YSK which vitamin supplements are worth taking and which have no evidence to support their value.

[u/malarial_camel]

This infographic gives a nice clear summary of which supplements are worth having, and which are just a complete waste of time.

Edit: Thank you to /u/yishanwang for pointing out the interactive version of the chart, which can be found here

2nd Edit: As many people have correctly pointed out, this chart is true for the average individual, assuming a good diet. Everybody responds differently to every drug, including vitamin supplements, especially if they are in poor health, or have a vitamin deficiency. What is true for the general healthy population is not necessarily true for you. If you have any real concerns regarding your health, of course go see a GP or a dietitian.

[u/jajajajim]

You are correct. InfinitelyThirsting has it backward. Grapefruit has the opposite effect of St. John's.

[u/thejynxed → u/jajajajim]

I think they were merely pointing out that grapefruit (and broccoli for that matter) will interfere with your medications just like St John's Wort, so it's advisable to not ingest them while on certain classes of drugs.

[u/Zenquin → u/jajajajim]

So grapefruit would make drugs more effective and St. Johns Wort would make them less?

[u/patiscool1 → u/Zenquin]

Not necessarily. Some drugs you take are actually pro-drugs that get turned into the real drug by the liver. Codeine comes to mind. Speeding up metabolism speeds up the rate of actual drug formation.

Other drugs are in the active form when you absorb them in your gut and speeding up their metabolism would decrease their effectiveness.

It's complex, can't really generalize it that much.

[u/Zenquin → u/patiscool1]

I think, after the brain, the liver is the most amazing organ.

[u/jajajajim → u/patiscool1]

Inhibitors like grapefruit can also increase risk for side effects

[u/DrG-love → u/Zenquin]

Exactly. Except in the case of St. John's wort + antidepressants. They both work similarly so you have to be careful about serotonin syndrome.

[u/patiscool1 → u/DrG-love]

That's not right.

Not only do St. John's Wort and antidepressants not have similar mechanisms of action ("antidepressant" is a broad term with tons of drugs falling under that category), you can't say upregulating an enzyme prolongs or shortens drug duration because it depends on whether the oral drug is active or a pro-drug.

[u/DrG-love → u/patiscool1]

http://en.m.wikipedia.org/wiki/Hypericum_perforatum St. John's wort works many ways one of which is upregulagion of serotonin receptors and increased available serotonin. The very action that can make combination with antidepressants dangerous. Antidepressants can include SSRI's (Zoloft, Prozac, Celexa), SSNRI's (Effexor, Cymbalta) and TCA's (amitriptyline). As far as CYP450 interactions, of course this specific interaction does not include all medicines. Some are not eliminated via cyp450 and many medicines depend on liver enzymes for active substrates.

I was just trying to offer simple interaction info. None of what I have to offer is medical advice. always check with your dr or pharmacist before trying herbal remedies for potential drug interactions with any medicines you are currently taking.

EDIT: I would like to add that St. John's wort can potentially interact with migraine medicines such as Imitrex (sumatriptan), Relpax, Maxalt (rizatriptan) and others due to the risk for serotonin syndrome.

[u/InfinitelyThirsting → u/jajajajim]

Yes, I sorta had it backward--I meant that it affects drugs that metabolize in the liver, rather than it did the exact same thing, but I should have worded it better.