Paleo nutrition and bone health: what we can learn from our ancestors
As a nutritionist I can’t help but notice the contemporary shopping basket brimming with denatured, processed, and even synthetic foodstuffs. As an anthropologist I can’t help but recall that we evolved over millions of years on a very different diet, eating a wide range of wild and unprocessed plant and animal foods. For more than 98% of our time as hominids we ate simply what we could gather or hunt in any given location, during any given season. Our entire physiology evolved in adaptation to these nutritional parameters.
Paleo eating: How does today’s diet differ from the diet we evolved on?
Nearly all of the last 2 to 3 million years of human evolution occurred in what is known as the Paleolithic or “Old Stone Age,” a time of widespread use of stone tools and other hand-made implements for successful hunting and gathering. More successful hunting allowed humans to survive in colder, even glacial climates, hence the popular image of Paleo folks as Ice Age big-game hunters. The Paleolithic period covered millions of years with diverse environments, climates, and varied nutrient sources. Nonetheless, anthropologists have been able to reconstruct an “average” Late Paleolithic eating pattern and this reconstruction demonstrates that our physiological and genetic machinery evolved in adaptation to a very nutrient-dense diet.
Paleo nutrition vs. contemporary nutrition
|Minerals:||Mineral intake was 2 to 8 times higher for most minerals except sodium. Sodium intake was at least 5 times lower than today, at 768 mg/day, while potassium intake was 4 times higher than ours at 10,500 mg/day. Iron intake was 8 times higher and manganese 4 times higher than ours and so forth.|
|Vitamins:||Vitamin intake was estimated to be 2 to 6 times higher than ours. For example, vitamin C intake was more than 6 times higher, and vitamin E nearly four-fold higher. Folate and vitamin A intakes were twice as high.|
|Fat:||Fat intake was estimated at 2/3 of ours at 21% total calories, including almost a 1 to 1 ratio of beneficial polyunsaturated Omega 3 fats to Omega 6 fats. Today we consume some 30% of calories from fat including some 10 to 15 times more Omega 6 than Omega 3 fats, with 18% of our fats being refined vegetable oils including substantial amounts of harmful trans fats. Paleo diets had no processed oils or trans fats, nor any refined vegetable oils.|
|Protein:||Protein intake was generally twice that of ours, estimated at 1/3 total calories. There were abundant sources of plant and animal protein, including wild animals, which have low body fat.|
|Fiber:||Fiber intake was 5 to 8 times higher than ours at 100 to 150 grams/day as opposed to the current 15 grams/day.|
|Carbohydrates:||Carbohydrate intake was similar to ours at 46% of calories, but all carbs were from whole, unprocessed, wild foods.|
|Refined Sugars:||None or minimal intake (some honey), as opposed to 15% of all calories in today’s diet. Today we average 20 teaspoons of added sugars a day, about 15% of total caloric intake, including 10% of our calories from fructose.|
|Grains and Cereals:||None or minimal. Today refined grains comprise 32% of our diet.|
|Dairy:||None beyond infancy. Today we average nearly 400 lbs of dairy products per year or 2 cups per day.|
|Acid-Alkaline Balance:||Paleo diets were largely alkaline-forming due to high potassium intake from vegetable, fruits, nuts, and seeds. On the other end of the scale, contemporary Westernized diets are low in vegetables and fruits yielding an average 50 meq of excess acid daily.|
|Alcohol:||None or minimal, as opposed to 7-10% of contemporary diets.|
Today’s diet, yesterday’s physiology
Some 10,000 years ago we entered the Neolithic or New Stone Age, a period marked by agriculture and animal domestication that allowed for permanent urban centers with dense populations. Whole grains and cereals, which were absent during the vast majority of human evolution, became the predominant sources of calories and nutrition, and the human diet change dramatically. The Industrial Revolution of the 1800s, only a mere 200 years ago, further dramatically transformed our dietary patterns with the advent and dramatic expansion of food refining, processing, and agribusiness.
While the Paleo diet was nutrient dense, our diet is nutrient depleted. Today the average American consumes about 32% of their calories from nutrient-stripped refined grains; 15% from added sugars; 30% from fats (largely refined and denatured); and often another 7% in alcohol, leaving only about 15% of one’s caloric intake for nutrient-dense foods.
