I loathe cynical advertising playing on the generally poor science education of the wider populace. We are not taught enough about how our own bodies work to spot the snakeoil salesmen.
Case in point: a company advertising a daily multi-vitamin/mineral supplement, a field with wide competition in which it is rather difficult to make one's product have a memorable "point of difference" to hang one's marketing hook on. So what do they come up with?
The old advertising standby: manufacture a problem of which you've never heard before and never noticed anybody suffering, and tell you that their product is the solution to this novel problem.
In this case, the voice-over informs us (with a tone of civil indignation that must have taken the voice performer quite some time to perfect), that other "daily multis" release their nutrients into your body "all at once" so that later in the day the nutrients might no longer be available "when you need them". However, [Clever Product] multis are slow release over 8 hours, so their nutrients will last for the entire working day! Wow!
I have to give it to the pharma company for cleverness: there are enough medications that are genuinely more effective in a slow-release format, particularly for arthritis and hypertension and other diseases of middle-age-and-beyond, that the general public has well and truly absorbed the concept that Slow Release Meds Are A Good Thing. Sure they are, when the therapeutic effect is short-acting and there is a need to extend that therapeutic effect in order to alleviate distinct symptoms.
But that is not how vitamins and minerals work.
Very simply: vitamins contained in our food and dietary supplement intake are stored in the body's own organs and gradually released: the body has its own slow-release system. As for the minerals, they mostly dissolve in the blood and help maintain the electrolyte balance which keeps our blood and organs within the proper pH balance for normal functioning. Some minerals are laid down in the bone and connective tissues, especially calcium, and if needed by the blood for pH balance or other tissue growth may be reabsorbed (this particularly happens in pregnancy and is a big reason why women are at greater risk for osteoporosis in later life).
Normal daily activity simply does not stress the supply of either vitamins or minerals sufficiently to be concerned about "running out of nutrients" halfway through the day. The vitamin absorption system is based on longer term cycles than that, and a balanced diet will easily supply sufficient minerals to get through the day. This is part of our body's natural homeostasis mechanisms: the collection of organic chemical repositories and chemical distribution networks that form our physiology and allow us to ingest external matter, break it down to its constituent chemicals, use it to live and grow, and excrete what we can't use.
Now, minerals such as sodium and potassium do get passed constantly out of the body through sweat and urine, particularly rapidly if the body is placed under severe stress by a gastric illness or prolonged aerobic physical activity, and these stressful physical events can affect the electrolyte balance quite rapidly.
And here's where the ad campaign above might actually be dangerous. When the body's electrolyte balance is truly upset, that can be a medical emergency (the athletes whose muscles "melted" during marathons - electrolyte imbalance, people with uncontrolled dysentery die of electrolyte imbalance) and what is needed then are mineral salts that get absorbed right away, not slowly released. Athletes drink electrolyte solutions to avoid collapse, in wealthy countries people with dysentery are hooked up to IV electrolyte drips and survive (in poor countries they die). More insidious mineral deficiencies which benefit more from an immediate supply than slow release of the needed mineral are anaemia and hypothyroidism.
Vitamin deficiencies are slower in onset than electrolyte imbalances, and the need for treatment not quite so life-and-death urgent in most instances. It is worth noting that vitamin deficiencies take months to manifest in visible symptoms, quite the opposite of the situation indicated by our cynical multivitamin advertisers. And when treating these deficiencies, the vitamin injections that are needed to correct severe cases of scurvy, beriberi, rickets, osteomalacia, pellagra, xerophthalmia and keratomalacia (note that we in the parts of the world with money to spare for daily multivitamin/mineral tablets have probably never known anyone suffering from any of these deficiency diseases) are needed in forms that are absorbable right now, not slowly released. Once the starving tissues are supplied, the liver and fatty tissues will absorb any excess and release it as the body requires.
Our body's own homeostasis regulates how vitamins and minerals are delivered to the tissues that need them far, far better than any multiple-enterically-coated capsule ever could. If your dietary intake is truly insufficient for the vitamins and minerals you need to remain healthy, at least don't let the manufacturers con you into paying more for some slow-release formulation that is absolutely not required.