Most allergic reactions to vitamins are to ingredients in vitamin supplements and will not occur if the vitamin is consumed naturally in foods. Most vitamin C supplements are synthetic and contain other inactive ingredients that may be the cause of an allergic reaction. If you develop reactions only when you take a certain amount of vitamin C supplements, your symptoms may be common side effects and not related to an allergy.
Allergy to Supplements
An allergy to vitamin C supplements is uncommon, but can occur if your immune system overreacts to the supplement. The body creates immunoglobulin E antibodies, according to the America Academy of Allergy, Asthma and Immunology. IgE antibodies are created by the body only during an allergic reaction. They cause the production of other chemicals throughout the body, leading to allergy symptoms.
Allergy symptoms typically develop within a few minutes of ingesting the supplement. The skin is one of the first places most symptoms appear. You may notice tingling, itching or swelling in your face, lips or mouth. Skin rashes, hives and eczema are common reactions from a vitamin C allergy. Other symptoms may include asthma, sinus pressure, nasal congestion, shortness of breath, wheezing and sinus headaches. Your digestive system may react later with diarrhea, vomiting, nausea and abdominal pain.
Overdose of Vitamin C
The University of Maryland Medical Center states that taking more than 2,000 mg of vitamin C daily is not recommended. Taking this high a dose can lead to nausea and diarrhea. You may also develop an upset stomach and vomiting, especially if you've taken vitamin C on an empty stomach. These side effects are not related to an allergy; you simply need to reduce the amount of vitamin C you take. The recommended amount for an adult is 75 to 90 mg per day.
Sources of Vitamin C
Vitamin C is a necessary nutrient. Not only is it an antioxidant, but it's vital for healthy tissues and wound healing. The body doesn't manufacture it, so you must ingest it. If you are sensitive to the supplements, don't worry, because many foods are rich sources of vitamin C, particularly citrus fruits. Other great sources are cantaloupe, green peppers, all sorts of berries, tomatoes, broccoli, winter squash, sweet potatoes and white potatoes.