Science changes all the time, at the end of the day lots of people see natural as better, even when we can make an identical chemical from combining others, there will always be the opinion with a lot of people that natural is better. However, very little we eat these days is natural anyway, so that argument seems rather silly to me.
Frankly they make a Vit C pill, science then shows its a different part of Vit C we find useful, its not that the Vit C pill is bad, its just new information changes what we "think" we need. But then someone will make a new Vit C pill that can be just as useful. Often though "cheap" and multi vitamins aren't great as many things absorbtion rate is effected by other vitamins. From what I recall calcium makes absorbing, Zinc maybe, or magnesium i forget, very difficult. Phosphorus, in a certain level increases the absorbtion of calcium. But we learn new things about what things effect others all the time, and decent quality vitamins adjust and change with the times and the current knowledge.
Many things you can take are designed to be different to the natural vitamin, theres plenty of supplements that are actually in more absorbable forms than can be found naturally, at least easily. So its give and take, some things are better, some are worse. Eat a rounded diet and you're still likely to be missing something, but thats life. The body copes extremely well without having the absolutely perfect amount of every last vitamin available. Diets in different countries/regions are vastly different, different varieties of the same fruits and veg will have differing levels of whatever that vitamin is.
Maybe one vit c pill has useless unabsorbable version of it, while another while use that same thing, combined with another vitamin that enables the body to use it. A lot of the things we take in anyway, are changed into other substances in the body. Flaxseed oil for instance, is changed into ALA in the body, which is then metabolised afaik, around 10-15% into EPA and 5-10% into DHA. If you have to high an intake of omega 6 though, the absorbtion and metabolised percentage of those two are changed quite significantly.
its almost impossible to get the perfect 4/5 meals in a day to get the right dosage of everything, this is where a multivit, or specific things you might be lacking can come in useful. Obviously if Vit C is the hardest to manufacture, try and get it naturally, and get something else that the body can accept and you can't add to your diet easily in pill form.
Take a multivit if you feel you probably don't eat varied enough, or enough veg, maybe it won't help, maybe it will, no one can say for certain at the moment. You could spend 3 months working out a fantastic diet and 30 single doses of different vitamins, but then you'll end up taking 30 pills a day and lifes to short. take a decent quality one, and hope for the best, its not like multivits or some supplements are hugely expensive anyway.
