Kiwi allergies to open up synthetic flavour market?
after findings from a small study in the UK show that the kiwi
fruit appears to be a significant food allergen capable of causing
severe reactions, particularly in young children with other
allergic reactions, reports Lindsey Partos.
The market for nature-identical kiwi flavours falls well behind the most popular fruit flavours in the marketplace - apple and orange - and is just a fraction of the strawberry market.
Today, food makers tend to select natural kiwi extract over the synthetic equivalent in food formulations. But if the kiwi fruit proves to be a strong food allergen, alternatives to the natural extracts will grow in popularity.
"Commercially manufactured kiwi flavours are mostly found in hard-boiled candies and chewing gum whereas the fruit extract is predominantly used in yoghurt, ice cream and other dairy products. But kiwi flavours as a whole is a niche market," Werner Morf at Givaudan, the number one global flavours player, told FoodNavigator.com.
The research team at the University of Southampton that carried out the kiwi study - the first large detailed study specifically designed to investigate the clinical characteristics of kiwi fruit allergy - concluded that the potential food allergen can severely impact young children. But the team also highlighted the increasing incidence of the allergic reaction to this tropical fruit.
Kiwi fruit was first introduced into the UK diet in the late 1960s, and consumption has increased steadily since then, with over 31,000 tonnes of the fruit imported into the UK alone in 2002.
According to the researchers, in the 1970s very few allergies to kiwi fruit were reported but reactions were increasingly reported in the 1980s, predominantly in adults. It was not until the 1990s that the kiwi fruit allergy was more commonly reported in children and young infants.
Dr Jane Lucas, a paediatrician and clinical research fellow at the University of Southampton explained to FoodNavigator.com that having completed the clinical slice of the research, in the next phase of the study - funded also by the Food Standards Agency - the team will now try to understand why children and adults react differently to the fruit.
"We are currently undergoing trials in the laboratory to work out the impact of the kiwi proteins on adults and children. We have over 100 blood samples to analyse," said Dr. Lucas. This next phase is due for completion in 18 months time.
About 300 people took part in the first phase of the study by completing a self-administered postal questionnaire. Those who reported symptoms suggesting they were allergic to the fruit were invited to undergo clinical investigation of their reported symptoms.
A total of 45 people over the age of six years took part in this phase of the research, selected primarily by their availability and motivation to attend the research centre. "The study confirmed a definite allergy to kiwi fruit in over half of these patients," reported the researchers, whose findings are published in the July issue of Clinical and Experimental Allergy.
The age of patients at the time of their first reaction ranged from four months to 71 years, with a considerable 13 per cent reacting below the age of five years. Nearly three quarters of children of 5 years or less on the study had reacted on their first known exposure to the fruit in comparison with only a fifth of adults.
The timing and severity of reactions was also examined. Sixty four per cent of all subjects reported suffering symptoms in under five minutes. Reactions included tingling and sore mouth; swelling of the lips, tongue and face; rash; vomiting and abdominal pain; and, in the most severe cases, breathing difficulties, wheezing and collapse.
The most common symptoms were unpleasant itching and soreness of the mouth, with the most common severe symptom being wheezing. Severe symptoms were most likely to occur in young children. In addition, over a third of those who initially suffered a mild reaction subsequently had moderate or severe symptoms.
The researchers at Southampton were careful to point out that their study has limitations, not least because all those taking part were self-selected volunteers who contacted the study with suspected kiwi fruit allergy.
"This may explain the greater number of adult females taking part, as well as a fairly high percentage of subjects with severe symptoms," write the scientists.
Tough new rules in Europe on food allergen labelling will come into force later this year. Directive 2003/89/EC, amending Directive 2000/13, means that manufacturers will have to list all sub-ingredients of compound ingredients, and so allergens cannot be 'hidden'. But kiwi fails to fall into the list of potential allergens. "They slipped through the net when the proposals were aired," Dr. Lucas commented.