Foods to help fight allergies

Onions contain a compound called quercetin, which is scientifically proven to have an anti-allergic action. Studies show that quercetin performs various functions in the body. It reduces inflammation, suppresses the production of IgE antibodies (the antibodies that your body produces against allergic substances) and inhibits the release of histamine.

Apart from onions, quercetin is also found in apples and berries like strawberries and blueberries, and black currants.

Animal studies show that topical application of red onions can reduce the symptoms of allergic rhinitis. 

Studies have also shown that eating raw onions can reduce the signs of allergy in some people. However, since onion is also a known food allergen, it is best to avoid it if you have a history of allergic reactions with previous use.

Read more: Home remedies for allergic rhinitis

Vitamin C reduces inflammation in the body without suppressing the normal immune function. Experts say that the levels of ascorbic acid are significantly reduced during allergic reactions or in those who have allergy-related diseases. And supplementation with vitamin C helps manage the symptoms of allergies.

This is because vitamin C can reduce the production of histamines and stimulate the removal of the histamines that are already present in the body. 

In a randomised placebo-controlled study done on 48 subjects, vitamin C nasal spray was found to reduce the symptoms of allergic rhinitis. Another study indicated that oral intake of vitamin C causes a reduction in allergic rhinitis symptoms.

Some of the vitamin C-rich foods you should include in your diet are citrus fruits like oranges, lemons, lime, kiwi, pineapple, green leafy vegetables like spinach and cabbage, broccoli, and potatoes. You can also take vitamin C in the form of supplements. However, it is best to consult a doctor before taking any supplements since an overdose of vitamin C can cause stomach cramps, nausea and diarrhoea.

Read more: Home remedies to get rid of excess mucus

Pineapple is one of the richest sources of vitamin C, which makes it an excellent food for reducing allergy symptoms. However, this tropical fruit has another anti-allergic compound - bromelain - that makes it the perfect choice of food to keep off allergic reactions. 

Animal studies suggest that bromelain modulates the immune system so that it does not produce an allergic reaction even in the presence of an allergen. Bromelain also has shown anti-inflammatory properties on oral administration.

Read more: Home remedies for chest congestion

Ginger is rich in both antioxidant and anti-inflammatory compounds which not only help to reduce the symptoms of allergy but also help prevent allergic reactions.

Preclinical (animal studies) studies indicate that the antioxidant action of ginger is equivalent to that of vitamin C.

According to a study published in the Canadian Journal of Physiology and Pharmacology, ginger prevents airway contraction that occurs in most respiratory diseases.

You can add ginger in your food or take it in the form of a tea. To make ginger tea, you will need:

• Half inch piece of ginger, grated
• One cup of water
• A saucepan
• Honey (optional)

How to make it:

• Add the ginger to the water and let it come to a boil.
• Let the water simmer for 5-10 minutes.
• Strain the solution and drink.
• To add some flavour to the tea, you can add honey to taste.

Turmeric is traditionally used for the treatment of allergies and other respiratory conditions like asthma. 

The anti-allergic properties of turmeric have been attributed to the presence of a compound called curcumin in it. Curcumin is proven to be an immunomodulatory compound. It reduces the release of histamines, thus suppressing allergy symptoms. Turmeric also prevents inflammation - a common symptom in allergies. 

A randomised double-blind study with 241 allergic rhinitis patients found that oral administration of curcumin can improve nasal airflow within two months. 

Just like ginger, turmeric can also be added in tasty and healthy recipes. You can also take turmeric in the form of golden milk or turmeric milk. Just add 1 teaspoon of turmeric in a cup of milk. If you like, add honey to taste.

Probiotics are microorganisms that are known to be beneficial for health. They are mostly some form of lactic acid bacteria. Though other bacteria like Bifidobacteria and Streptococcus are also used as probiotics. 

Various studies show the beneficial effects of probiotics in the prevention and management of allergic reactions like atopic dermatitis, allergic rhinitis, and asthma. 

Probiotics reduce the levels of inflammatory markers in blood and balance the levels of IgE in allergic rhinitis patients.

A meta-analysis found that children born to women who take probiotics during pregnancy have a lower chance of developing eczema. (Read more: What to eat and what not to eat during pregnancy)

Probiotics are available in the form of supplements (tablets and pills). However, you can also take probiotics in the form of foods. Probiotic foods include dairy products like yoghurt, fermented milk, lassi and chhachh, and from preparations like miso (fermented soybean and rice koji) and kimchi (fermented cabbage).

Fatty fish, especially those that are rich in omega-3 fats are considered to be good for preventing and managing allergies. 

Evidence suggests that if women take fatty fish during pregnancy, their children are less likely to develop allergies.

A recent study indicated that the levels of omega-3 fatty acids in your serum (blood) are inversely proportional to your risk of getting respiratory allergies.

Some fish that are rich in omega-3 fatty acids are salmon, sardines and trout. You can also get omega-3 fatty acids from fish oil, which is available in the form of capsules in the market. However, it is best to ask your doctor before taking any supplements.

That said, shellfish and fish allergy are among the most common food allergies in the world. People who are allergic to seafood should obviously avoid eating it.