On this Thanksgiving, you're sure to get your fill of nutrients and vitamins from your holiday meal. But many are still taking supplements to offset their diet mistakes. 

More than 150 million Americans take dietary supplements.  Choosing a daily vitamin can be confusing. Especially due to the sheer number available. So what works and what doesn't? 

They range from having weird names you can't spell, not to mention pronounce, to those you're familiar with like Vitamin C. 

"It's always best if you can get a well-balanced diet. But it's hard sometimes to really know that we're getting everything that we should. And a multivitamin kind of helps round that out to make sure we're getting everything that we need,” Dr. Bruce Schulz said.

Sanford Family Medicine Doctor Bruce Schulz takes a multivitamin occasionally.  He tends to stay away from those he wouldn't recommend to his own patients like C, D, and E. 

“I think the evidence is pretty minimal that they really are of benefit for most situations and at times may be harmful for overdoing doses of those vitamins,” Schulz said.  

Men should especially stay away from iron because it can be dangerous in high doses. And Schulz says calcium can also affect a man's health negatively. 

“That's one of those things that's maybe best for women to supplement with calcium. For men, some of the information suggests that maybe calcium supplementation could increase their risk for prostate cancer,” he said. 

So what vitamins should women be tossing back or tossing in the trash? 

“If a woman is of child-bearing age, then typically, we like them to have about 400 micrograms of the folic acid and this helps prevent birth defects in the chance that they do become pregnant,”Sanford Family Medicine Dr. Beth Jensen said.  

Jensen recommends a pre-natal vitamin if a woman is trying to conceive or is pregnant. But like men, there are vitamins women should avoid. 

“The fat soluble vitamins can be toxic in high doses. And particularly the vitamin A can cause birth defects. So in general I don't recommend that they supplement or if they do, supplement in much lower doses,” she said.  

High doses of Vitamin E can cause bleeding problems.  If you smoke, you need to take extra precaution.
 
“If you're a smoker, Beta Keratin can increase the amount of lung disease and lung cancer,” Jensen said. 

Information on vitamins, minerals and supplements