Environmental changes, including diet and lifestyle, which took place 10,000 years ago have been too recent for the human genome to make a proper adjustment. As a result “diseases of civilization” have emerged. The types of foods and food processing developed in the recent Neolithic and Industrial Periods have changed the following elements of our diets:
Fatty acid composition.
The above changes, without a parallel change in the human genome, may be the cause of many of our current chronic diseases. This maladjustment is called “evolutionary discordance theory.” This discordance results in increased morbidity, mortality and reduced reproductive success. We live with a genetic inheritance from our ancient Paleolithic ancestors, but we have recently developed very new diets and lifestyles in the Neolithic and Industrial Periods.
Diet related diseases provide a serious threat to our population at the present time. Sixty-five percent of our adults are obese. Cardiovascular disease is the leading cause of death in the U.S. (38.5% of all deaths). Cancer is the second leading cause of death in the U.S. (25%), with one-third of cancer deaths being due to nutritional factors, such as obesity.
For 5-7 million years our ancestors were hunter-gatherers. Pre-industrial and pre-agricultural diets are of benefit in treating today’s chronic diseases in many studies. This agrees with the “evolutionary discordance theory.”
Hunter-gatherer diets would have included minimally processed plant and animal foods. With domestication of these plants and animals there were changes in their nutrient values, especially with modern technology. New foods were introduced that humans were not used to. Whereas, dairy products, cereals, refined sugars, refined vegetable oils and alcohol comprise 72.1% of our diets today, these would have contributed little to the pre-agricultural diet. The following paragraphs list types of foods that have been added to our diets, recently, in terms of geologic time.
Dairy products were consumed only by infants and from the same species, prehistorically. Evidence for dairy products in Britain has only been seen for 6100 to 5500 years.
Tools for grinding grains appeared 40,000 to 12,000 years ago and regular use of grains began about 13,000 years ago. Today, 85.3% of cereal grains are highly refined and the germ and bran are removed. This has only been done for 150-200 years.
Sucrose production began about 500 BC in India and prior use of concentrated sugar was in the form of occasional honey. Per capita use of sucrose in the U.S. was 69.1 kg. in the year 2000. Sucrose is broken down in the gut to glucose and fructose.
High fructose corn syrup (HFCS) became available with new technology in the 1970’s. There are two forms HFCS 42 and HFCS 55, liquid mixtures of fructose and glucose (42% fructose and 53% glucose and 55% fructose and 42% glucose, respectively).
Refined vegetable oils were first produced between 5000 and 6000 years ago. The oils were mostly from olives, almonds, flax, sesame seeds, and walnuts for mechanical, medicinal and illumination uses. Oils for oral consumption increased greatly from 1909 to 1999. New oils such as cottonseed, margarine and hydrogenated oils were developed very recently.
Alcohol use as wine developed in northern Iran 7400-7100 years ago. Beer brewing began about 4,000 B.C. and distilled liquor came even later. Fermentation occurs naturally, but since fruits are so seasonal, the author believes that fermented drinks provided little in the normal diet in the remote past.
Manufactured salt added to the food supply is 90% of our salt consumption. Systematic production of salt began about 6000 B.C. Before that, people who lived close to the sea probably dipped their food in seawater.
Fat deposits in wild animals in muscles are composed, mainly, of polyunsaturated fatty acids (PUFA) and monounsaturated fatty acids (MUFA). Excess energy is stored in the abdomen and under the skin as triacylglycerols, mostly saturated fatty acids (SFA). Wild animals had little triacylglycerols, and therefore primitive man would have eaten little SFA’s. Today, feeding cattle in feedlots with grains makes it possible for humans to eat large amounts of SFA’s, with lower omega-3 fats and more omega-6 fats. Grain-fed feedlot cattle did not exist over 200 years ago.
The glycemic index is a measure of the ability of an individual food to raise the blood sugar. The glycemic load is increased in foods that are more processed foods and contain more sugars. Foods commonly eaten by primitive hunter-gatherers would have had a very low glycemic index. Chronic consumption of high glycemic index foods leads to insulin resistance as seen as the primary defect in the metabolic syndrome. Diseases seen with the metabolic syndrome as “Diseases of Civilization” include obesity, coronary heart disease, type 2 diabetes, hypertension and dyslipidemia. These diseases were unknown in primitive hunter-gatherers. (Fructose is related to insulin resistance.)
Our dietary fats are mostly triacylglycerols. Fatty acids include SFA’s, MUFA’s, and PUFA’s, including omega-6 and omega-3 fatty acids. SFA’s and trans-fats are unhealthy in large amounts and promote vascular disease (CVD). PUFA’s and MUFA’s are more nutritious and the omega-3 fatty acids reduce the risk of cardiovascular disease and autoimmune disease. The major sources of SFA’s in the U.S. diet are fatty meats, baked goods, cheese, milk, margarine and butter.
Concentrated vegetable oils were added to our diets in the early 20th century and this greatly increased our intake of omega-6 fatty acids. The hydrogenation process introduced new trans-fats into our diets, which increases cardiovascular disease risk.
Macronutrient intake includes carbohydrates, fats and proteins. Current suggestions for diet to lower risk of CVD is to limit fat intake to 30% of energy intake, maintain protein intake at 15% of total energy intake and increase complex carbohydrates to 50 or 60% of energy intake. Some studies have shown that increasing protein intakes can improve dyslipidemias and type 2 diabetes.
Micronutrient density is the amount of micronutrients in foods as compared to energy density. Much of our energy foods today are high in sugars and fats and they don’t supply needed nutrients, thus they have low micronutrient density. Fifty percent of the U.S. population does not get the RDA of vitamin B-6, vitamin A, magnesium, calcium and zinc. One third of the population does not get the RDA of folate, which increases the risk of CVD. Whole grains and milk are of low micronutrient density and have replaced nutrient dense foods of the hunter-gatherer diet. The wild plant foods were of higher nutrient density before they were domesticated.
All foods, after being fully digested, release either acid or carbonate (base) into the system. Fish, meat, poultry, eggs, shellfish, cheese, milk and grains are acid producing. Fresh fruit, vegetables, tubers, roots and nuts are base producing. “As a result, healthy adults consuming the standard U.S. diet sustain a chronic, low-grade pathogenic metabolic acidosis, which worsens with age as kidney function declines.” The pre-agricultural diets were primarily base forming and had the following benefits:
Prevent and treat osteoporosis.
Prevent age-related muscle wasting.
Prevents kidney stones.
Prevents exercise-induced asthma.
Prevents chronic renal insufficiency.
Sodium to potassium ratios are greatly increased in today’s diets because of the use of manufactured sodium, the increased use of oils, the reduced use of fruits and vegetables and the increased use of grains. The result is an overall decline of potassium consumption by 400%.
The fiber content of hunter-gatherer diets was quite high. The foods introduced during the Neolithic and industrial periods are generally low in fiber. Fibers have many functions for health including maintaining healthy lipid levels.
CONCLUSION: Many of today’s illnesses are the result of “the collision of our ancient human genome with the new conditions of life in affluent nations.” The foods added to the human diet since Paleolithic times are responsible for the epidemic levels of chronic diseases seen in the U.S. and in Western diet consuming populations. These diseases affect 50-65% of our population. The foods added include dairy products, cereals, refined cereals, refined sugars, refined vegetable oils, fatty meats, low fiber foods and refined salts.
NOTE: Omega-3 fatty acids tend to be anti-inflammatory and are difficult to obtain in today’s diets. Omega-6 fatty acids increase the inflammatory response.
pH paper can be used to check the pH of the urine to moniter your progress.