Essential Nutrients
Appendix B: A Whole Foods Plant-Based Diet
Appendix C: Stone Age Hominins
Appendix D: Chimpanzees