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"Bioavailable" and What It Really Means with Supplements

  • September 02, 2023
7 minute read

Bioavailability is a term that is often tossed around in discussions about dietary supplements. But what does it actually mean? In this article, we'll delve into the concept of bioavailability and its importance when it comes to taking supplements.

Understanding the Concept of 'Bioavailability'

To understand bioavailability, we first need to define it. Bioavailability refers to the extent and rate at which a substance, in this case, a nutrient or compound from a dietary supplement, is absorbed and used by the body.

Bioavailability is essentially a measure of how much of a substance is available to the body's cells after consumption. It takes into account factors such as absorption, distribution, metabolism, and excretion.

When we consume a dietary supplement or any form of nutrition, our body goes through a complex process to extract the necessary components. Bioavailability plays a crucial role in determining the effectiveness of dietary supplements. Even if a supplement contains high amounts of a particular nutrient, it doesn't necessarily mean that the body can absorb and utilize it efficiently. In other words, high bioavailability is essential for optimal nutrient uptake and utilization.

Let's delve deeper into the factors that influence bioavailability. One of the primary factors is the form in which the nutrient or compound is presented. For example, some nutrients are more readily absorbed in their natural form, while others require specific chemical modifications to be effectively utilized by the body.

The efficiency of absorption also depends on the interaction between the nutrient and other substances present in the digestive system. Some nutrients may compete for absorption, limiting the bioavailability of certain compounds. On the other hand, certain substances can enhance the absorption of nutrients, increasing their bioavailability.

Once absorbed, the distribution of nutrients throughout the body is another crucial aspect of bioavailability. Some nutrients have specific transport mechanisms, allowing them to reach their target tissues efficiently. Others may require carrier molecules or undergo metabolic transformations to be transported effectively.

Metabolism plays a significant role in determining the bioavailability of nutrients. The body may metabolize certain compounds into different forms, affecting their availability to cells. Furthermore, individual variations in metabolism can influence how efficiently a nutrient is utilized, leading to differences in bioavailability among individuals.

Lastly, excretion is an essential factor to consider in bioavailability. After nutrients have been absorbed and utilized, the body eliminates any excess or waste products. The efficiency of excretion processes can impact the overall bioavailability of nutrients, as inefficient excretion may lead to accumulation and potential toxicity.

In conclusion, bioavailability is a multifaceted concept that encompasses various processes involved in the absorption, distribution, metabolism, and excretion of nutrients. Understanding the factors that influence bioavailability is crucial for maximizing the effectiveness of dietary supplements and ensuring optimal nutrient uptake and utilization in the body.

The Science Behind Bioavailability

To understand how bioavailability works, let's explore how the body absorbs nutrients and the various factors that can influence bioavailability.

How the Body Absorbs Nutrients

When we consume food or supplements, the digestive system breaks them down into smaller molecules for absorption. The small intestine is the primary site of nutrient absorption, where nutrients can pass into the bloodstream and be transported to various cells and tissues in the body.

Different nutrients have different absorption mechanisms. For instance, water-soluble vitamins like vitamin C are readily absorbed across the intestinal wall, while fat-soluble vitamins like vitamin D require the presence of dietary fats for optimal absorption.

Factors Affecting Bioavailability

Several factors can influence the bioavailability of nutrients in supplements. These include:

  1. Form of the supplement: The physical form of a supplement, such as tablets, capsules, or powders, can affect how well the body can access and absorb the nutrients it contains.
  2. Interactions with other substances: Certain substances, such as fiber, calcium, or medications, can enhance or inhibit the absorption of specific nutrients.
  3. Individual differences: Each person's unique physiology and genetics can impact their ability to absorb and utilize nutrients.
  4. Timing of consumption: The timing of when a supplement is taken in relation to meals or other supplements can influence its bioavailability.

Bioavailability in Dietary Supplements

Now that we understand what bioavailability is and how it works in the body, let's explore why it matters in the context of dietary supplements.

Why Bioavailability Matters in Supplements

The primary purpose of taking supplements is to provide the body with additional nutrients that may be lacking in our diet. However, if these nutrients aren't effectively absorbed and utilized by the body, the benefits of the supplements may be limited.

By choosing supplements with high bioavailability, we can ensure that the nutrients they contain are readily absorbed and put to good use by the body.

Common Supplements with High Bioavailability

Several dietary supplements are known for their high bioavailability, meaning that the nutrients they contain are easily absorbed and utilized. Some examples include:

  • Iron bisglycinate
  • Coenzyme Q10
  • Magnesium citrate
  • Omega-3 fatty acids
  • Curcumin with black pepper extract

How to Increase Supplement Bioavailability

While certain supplements may already have high bioavailability, there are strategies you can employ to enhance the bioavailability of supplements you take.

Timing and Dosage

Take supplements at the recommended time and dosage to optimize their bioavailability. Some supplements may be better absorbed when taken with meals, while others are best taken on an empty stomach. Following the instructions provided by the supplement manufacturer can help maximize bioavailability.

Combining Supplements for Enhanced Bioavailability

Some nutrients work synergistically, enhancing each other's absorption and utilization. For example, combining vitamin C with iron can improve the absorption of iron. Understanding these interactions can help you formulate an effective supplement regimen that maximizes bioavailability.

Potential Risks and Considerations

While bioavailability is essential for optimal supplement effectiveness, it's crucial to be aware of potential risks and consider certain factors.

Overdosing and Bioavailability

Just because a supplement has high bioavailability doesn't mean that larger doses are always better. Some nutrients, such as fat-soluble vitamins, can accumulate to toxic levels in the body if consumed excessively. It's important to follow recommended dosages and consult with a healthcare professional if you have any concerns.

Interactions with Medications and Health Conditions

Supplements, especially those with high bioavailability, can interact with medications or exacerbate certain health conditions. It's crucial to disclose all medications and existing health conditions to your healthcare provider before starting any new supplement regimen.


Bioavailability is a critical factor to consider when taking dietary supplements. Understanding how nutrients are absorbed, the factors that influence bioavailability, and knowing which supplements have high bioavailability can help optimize the effectiveness of supplementation. By following recommended dosages and considering potential risks and interactions, we can make informed decisions about our supplement choices and maximize their bioavailability for better health.