Most of the "multis" people buy are in tablet form. More often than not, tablets, which are compressed with binders and fillers at pressures sometimes as high as 50,000 pounds per square inch pass right through the body, undissolved. Remember, it doesn't matter how much of a supplement you put in your mouth. What matters is how much of that supplement you actually absorb.
Calcium has proven to be one of the main culprits that prevents mineral absorption.. When taken together with other minerals, calcium blocks up to 70% of their absorption. A Very serious athlete, who is very often low or deficient in one or more trace minerals, the lesson should be very clear. Multi-mineral preparations are usually a waste of money. They do not provide an adequate source of trace mineral nutrition.
Dr D - You have a number of unrelated issues going on here none of which are entirely accurate. While it is accurate to state that many tablets are produced under high pressure, most reputable manufacturers (notice that I did not say supplement marketing companies who are farming out manufacturing to the lowest bidder) follow USP production standards for dissolution and disintegration which state that a tablet must break down fully in a pH equivalent to stomach acid in 45 minutes or less.
At the same time one must keep in mind that there are a huge number of factors that influence dissolution and disintegration of any supplement including but not limited to the general health of the individual, the age of the individual, the pH of the individual, other foods consumed at the same time (such as fiber), etc.
With that said there are a couple of general rules of thumb that anyone can follow to help maximize absorption of multis...
1) Always choose a product from a major manufacturer
2) Always choose a product with the longest possible shelf date
3) Store your supplements in a cool dry place away from heat, humidity, and light
4) Consume within 6 months of opening
5) Always take multis with food as the body needs a larger volume of food to trigger sufficient digestive enzyme product for maximum absorption
6) Consume your multi with protein as the body needs higher acid levels to absorb minerals
In respect to Calcium, keeping it brief, remember that the body is a tightly closed system meaning that it will only uptake what it needs when it needs it so to make a blanket statement for the entire population of 70% blockage is simply not accurate.
Lastly, the vast majority of multis are combinations of vitamins and essential "macro" minerals - not trace minerals.
While there are a few multis that do include trace minerals, generally speaking, if you want to supplement with trace minerals you need a separate product.
And in my personal opinion, I would be very careful with most trace mineral supplements on the market as independent studies have shown a disturbingly high level of lead and/or arsenic (both of which are naturally occurring).
So yes, whole foods are ideally our best source of nutrition, with overfarming, depleted soil conditions, foods that sit long periods in storage exposed to adverse conditions, and an increasing dependence on processed and "fast" foods, taking a daily multi provides good, inexpensive "nutrition insurance" for most individuals - a postion now supported and endoresed even by the ultraconservative AMA.
Jay