Allergens, especially those in the form of allergens, can cause a range of symptoms, from itching to runny nose to wheezing.
But a new Australian study suggests the symptoms may not be related to using herbalife products.
Allergied individuals are likely to have lower levels of specific IgE antibodies, a marker of allergy, than the general population, but the same is not true of those who have used the products, according to the new study published in the journal Clinical Allergy.
In this article, a team of Australian researchers describe how a new analysis of allergy tests was conducted and compare it to a recent Australian study.
A team of researchers at the University of New South Wales analysed the clinical symptoms of 3,000 people with allergies who used herbalife and 3,600 people who did not.
The results were released today in the Australian Journal of Allergy and Clinical Immunology.
The research team found there was no evidence that those who used the herbalife product had an increased risk of developing allergy symptoms, but a higher risk of allergic rhinitis and eczema was found among people who had used the product.
The study found a similar number of people with allergic rhimias had used herbalisers than those who did no.
The researchers also looked at people who reported having allergies but did not use any of the herbalisers.
In their analysis, the researchers found people who used a herbaliser and did not have an allergy had similar numbers of specific antibodies as those who had never used a product, but there was also a greater likelihood of having allergies when they had used a higher number of herbaliser products.
These findings suggest there is no evidence to support the use and marketing of herbal products, the team said.
“This suggests the use in allergy sufferers is not associated with increased allergy risk,” said lead author Dr Helen Fenton.
“People may also have a lower prevalence of allergic symptoms in those who are not allergic to herbal products.”
Dr Fenton said her team’s analysis was consistent with previous research showing herbalife was associated with allergic symptoms, although it was not clear why.
Dr Fentons study team is led by Dr Michael Kelly from the School of Pharmacy at the Queensland University of Technology.
They studied data from a sample of 3.8 million people with a wide range of allergy symptoms.
“We found no association between allergy and use of medicinal herbs, but we did find an association between the use or non-use of medicinal herb products and a higher prevalence of allergy,” Dr Fentsons study said.
This study has limitations, the authors said.
It does not investigate whether the people who are allergic to medicinal herbs are also allergic to their own body fluids, and whether the results are generalised to people who use other herbal products.
A second study looked at the use by people with asthma and a range the use herbalised products.
The authors also found the same patterns were seen, with a greater risk of asthma symptoms being associated with the use a greater number of medicinal herbal products than those using no herbal products and no herbaliser.
Dr Kelly said the results of their study were also in line with a previous study.
“While we found that the use [of herbaliser] is associated with an increased prevalence of asthma, we also found that those using herbaliser did not differ from the non-users in terms of asthma severity,” Dr Kelly told the ABC.
Dr Jules Dornbusch from the University College, Sydney, who was not involved in the research, said the findings were “quite interesting” and suggested it was possible there were some people who were allergic to a certain herbal product but were not allergic.
“I would be surprised if there is a significant difference between the groups,” he said.
But he said there was little evidence that the products were the cause of allergic reactions, but he urged people to not take their asthma seriously.
“For those who do develop asthma, it may be helpful to consider using a natural alternative to herbalisers and other alternative therapies,” he told the BBC.