What Does "Bioavailability" Mean?

If the vitamins you’re taking aren’t being properly absorbed by your body, you might as well be popping gum drops instead of nutritional supplements. 

The whole point of including vitamins and minerals in your health regimen is to experience a noticeable improvement in how your body functions and feels, not only in the short term, but over the course of your life as well. But if your body is not properly absorbing those vitamins and minerals, then you are not reaping the benefits you seek. That’s where the term “bioavailability” comes in to play.

Simply defined, bioavailability refers to the amount of a substance that is absorbed into your body via your intestines, which impacts how much of that substance is available for biological activity within your cells and tissues. When you consume a nutrient, it’s only available in your body to a certain degree, and bioavailability is the measurement used to determine what that degree is. 

It’s important to remember that the simple act of consuming nutrients does not guarantee that 100 percent of those nutrients will survive your gastrointestinal tract and subsequently distributed throughout your bloodstream and eventually into your cells. All in all, the various vitamins, minerals, and phytonutrients you’re familiar with vary greatly in their rate of bioavailability. 

As an example, consider manganese and calcium, two minerals required for various processes in your body. No matter how much of these minerals you consume, your body will only utilize, on average, about 5 percent of the manganese and 30 to 40 percent of the calcium. Here, bioavailability is a natural process—your body knows how much of these minerals you need and evacuates the excess.

Besides your body’s particular needs, other factors that contribute to a nutrient’s bioavailability include the source (food or supplement), other foods or supplements ingested at the same time, how foods are processed and cooked, and the quality of the food or supplement. Other factors that decide your body’s absorption of nutrients include your age, biological gender, overall health, and the level of nutrients present in your body; for example, someone with anemia is likely to absorb less iron that someone who isn’t anemic. 

Why Is Nutrient Absorption Important & How Do We Absorb Nutrients?

The absorption of nutrients is essential to the survival of all living organisms—how’s that for important? As a human being and one of the most complex living organisms on the planet, your gastrointestinal system was created as an intricate and specific system for nutrient absorption. 

During your digestive process, molecules of food and any supplements you might have ingested, are absorbed from the upper small intestine and are whisked away in the bloodstream, which carries the digested matter to other parts of the body for the next step in the absorption process. 

Your digestive system does have at least one ally in the effort to absorb nutrients—namely, probiotics. In a recent article, we discussed the myriad functions of probiotics in the body, but one of the most recently researched probiotic benefits is the live culture’s ability to aid your body in the efficient absorption of protein and other important nutrients. It seems that once probiotics are active in the small intestine, these beneficial bacteria get a head start in breaking down the ingested nutrients. 

Synthetic Nutrients & Natural Nutrients: Are They Absorbed Differently?

Since a large number of Americans don’t get enough nutrients from their diet, supplementation is often a recommended nutritional tactic. But if supplementation is your go-to source for some nutrients, how can you ensure maximum absorption?

There’s a widely accepted belief that synthetic nutrients are essentially an exact chemical match to the nutrients that are found in food. And while this might be anecdotally true, the fact that there’s a production process for synthetic nutrients as opposed to the natural processes of plants and animals means that your body could experience different rates of absorption when using synthetics. 

What is the main reason for different rates of absorption? When you consume single-ingredient supplements, you’re missing out on the total package of vitamins, minerals, enzymes, and certain compounds that could contribute to your body’s ability to fully utilize the nutrients. Illustrating this, studies show that natural vitamin E has roughly twice the bioavailability as the synthetic form of the vitamin. 

Synthetic Vitamin B12 vs. Natural Vitamin B12

One particularly interesting example of a natural nutrient and its synthetic counterpart is vitamin B12’s methylcobalamin (natural) and cyanocobalamin (synthetic). As we’ve learned before, vitamin B12 is an essential nutrient that can boost energy, support bone health, prevent age-related eye conditions, and strengthen your brain against cognitive decline. 

Methylcobalamin—such as found in the trademarked B12 vitamin MecobalActive®—is naturally occurring in animal-based foods, while cyanocobalamin is chemically synthesized. Methylcobalamin and cyanocobalamin are the two forms of vitamin B12 you’re most likely to come across—making this one example of why it is important to check the ingredient labels of your supplements. 

The main difference between the two forms of vitamin B12 is that methylcobalamin has a carbon- and hydrogen-based methyl group, while cyanocobalamin contains a cyanide molecule—yes, that cyanide. And although the amount of cyanide in the B12 supplement cyanocobalamin is too small to cause any harm, your body must convert that cyanocobalamin into the more bioavailable methylcobalamin form. 

Curcumin And the Various Pigments Of The Ancient Spice

Curcumin is the yellow pigment in turmeric, the common spice-rack resident in your kitchen. But this mildly aromatic spice also delivers antioxidant and anti-inflammatory properties—with the backing of numerous clinical studies. 

Described in ancient texts for thousands of years for its efficacy in various inflammatory conditions, curcumin is available in various versions today, like the nootropic Longvida® Curcumin, and Meriva® Curcumin, which has been described as the most bioavailable version of curcumin. According to studies, Meriva® curcumin has helped to decrease joint pain and also improved joint function in participants with osteoarthritis. 

But what makes Meriva® such a popular version of curcumin is its high rate of absorption, which is due to the proprietary phytosome matrix that surrounds the compound. In a random, double-blind study, the absorption of a curcuminoid mixture with Meriva® displayed a much higher rate of bioavailability than a mixture without Meriva®. 

With Nutrients, It’s All About Absorption

The bioavailability of the nutrients you ingest has a direct correlation with the positive effects these nutrients have on your overall health. Though making the decision to add nutrients into your lifestyle is a step in the right direction, choosing nutrients with the highest rate of absorption will ensure your body truly reaps the available health benefits.