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Practical Considerations of Vitamin C


Why Vitamin C?

Humans and other primates do not have the ability to create their own vitamin c. Interestingly several bat species, guinea pigs, and some birds also must obtain vitamin c from their diet. Humans’ daily requirement for vitamin c is the highest of all vitamins. Officially it is recommended that women consume 75mg and men 90mg vitamin c. There may be compelling reasons to take in more. Intravenous vitamin c has a tolerable safety profile in cancer treatment, and has been associated with spontaneous remissions though high quality evidence is still forthcoming. It actually creates hydrogen peroxide inside cancer cells- causing them to die. New exciting research shows a potent effect of combining vitamin c with doxycycline as a metabolic shutdown for cancer stem cells.

But Vitamin c has also been shown to be essential in other areas of health. Most people know it is needed for our collagen- literally holding us together. Without vitamin c we develop scurvy. The collagen impact reaches all the way to our blood vessel health as we see a protective role in heart disease. Vitamin c is essential in brain health. It is essential in the processes creating many neurotransmitters– when these malfunction we see depression, anxiety, bipolar and other mood disorders. Ascorbic acid modulates dopamine, GABA, and cholinergic effects and thus plays a role in dementia and Parkinson’s.


Vitamin C is absorbed by the gut up to a point- 200mg at a time seems to saturate our body. We can absorb more but our kidneys work fast to excrete it and we don’t end up benefiting so much. We can take lots of small doses per day to do the best job we can with oral intake. Vitamin C (ascorbic acid) is high in osmolarity- this means it acts to pull fluid to itself like a magnet (sort of like a salt shaker in the humid South). If it is not absorbed this means it pulls fluid into the gut and will cause diarrhea. 

Some Precautions in Intravenous Use

Vitamin c at extreme doses can be generated only with intravenous dosing. We will look at dosing protocols at a later point. Because of a rare genetic disorder called G6PD deficiency, which can cause bursting of red blood cells if given IV vitamin c, the precaution must be taken to first rule the condition out with a lab test. Almost everyone I test is negative.

The other precaution is more complex.

Ascorbic acid is bound to sodium. In fact for every gram of intravenous vitamin c, we are giving 111mg of sodium. This can add up- it is not unusual to give 100 grams of intravenous vitamin c (this is not medical advice, just my musings). Assuming it is given in sterile water or dextrose (I prefer sterile water because SUGAR…) we are giving 11100mg or 11 grams of sodium. Hot dogs have about 500mg sodium per dog (not encouraging anyone to eat these). So this dose of vitamin c is as salty as eating 20 hot dogs. 

hot dog salty

In the hospital we have to think about this sort of sodium load. A healthy person can tolerate this much sodium- slowly. But even smaller amounts can cause trouble. Some people need saline and need it fast for giving back their volume. Giving a large bag (a liter) of saline to a person with kidney failure, liver failure, or heart failure exceeds their recommended daily intake of 2000mg of sodium (a liter of normal saline contains 3542mg of sodium). Sometimes we can inadvertantly cause issues like pulmonary edema when giving such fluids. We can definitely cause these issues with high dose vitamin c if we are not thinking about it. Fortunately there are ways to prevent these complications and continue giving the patient benefits from vitamin c.