Vitamin C for Allergies

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Relief from itchy eyes and wheezy lungs

Picture a latex balloon filled not only with helium gas, but also confetti. What would happen if somebody took a pin to the balloon? An exhilarating POP! would accompany the explosion of confetti, creating not only a racket, but also a mess.

Histamine “confetti”

A certain type of immune cell is a lot like the confetti-filled balloon. The mast cell, as it is known, is found throughout the body and is filled with confetti-like granules rich in heparin and histamine as well as many other molecules that call other immune cell responders to the scene. These granules are released into the body when the mast cells “pop” in a process known as degranulation, which can occur in the event of injury, infection, or allergy. If you’ve ever had an allergic reaction, you know all too well the effects of the histamine release that follows mast cell degranulation – symptoms like inflammation, itching, sneezing, nasal congestion, and watery eyes.[1]

Vitamin C has been shown to reduce the histamine response seen in allergies and asthma.

Those with allergic conditions like asthma, eczema, and allergic rhinitis tend to have “leakier” or less stable mast cells than those without allergies, in large part due to greater activity of immunoglobulin E (IgE), the major antibody in allergic disease.[2] Mast cell stabilization and histamine degradation are thus prominent goals in the treatment of allergic conditions.

Also known as ascorbic acid, vitamin C has been shown to reduce the histamine response seen in allergies and asthma.[3],[4],[5] In addition to supporting the joints,^[6] building bone density,[7] alleviating anxiety,[8] reducing addiction-related cravings,[9] and enhancing resistance to infections,[10],[11] vitamin C is also a key player in taming allergic responses as one of the most readily available mast cell stabilizers.[12],[13]

Eosinophils, the allergic cells

In addition to mast cells, a type of white blood cell known as the eosinophil helps control the response seen in allergies and asthma. In healthy individuals, eosinophils comprise only 1-3% of all white blood cells in the body, but the count is higher in those with allergic conditions or asthma.[14] Eosinophils can also congregate in a specific body part and cause inflammation and tissue damage, as is seen in various advanced allergic conditions like asthma (when the eosinophils infiltrate the lungs) and allergic rhinitis (when they accumulate in the mucus membranes of the sinuses and nose).[15] The development of eosinophils occurs in the bone marrow, specifically when the marrow is stimulated by an immune cytokine known as interleukin 5 (IL-5).[16]

Thankfully, vitamin C might may help dampen these eosinophil-related pro-allergic events. In fact, vitamin C has been shown to lower IL-5 expression and reduce eosinophilic infiltration of the lungs in a study performed on rats with asthma.[17]

Antioxidant activity of vitamin C

Epidemiological studies show that vitamin C consumption is inversely related to asthma incidence, suggesting that diets low in vitamin C increase one’s risk of developing asthma. It has also been shown that those who already have asthma experience fewer symptoms of the condition when they take vitamin C supplements.[18]

Those who have asthma experience fewer symptoms of the condition when they take vitamin C supplements.

In addition to the above-described actions of vitamin C, the nutrient can further offer protection to the lungs by acting as an antioxidant. The free radical scavenging activity of vitamin C acts throughout the body, including the mucus membranes of the lungs. In this way vitamin C can protect the lungs against both the oxidative stress caused by products made within the body and by inhaled triggers from the environment.[19]

Vitamin C, adrenals, and allergies

Vitamin C is stored in many tissues throughout the body, with the highest concentrations residing in the adrenal glands.[20] Located above the kidneys, the adrenal glands produce cortisol, a hormone that not only helps us react to and deal with stress but also moderates our immune system response.[21] The same stress-driven signals that cause the adrenal glands to secrete cortisol also cause them to release ascorbic acid (vitamin C) into the blood.[22] In other words, the more stress we experience, the more our adrenal glands pump out ascorbic acid, and the more likely we are to become deficient in vitamin C. To make matters worse, cortisol itself slows the adrenal glands’ ability to accumulate the ascorbic acid they need to keep up. Putting it simply, stress cuts off the adrenal glands’ ability to absorb vitamin C while simultaneously draining the vitamin C reserves they contain.[23] This is one of the mechanisms by which stress can predispose us to allergic troubles, and why those of us dealing with high stress levels could benefit from some extra vitamin C in our diets and/or supplement regimens.

The more stress we experience, the more our adrenal glands pump out ascorbic acid, and the more likely we are to become deficient in vitamin C.

Because vitamin C is water-soluble, excess amounts are flushed out in the urine. Unlike vitamin D3, which can be stored in the fat tissue,[24] vitamin C passes through the body and then is literally flushed down the toilet. Humans, furthermore, are one of the few species on earth that cannot synthesize vitamin C and must obtain it from nutritional sources.[25] Regular intake of vitamin C is therefore important to ensure optimal health, in allergy season and beyond.

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