Vitamin C increases diamine oxidase, which metabolizes excess histamine, reduces blood histamine, and protects cells from immune stimulating oxidization, making Vitamin C one of the most effective anti-histamines.

Vitamin C is not, however, a mast-cell stabilizer as it does not stop histamine degranulation from mast cells.

Vitamin C deficiencies, however, are extremely common with histamine type symptoms.

Vitamin C Increases Diamine Oxidase

Testing for Vitamin C Sufficiency

A simple blood test, to measure fasting plasma ascorbate, will establish vitamin C status. To be reliable the blood test should be fasting and no vitamin C should be taken for 12 hours prior.

Alternatively, a vitamin C deficiency can be deduced from:

  • A basic blood panel when interpreted from the narrow functional "health" ranges. Most blood tests results are based on sickness not on health ranges.
  • The Organic Acids Test also has a urine-based marker for vitamin C sufficiency.

The fasting plasma ascorbate blood tests, however, is a more direct measure of vitamin C.

What Causes Vitamin Deficiency?

Vitamin C is an essential nutrient that can become depleted where:

  • A diet is low in vitamin C rich fresh fruit and vegetables, or
  • There is an abnormally high level of cellular stressors, including emotional stress, viruses, venoms, poisons, heavy metals, toxins, allergens, cigarette smoke, and microbes, that consume vitamin C, or
  • Physical illness, including cancer, hyperglycemia, and diabetes.

As such, Vitamin C levels can be seen not only as an indicator of histamine levels but an overall marker of health.  Simplistically, the higher the depletion, the more chronic the condition.

Vitamin C Rich Foods

Where the deficiency is due to poor diet, or mild, it makes sense to start by increasing fruit and vegetable intake.

To boost levels further, there are four Vitamin C super-nutrients, which are easy to slip into a smoothie including:

  • Kakadu Plum (Gubinge)  - Kakadu plum is a native fruit of Australia. It has the highest concentration of Vitamin C of any food. Just 15g will provide 2g of Vitamin C. I use the Loving Earth Wild Harvested Gubinge.
  • Camu Camu - Camu Camu is a native fruit of Peru. It has a high concentration of Vitamin C (second only to Kakadu Plum). Just 17g will provide 2g of Vitamin C making it a substitute for Kakadu Plum. It has a consistency and taste similar to Kakadu Plum so I tend to just use one or the other.
  • Rosehips - Whilst Rosehips contain less vitamin C (relative to Kakadu plum or Camu Camu) they also contain high levels of anti-oxidants and flavonoids.
  • Aloe Vera - whilst not strictly rich in vitamin C it has been shown to boost gastric absorption of vitamin C by as much as 300%.  As its also a mast-cell stabilizer it makes sense to include this in the diet.

Vitamin C Supplement

Vitamin C can also be used therapeutically to help manage chronic conditions.

Here is a quick summary of current research findings:

  • For general health, around 200 milligrams (if not obtained through dietary supplementation).
  • For histamine intolerance between 1 - 3 grams a day, with 2 grams a general recommendation.
  • For diabetes or a suppressed immune system at least 6 grams a day.
  • For bacterial or viral infections, including UTIs, taking 1 - 2 grams every hour for 6 - 8 hours on the day of onset.
  • Higher longer-term doses (such as 1- 4 grams each hour) may be indicated in acute cases under supervision.
  • Frequent small intakes are much better than single large daily dosage as Vitamin C has a short half-life.

Oral Vitamin C is poorly absorbed (only 20% is typically absorbed) and has a bowel tolerance limit.

If there is a high need for vitamin C liposomal formulas which are nearly 100% absorbed and have no bowel tolerance limit is more practical. Whilst intravenous Vitamin C can give rapid relief in a crisis (for example an anaphylactic shock).


Vitamin C is generally safe with a few exceptions. It aggravates oxalate issues and worsens genetic hemochromatosis.

2 grams is generally considered safe. Other than that, at long-term higher doses, it can:

  • Remove heavy metals. The use of binders should, therefore, be considered.
  • Upset trace minerals such as copper, zinc, and magnesium.  A trace mineral supplement should be considered.  High levels of vitamin c may also be difficult in cases of unbound copper.
  • Reduce estrogen, which if low may worsen low estrogen symptoms. Estrogen levels should be monitored.
  • Lead to osteopenia or osteoporosis, if calcium is low.  Calcium levels should be monitored.
  • Vitamin E should also be given, as they work symbiotically.

This is why at higher doses long term should be done under supervision where any interactions can be monitored.


Along with zeolite, Vitamin C is one of my go-to remedies.

So if you are having histamine flares it is a clue that your vitamin C levels might be insufficient.

Rather than reaching for an anti-histamine, which is designed to stop your body responding, you may want to consider increasing your vitamin C, and giving your body the raw materials it needs to work as it was designed.


Additional Reading

Johnston, C. S. (1996). The antihistamine action of ascorbic acid. In Sub-cellular Biochemistry (pp. 189-213). Springer US.

Jarish, R, Editor (2015). Histamine Intolerance: Histamine and Seasickness.

Ricardo Gonzalez Alvarez, Milagros Garcia Mesa, Ascorbic acid and pyridoxine in experimental anaphylaxis, Agents and Actions, April 1981, Volume 11, Issue 1-2, pp 89-93.

Nandi, B. K., et al. "Effect of ascorbic acid on detoxification of histamine under stress conditions." Biochemical pharmacology 23.3 (1974): 643-647.

Oudemans-van Straaten, Heleen M., Angelique ME Spoelstra-de Man, and Monique C. de Waard. "Vitamin C revisited." Critical care 18.4 (2014): 460.

How Vitamin C Works


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