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Evolution and Nutrition

Evolutionary medicine suggests that the end of the Paleolithic era (the “Stone Age,” lasting from roughly 2.5 million years ago to about 10,000 BCE) was marked by our ancestors transitioning to what we now call the “modern” diet and lifestyle. This was a radical change for human bodies, which had adapted genetically to Paleolithic demands. As a result, evolutionary medicine argues, our modern lifestyle is causing us to deal with modern problems, including the increasing incidence of diseases such as cancer.

The genes we inherit from our ancestors are the result of adaptations to certain activities, foods, climate, stress, and other environmental factors. When there is a significant change in any of these, the result is a generational mismatch of genes, which can have serious health consequences down the line. Mismatch diseases like cancer evolve when a stimulus either increases (e.g. too much sugar in food) or decreases (e.g. food becomes too nutrient-poor) beyond levels to which the genome is adapted. Mismatch diseases can also occur when the stimulus is entirely novel (e.g. chemical food additives).

Our hunter-gatherer ancestors ate a far more varied diet, which included 60-70 types of food per year. When our more recent ancestors switched to settled agriculture, we became dependent on less than a dozen crops. These include cereal grains such as wheat, barley, rice, corn, and potatoes. They continue to provide the bulk of calories for the world’s population, and yet they contain less protein, fat, fiber, vitamins, and minerals than wild plants and animals.

Cereals contain little iron, but are high in phytates, which further inhibit iron, zinc and calcium absorption. Corn is low in essential amino acids, such as lysine, isoleucine and tryptophan, whose deficiency prevents DNA production, while rice inhibits Vitamin A absorption.

Research suggests that malnutrition and related illnesses were more common in early farmers, whose diets were grain-based, than in hunter-gatherers. Switching away from a meat-based diet reduced our intake of zinc, Vitamin A, and Vitamin B12, which are only available in animal foods and are critical to immune system and DNA function.


As people began farming and increased their consumption of cereal grains, which are lower in iron than red meat (the predominant Stone Age food), adaptive genetic mutations occurred. Over time, these mutations allowed for increased iron absorption from plant sources in order to decrease anemia. Today, however, they manifest as high serum levels of iron and a condition called hemochromatosis, which fuels the cancer process at large and is a risk factor for liver cancer specifically.

New foods can create new problems. Take lectins, for example, which are proteins that bind to carbohydrates and are present in staples of the modern diet such as grains, legumes and cereals. They are heat stable and resistant to breakdown in the gastrointestinal tract. They are also related to autoimmunity, allergy, inflammation, leaky gut, and bind to cancer cells in the prostate and brain.
Another modern problem are aflatoxins, which are carcinogens produced by fungi and molds that thrive on cereals, nuts and grains (in long-term storage), and can cause liver, kidney, and colon cancer. Milk, eggs, and meat products can be contaminated by aflatoxins from the feed of the animals they come from. Foods with the highest risk of aflatoxin contamination are corn, peanuts, and cottonseed.

The “green revolution” of the 1940s accelerated the use of synthetic pesticides, many of which are considered carcinogenic. This has affected most commercially raised fruits and vegetables. Modern agriculture also uses synthetic fertilizers, which pose an environmental risk to both soil and microbes while leaching heavy metals, which are known or suspected carcinogens, into groundwater.


Modern breeding practices can also reduce nutrient content in our produce. Studies show that much of it is relatively low in phytonutrients, which are compounds with the potential to reduce the risk of cancer. Due to breeding practices, modern fruits and vegetables are significantly lower in vitamins, protein, and fatty acids compared to wild varieties, while being higher in sugar and starch.

Concentrated animal feeding operations, which started around 1926, contribute to cancer because livestock is fed specially formulated feeds and animal pharmaceuticals in order to increase efficiency and productivity. Antibiotics in animal feed destroy essential microbes needed for immune function. Increased oxidative stress causes antibiotic resistance and decreased response to chemotherapy. Chemical compounds in animal feed such as dioxins are also linked to cancer as they accumulate in the fatty tissue of animals when used as feed components. These are linked to lung cancer and non-Hodgkin’s lymphoma.

The displacement of nutrient-dense foods by less dense foods, including refined sugars, grains, and vegetable oils, has caused a decline in human vitamin and mineral density. About 50-85% of the US population fails to meet the recommended dietary allowance (RDA) of Vitamin B6, Vitamin A, magnesium, Vitamin D, calcium, potassium, zinc, and folate. Low levels of vitamins and minerals are linked to cancer because of their impact on immune and genetic function.

The intake of fewer vegetables, which is typical for the US diet, leads to low fiber content. Fiber is important for our microbiome, which acts as a “second genome” and “third arm” of the immune system. Diets low in fiber are linked to colon cancer.

Food additives, which are chemical substances, are intentionally added to foods to modify flavor, color, stability, and texture. Butylated Hydroxy anisole (BHA) is classified by the FDA as an additive, and used in potato chips and meat, but the National Toxicology Program classifies it as a human carcinogen. Additionally, an estimated 12,000 substances are used in such a way that they may unintentionally enter the food supply, including food packaging materials and processing aids.

Emulsifiers are substances that prevent oil and water from separating in food, and are considered carcinogens. They alter the makeup of bacteria in the colon, promoting inflammatory gut diseases. One commonly used type is lecithin, which is found in many organic products.

Irradiation is another modern food processing practice, which is used to kill mold, bacteria and insects that hide in meat, grains, nuts, and other foods. However, irradiation is still a form of radiation, and is considered a Group 1 carcinogen.
Studies show that Americans consume a limited variety of foods, many of which are low quality. The most consumed types of items are grain-based desserts, yeast breads, soda and energy sports drinks, chicken and chicken dishes, pizza, alcoholic beverages, pasta and pasta dishes, tortillas, burritos, tacos, beef and beef mixed dishes, and ready-to-eat cereals. Many other foods that are considered part of the Standard American Diet (SAD) contain carcinogens, including yogurt (rBGH), coffee (Dioxins), McDonald’s salad (three carcinogenic pesticides), chocolate bars (ethylene oxide), as well as steaks and fries (HCAs and skyrosak).

The food staples and food-processing procedures introduced during the Neolithic and Industrial Periods altered six crucial nutritional characteristics of ancestral Paleo-type diets, resulting in higher cancer rates. The new diet tends to have a high glycemic load, imbalanced fatty acid composition, low micronutrient and antioxidant density, low fiber content, and a high toxic load.

The human diet has changed considerably in the past 15,000 years, and especially so in the past 150. This is a major epigenetic modifier. Carcinogens are present in practically all modern foods, even vegetables. Organic foods are an exception. Everyone needs to be educated on the various places where carcinogens are found in the Standard American Diet - and how they can be avoided.
References
  1. Lieberman, Daniel. “The Story of the Human Body: Evolution, Health and Disease.” Amazon, Penguin Books, 2014.
  2. Jönsson, Tommy, et al. “Agrarian Diet and Diseases of Affluence--Do Evolutionary Novel Dietary Lectins Cause Leptin Resistance?” CORE, 'Springer Science and Business Media LLC', 1 Jan. 1970.
  3. Christian C. Abnet (2007) Carcinogenic Food Contaminants, Cancer Investigation, 25:3, 189-196, DOI: 10.1080/07357900701208733.
  4. Amy R. Sapkota, Lisa Y. Lefferts, Shawn McKenzie and Polly Walker “What Do We Feed to Food-Production Animals? A Review of Animal Feed Ingredients and Their Potential Impacts on Human Health” Environmental Health Perspectives, Vol. 115, No. 5 (May, 2007), pp. 663-670.