Can taking supplements hurt me?

I do not take a multivitamin but I do take fish oil, calcium, and potassium supplements. I am very lazy when it comes to food and I hate logging calories. I try to eat intuitively but somedays I know I lack in some important nutrients. 

I've tried waiting until the end of the day to take my supplements to see if I really need them or not, but I find it's really easy for me to forget what I've eaten. 

Is it okay if I take supplements even though I may get enough calcium, fish oil, etc. some days? Does it harm me to have excess calcium, etc.?

Thanks :)

calcium and potassium could be problematic in higher doses, yes. You don't want to go too far over the RDA. Calcium can end up accumulating in places you don't want it. I can't remember the deal with potassium, but I know that they don't include it in many supplements because it's (supposedly) so easy to get from food and (for some reason) having too much is bad. I'd do a search on that one.

Fat-soluble vitamins can be bad in high doses: Vit A, E, K

Water-soluble vitamins you can have as much as you want. Vit B, C.

Iron - only the RDA and  no more.

Sorry, don't have a list of all the fat vs water solubles.

 AFAIK the fish oil is fine.

the dose makes the poison

Thanks for the replies! Here are the actual values I take: 

Fish oil - 2000mg/day (38% of DV)

Potassium - 99mg/day (which is very little...only 3% of DV)

Calcium - 400mg/day (40% of DV)

I didn't realize this till just now, but my calcium supplements also have Vitamin D - 125% of DV. 

I think I'm going to try to pay more attention to my diet and only take the supplements if I really need them. 

If you take a one a day tablet you are not likely to overdose.  However there has been some question as to whether our body can use manufactured nutrients.  Best to get it from your food if you can.

Agreed that high doses of A, E and K can be toxic - but a daily multivitamin, or the equivalent from separate supplements, won't put you in danger of that.

People who take multivitamins are healthier. But, that's because they generally eat better, sleep better, exercise more and are generally wealthier health conscious individuals. So be the type of person who takes a multivitamin, because it's not the vitamins themselves that usually have an effect on your health.

Original Post by crazydiamondchrysalis:

Iron - only the RDA and  no more.

You should have seen the dosage they gave me with my first pregnancy!  I know pregnant women need more, but they had me on both prenatal vitamins and a huge iron supplement, for a total of over 500% RDA  for a normal person!  They made me so sick, I threw up after taking them.  I thought it was just morning sickness at first, but when I stopped taking the iron supplement I didn't throw up my breakfast anymore.  I figured, better that I actually get some nutrients from food rather than taking a pill that makes me lose both my food and the pill itself.

Feel free to ignore this random personal anecdote.  Apparently I'm just chatty tonight.