Claims for blueberry extract doubted
Evidence 'lacking' for improved vision
People taking blueberry or bilberry extract to boost their night vision had their eyes opened yesterday.
The Consumer Council warned that scientific evidence 'is sadly lacking' to support manufacturers' claims for such products - and said there was a chance they could carry harmful side effects.
The warning comes after a council study, undertaken with the collaboration of academics, dietitians and pharmacists, together with the Department of Health and the Centre for Food Safety.
The department is investigating whether the claims violate the Undesirable Medical Advertisement Ordinance and says 'appropriate action' could be taken.
In a report headed 'The Myth of Blueberry Extract as Eye-Vision Booster', the council said dietary supplements made from blueberries or bilberries had been heavily promoted recently.
Some of the benefits listed included an improvement in night vision, and having anti-oxidant properties and an anti-inflammatory effect.
But there was no scientific evidence proving that the products could improve vision, the council said, also noting that a medical expert had said such extracts could lower blood sugar or blood pressure, or cause diarrhoea.
Lawmaker Fred Li Wah-ming, a council member, reminded the public to be careful of exaggerated claims in advertisements and said they should eat natural fruit instead of concentrates.
A Chinese University eye expert said laboratory studies had shown that anthocyanins, a group of water-soluble pigments found in berries and various fruits and vegetables, might carry some potential beneficial effects to visual health, but these had not been confirmed by proper clinical trials.
'I think nowadays we're bombarded with lots of messages about the beneficial effects of taking blueberry and bilberry,' said Clement Tham Chee-yung, a professor in the university's department of ophthalmology and visual sciences.
'My important message is not saying these things aren't beneficial but rather we do not yet have scientific evidence to confirm a lot of these claims.'
Professor Tham said people with such conditions as hypertension or diabetes should 'really be careful or should consult their doctors before consuming such products'.
Such conditions could affect vision so patients might be more likely to buy vision-enhancing supplements, but he stressed that taking too much anthocyanin might affect their other medications.
Professor Tham added that anthocyanins could also be found in products such as strawberries, grapes, cherries and sweet potatoes. He urged the public to stick to a well-balanced diet.
A spokeswoman for Universal Pharmaceutical Laboratories, distributor of Jamieson Laboratories' bilberry-extract capsules from Canada, said it only distributed the products in Hong Kong and did not have their scientific backgrounds and research.
But she said that based on customer feedback, most were satisfied with the product and they said it worked well improving their vision.