Carambola is a food which may result in allergy symptoms in sensitised individuals.

Carambola Allergy Test: Allergen Exposure

Carambola fruit originates from a tree which grows up to 12 metres in height. Carambola is cultivated in Southeast Asia, specifically in Malaysia, where it has been grown for several hundred years.

The fruit itself ranges from yellow to green in colour with a waxy rind which is partially translucent. It is between six and 13 centimetres in length with 5 longitudinal ridges which give the cross section of the fruit its characteristic shape, leading to the alternate name ‘starfruit’. The interior flesh holds up to 12 flattened seeds which are brown in colour.

Two main variants of carambola are cultivated, a smaller sour flavoured fruit which contains a high proportion of oxalic acid which lends it a rich flavour, and a larger version which contains less oxalic acid, with a consequently milder flavour.

The ripe fruit is commonly consumed in it’s raw natural state, as well as being sliced and added to salads or used as a garnish. The raw juice is also popular as a drink in it’s pure state or added to other beverages. Carambola can also be cooked as an ingredient in stews, puddings, curries and desserts, as well as in sherbets, jellies and relishes.

Carambola can also be preserved in a variety of ways including by stewing, pickling, canning drying or candying.

Carambola has traditionally been used for medical applications against a variety of illnesses or conditions, including haemorrhages, fevers, diarrhoea, eye afflictions, eczema, and kidney, liver and bladder complaints.

There is however a potential danger to health from the levels of oxalic acid found in the fully ripened fruit (discussed under Clinical Experience) below.

The oxalic acid content also means that carambola fruit can be pressed into service as a cleaning product. The more acidic types can be used to polish metal such as brass, as the juice effectively dissolves tarnish or rust. Carambola juice is also used as a stain remover, and the unripe fruit can be used in the application of fabric dyes.

Carambola Allergy Test: Allergen Description

To date no allergens have been characterised from carambola.

Carambola Allergy Test: Potential Cross-Reactivity

To date no cross-reactivity has been reported from carambola.

Carambola Allergy Test: Clinical Experience

While there are no studies reporting allergenic properties associated with carambola, there is anecdotal evidence to suggest that it may induce symptoms of food allergy in sensitised individuals.

Reports exist of nausea, vomiting, intractable hiccups, severe encephalopathy along with mental confusion, disorientation, agitation, and seizures, and occasional fatal outcomes in uraemic patients after having ingested carambola.

Additionally six patients in a dialysis programme were apparently intoxicated by ingestion of 2-3 fruits or 150-200ml of the juice, and developed a variety of symptoms – ranging from insomnia and hiccups, to agitation and mental confusion – which in one case resulted in death. The effects were believed to come from an excitatory neurotoxin in the fruit.

There is some evidence to suggest he cause of the adverse effect is the oxalate content of carambola. Carambola has also been observed to interfere with the metabolism of some drugs.