Vitamin K
TL;DR
something.
Fat soluble so take with food containing fat.
K2 Helps with vitamin D absorption.
Vitamin K2 plays an essential role in bone health by activating bone-building proteins that help bring calcium into your bones and keep it there, thus increasing bone mineral density (BMD).
It should not be confused with vitamin K1, which plays an important role in blood clotting.
Avoid taking vitamins, minerals (such as calcium) and other supplements for 30-60 minutes after consuming coffee - it contains compounds (polyphenols) that limit the absorption of many micronutrients.
Food Sources
Forms/Types
Quality
As with all supplements - buyer beware. It's quite common for supplements to be contaminated with a variety of impurities, often in the form of heavy metals, and/or contain far more or less of the ingredients stated on the label. There's no simple rule of thumb to avoid this, such as avoiding cheap or imported products; expensive or well-known brands produced in-country may be just as bad. Ideally you should take some time to find products (if you can) that;
- have been laboratory tested on behalf of the manufacturer by a reputable body or company that operates in your country or region (here's an example of a Peak Supps creatine supplement available on Amazon in the UK which has been tested by Eurofins: Creatine Monohydrate Powder 1Kg | Pure Micronised | Packaging May Vary - see pictures 3 & 4)
- in the UK & EU, are manufactured in facilities that meet the minimum standards of good manufacturing practice (GMP) in their production processes (for medicines).12 Facilities are inspected for compliance and manufacturers' product(s) must:
- be of consistent high quality
- be appropriate to their intended use
- meet the requirements of the marketing authorisation (MA) or product specification
Be wary of any manufacturers or brands making claims around these valid but irrelevant standards;
- HACCP: this standard relates to food safety which indicates that the seller is claiming their supplement is a food; whilst meeting this standard is worthwhile, GMP (detailed above) would be a more appropriate standard
- ISO22000: same as HACPP
- ISO9001: this standard is focussed on quality control management systems in the context of managing a business or organisation, not directly on the the quality of the products that business produces (although it may have a beneficial impact)