Origins and evolution of the Western diet
By Maelán Fontes Villalba
The Western diet has been formed based on two historical events: the agricultural revolution (which occurred hace10.000 years) and the Industrial Revolution (happened 200 years ago). These events are the cause of the arrival of cereals, dairy products, refined vegetable oils and refined sugars to the diet that men came consuming for two and a half million years.
To understand the importance of these events in the Western diet, remember that the human being is the result of millions of years of evolution and adaptation to an environment that existed for 2.6 million years in East Africa. This period is known as the Paleolithic or Stone Age.
Evolutionary medicine, developed by scientist Charles Darwin in the nineteenth century, postulated that all living things adapt to the environment in which they live and only pass on their genes to the next generation individuals who are best suited. This is what is known as natural selection. For years it has been known that our genes change very slowly (Tishkoff, 2002), and in the last 10,000 years, the change has been even slower by the development of technology. Which leads us to tailor the environment to us and not us the environment (Pritchard, 2010).
Foods recently introduced (a evolutionary scale) are cereals, dairy, refined vegetable oils and refined sugars (Cordain, 2005) .These foods account for over 70% of the energy normally consumed a Western citizen. However, these foods were not part of the human diet during their evolution (Cardan, 2005).
It is recalled that these new foods were introduced in an abrupt and too quickly; hence our ancient genome has not been adapted successfully to change, and this discordance between our genes and the environment (in this case food) has led to the so-called diseases of civilization: cardiovascular disease (coronary heart disease or heart attacks brain), metabolic syndrome (obesity, diabetes or hypertension), acne, polycystic ovaries, myopia or certain autoimmune diseases (Cordain, 2005 syndrome Cordain, 2003).
Proof of the relationship between these diseases and the introduction of cereals in our diet 10,000 years ago is that these diseases are rare or nonexistent in preagriculturales populations (which have not adopted agriculture and live as hunter-gatherers). This is the case of the inhabitants of the island of Kitava in Papua New Guinea (Lindeberg, 2003), among others. On this island of 2,300 inhabitants, studied by Dr. StaffanLindeberg, in 1990 had no heart attacks, strokes, hypertension, obesity, diabetes or acne, although 6% of the population had an age understood between 60 and 96 years (Lindeberg, 1993, Lindeberg, 2003).
These data are consistent with findings in other traditional hunter-gatherer populations (Bribiescas, 2003; Lindeberg, 2009). In addition, an important porO'Dea article published in 1984 showed that Australian aborigines with type 2 diabetes was achieved great improvement in their condition to return temporarily, for 7 weeks, his previous lifestyle, ie, hunting and gathering ( O'Dea 1984).
Thus, evolutionary medicine gives us a paradigm to understand what is the optimal food for humans: the one with which we evolved in East Africa during 2,6millones years. Therefore, adjusting our ancient genes to an environment (physical exercise, sun, food, etc.) like we had during our evolution can be an effective treatment for so-called diseases of civilization virtually nonexistent in populations of hunter gatherers.
The last food introduced by the agricultural revolution, which make up 70% of the Western diet are cereals, dairy, refined vegetable oils and refined sugars (Cordain, 2005) and the fact that we have not adapted correctly this change is what has led to the so-called diseases of civilization.
Proof of the relationship between these new diseases and the introduction of cereals in our diet 10,000 years ago is that these diseases are rare or nonexistent in preagriculturales populations (which have not adopted agriculture and live as hunter-gatherers).
And it is that, there are several components paleolithic diet that have been altered by the Western diet, among which are the following:
- Introduction of anti nutrients: Anti nutrients are substances found in significant amounts in cereals and produce different adverse effects on human metabolism. One of them is the gluten, found in wheat, rye and barley, which produces an inflammatory reaction of the innate immune system in people with or without genetic predisposition to celiac disease, as has been demonstrated by a Spanish research team (Bernardo , 2007). That means that wheat consumption may produce chronic inflammation in virtually all individuals, and inflammation is related to a host of diseases (Hotamisligil, 2006). Moreover, the prevalence of celiac disease (immune system reaction to gluten) is greater than previously thought, even in populations that carry several thousand years consuming (Catassi, 2005). Another anti nutrient present in cereals are lectins that can block the receptors of certain hormones, causing metabolic problems such as loss of sensation of satiety (Jönsson, 2005). The same authors have recently published data from a study of intervention where it is demonstrated that the consumption of cereals produces an altered sense of satiety, which leads to eating more, causing problems with body weight or control blood sugar (Jönsson, 2010).
