Throughout history, humans have been considered omnivores, eating from multiple kingdoms of life including plants, algae, fungi and animals. This has been true for as long as far back as we have archaeological data. It wasn’t until our Palaeolithic ancestors, homo erectus, started broadening the human diet to include more plant, algal and fungal foods. Our current evolutionary form, homo sapiens, have been true omnivores for the entirety of their existence – an estimated 300,000 years.
While modern humans still largely consume animal products, there has been a recent shift towards a more plant-based diet, with the perception that it is a healthier or more socially responsible way of eating. Unfortunately, this shift, combined with the dramatic increase in industrialized and processed foods, has resulted in rampant nutrient deficiencies despite our adequate (and often excessive) caloric intake. As human animals, we have moved away from our biologically appropriate and ancestrally consistent diet. As a result, humans have become increasingly susceptible to acute infection, develop chronic (often fatal) diseases, and suffer regularly from a range of seemingly random symptoms.
Nutrient density is a big piece of this equation. Agriculture has selectively bred plants and animals to increase yield, diluting nutrients with extra carbohydrate and water, and to create milder flavours, removing the most nutrient dense and medicinal compounds from the plant. This is likely a large contributing factor, as around the time that agriculture was introduced (~10,000 years ago), we began to see deformities and deficiencies in the skeletal system, including dental formation.
Some of the most prolific deficiencies in our modern diet include fat soluble vitamins D3, K2 and A. This is in part due to the misleading and inaccurate studies demonizing saturated fats in the 1950’s. When the low-fat guidelines were added to government food guides and saturated fat consumption went down, so did the consumption of fat-soluble vitamins. Not only is fat required for the absorption of these vitamins, but vitamins A, D, and K2 are found primarily in fatty animal products such as skin, bones and marrow, raw dairy, and eggs.
These fat soluble nutrients are essential for a range of mechanisms in the body. Vitamin A is vital to support brain health, thyroid health (energy production), adrenal health (stress response), and to maintain a robust immune system. It’s also essential for the absorption of vitamin D. The best food sources of vitamin A include livers of ruminant animals, poultry or fish; some cheeses (cheddar, feta), and certain fish (salmon, mackerel). Plant based vitamin A (beta carotene) is not equivalent to animal based vitamin A (retinol), and should be considered a separate nutrient.
Vitamin D’s primary functions include optimizing immune health, maintaining the integrity of the structural system (bones and teeth), supporting cognitive function, and promoting a stable mood and balanced energy levels. The best food sources of vitamin D include fish roe, oily fish, pasture raised lard, egg yolks, and cod livers.
Vitamin K2 also plays a role in vitamin D absorption, and helps to maintain the structural system. Vitamin K2 ensures calcium is deposited appropriately in the body, and is responsible for encouraging calcium into the bones and teeth. It also prevents calcification of arteries, and prevents stone formation, giving it cardiovascular and renal (kidney)-protective properties. cardiovascular-protective properties. The best food sources of vitamin K2 are dark poultry meat, aged hard cheeses, and natto (fermented soybean). Vitamin K2 should not be confused with vitamin K1, which has different biological functions.
Kayla MacDonald, R.H.N.
Barefoot Nutrition 