Dear Dr. Mo: Is it possible to have a vitamin C overdose? Can it become toxic or harmful if we take a lot of it?
Dear reader: Vitamin C is a very important nutrient – in fact it is so important that without pickled cucumbers stored in barrels below deck to provide enough vitamin C to prevent scurvy, Amerigo Vespucci may never had reached the Americas and hence, who knows what the Americas would be named today.
In terms of overdose, our bodies are not able to store vitamin C as it is a water soluble vitamin so we can’t really overdose ourselves with it – it would make a very poor suicide/poisoning choice.
Water solubility means that whatever extra amount of it we consume, our kidneys flush it out in urine – we pee it out.
Therein lies a catch and an answer to your questions – because we get rid of excess vitamin C through the kidneys, if we take a whole lot of it over time – a whole lot meaning anywhere above 2000 mg (2 grams) per day – vitamin C tends to crystallize and to create oxalate deposits in the kidneys.
All this medical mumbo-jumbo I just said means in a nut shell that a lot of vitamin C may end up forming stones in your kidneys and this is a (very) painful condition, which at times becomes a medical emergency requiring surgical interventions, causing kidney damage and what not.
In addition, a lot of vitamin C can cause a diarrhea, cramps, bloating, vomiting, nausea (often times all of it together), headache and insomnia. Who’d have thought, right?
On the other hand, take too little of it over time (daily dose for adults is 60 – 90 mg) and you can become anemic, get bleeding gums, dry hair, your wounds’ ability to heal would decrease, your skin would become dry, teeth would weaken and crumble, you’d get nosebleeds, gingivitis etc.
A very severe and prolonged vitamin C deficiency causes Scurvy (basically all of the afore mentioned symptoms happening together plus the bleeding from the skin), which had plagued and claimed many a sailor back in a day.
A common fad, which causes many people to pour a lot of vitamin C into themselves (and shortly thereafter, pour it out in a toilet) is the TV ad-driven belief that vitamin C will somehow miraculously treat or prevent your cold or flu.
The scientific truth is that at best (and that’s not even 100%), vitamin C may shorten your period of illness by one day – that’s it. No evidence exists that it can prevent your cold from ever setting in so don’t bother.
This doesn’t mean of course that we don’t need it at times of illness, but we need it no more or less than on any other day.
All we need to get our daily dose of this important vitamin is a balanced or relatively balanced diet (don’t go on a boat for a month with nothing but rice and rum) – one orange a day for example makes the cut; or grapefruit, or mango, or any of the berries and if you prefer veggies, try some broccoli, spinach, cabbage, pickled cucumbers, peppers, tomatoes or tomato juice. Or you can make a salad.
You don’t need to throw your money away on vitamin C supplements – why in the world would you pay for a kidney stone?
Most of us will get that for free – just wait long enough.
Yours in health,