Wednesday, June 17, 2009

The Pleistocene diet: a recipe for diet and health?

To answer this question I shall begin by giving a brief description of what is meant by “The Pleistocene diet”. Starting with what or should I say when the Pleistocene epoch was in our history. The Pleistocene era is the earlier of the two epochs of the Quaternary Period, from about 2 million to 10,000 years ago, and was characterized by the formation of widespread glaciers in the Northern Hemisphere and by the appearance of humans. Mammals included both small forms, such as sabre-toothed tigers and horses and giant ones, such as mammoths and mastodons. Almost all the giant mammals, including woolly mammoths, giant wolves, giant ground sloths, and massive wombats disappeared at the end of the Pleistocene and the start of the Holocene.

The Pleistocene diet refers to a diet which is similar to that of the humans at that time, without the invention of food preparation or cooking. It’s principle is that it is based around foods that were readily available, “on the table” during our evolution, foods such as meat, fish, fowl, and the roots and fruits of many plants. As whilst food stuffs such as grains, beans and potatoes are useful sources of energy, our bodies are not adapted to utilising them as a food source, as when eaten raw they contain many harmful toxins, so rendering them inedible to our evolutionary predecessors. The Pleistocene diet considers such foods as Neolithic, as they were only edible after the discovery of cooking around 10,000 years ago, and so their ingestion is not “coded for in our genes”. (1)

Furthermore the diet is based around the idea that as much as individual genetics and experiences influence your nutritional requirements, millions of years of evolution have also shaped our need for specific nutrients, that our dietary changes have outpaced our ability to genetically adapt to them, as according to Eaton. "That the vast majority of our genes are ancient in origin means that nearly all of our biochemistry and physiology are fine-tuned to conditions of life that existed before 10,000 years ago.(2)

In comparison with our evolutionary diet, today’s diet fails to meet sufficient biochemical and molecular requirements of homosapians. Evolutionary diet consisted of prehistoric man consuming around 50% of his calories from carbohydrate, mainly from fruits and roots, in comparison with modern times, where carbohydrate often takes the form of sugar and sweeteners and is devoid of essential vitamins and fatty acids.(2) The best available estimates suggest that our ancestors obtained about 35% of their dietary energy from fats, 35% from carbohydrates and 30% from protein. Saturated fats contributed approximately 7.5% total energy and harmful trans-fatty acids contributed negligible amounts. Polyunsaturated fat intake was high, with substantial cholesterol consumption. Carbohydrate came from uncultivated fruits and vegetables, approximately 50% energy intake as compared with the present level of 16% energy intake for Americans. High fruit and vegetable intake and minimal grain and dairy consumption made ancestral diets base-yielding, unlike today's acid-producing pattern. . Fibre consumption was high and Vitamin, mineral and (probably) phytochemical intake was typically 1.5 to eight times that of today except for that of Na, generally <1000 mg/d, i.e. much less than that of K.(3)

The Pleistocene diet was said to include a much greater quantity and variety of fruits and vegetables as well as dietary fibre, which aids in gastro-intestinal health. This is often a criticism of modern western diets, where the quantity and variation of fruit and vegetable intake is much lower and often insufficient to the Palaeolithic, with fewer than 9% having the recommended 5 portions per day.

A further advantage of this diet can be seen to be that it contained a greater ratio of omega 3 to omega 6 fatty acids and also a greater proportion of potassium with a lower Sodium intake, due to a diet containing less processed food.(2)

The diet advocates a high intake of:
Meat, chicken and fish
Eggs
Fruit
Vegetables (especially root vegetables, but definitely not including potatoes or sweet potatoes)
Nuts, e.g. walnuts, brazil nuts, macadamia, almond. Do not eat peanuts (a bean) or cashews (a family of their own)
Berries- strawberries, blueberries, raspberries etc.

Whilst in taking none of the following
· Grains- including bread,
· Pasta,
· Noodles
· Beans- including string beans, kidney beans, lentils
· Potatoes
· Dairy products

· Sugar

· Salt


So is this type of diet nutritionally viable and compliant with today’s recommended food intake?
The food standards agency advocates a healthy diet to be one that contains a variety of foods including plenty of fruit and vegetables, plenty of starchy foods such as wholegrain bread, pasta and rice, some protein-rich foods such as meat, fish, eggs and lentils and some dairy foods. It should also be low in fat (especially saturated fat), salt and sugar.(4)

The Pleistocene diet does seem to meet much of this criteria, in the form of the high content of fruits, vegetables, and protein, and low salt, and sugar intake. However it does not include any dairy products which are said to be included in modern diets.
So in theory the diet does seem suitably nutritious and provides the basis fo a healthy lifestyle, but what effects does it have when applied to modern people?
One study which looked at the short-term effects of such a diet on 14 healthy volunteers concluded that the intervention in their diets did produce some positive effects, namely reduced fat composition, and increased intake of anti-oxidants. The total energy intake was also reduced by 36% and with this the subjects mean weight decreased by 2.3kg, and their BMI also decreased by 0.8, indicating positive effects. However there was also a reduced calcium intake which in the long term could be problematic and further studies must be carried out before a definitive conclusion can be made. (5)

However one problem concerning the Pleistocene diet is its effect on teeth, and that whilst our DNA had not evolved or changed massively from that era to now, the structure and make up of our jaws and teeth have changed sufficiently to make consuming a diet of purely raw, and so often tough food, slightly problematic and predispose the partaker to dental problems.(6)

