By Denise Lodge
Eating healthy, nutritious food is the best kind of diet, but specific diets can be useful to give guidelines for eating. Our society focuses on diet and weight loss and the dieting section at the bookstore continues to grow at a seemingly exponential rate with every book promising to be the best.
Impowerage has begun a new series in which we will analyse a particular diet, and present its basics, benefits, and also any opposing views that have arisen from within the medical and nutritional community. The first diet we are examining is the paleolithic diet, which is also called the hunter-gatherer diet, or the stone-age diet.
The basic principle behind the paleolithic diet is that human physiology has changed little since the paleolithic era (estimated to be 2.5 million years ago), and that our digestive and metabolic systems were designed for foods eaten during that period, not for modern-day foods. The discrepancy between our physiology and modern diets has resulted in many modern diseases, according to the proponents of the paleolithic diet.
During the paleolithic era, staples included very lean wild meat, low-energy, high-density vegetables, fruits, and nuts. When agriculture emerged, an estimated 10,000 years ago, the paleolithic era ended, and a new era, in which food was much more readily available, began.
Applying Stone-Age Principles to Modern-Day Eating
The aim of a modern paleolithic diet is not to eat paleolithic food in a paleolithic fashion, but to find the nutritional value of paleolithic food in modern-day food. While it is not practical to live as a paleolithic person, it is possible to benefit from the nutritional value of a historically studied hunter-gatherer diet.
Fruit and Vegetables
During the paleolithic era, a large variety of plants were eaten, and fewer seeds and beans were eaten. Corn and potatoes are not considered part of the vegetable group, because corn is a cereal grain, and potatoes have nutrient properties uncharacteristic of traditional hunter-gatherer plant foods.
Studies of hunter-gatherer societies reported in the Journal of the American Nutraceutical Association show that in their diets, animal foods comprised more than half (55-65%) of daily energy intake, with plant foods comprising the remaining 35 to 45 percent. Animals foods consumed among the hunter-gatherer groups studied were approximately half aquatic animals and half land animals.
Meat consumed during the paleolithic period was wild game meat, not domesticated, farmed meat. The nutritional value of very lean, skinless cuts of turkey and chicken breasts, skinless poultry, and fish compares to wild game meat. Wild game is typically about 2 to 4 percent fat by weight, whereas domestic meats can contain 20 to 25 percent fat by weight. Cordain, author of The Paleo Diet, advises that that modern meats are much higher in saturated fat, and that we should supplement low-fat meats with fats from other sources, such as flaxseed oil.
Grains and Dairy
Eating contemporary foods that mimic paleolithic food means eliminating two major food groups. Grains and dairy are not part of a paleolithic diet, because these foods were rarely or never consumed by paleolithic hunter-gatherers. Dry beans and grains did not become dietary staples until agriculture was introduced. Foods that contain mixtures of grains, refined sugars and oils, salt, and food additives are also excluded from a modern paleolithic diet.
Paleolithic populations drank water almost exclusively. Water increases blood flow, making it easier for your heart to provide your muscles with the oxygen they need. Water is necessary for digestion, nutrient-absorption, and circulation.
Benefits of a Paleolithic Diet
The Journal of the American Nutraceutical Association published a sample paleolithic diet, and found that food energy was comprised of 39 percent fat, 38 percent protein, and 23 percent carbohydrates. This nutritional composition varies significantly from current western values: food energy in modern diets is usually comprised of less fat and protein and more carbs (34 percent fat, 16 percent protein, and 49 percent carbohydrates).
Although the fat content of the sample paleolithic diet was 5 percent higher than the average content in modern diets, it was due to a greater intake of both polyunsaturated and monounsaturated fats. Polyunsaturated fats are found in cold-water fish, such as cod and salmon, and have been associated with a reduced risk of cardiovascular disease. Monounsaturated fats, such as those in olive oil, have been shown to reduce LDL cholesterol.
The sample contemporary paleolithic diet contained 42.5 grams of plant fibre, which is about 30 grams higher than values in the typical Canadian diet.
The sample diet included 726 milligrams of sodium. Health Canada recommends 1,300 milligrams for adults age 51 to 70, and 1,200 milligrams for adults over 70, yet Canadians consume an average of 3,400 milligrams of sodium every day. While some sodium is necessary for the body to function, too much may lead to high blood pressure, which is a major risk factor for stroke, heart disease and kidney disease.
Can a Paleo Diet Help Prevent Disease?
Some advocates of paleolithic diets claim that they can help cure modern diseases such as Chron’s disease, irritable bowel syndrome (IBS), acne, and diabetes.
