What is bioavailability?
A substance will only take effect if it can be absorbed by the body, so bioavailability is the key to creating a supplement that delivers proven benefits.
Bioavailability is a measure of how easily a substance can be absorbed by the body. In pharmacology, for example, it refers to how quickly a drug enters the circulatory system and reaches the desired area, so that it can take effect.
Nutritional scientists are well aware of the importance of bioavailability. For example, when you eat, the food is taken into your digestive system. Some of the useful nutrients are then absorbed into your bloodstream and are either stored or used by your cells. However, because your body is not perfectly efficient, some of the nutrients are excreted or destroyed in the stomach and intestines.
Macronutrients such as carbs and fats are highly bioavailable, but the beneficial micronutrients commonly sold as supplements – vitamins, minerals, flavonoids and carotenoids – are often difficult to for the body to absorb.
Can bioavailability be increased?
Administering a substance directly into the bloodstream (for example, via a drip) ensures that it will have the full effect.
Other methods, such as taking a tablet orally, are less intrusive but also less effective. Stomach acid, for example, can destroy beneficial substances before they reach the bloodstream. In these cases, it is important to boost bioavailability to increase absorption and effectiveness.
Bioavailability in supplements is affected by a whole variety of factors:
- The formulation of the supplement
- The delivery method. For example, in some cases capsules are more effective than tablets
- Circadian rhythm – it is recommended that some supplements are taken at a particular time of day to ensure maximum absorption
- Interactions with other substances in your system. For example, calcium supplements make absorption of iron more difficult, so it is important to wait two hours between taking calcium and iron
- gastrointestinal health
These factors help to explain why a supplement that is ineffective for one person can be highly effective for another. Fortunately, some of them can be addressed by taking a scientific approach to creating supplements. As with any drug, there is no guarantee of success, but by choosing a highly bioavailable supplement you will increase the chance that it will help you achieve your health goals.
How do bioavailable supplements work?
Supplements that are formulated to have high bioavailability will be more effective. The precise methods or reasons for increasing bioavailability will vary by active ingredient. Here are just a few examples.
Curcumin, the active ingredient in turmeric, is more easily absorbed when ingested with an oil or fat. This is because the body usually destroys the curcumin in the digestive system, but the oil will ‘sacrifice’ itself – allowing more of the beneficial curcumin to reach the bloodstream.
Lycopene is a carotenoid most commonly found in the skin of tomatoes. As with curcumin, it is difficult for the body to absorb unless combined with something else, such as whey protein.
Magnesium – an essential mineral that plays a key role in hundreds of bodily processes – is difficult to absorb. To make up for this, many magnesium supplements include high levels of magnesium oxide to ensure that people absorb enough to make a difference. However, this can have unpleasant side effects such as diarrhoea and constipation.
A supplement that uses highly bioavailable magnesium lactate ensures that the body can absorb the optimum amount of the mineral without requiring a large dose. This helps people to get the advantages of magnesium without the side effects.
Found in garlic, s-allylcysteine and polyphenols have a positive effect on heart health and cholesterol levels. Fermenting the garlic helps to increase the concentration of these beneficial ingredients, ensuring that more is absorbed by the body.