Today's edition of Paleo Diet Q & A focuses on legumes and protein.
Q: I was just forwarded your peanut manifesto & found it interesting. I love the concept of the whole foods Paleo diet, but no legumes? That goes against everything I have been taught about nutrition. I'm not veg, but eat a primarily whole foods/low animal protein diet. Exactly how would you get enough protein without meat & without legumes? Nuts alone cannot provide the protein & consumed in high quantities would add too much fat to one's diet. Between the protein, fiber & other nutrients, beans are so good for you. I understand the points about peanuts & don't disagree with that...too many peanut allergies out there not to mention the aflotoxin issue.
A: Dear Amy,
From an evolutionary perspective, legumes are not part of the human's diet. Prior to the agricultural revolution regular consumption of legumes was not common.
As cereal grains, legumes are great sources of antinutrients, such as lectins, saponins or protease inhibitors which wreak havoc the hormonal and immune systems.
Increased intestinal permeability has been associated to many chronic low-grade inflammatory and autoimmune diseases, such as celiac disease, rheumatoid arthritis, type 1 diabetes or multiple sclerosis. Lectins and saponins are able to increase intestinal permeability hence increasing the risk of inflammatory diseases, see Dr. Cordain's scientific paper:
Regarding the protein content, the paleo diet (based on high protein foods such as lean meats, fish or even eggs) has been shown to be superior in protein than a grain-legume rich diet, as you could see in Dr. Cordain's paper (http://www.thepaleodiet.com/articles/Origins%20Paper%20Final.pdf).
Regarding fiber, vegetables have the higher fiber content among all nutrients.
I hope this helps.
Q: The research in The China Study would disagree with Dr. Cordain's findings re: animal protein being superior to plant protein. Although lean meats, like natural grass-fed beef, are certainly superior to corn fed factory farmed beef. Also to consider, Paleolithic people were not living into their 70s, 80s, 90s, 100s like people are today. I imagine that the average life span back then was about 30-35? Eating to make it to 30 is different than eating to live until you are 80+. Are you aware of the "blue spots" in the world, i.e. areas of the world with high numbers of centenarians? Those people eat a diet relatively low or devoid of animal products (the latter being in Loma Linda, California where there is a huge population of vegan Seventh Day Adventists) and probably consume a fair amount of legumes. The other areas are located in Central America, Japan & Sardinia.
I do find it disturbing that there appears to be an increasing number of cases of Celiac's disease and gluten-sensitivity in the world. I have developed an allergy to casein & am senstive to gluten (like many other people) so I understand the merit in limiting or eliminating the sources of these proteins. Has Dr Cordain done any research on sprouting legumes & grains & the positive effects it has on digestion? There is interesting research in that area.
I have immense respect for the evolutionary process, the scientists who study it and how it relates to our health today. Eating a diet of unprocessed, local food is undoubtedly a superior way to nourish oneself. There are many merits to the Paleo diet, but there appears to be some flaws as well. Has Dr Cordain's findings been replicated by any other scientists?
Thank you for your response.
A: Dear Amy,
Thanks for your comments, I’ll try to clarify your doubts.
a) Regarding animal/plant protein: please see the discussion between the china study author, Colin Campbell, and Dr. Cordain. Since I believe you are a sophisticated reader you can draw your own conclusions from that report.
b) The popular belief that paleolithic populations did not lived into their 70s, 80s, 90s or 100s is a misconception, as you can read in Dr. Cordain’s scientific papers:
Maybe you are not aware of the Kitava Study conducted by our colleague Staffan Lindeberg. This is a pre-agricultural population in Kitava-Papua New Guinea. It turns out that 6% of the population is between 60-95 years old, yet they are virtually free of western disease, such as type 2 diabetes, obesity, cardiac infarction or stroke. This number is not bigger due to the high childhood mortality due to infections and birth problems, among others. I will quote a piece from one of the above studies: “Actually, adoption of farming and settled living appears to have adversely affected longevity, precipitating a substantial decline to about 20 years. Life expectancy in London in 1667 was 18, and it seems likely that from the Neolithic Revolution until the late 18th century, expectation of life in “civilized” nations seldom or never exceeded 25 years. Thereafter, technological breakthroughs in food production, manufacturing, transportation, trade communications, and energy generation gave rise to what economists call modern economic growth”. (Eaton et al. Preventive Medicine, 2002).
The bottom line is that life expectancy does not rely much on nutrition.
c) Regarding your comments on “the blue spots” in the world I’ll copy a previous reply to a similar question by our colleague Pedro Bastos:
Concerning longevity, it is well known that caloric restriction is the only proven method to extend live in various animals including primates (1-6) .
One of the reasons why people from Okinawa live more is because they eat less calories than people from mainland Japan (7). Well, 2 of the 3 intervention studies with a Pre-agriculture Diet show that one people are advised to eat the food groups available in Paleolithic era they eat less calories, although they haven't been advised to do that (8, 9).
