While looking into the various CBD products available or trying to learn more about the different plant-based supplements that are out there, you may have come across this word quite a bit in your research on dosage forms: bioavailability.
Now, if this term brings back fears from your high school biology exam days about drug formulations and pharmacokinetics, that’s okay!
We are here to break down the concept so you can move forward in your research with confidence, knowing how to understand bioavailability when it comes to getting the most out of your products.
Absorption vs. Bioavailability: What’s the Difference?
Bioavailability defines how much of the substance successfully makes it into the bloodstream in a ready-to-use form versus how much passed through the body unused.
To make it simple: the bioavailability of nutrients is a way of measuring how much of a substance your body absorbs.
When you take a substance orally, the compounds travel from the site of intake (in this case, the mouth) through the gastrointestinal tract and intestines and then into the bloodstream. This process of a substance reaching the body’s systemic circulation (or bloodstream) is defined as absorption.
A substance with high bioavailability will mean a large portion of the original substance is accepted and put to use within the body, whereas a substance with low bioavailability will mean more if its content is destroyed or wasted in the body without having any health effects.
Is Low Bioavailability Bad?
Now, this all may make it seem like a bad substance with low bioavailability, but that isn’t the case!
Our immune system is simply doing its job by being wary of foreign objects, even ones that can provide health benefits like CBD or other plant extracts with high solubility.
However, suppose you are taking a substance with low bioavailability. In that case, there’s a chance that those chemical compounds are moving through you without being put to use, causing you to lose out on micronutrients, nutritional status, and the boost to your wellbeing.
Luckily, there are ways to increase a substance’s bioavailability for better therapeutic efficacy, which we will go over in more detail below!
How Is Bioavailability Measured?
Bioavailability measures the fraction of a drug that is successfully absorbed into the body’s circulation system and is not lost through elimination. If a product’s bioavailability rate is 80%, the body absorbs 80%.
It wastes 20% of the original dose, whereas a product with a bioavailability rate of 10% will only absorb 10% of the dose, while the other 90% is wasted.
What Factors Impact Bioavailability?
The main factors that impact bioavailability are absorption, effects of food, drug molecule metabolism, the Physico-chemical mechanisms of the substance, the administered dose, and how the substance is administered.
Absorption
The absorption of a drug can be affected by either the body or the drug itself. For instance, our immune system may reject a certain substance applied to the skin, or our digestive system may destroy parts of a drug before they can reach the bloodstream, limiting absorption and therefore lowering the drug’s bioavailability.
At the same time, the ingredients of some drugs may be easier for the body to absorb than others, especially if the ingredients react together in a way that helps the substance breakdown. This would make absorption of the drug easier, increasing its bioavailability.
Effects of Food
Certain foods can have powerful effects on the bioavailability of a compound.
Depending on how the different molecules work together, some foods can help break down or dissolve the active ingredients within a drug, making it easier for the body to absorb. When this happens, the substance’s bioavailability goes up.
For instance, CBD is fat-soluble but not water-soluble.
So if you were to mix pure CBD extract with water, the cannabinoids would not break down, and your body would have a more challenging time absorbing them, causing much of the CBD to pass through you.
When mixed with oil, however, more of the extract would get broken down into a form your body could absorb, allowing a higher percent (bioavailability!) to enter your bloodstream and connect with your endocannabinoid system, providing benefits to your physical and mental wellbeing.
It is important to note that not all foods interact with substances in the same way and vice versa.
Some drugs have a higher bioavailability when taken on an empty stomach, and other drugs that require a specific type of food or vitamin, like calcium, make it break it down and boost its bioavailability.
Drug Metabolism
Drug metabolism refers to the process of a drug being changed within the body to help eliminate it.
For instance, an oral drug needs to go through the GI tract and liver before reaching the bloodstream. During that passage, digestive or liver enzymes are able to shift the structure of the drug, turning parts of it into metabolic waste. This ultimately lowers the amount of the drug that reaches the circulatory system from the liver, reducing the drug’s bioavailability.
When enzymes turn part of a substance into waste in the gut wall or liver, it is considered first pass effect or first-pass metabolism.
Because everyone’s metabolism is different, the rate of drug metabolism can also vary from person to person. This means that the same drug can have a higher or lower bioavailability, depending on the person taking it.
Physico-Chemical Properties of the Drug
The Physico-chemical properties of an active drug refer to physical and chemical makeup of a substance. Variables, like how a drug’s physical and chemical properties react in the body and what they are soluble in, can affect how easily the body absorbs the drug and how much is lost through urine.
Route of Administration
The way a substance is introduced into the body can also impact its bioavailability ratio. Some of the main routes of administration for drug products include oral administration, intravenous administration (through an IV), and topical administration (being rubbed directly into the skin).
Drugs administered via intravenous routes tend to have the highest bioavailability, as they are being sent straight into the bloodstream, bypassing any first-pass metabolism in the gut or liver.
Topical substances such as CBD lotions and creams aren’t meant to reach the bloodstream as their site of action but rather be absorbed directly into the skin and nearby muscles.
Depending on what other active ingredients are infused into the topical, its absolute bioavailability can be higher than orals as they aren’t metabolized in the digestive tract.
However, the immune system works within skin cells to keep foreign objects from passing the surface level of the skin, affecting the relative bioavailability.
In this case, having a product with more oil could help the body absorb more of the CBD.
How Can Bioavailability Be Increased?
While there are a lot of factors that impact bioavailability, this also means there is a lot we can do to increase bioavailability! Here are some simple ways you can up a substance’s bioavailability and get the most out of it:
Take CBD With the Right Food
Remember how we said CBD is fat-soluble? Studies show that ingesting a CBD product right after eating a fatty meal can boost the CBD’s bioavailability by four times as much as taking on an empty stomach.
Knowing which types of food improve absorption for which substances can help you plan and time your meals for the best rate of bioavailability.
Know What Else Is in the Product
Along with considering the cost and quality of ingredients, you want to check that the ingredient list of any product is built with bioavailability in mind.
For instance, since CBD isn’t water-soluble, you’ll want to make sure your CBD tea has fat content. Without the fat to break it down, your body won’t be able to absorb enough of the CBD to feel its effects.
At The Brothers Apothecary, we always pair our ingredients for optimal bioavailability.
That’s why our turmeric products will include piperline, the active ingredient in black pepper known to break down turmeric’s healthy compounds, our CBD topicals will be infused with nourishing fatty oils, and our teas and superfoods include a coconut-based fat infusion so they can be best absorbed by the body and provide you with the full effect of their benefits.
How Does Bioavailability Impact Efficacy?
Bioequivalence studies indicate that if your body isn’t able to absorb much of a product, the efficacy will be lower. Understanding how bioavailability works and using the tips listed above to increase the bioavailability of a substance can also improve its efficacy.
Conclusion
We know we covered a lot here, but remember that understanding the science behind bioavailability can boost your confidence as well as your CBD’s efficacy.
With this newfound knowledge, you can confidently shop for and use CBD with the know-how to get the most out of your product.
Sources:
Influence of food on the bioavailability of drugs | National Library of Medicine
Drug Metabolism | News Medical
High fat foods can increase oral cannabidiol absorption into the body | Science Daily
Jesse Richardson is the co-founder of The Brothers Apothecary. He's an avid tea drinker and the primary creator behind The Brothers' products. An undergraduate of UCLA for Political Science, Jesse currently studies Medicinal Plants at Cornell University and The International School of Herbal Arts & Sciences.
