You may have heard the word ‘bioavailability’ and wondered what, exactly, it means; often it is used in relation to micronutrients and supplements, whose benefits are directly associated with bioavailability.
In short, bioavailability is a measure of how much a substance is able to access the circulation and reach the target area, and it depends on absorption (how much we get it) and secretion (how much we get out). While macronutrients – carbohydrate, protein and fat – are highly bioavailable, micronutrients (vitamins, minerals, flavonoids and carotenoids), which are accessible in both food and supplements, are not always absorbed optimally in the digestive process.
Orally-taken tablets are a common form of supplementation but effectiveness can be compromised by stomach acid, which can destroy beneficial substances before they reach the bloodstream and can be absorbed by the body at a cellular level. It is important to select highly bioavailable supplements for maximum effectiveness, and there are several methods to increase bioavailability of active ingredients: one example is curcumin, the active ingredient in turmeric, which is more easily absorbed when ingested with an oil or fat but practically insoluble in water.
Another key micronutrient is magnesium, which in a supplement will be used in a bioavailable form such as magnesium lactate, so the body can absorb the optimum amount of the mineral without requiring a large does, which can cause unpleasant side effects.
Most importantly, consumers should do their own research as to the quality of supplements and the bioavailability of the micronutrients they contain, especially as bioavailability can be affected by the formulation of the supplement; the delivery method (sometimes capsules are more effective than tablets, for instance); what you are taking or eating with it (some nutrients absorb better when taken with food; other supplements will interact negatively, such as calcium interfering with iron absorption); and general gastrointestinal health – gut inflammation or poor gastric acid secretion can affect absorption of micronutrients.
It is also advisable to talk to your GP before embarking on a supplementation programme. If you have micronutrient deficiencies or gastrointestinal issues you may require additional support to get the optimal bioavailability from your supplements, and in some cases it may be risky to health to over-supplement with certain micronutrients (e.g. iron) outside a doctor’s supervision.
Perhaps the most valuable work you can do with supplements and bioavailability is thoroughly research them, so you can distinguish between marketing promises and quality data; know whether a given supplement focuses more on absorption or secretion; and understand exactly what the supplement purports to do for your health.
For sound advice on how to source trustworthy health information in the internet age (tip: be careful when using Dr Google), listen to our latest At Source podcast with Dr Gill Webster (biotechnology and immunology expert and Chief Scientist at NatureBee) and medical microbiology scientist Ben Harris.
More broadly, Dr Webster and Mr Harris also discuss ways to support natural health and wellbeing and the importance of immunity and microbiology as the global community works to counter the pandemic.