Supplements - how much do you need to take?

Anti aging supplements are confusing - so many different nutrients offered in so many different forms.
One of the key questions most of us want answering about any supplement is 'how much should I take?'
You would expect that in a perfect world you could go somewhere and look up the exact amounts of every nutrient you need.
Unfortunately - in the real world - it doesn't work like that. True - many countries do publish a Recommended Daily Amount (RDA) for vitamins and minerals. Most European countries including the UK do this.
In the US the Medical Institute at the National Association of Science publishes an Adequate Intake (AI) table for most nutrients which is updated regularly. The NAS also produces an Upper Limit (UL) guideline for many nutrients which is helpful for supplement takers.
From there on in though - understanding exactly what you should be taking and in what quantities becomes a bit more difficult. Like the AI, the RDA in Europe is intended as a minimum standard for the intake of certain vitamins and minerals including nutrients taken as food.
The other thing you need to be aware of is that RDA levels are very conservative and - in some countries - not regularly updated. For example science has moved on in respect of Vitamin C and its health-giving immune boosting properties. The recommended daily amounts issued by some countries look a little ridiculous in the light of what is now known.
There is also a lot of ongoing research published all the time which has brought to light minerals, enzymes and hormones in supplement form which are not included on the RDA list for many countries at all.
For this reason it's better to use the US National Association of Science guidelines for minimum and maximum daily amounts which tend to be updated more frequently in response to recent research findings.
Those are the guidelines used here to give you the best information about safe supplement levels.
Generally, suppliers of supplements package their products in amounts they think are appropriate and which most users take. You can get further advice from a specialist in nutritional health or from more detailed research if you are concerned but you probably don't need to.
What you definitely should find out before buying any supplement is how the supplement will interact with medication you may already be taking. The best advice - if you regularly take medication - check with your doctor first before taking a supplement.
This is especially important if you take: anti-depressants, anti-seizure drugs, blood thinners, blood pressure, coronary or diabetic medication or any drugs related to the treatment of cancer. This doesn't mean you won't be able to take supplements - it just means that its not advisable to take some supplements and your doctor is the best person to advise you.