Introduction

Many of us have experienced the discomfort and annoyance of allergies and some face a daily battle of avoiding triggers which could cause life-threatening reactions. So, what exactly is an allergy? An allergy is the body’s immune response to a usually harmless substance, the substances that cause an allergy are known as an ‘allergen’.¹ In most normal people these allergens pose no threat, however, in allergic individuals, their immune system will inappropriately identify the substance as a foreign threat and consequently produce an inappropriate response known as an allergic reaction. For some people, this response can be minor such as itching restricted to one region, but in some individuals, the response is severe and can result in anaphylaxis. Anaphylaxis is a severe life-threatening condition and symptoms usually present within minutes of encountering the allergen and require immediate medical attention.

Symptoms of anaphylaxis include:²

• Swelling of the throat and tongue
• Respiratory obstruction 
• Difficulty swallowing and talking
• Wheezing and coughing
• Extreme fatigue
• Feeling faint and fainting
• Skin that feels cold to the touch
• Pale skin
• Raised hives or rashes

So, what causes the reaction?

When an allergic person is exposed to an allergen, the immune system overreacts by producing many antibodies called Immunoglobulin E (IgE).³ This IgE travels to certain cells which release chemicals such as histamine, starting the allergic reaction. Each type of IgE is specifically triggered by one type of allergen, which is why some people are only allergic to peanuts (because they only have the IgE antibodies specific to peanuts),  whilst others who have multiple allergies have a larger variety of IgE antibodies.

The most common allergens:⁴

• Foods: nuts (particularly peanuts), wheat, soy, shellfish, dairy
• Insect stings: bee, wasp, mosquito
• Medicines: commonly penicillin
• Animal dander (hair or flakes of skin)
• Latex
• Mould-producing airborne particles that can be inhaled

The promising  link between dragon fruit and allergy reduction

The pitaya fruit, most commonly referred to as dragon fruit, has been reported as having potentially medicinal properties including the potential to reduce the allergic response. There are several varieties of dragon fruit, the three are distinguished by the skin and flesh colour which are: yellow skin and white flesh, red skin and white flesh and red skin and red flesh. The seeds in all varieties are small and black, and the fruits are oval-shaped with a sweet and sour taste.⁵

The seeds within the dragon fruit are incredibly rich in molecules called antioxidants, notably an antioxidant called ‘tocopherol’.⁵ Antioxidants fight free radicals in your body which are compounds that can become harmful to the body if their levels become too high. The neutralising effects of antioxidants help defend the body from oxidative stress. Oxidative stress can trigger inflammatory responses which consequently produce free radicals, free radicals themselves can also cause inflammation which results in oxidative stress, creating a cycle of events.⁶ Oxidative stress occurs during an allergic reaction and therefore It has been proposed that introducing foods rich in antioxidants, such as dragon fruit, may help reduce the inflammatory process that occurs in an allergic response resulting in a much milder reaction. Moreover, Dragon fruit peel and pulp are extremely rich in vitamin C. Vitamin C (ascorbate/ascorbic acid) is one of the most effective antioxidants in human blood plasma.⁷

Studies of the use of antioxidants in reducing the allergic response

It has been proposed that allergic individuals may have a lower level of Vitamin C, which could contribute to a more severe allergic reaction through increased oxidative stress and inflammation. One group administered 71 allergic patients with an IV vitamin C drip. They found that between the start and end of the treatment, the allergy-related symptoms had reduced drastically, with 50% of the group not needing to take allergy-related medication besides vitamin C. The group also found evidence of naturally lower levels of vitamin C in all of the allergic patients.⁸

Another study concluded that dragon fruit has the potential to manage inflammation by reducing the levels of pro-inflammatory enzymes.⁹ These enzymes are also involved in the inflammation associated with the allergic response. Despite these findings, there is no rigid clinical trial data which supports an increased dietary intake of antioxidants in preventing the allergic response and therefore further larger-scale trials need to be conducted.¹⁰

How to incorporate dragon fruit into the diet

Despite the lack of large-scale clinical evidence of antioxidants in dragon fruit being effective in reducing the allergic response, there is still research suggesting a diet rich in vitamin C and antioxidants are beneficial in reducing inflammation and therefore could potentially minimise an allergic reaction. There are several ways in which you can incorporate dragon fruit into daily meals here are some examples:

