People with allergies may find relief by using natural plant extracts and foods that act as antihistamines.
Antihistamines are substances that block histamine activity in the body. Histamine is a protein that triggers allergy symptoms, such as sneezing, itchy eyes, and a scratchy throat.
In this article, we describe the five best natural antihistamines, and we take a look at the science behind them.
1. Vitamin C
Vitamin C boosts the immune system. It also acts as a natural antihistamine.
According to a 2018 study on vitamin C in the treatment of allergies, oxidative stress plays a key role in allergic diseases. As vitamin C is a powerful antioxidant and anti-inflammatory, it may act as a treatment for allergies.
The researchers observed that high doses of intravenous vitamin C reduced allergy symptoms. They also reported that a deficiency in vitamin C might lead to allergy-related diseases.
Another study from 2000 suggests taking 2 grams (g) of vitamin C daily to act as an antihistamine.
The vitamin is present in many fruits and vegetables, including:
- bell peppers
- cantaloupe melon
- citrus fruits
- tomatoes and tomato juice
- winter squash
Vitamin C supplements, with and without bioflavonoids, are available in health stores, drug stores, and online.
According to the National Center for Complementary and Integrative Health (NCCIH), butterbur may have antihistamine effects.
A 2007 review of 16 randomized controlled trials, testing 10 herbal products, suggests that butterbur could be an effective herbal treatment for hay fever.
This review suggested that butterbur was better than a placebo, or as effective as antihistamine medications, for relieving allergy symptoms.
However, the authors of the review point out that some large studies received funding from industry manufacturers, and so further independent research is needed.
Most people tolerate butterbur well, according to the NCCIH, but it may cause side effects such as:
Raw butterbur extracts contain certain compounds called alkaloids that can cause liver damage and cancer. Extracts of butterbur that do not contain these substances are available. However, no studies have looked into the long-term effects of using these products.
The plant extract can also cause allergic reactions in people with sensitivities to ragweed, chrysanthemums, marigolds, and daisies.
Bromelain is an enzyme found in the core and juice of pineapples and is also available as a supplement.
Bromelain is a popular natural remedy for swelling or inflammation, especially of the sinuses and following injury or surgery.
Research on mice suggests that bromelain can reduce allergic sensitization and allergic airway disease thanks to its anti-inflammatory and anti-allergic properties.
In some people, oral supplementation of bromelain may cause adverse reactions such as:
- changes in menstruation
- digestive upset
- an increased heart rate
People who are allergic to pineapple should avoid bromelain.
Bromelain supplements are available at health stores and online.
Probiotics are microorganisms that might offer health benefits by helping the body maintain a healthful balance of gut bacteria.
Probiotics may boost a person's immune system, which can help the body fight off allergies.
The NCCIH say that the evidence for probiotics is mixed and that some probiotics may help while others may not.
Quercetin is an antioxidant flavonoid found in many plants and foods. Research suggests that adding quercetin to the diet may help to relieve allergy symptoms.
Research reports that quercetin can have anti-allergic and antihistamine properties.
In one animal study, researchers found that quercetin could reduce the respiratory effects of allergies in mice by lowering airway inflammation.
However, the evidence for its effectiveness is mixed, and according to the NCCIH, there is not enough evidence to suggest that quercetin can relieve allergic rhinitis.
Quercetin is naturally present in many foods and herbs, including:
- black tea
- buckwheat tea
- Ginkgo biloba
- green tea
- red onions
- red wine
However, taking supplements of quercetin will work better in the treatment of allergies than eating foods that contain it. This is because foods contain significantly lower levels of the flavonoid.
Quercetin is generally safe for most people. It may cause headaches and tingling in the arms and legs of some people. Very high doses, especially when taken long-term, may cause kidney damage.
People can buy quercetin supplements at health stores or online.