Plognark

I don't exactly have the best diet in the world, so I take a vitamin every day. I know I've mentioned it a few times before, but I got brittle fingernails for a while because all I could afford was crappy college-student grade food. Not sure what vitamins I was missing, but a month after I started taking them they grew in noramlly again.

I'm not 100% sure of the cause/effect there, but the cost is marginal and it seemed to coincide rather well.

Schneibster

There may be as many as twenty average, healthy adults on the planet. :P

BioBeing

By "average, healthy adult" I infer someone without any major outstanding health issues such as diabetes, heart disease, severe infections etc.

starling

Can't do a double blind test, but I've had some extreme depressive reactions from multivitamins, experimentally verified. Might be the taurine in them or something.

Jackalope

Probably biotin, a B-vitamin. Also helps hair grow. When I lost a good deal of my hair and got brittle nails from chemotherapy, I took a very, very large dose (5mg) of biotin every day. Some studies have used even larger doses than that, but I figured it'd be a waste of money to take a bigger dose.

Keep in mind that if you supplement folic acid that you can unintentionally mask a type of anemia caused by vitamin B-12 deficiency. Make sure to tell your doctor if you take more than 400mg/day.

TheMostHumbleofAll

The question of diet is much more complicated than those other things. The fundamentals of physics/math is fairly static, but with diet there are many dynamic variables, many with a localized bias. When you talk about diet, you're talking about adaptation/evolution. Over time, organisms get used to things in their environment (or else they die or migrate). We go though that as well. "One man's meat is another man's poison," right?

In a few generations, the growth hormones, antibiotics, et al., will be part of the nutritional pyramid.

We will survive/adapt because we're not getting leathal doses. Just like any poison, one can develop resistance with small enough doses over a long enough timeline.

Corona688

Things like milk weren't fortified with vitamins on a lark. But perhaps things have changed since then.

repoman

Speaking of milk, vitamin A has been taken out because too much will cause boneloss. Of course it is complicated and I'm too tired to hash it out now.

epepke

Some, but not completely. You still see pellagra in the South.

BioBeing

I think it was talking about taking a supplemental multivitamin on top of the various vitamins added to food.