So how did these nutritional changes impact our skeletal fitness?
Paleo nutrition and skeletal wellbeing
The stereotypical image of our Paleolithic ancestors is one of a large-boned, rough-and-ready primitive individual, and the archaeological record indeed suggests that the bones of our Paleolithic ancestors were stronger than ours, with very little archaeological record of low-trauma fractures. The mandatory physical demands in the wild clearly contributed to our ancestors’ bone strength, but I would argue that the nutrient density of their diet was an equally important factor. The decline in nutrient intake with the New Stone Age, and then the even more dramatic weakening of our nutrient intake over the last 200 years, is difficult to overstate.
When we compare the average Paleolithic nutrient intake with that of contemporary societies, we find that the same base human body, the same genetically determined human physiology, is now being asked to run on a very low octane fuel. And it is being asked to run for decades more than it did in the past. The impact of this nutritional downgrade can be seen in the degeneration of the human skeleton as well as in the rise of today’s other degenerative diseases. We all know the statistics—half of women over 50 will experience some sort of needless fracture; 25% of us now die of heart disease and another 25% from cancer; 75 % of the population is overweight or obese; more than 1 out of 4 Americans aged 65 and older has diagnosed or undiagnosed diabetes; and on and on the list goes.
How can we regain the bone-strengthening, health-promoting Paleolithic nutritional edge?
Most of us are not going back to eating grubs, gnawing on bone marrow, eating organ meats, or savoring seemingly endless types of wild plant roots. Yet there are many changes most of us could easily make to give our physiology more of the nutrition our bodies evolved in response to. Here are 10 things you can do to “Paleo-Up” your eating patterns in order to build health and reduce your risk of today’s degenerative diseases.
- Increase your intake of vitamins, minerals, and antioxidant phytochemicals from plants. Make the greatest volume of your diet plant-based with at least two cups of low carbohydrate vegetables (greens) for lunch and dinner, and consume root crops once or twice a day (yams/carrots/turnips).
- With the move to a more plant-centered diet your fiber intake will reach at least the current USDA recommendation of 21 to 38 grams a day. While still a far cry from the Paleo fiber intake of 100 to 150 grams, you are moving in the right direction.
- Increase your intake of alkalizing potassium compounds from vegetables, fruits, beans, nuts, and seeds. Strive for a minimum of 10 one-half cup servings a day of these foods to reach or exceed the current recommendation of 4,700 mg potassium/day (which is still less than half the intake of our Paleo ancestors). Our ancestral diet was high in potassium, thus our kidneys were designed over millions of years to easily excrete potassium while retaining sodium—which they still do!
- Reduce sodium from our average 4,000 mg/day to the recommended 1,500 mg/day or less (unless you have low blood pressure). This can be accomplished by cutting back on processed foods which contain high amounts of sodium. Our Paleo ancestors consumed less than 800 mg sodium/day, so our kidneys were designed to conserve sodium. Low dietary potassium and high sodium is acid-forming and contributes to osteoporosis and excessive bone loss.
- Use alkalizing, mineral-rich root crops instead of breads, pastas, and other acid-forming, denatured flour products.
- Consume adequate protein with a minimum of 1.0 gram per every 2.2 lbs of body weight (a 135-lb person would consume 61 grams protein). The acidifying effect of any excess protein will be balanced off by the alkalizing effect of vegetable foods high in potassium.
- Increase Omega-3 fats from sources like coldwater fish, grassfed beef, walnuts, flaxseeds, and Omega-3 supplements. Eliminate processed trans fats (hydrogenated vegetable oil) altogether, and favor high quality, fresh, cold pressed oils, like olive and coconut oils.
- Dramatically reduce intake of all sugars from the current 15-20% of calories. Favor small amounts of natural sweeteners. Eliminate all sugared drinks, including fruit juices.
- Alcohol, if used at all, should be consumed in moderation, not exceeding 1 or perhaps 2 servings a day.
- Use nutrient supplements as necessary to insure adequate nutrient intake.