Over time humans have evolved to have smaller teeth, with a thinner enamel coating which renders them less effective at cutting into, tearing and peeling tougher food stuffs. The reason for these changes in dental structure are rooted not in the lifestyle of the earlier humans in the sense of changing from gathering to producing food, but from changes in food-preparation techniques and non-dietary usage of the teeth.(7)

Casting that issue aside for the meantime though, there are other benefits that this diet provides which can be particularly pertinent for those which long standing chronic condition. Studies have shown that a “prehistoric” diet can be of benefit to those suffering with diabetes and ischaemic heart disease by improving glucose tolerance.(8)

Another positive aspect of this diet is the reduced salt intake, as salt has been linked in with high blood pressure and so a reduction in salt intake from following such a diet can reduce the risk of hypertension.(9)

As well as this foods such as snacks, particularly in the form of energy drinks, which are much more energy dense then many of the foods available to Pleistocene man have been accredited to one of the main nutritional problems of modern society in obesity, as people are often partaking in such snacks and not compensating for them in their diet, leading to a positive energy balance, and from evolution, humans have a weak defence against over eating and so problems arise. So as a Palaeolithic diet is without these items it could also be seen as a healthier option.(10). Also humans are evolutionarily adapted to a calorie restricted diet and to survive in a state of under nutrition, 10, where due to conditions such as increased soil aridity and cooler temperatures, led to a reduction in potential food sources for Pleistocene man, and so they would change or alter the way in which they metabolised their food.(11)

It can be seen that a Pleistocene diet does vary from most modern diets, both in its type and proportion of food consumed. Results have shown that this can be a healthier lifestyle, as the high intake of animal-based foods would not have necessarily elicited unfavourable blood lipid levels due to the hypolipidemic effects of high dietary protein (19-35% energy) and the relatively low level of dietary carbohydrate (22-40% energy). Although fat intake (28-58% energy) would have been similar to or higher than that found in Western diets, it is the case that the proportion and types of fat ingested would have been vastly different with relatively high levels of MUFA and PUFA and a lower omega-6/omega-3 fatty acid ratio, would have served to inhibit the development of CVD.(12)

Therefore the Pleistocene diet, in my opinion is useful as a reference point and provides important clues to the "baseline" levels and ratios of nutrients needed for health. Suggesting that we should be eating a lot of plant foods and modest amounts of game meat, with a reduced intake of salt and refined foods, and despite it perhaps not being practical to follow it to its entirety, with an increased understanding of it, it can aid us to lead healthier and more natural lives, optimizing our surroundings and what our bodies are able to deal with.


(1) Dr. Ben Balzer. Introduction to the Paleolithic diet. Available at: http://www.earth360.com/diet_paleodiet_balzer.html.
(2) Challem J. Paleolithic Nutrition:Your Future Is In Your Dietary Past.
(3) Eaton SB. The ancestral human diet: what was it and should it be a paradigm for contemporary nutrition? Proc Nutr Soc. 2006;1(65):1-6.
(4) Healthy diet. Available at: http://www.eatwell.gov.uk/healthydiet/.
(5) Osterdahl M, Kocturk T, Koochek A, Wändell PE. Effects of a short-term intervention with a paleolithic diet in healthy volunteers. Eur J Clin Nutr. 2008;62(5):682-5.
(6) Lucas PW, Constantino PJ, Wood BA. Inferences regarding the diet of extinct hominins: structural and functional trends in dental and mandibular morphology within the hominin clade. J Anat. 2008;4(212):486-500.
(7) Eshed V, Gopher A, Hershkovitz I. Tooth wear and dental pathology at the advent of agriculture: new evidence from the Levant. Am J Phys Anthropol 2006;2(130):145-59.
(8) Lindeberg S, Jönsson T, Granfeldt Y, Borgstrand E, Soffman J, Sjöström K, Ahrén B. A Palaeolithic diet improves glucose tolerance more than a Mediterranean-like diet in individuals with ischaemic heart disease. Diabetologia 2007;9(50):1795-807.
(9) Elliott P, Walker LL, Little MP, Blair-West JR, Shade RE, Lee DR, et al. Change in salt intake affects blood pressure of chimpanzees: implications for human populations. Circulation 2007;14(116):1563-8.
(10) de Graaf C. Effects of snacks on energy intake: an evolutionary perspective. Appetite 2006;1(47):18-23.
(11) Amen-Ra N. Humans are evolutionarily adapted to caloric restriction resulting from ecologically dictated dietary deprivation imposed during the Plio-Pleistocene period. Med Hypotheses. 2006;5(66):978-84.
(12) Cordain L, Eaton SB, Miller JB, Mann N, Hill K. The paradoxical nature of hunter-gatherer diets: meat-based, yet non-atherogenic. Eur J Clin Nutr. 2002;56:42-52.

5 comments:

  1. A good summary, although the arguments could be a bit more structured. Note Linnean taxonomy requires genus and species to be separate words, both in italics and with a capital letter for genus: Homo sapiens. It is good that you note the mismatch between the Pleistocene diet and our modern dentition, but it is also worth considering how much time it would take to comply with a Pleistocene diet compared to a modern one. I would guess it might double the time devoted just to eating!

    ReplyDelete
  2. when a person make a diet is important to have a good control with a doctor and is necessary to combine it with frequent exercises but if you want to encrease your sexual health is necessary to
    buy viagra, so your problem will solve too fast and you will notice a great and powerful sexual health.

    ReplyDelete
  3. It’s principle is that it is based around foods that were readily available, “on the table” during our evolution, foods such as meat, fish, fowl, and the roots and fruits of many plants. Mike Hunt

    ReplyDelete