Smoothies: combining dragon fruit with other vitamin C-rich foods such as mango and strawberries is a quick and efficient way to get a vitamin hit. Vitamin C absorption is optimised when eaten with iron,¹¹ so adding spinach, pumpkin seeds, or other iron-rich foods could heighten the benefits

Salads: cutting dragon fruit into small cubes and adding it to a salad or utilising its sweet and sour flavour for a salad dressing is another easy way to eat dragon fruit daily

A topping for yoghurt/granola: simply dicing dragon fruit as a tangy topping with other vitamin-rich fruits is an excellent micronutrient-dense breakfast. Using Greek yoghurt as a base is also a good way to get protein into the diet

Salsa: using dragon fruit as an alternative to tomato in salsa is a great vitamin-dense dip or taco topping¹²

Sorbet: blending frozen bananas, dragon fruit and a spoonful of honey creates a healthy and tasty sorbet. Swapping out a sweet treat you would normally have for this alternative is an easy way to incorporate dragon fruit into the diet while satisfying your sweet tooth¹²

Allergic individuals need to maintain a diet that avoids foods which could potentially trigger a reaction. Therefore, if an individual has many food-related allergies any new foods introduced should be introduced slowly and in small amounts, with constant checks for any unusual reactions. An allergy to dragon fruit is considered rare however, individuals who are allergic to fruit, particularly kiwi, are more likely to have a dragon fruit allergy and should exercise caution when consuming.⁶ 

Current allergy treatments 

Some current treatment examples for allergies include:¹⁴

• Antihistamines: antihistamines block histamine which is released during an allergic reaction by your immune system, therefore preventing or reducing a reaction. Antihistamines are usually taken orally as pills or liquids
  • Side effects: can feel drowsy and tired so it’s advised to take caution when driving
• Decongestants: decongestants are used for temporary relief of congestion in the nose and sinuses. They’re normally taken as a nasal spray or as a pill
  • Side effects: may cause headaches, increased blood pressure and irritability
• Corticosteroids: corticosteroids relieve some inflammation caused by allergies. They’re administered through nasal sprays, inhalers, eyedrops, pills (more severe inflammation) and skin creams (relieves itching and redness) 
  • Side effects: may vary depending on how they’re administered, orally they can cause more severe side effects such as stomach ulcers and cataracts, while skin creams often cause skin thinning and irritation
• Emergency epinephrine shots: used to treat anaphylaxis in severe allergic reactions, it's administered with a syringe that you inject yourself. Sometimes a second injection is needed and if this is the case an ambulance should be called.
  • Side effects: heart palpitations, weakness, vomiting

Due to the plethora of unpleasant side effects from allergy medications, allergic individuals are often looking for other avenues of allergy management with fewer side effects. Therefore, dragon fruit could be a viable and natural option for these individuals to try to minimise their reactions.

FAQs

Is over-consumption of dragon fruit harmful?

Due to dragon fruit being high in fibre, overconsumption or eating too much too quickly, can lead to diarrhoea, bloating and increased abdominal gas.¹³ However, it is considered safe to consume dragon fruit daily.

Where can I get dragon fruit?

Most supermarkets will stock dragon fruit all year around, however, its peak season is between June and September,⁶ and it is sweetest at this time of year. It’s also suitable for freezing to keep for longer.

Summary

There’s evidence to suggest that specific antioxidants, particularly vitamin C, can reduce oxidative stress and inflammation associated with the allergic response, potentially resulting in a minimised reaction. Dragon fruit seeds are rich in antioxidants and their peel and pulp are packed with vitamin C, highlighting them as a reliable source of dietary antioxidants which could aid allergic individuals. Although there is no rigid large-scale clinical evidence that dietary antioxidants significantly minimise allergic reactions, there are smaller-scale studies which suggest specific antioxidants such as vitamin C have anti-inflammatory properties which have been shown to reduce the inflammatory process of an allergic reaction. It’s easy and accessible to incorporate dragon fruit into your diet and is a good option for allergic individuals to try. Further research into the use of dragon fruit in reducing allergic responses needs to be conducted to provide concrete evidence.