Some of the mechanisms by which caloric restriction is beneficial for longevity are:
1 - Decrease in visceral fat - a Paleo type Diet has been shown to do that (8)
2 - Decrease IGF-1/IGFBP-3 - by eating a low glycemic load diet and avoiding high fructose foods you will normalize insulin metabolism and your IGF-1/IGBP-3 may decrease (see this paper to understand what I'm saying: http://www.thepaleodiet.com/articles/Hyperinsulinemic%20Diseases%20Final.pdf )
3 - Decreased glycation - by eating a low glycemic load diet, ingesting plenty of carnosine (10), reducing fructose (11), avoiding galactose (12) and avoiding cooking at high temperatures, you will be decreasing glycation.
4 - Decreased glycolysis (14) - a low Glycemic load diet will achieve this.
5 - Elevated insulin sensitivity - the studies with the Paleo Diet have shown that it increases insulin sensitivity (8, 15)
Moreover, if you read some of Dr. Cordain's papers available here, you will see how the modern diet is responsible for most of the so called diseases of civilization, who normally aflict people in the post reproductive years.
Finally, it should be mentioned that many of the so called healthy diets that are being promoted for longevity and optimal health actually contain one or more characteristics of a pre-agriculture diet (The Paleo Diet), so presumably we would expect them to lead to better health outcomes. For instance, the diet of Crete (which was then used to formulate the Mediterrean diet) has a low w6/w3 ratio, contains plenty of fruits and vegetables and most of the fat is monounsaturated (16), just like pre-agricultures diets.
And the traditional diet of Okinawas is composed by fruit, vegetables, sweet potatoes (not potatoes, which contain harmful glykoalcaloids), rice (it doesn't include gluten grains, which are worse than rice), fish, fermented soy (it is better than normal soy, although it still has harmful saponins and lectins and as so, we don't advise it) and some pork, so it has a lower w6/w3 ratio and no trans fatty acids, which are very important characteristics of pre-agricultures diets.
Furthermore, it's not just diet: we also have to look at their lifestyle which is closer to the one followed by our H/G ancestors: sun exposure, exercise, good sleep patterns and acute stress (exercise) as opposed to chronic stress (the one we experience).
d) Regarding sprouting legumes: Yes, sprouted grains and beans are a much healthier option. When we 'sprout grains' we are allowing the seed to germinate and a shoot will emerge from the seed. This is the part that is cut off and eaten. Therefore, the seed itself is not actually consumed (as is the case with whole grains and wheat flours here the seed proteins and starches are milled and eaten). Since lectins are packaged long with the seed to protect against predation, once the seed sprouts, the lectin concentration diminishes within a couple days. At least by the end of a week, the sprouts should have no residual lectins. Gliadin and glutenin are the dominate proteins located in the endosperm of the seed. The starchy endosperm is located alongside the embryo (germ) within the seed and provides nutrients the embryo needs as it is sprouting and growing.
Therefore, there should be no gliadin or glutenin proteins in the sprout, but rather primarily non-digestible cellulous (dietary fiber). One can consume sprouted grains and beans without fear of anti- nutrients, however keep in mind that these are still nutritionally poor in terms of micronutrients. Leafy greens and other vegetables contribute high fiber AND a higher concentration of nutrients-grains are still 'nutritional lightweights'. I would like to add an amendment to my earlier statement: We can consume GRAIN sprouts without fear of anti-nutrients however, legume sprouts still appear to contain considerable concentrations of saponins--the secondary compounds responsible for increasing gut permeability. Alfalfa sprouts (which are actually in the pea family) have an especially high concentration.
e) Regarding your question: has Dr. Cordain’s findings been replicated by any other scientist? The answer is yes, as you can check in these scientific papers. In one of them (Lindeberg et al. Diabetologia, 2007) it was shown that a paleolithic diet was superior to a Mediterranean diet where they consume legumes and grains.
Beneficial effects of a Paleolithic diet on cardiovascular risk factors in type 2 diabetes: a randomized cross-over pilot study.
Jönsson T, Granfeldt Y, Ahrén B, Branell UC, Pålsson G, Hansson A, Söderström M, Lindeberg S. Cardiovasc Diabetol. 2009 Jul 16;8:35.
Metabolic and physiologic improvements from consuming a paleolithic, hunter-gatherer type diet.
Frassetto LA, Schloetter M, Mietus-Synder M, Morris RC Jr, Sebastian A.
Eur J Clin Nutr. 2009 Aug;63(8):947-55. Epub 2009 Feb 11.
Effects of a short-term intervention with a paleolithic diet in healthy volunteers.
Osterdahl M, Kocturk T, Koochek A, Wändell PE.
Eur J Clin Nutr. 2008 May;62(5):682-5. Epub 2007 May 16.15.
A Paleolithic diet confers higher insulin sensitivity, lower C-reactive protein and lower blood pressure than a cereal-based diet in domestic pigs.
Jönsson T, Ahrén B, Pacini G, Sundler F, Wierup N, Steen S, Sjöberg T, Ugander M, Frostegård J, Göransson L, Lindeberg S.
Nutr Metab (Lond). 2006 Nov 2;3:39.
A Palaeolithic diet improves glucose tolerance more than a Mediterranean-like diet in individuals with ischaemic heart disease.
Lindeberg S, Jönsson T, Granfeldt Y, Borgstrand E, Soffman J, Sjöström K, Ahrén B.
Diabetologia. 2007 Sep;50(9):1795-807. Epub 2007 Jun 22.