Impact of Food Habits (note 2)
Several sources of information suggest that human beings evolved on a diet that had a ratio of omega-6 to omega-3 fatty acids (FA) of about 1:1. Whereas today, Western diets have a ratio of 10:1 to 20– 25:1, indicating that Western diets are deficient in omega-3 (FA) compared with the diet on which humans evolved and their genetic patterns were established(Simopoulos, 2011). Omega-6 and omega-3 (FA) are not interconvertible in the human body and are important components of practically all cell membranes. Studies with nonhuman primates and human newborns indicate that Docosahexaenoic acid (DHA) is essential for the normal functional development of the brain and retina, particularly in premature infants. DHA accounts for 40% of the membrane phospholipids FA in the brain. Both Eicosapentaenoic acid (EPA) and DHA have an effect on membrane receptor function and even neurotransmitter generation and metabolism (Simopoulos, 2011).
Modern day human eating behaviour consists mostly of high-energy-density diets and often unstructured feeding patterns depending upon seasonality and food availability as well. Mostly, this consuming pattern is common among developed and developing nations (Ulijasek, 2002). Human populations living in developing and developed settings today, mostly rely on meats with lipid compositions that when eaten in excess promote cardiovascular disease. As humans become more sedentary and eat more high fat foods, we can expect to see increases in heart disease, osteoporosis and other diseases of Modern civilization (Larsen, 2003). This fundamental dietary change resulted in a narrowing of diet, reduced consumption of meat and increased focus on domesticated grains. The study of archaeological human remains from around the world reveals that the agricultural development and dependency made human get less active in hunting, foraging and gathering causing a drastic change in the diet consumption pattern resulting in a declined health.
This also included, increased evidence of morbidity like poorer dental health, increased occlusal abnormalities, increased iron deficiency anemia, increased infection and bone loss (Larsen, 2003). Human body consists of trillions of microorganisms, but the evolutionary history of this microbes is obscured by lacking knowledge about the microbiome. Ochman et al., (2014) in his study regarding the rapid change in human microbiome during human evolution, sequenced gut communities of hundreds of chimpanzees, bonobos, and gorillas through a phylogenetic approach and made it clear that the present-day human microbiomes have diverged from those of ancestral populations. Relative to the microbiomes of wild apes, human microbiomes have lost ancestral microbial diversity while becoming specialized for animal-based diets. These results indicate that humanity has experienced a depletion of the gut flora (Ochman et al., 2014).
Today industrialized societies are characterized by :
(1) an increase in energy intake and decrease in energy expenditure;
(2) an increase in saturated fat, omega-6 fatty acids, and trans-fatty acids, and a decrease in omega-3 fatty acid intake;
(3) a decrease in complex carbohydrates and fiber intake;
(4) an increase in cereal grains and a decrease in fruits and vegetables intake; and
(5) a decrease in protein, antioxidants, vitamin D, and calcium intake .
(Source: Evolutionary Aspects of Diet: The Omega-6/Omega-3 Ratio and the Brain Artemis P. Simopoulos, 2011
The increase in trans-fatty acids is detrimental to health (Simopoulos, 1995). In addition, trans-fatty acids interfere with the desaturation and elongation of both omega-6 and omega-3 fatty acids, which reduce the amount of arachidonic acid (ADA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) that are required for human metabolism. Before the 1940s cod-liver oil was ingested mainly by children as a source of vitamin A and vitamin D with the usual dose being a teaspoon. Once these vitamins were synthesized, consumption of cod-liver oil was drastically decreased, contributing further to the decrease of EPA and DHA intake (Weber, 1989). About 80 years ago (1929–1930) Burr and Burr were the first to discover the importance of linoleic acid (LA) and alpha-linolenic acid (ALA) in restoring the effects caused by the fat-free diet in deprived animals. They coined the term “essential fatty acids” (EFAs). We know that LA and ALA are essential for normal growth and development of human beings. The two families of omega-6 (LA) and omega-3 (ALA) fatty acids are physiologically and metabolically distinct, cannot be synthesized in the human body and must be obtained from the diet (Robinson, 1999).
