Calcium
Blocks iron absorption.
Vitamin d aids/boosts absorption.
Essential mineral and electrolyte
Plus bones etc.
vit d and k thing
See: electrolytes
See: salt.
Avoid taking vitamins, minerals and other supplements for 30-60 minutes after consuming coffee - it contains compounds (polyphenols) that limit the absorption of many micronutrients.
Forms/Types
Calcium citrate can absorb well when taken with or without food. Other forms cannot.
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)
Dosage - How Much?
Calcium is absorbed best when taken in amounts of 500 – 600 mg or less - https://www.bonehealthandosteoporosis.org/patients/treatment/calciumvitamin-d/.
Also spread dosage over the day.
Deficiency - Too Little
Known as hypocalcemia.
Toxicity - Too Much
Known as hypercalcemia.
Careful about taking too much.
2500mg or 2000mg per day for adults and those over 50 years old, respectively.