- Increased consumption of omega-6 to the detriment of omega-3: The use of refined vegetable oils (sunflower, millet or soybean) produces a high intake of omega-6 oils, which together with the decrease in consumption of sources grasasomega -3 animals (is part of the omega-3 that have beneficial effects on health, such as EPA and DHA), resulting in a balance of fat that causes inflammation. During the Palaeolithic, it is estimated that the proportion of consumption grasasomega-6: omega-3 was 2: 1, and is currently 15: 1 (Simopoulos, 2008). This results in a state of inflammation which as mentioned earlier is partly responsible for many degenerative diseases.
- Increased glycemic load diet: The glycemic load of the diet is the ability of a food to raise blood glucose feed ration. The increased consumption of carbohydrates derived from cereals produces an increase in the glycemic load that is not produced by eating carbohydrates derived from fruits and vegetables (Brand-Miller, 2009; Cordain, 2003). Increasing glycemic load diet produces elevated insulin levels, which has been associated with a number of diseases such as acne, polycystic ovary syndrome, myopia, certain cancers, obesity or diabetes (Cordain, 2003). However, the glycemic load of the diet itself does not explain the negative effects of consumption of carbohydrates derived from cereals, as on the island of Kitava (and in other populations of hunter-gatherers such as the Tanzania-data Hadzade unpublished by Kuipers, RS) energy derived from carbohydrates represents 69% of the energy consumed, much higher than current recommendations, and yet there are striking absence of diseases of civilization (Lindeberg, 1997). This demystifies the popular belief that the paleolithic diets are low in carbohydrates as few diets in the world come to 69% of energy consumption from carbohydrates. A paleolithic diet does not contain carbohydrates derived from cereals, which does not mean it is a diet low in carbohydrates. The explanation that despite consuming a diet rich in carbohydrates and high glycemic load, residents of Kitava not have associated with a high glycemic load conditions, is that carbohydrates consumed in Kitava derived from fruits, vegetables and tubers, which do not contain anti-nutrients such as cereals (Jönsson, 2010).
There are other changes in the very power of man, introduced by the agricultural and industrial revolution, as an alteration in the composition of macronutrients, decreased micronutrient intake, increased metabolic acidosis, increased sodium / potassium ratio and decrease in fiber (Cordain, 2005).
Note that there are no conclusive studies of intervention where it is shown that the consumption of cereals improves the risk of cardiovascular disease as evidenced by the largest intervention study done so far (Howard, 2006). This randomized controlled trial (Women's Health Initiative Dietary Modification Trial) studied nearly 49,000 post-menopausal women. Patients were divided into two groups at random (randomly) and one group was advised to eat a diet low in fat (<20% of energy), more than 6 servings of grains a day, more than 5 fruits a day and rich in vegetables. The other group were given general recommendations. After 8 years not only they not produced positive changes in women who were recommended to consume the diet study, but in women who at baseline had been diagnosed with cardiovascular disease, increased risk of worsening of the disease. In another intervention study 2033 patients who had had myocardial infarction were divided into groups where they recommended different diets. In patients who were recommended a diet rich in fiber from whole grains there were fewer survivors after 2 years (higher mortality from a second heart attack), but the group that consumed more fish had a higher percentage of survival (lower second heart attack mortality) (Burr, 1989). On the other hand, our research team has shown in two intervention studies comparing a diet without grains or dairy diet with cereal and milk, after three months an improvement was observed in glucose control and related markers with cardiovascular disease (Lindeberg, 2007: Jönsson, 2009). A third intervention study is underway in Sweden which will have results soon.
Evolutionary medicine gives us a paradigm to understand what is the optimal food for humans: the one with which we evolved in eastern Africa for 2.6 million years. Therefore, adjusting our ancient genes to an environment (physical exercise, sun, food, etc.) like we had during our evolution can be an effective treatment for so-called diseases of civilization virtually nonexistent in populations of hunter gatherers.
Maelán Fontes Villalba
Center for Health Research in Primary Care
School of Medicine. University of Lund. Sweden.
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