Chron’s Disease and IBS
Lectins, a type of protein, are abundant in raw legumes and grains, and are also found in dairy products and certain vegetables. In humans, lectins resist the digestion system, entering the blood. Some lectins can damage the intestinal lining as they pass through the gut. Once the gut is damaged, it can become “leaky,” allowing bacteria, toxins and food to leak into the blood stream. Symptoms of a leaky gut can include chronic fatigue, skin rashes, and joint pain.
People suffering from Crohn’s disease or IBS tend to be more sensitive to lectins in food. The elimination of grains and dairy in the paleolithic diet has led to claims that paleolithic diets can cure Chron’s disease and IBS. However, according to an article published in Research Reports in Clinical Cardiology, “the effects of lectins […] on intestinal permeability […] have been poorly studied in humans to allow us to draw significant conclusions.”
Acne and Diabetes
In 2002, a study was published in the Archives of Dermatology, one author of which is Loren Cordain, author of The Paleo Diet. The prevalence of acne in 2 non-westernized populations was studied; no acne was present in either population of 1200Kitavan Islanders of Papua New Guinea, and 115 Achéhunter-gatherers of Paraguay. Moreover, the study showed that “neither the Kitavan islanders nor the Aché hunter-gatherers manifest the classic symptoms of insulin resistance,” and that “hunter-gatherer populations who have adopted Western diets frequently are hyperinsulinemic and insulin resistant and have high rates of type-2 diabetes.” This study has led to claims that paleolithic diets can cure acne and type-2 diabetes, but further research is required for conclusive results.
Cardiovascular Disease and Stroke
According to the Scandinavian Journal of Nutrition, several studies have shown that “overweight and the metabolic syndrome have been conspicuously absent in twentieth-century populations with paleolithic lifestyles.” The journal reports that before the transition to a modern lifestyle, “cardiovascular disease including stroke was apparently unknown in East Africa.”
According to a study published in the European Journal of Clinical Nutrition, “it is difficult to accurately determine the nature of past hominid diets, or define the “Palaeolithic” diet, due to the limitations of the archaeological record, a problem which is amplified in the Palaeolithic period where survival of organic materials is very rare.” Archaeological sites dating to before 10,000 years ago are rare, and many artefacts have disappeared through time.
The calcium value of the modern paleolithic diet is considerably lower than Health Canada’s recommended dietary allowance of 1,000 to 1,200 milligrams for adults ages 50 to 70, and 1,200 milligrams for those over 70. Low calcium intake may increase the risk of developing osteoporosis.
However, paleolithic skeletons have shown bones free from symptoms of osteoporosis, despite consuming no dairy products. This may be due to their high fruit and vegetable intake, which has been shown to reduce urinary calcium excretion rates.
Vitamin D-absorption may also explain the positive calcium balance, despite a relatively low calcium intake. According to Vancouver-based Registered Dietitian Jennifer Hill, “vitamin D enhances calcium absorption in the gut and maintains the right balance of calcium and phosphorus in the blood for normal bone mineralization.” Paleolithic populations experienced high sunlight exposure, which increases vitamin D synthesis, leading to increased calcium absorption. The contemporary paleolithic diet provides no dietary vitamin D. However, absorbing vitamin D, and consequentially calcium, from sunlight is not recommended by dermatologists, as sunlight’s benefits cannot be separated from an increased risk of skin cancer.
The cholesterol content of the sample paleolithic diet reported by the Journal of the American Nutraceutical Association is more than 50 percent higher than recommended values (300 milligrams). According to a survey published by Statistics Canada in March 2010, 47 percent of adults ages 40 to 59 had high cholesterol levels, and 54 percent of those ages 60 to 79 did. Left untreated, high cholesterol increases the risk of developing heart disease.
Paleo Diet Overview Conclusion
The paleolithic diet has the nutritional benefits of high dietary protein and fibre, and low sodium, but the possible disadvantages of low calcium and vitamin D. Meals are comprised of easily accessible ingredients, and are not complicated to prepare. If you would like to try a paleo approved recipe, you can try making Braised Oxtail.
The Paleo Diet: Win a Free Copy
The Paleo Diet (Revised Edition) by Loren Cordain includes a history of paleolithic eating, disease-prevention information, and recipes. If the idea of a paleolithic diet intrigues you, and you are interested in exploring recipes and potential benefits of the diet, enter to win a free copy by leaving a comment below, or on Impowerage’s Facebook page by 11:59 PST on November 30th, 2011.
Congratulations to Elizabeth for winning a copy of the book.