What is Bioavailability? How Your Body Gets its Fuel

Good nutrition depends on more than which foods are on your plate. It also depends on whether the nutrients in those foods can make it into your bloodstream. The measure of how efficiently these nutrients are absorbed by your body is called their bioavailability. But what is bioavailability and how does it work? We’re here to break down the science as best we can. 

What is Bioavailability, Exactly? 

How it works is fascinating. To understand bioavailability, let’s start with the soil. Microbes in the soil ferment dead plant material such as leaves from last autumn and the fallen stems and stalks of last summer’s growth, releasing their nutrients into the soil where the next season’s living plants can use them. But the ability of plants to take up these nutrients is affected by the soil’s acidity or alkalinity. 

Most nutrients are most bioavailable when the soil is slightly acid. As soils become more acidic or more alkaline, more and more nutrients are chemically locked up and unavailable for plants to use. 

Similar processes occur within our digestive systems. The foods we eat are dismantled first by enzymes in our saliva, then by gastric juices in our stomach, and finally by the bacteria in our gut. Once dismantled, the nutrients in our food are in fluid form and make their way through the intestinal wall to enter our bloodstream, where they’re transported around our bodies to build tissue, strengthen our immune system, and do the umpteen tasks that keep our bodies running smoothly. In addition, lactobacilli-fermented foods, like wildbrine’s, create a slightly more acid condition in the large intestine, and that creates a more hospitable environment for nutrient uptake.

Food’s bioavailability can be weakened for several reasons. First, the food itself may not be as vibrantly nutritious as it might be if it were grown under ideal conditions. Second, processed foods can be nutrient-poor, and the heat of processing or cooking kills enzymes. Third, if a person is in poor physical shape, his or her body may not be able to optimally utilize the food’s nutrients. And finally, anti-nutritive factors, such as phytic acid -- found in nuts, grains, and legumes -- impair the absorption of iron, zinc, and calcium if eaten as a dietary staple. 

Lactic Acid, Yeasts and Enzymes... Oh My!

Fermenting food corrects this bioavailability nutrient challenge. Think of fermentation as pre-digestion. Lactic acid bacteria, yeasts, and other microbes used to ferment foods, like wildbrine’s sauerkraut, do some of the body’s digestive work beforehand, making digestion and assimilation easier. During fermentation, these beneficial microbes also produce enzymes that pre-digest food; for example, their enzymes make minerals in the cultured foods more bioavailable. They replenish and nourish the correct mix of gut bacteria that live within us, support our health, and dismantle our food into fluid nutrients that are able to pass through the intestinal wall to nourish the human body that hosts them. 

The enzymes produced by beneficial microbes during fermentation are crucially important for proper nutrition. There are more than 150,000 different enzymes in the human body and all of our bodily functions need them. The proteins, fats, and carbohydrates in our food have to be broken down into simpler molecules in order for the body to absorb and use them. This is achieved by the action of specific enzymes on foodstuffs they are designed by nature to dismantle. While our gut bacteria produce enzymes when they digest food in the intestines, eating enzyme-rich, fermented foods also build up the enzyme supply and increase bioavailability. 

It’s known that as people age, the digestive process loses some of its punch, lessening the bioavailability of some nutrients. Adding fermented foods to the diet can counteract this normal part of aging, giving the body’s digestive workload a helping hand, and making sure that the gut microbiome is strongly supportive of the immune system. Basically, fermented foods are your gut’s best friend for life.