Bilberry Extract and Vision
What the research says about bilberry for vision.
What Is Bilberry Extract?
Because fresh bilberries are nearly impossible to come by in the U.S., consumers gobble up bilberry extract, one of the top-selling herbal supplements in the U.S., with sales of $28 million in 2010.
The standardized amount of anthocyanosides contained in bilberry extract is 25%. In a bilberry itself, anthocyanidin content ranges from 300 mg to 700 mg per 100 grams of fruit (3.5 ounces), depending on the region where they are picked.
In recent studies of the extract's effects on health, the most compelling evidence is its reduction of retinal inflammation -- although studies have been small and mostly conducted in lab animals.
However, research has not turned up conclusive evidence about bilberry extract's effect on blood glucose levels, or heart or gut health.
Is Bilberry Extract Safe to Take?
Bilberries are safe to eat and to take in extract form, according to the Natural Medicines Comprehensive Database, a compendium of information on herbs and their medicinal properties.
But because anthocyanosides prevent blood platelets from sticking together, bilberry extract may interfere with anticoagulant drugs like warfarin, Kiefer says. "I would use it with caution, due to some of those reports,'' he says.
There is also a question of quality. Foster cautions against buying cheap bilberry extract, which could contain chemicals like dyes. And he advises staying away from bilberry extract that is light in color. That's a tip-off that the content of anthocyanosides may be low.
"It's important to buy from trusted sources," Foster says.
Where Can I Find Bilberries?
Don't put on your dungarees and grab a pail. Bilberries are not easy to find in North America, says Foster. However, it's possible to find bilberry jam, which Foster spreads on his morning toast.
In general, Lausier advises consumers to stick with blueberries or other dark berries if they're looking for a natural source of antioxidants. They scavenge for free radicals, substances that damage healthy cells, she says, and as a low-glycemic index fruit, they're absorbed slowly, making blueberries a fine snack for people with or without diabetes.
"It's one of those things we have no trouble recommending in a diet. They're tasty, they're available, and most people like blueberries," she says.
Kiefer agrees. "There are a lot of us focusing on what's local," he says. "Are there blueberries or blackberries in your backyard? Go for it.''