What does bioavailability mean?

To put it simply, bioavailability refers to the extent a substance (i.e curcumin), reaches its intended destination (i.e the bloodstream), whilst remaining "biologically active".(1)

Contrary to what most people think, a significant proportion of the nutrients we consume are not absorbed by our gut. The bioavailability of nutrients varies depending on many different factors. Some of these include:

• whether it's fat or water-soluble - does it dissolve in water
• The stability of the substance - does it break down in the presence of stomach acid? 
• Once the nutrient reaches its intended destination, how quickly does your body break it down

These are just some of the factors that determine how "bioavailable" a nutrient is. 

Why is the bioavailability of turmeric so low?

With turmeric and curcumin, the factors mentioned above are a problem.

Firstly, curcumin is fat-soluble. This means that the majority water environment of our gut is not ideal for absorption. 

Secondly, by the time curcumin reaches the bloodstream, it's broken down by your liver into an inactive compound. To add to this, it also quickly binds to blood cells which also renders it inactive.(2)

In combination, this means that the bioavailability of turmeric is very poor. Not only is it poorly absorbed, but it's also quickly "deactivated". And this has been the main problem when studying turmeric in research studies to date. Scientists result in using very large doses of turmeric to get a measurable amount of curcumin in the blood. 

Why it's important to be aware of turmerics low bioavailability

Because it makes a big difference on whether a turmeric supplement is worth taking or not. 

Being aware of turmerics' low bioavailability means that standard food sources such as juices or turmeric-containing dishes are unlikely to provide your body with a measurable dose of curcumin. 

Similarly, when it comes to choosing a turmeric supplement, bioavailability is arguably the most important factor. 

Nowadays, the better turmeric supplements only use "standardized" curcumin. 

To explain this concept, we need to go back to raw turmeric powder. If you sampled different turmeric from around the world, you'd find that each batch would contain a different amount of curcumin. Some will have negligible amounts and it all depends on the quality of the crop.

To solve this issue, good supplement manufacturers ensure that they use a standardized extract of turmeric which contains a guaranteed amount of curcumin. And the industry standard for a top product is 95% curcumin. In other words, 95% of the weight of your turmeric supplement will contain curcumin. Whereas with raw packed turmeric powder, it's impossible to know. 

The other way to get around the issue of turmeric bioavailability is to use another natural agent which will enhance absorption. As so, these are known as "bioavailability enhancers" which we will look into next. 

How to increase the bioavailability of turmeric

The low bioavailability of turmeric has been well-researched for years now and, as a result, there are now several proven bioavailability enhancers on the market. 

They can be broadly separated into two categories.  

1) Natural bioavailability enhancers - BioPerine® and AstraGin®

You may have noticed that most turmeric supplements now contain BioPerine® or AstraGin® alongside a standardized extract of turmeric. 

For example, BioPerine® is a patented extract of black pepper and has been shown in studies to increase the absorption of curcumin by 20x.(3)

In the case of BioPerine®, it's thought that the active ingredient in black pepper extract stimulates the absorption of certain nutrients from our gut lining.(4)

2) Converting curcumin to a more absorbable form - Micellar/lipid technology

A more recent technology is the use of lipids (certain types of fat) to "coat" curcumin so that our body can absorb it better. 

In fact, studies into curcumin packaged in this way showed an increase in absorption by over 180x.(5)

We mentioned that curcumin is a fat-soluble substance and packaging it with fats so our body can absorb it better has (at the time of writing) been proven to be the most bioavailable form of curcumin. 

Anything else to consider aside from absorption?

The final thing to consider when it comes to curcumin bioavailability is how long it remains active in your bloodstream after it's been absorbed. 

Curcumin is quickly broken down by your liver and also reacts with your red blood cells to become inactive. This poses another problem with the usefulness of curcumin once it's been absorbed - it doesn't remain active for very long. 

Studies have shown that curcumin from standard supplements peak at around 1 to 2 hours after ingestion and quickly become undetectable.(6)

With that said, studies in curcumin products utilizing the micellar / lipid technology have shown curcumin being detectable for up to 24 hours in blood. 

Bioavailability of Turmeric - Takeaway points

For curcumin to be useful, it needs to overcome two main hurdles. First, it needs to get through the gut lining into your bloodstream. And secondly, it needs to remain active in the bloodstream to exert its benefits. 

In other words, the bioavailability of curcumin is a crucial factor to consider when taking turmeric for its health benefits. 

Turmeric root powder has very limited bioavailability. But when taken with a bioavailability enhancer like BioPerine®, the absorption is greatly improved (by 20x). 

Better still, studies have shown that liquid curcumin using micellar lipid technology is even more bioavailable (by 185x). 

On that note, check out our post on what makes a top turmeric supplement.