Are berries good for the eyes?
During World War II, the British Air Force ate bilberry jam. Not only did it taste good, but according to the reference book Comprehensive Medicinal Chemistry II, they believed the berries improved night vision.
Do bilberries improve night vision?
Like blueberries, they’re great sources of anthocyanins. And substantial evidence says that anthocyanin-rich foods are good for the eyes.
The Journal of Agricultural and Food Chemistry lists the concentrations (per 100 grams) of several widely-consumed berries in descending order:
- Raspberries 390 mg
- Blueberries 365 mg
- Blackberries 245 mg
- Cranberries 140 mg
- Strawberries 21 mg
And cancer researchers from the Northeastern Ohio Universities Colleges of Medicine and Pharmacy report an impressive 250 mg of anthocyanins per 100 grams of black currant berries.
However, the actual anthocyanin content per serving of any berries can vary greatly. That’s true of most natural ingredients; huge differences in nutrient content occur within the same types of fruits.
So, to get their benefits, must we consume a specific number of anthocyanin milligrams every day?
Not necessarily, according to Dutch researchers in a research review published this week by the International Journal of Molecular Sciences. They found that berries’ beneficial effects on cognitive performance weren’t dose-dependent.
In other words, it isn’t a case of “the more anthocyanins, the better.” A small daily handful of berries should be enough to provide health benefits.
But besides bilberries potentially helping night vision, how else are berries good for the eyes? Let’s see what the research says!
In What Ways Are Berries Good for the Eyes?
Have you ever looked into the sun and walked away seeing white spots? If so, you’ve experienced photobleaching.
It happens because your eye’s rods (responsible for your color vision) go transparent when exposed to intense light. Photobleaching can be temporary or permanent.
Photobleaching reminds me of an experience I once had with a hard-core vegan employee who had some strange ideas. He was so committed to his lifestyle that he’d spend his breaks doing yoga and transcendental meditation.
As I passed him one day while he was staring at the sun, he asked, “Do you ever stop and just stare at the sun?”
“No,” I responded. “My mom always said that’s a good way to lose your eyesight.”
“Naw, man. You get sooo much energy from the sun!”
Shaking my head, I walked away. He worked for me for another year. Last I heard, he was teaching yoga and meditation in Thailand.
He certainly experienced temporary photobleaching by staring into the sun. I’m not sure if he did permanent damage.
In any case, he may have been a prime candidate for a 2014 Canadian study on blueberries and vision headed by food researcher Dr. Wilhelmina Kalt, Ph.D.
One of its trials tested the participants for photobleaching, night vision, and dark adaption. It was seeking a partial answer to the question, “Are berries good for the eyes?”
Its two different placebo-controlled crossover studies – with 72 and 59 participants respectively – yielded similar results.
The dramatically different blueberry anthocyanin doses:
- 271 mg (blueberry juice)
- 7.11 mg (blueberry juice)
- 346 mg (blueberry juice powder)
- placebo (fake)
showed no improvement in dark adaptation or night vision.
However, the three groups receiving the blueberry juice or powder enjoyed a noticeable improvement in photobleaching, regardless of their anthocyanin dose.
Dr. Kalt’s team observed that the blueberry groups’ time to “recover visual acuity after exposure of the retina to bright light showed significantly shorter recovery times” than the placebo group.
Maybe my former employee’s berry-packed vegan diet (along with a lot of luck!) helped him recover more quickly from photobleaching?
Berries Consumption and Glaucoma
Normal-tension glaucoma (NTG) results when abnormally high pressure inside the eye damages the optic nerve. Estimates indicate that by 2024, nearly 112 million people will suffer from glaucoma.
Researchers from Japan’s Hirosaki University Department of Opthalmology examined the effects of black currant tablets on people with NTG.
Every day for six months, the study’s 30 enrollees took a black currant tablet. During that time, their blood and eye pressures were unchanged. However, the blood flow to specific retinal areas “significantly increased.”
More importantly, not one had their “visual field defects” worsen during the study. The researchers concluded that anthocyanins might be “a safe and valuable choice for neuroprotective treatment of patients with NTG.”
Are berries good for the eyes?
According to current research, bilberry jam probably didn’t improve the pilot’s night vision, but the British Air Force wasn’t far off the mark. The benefits from their anthocyanins-rich berry intake included an increase in visual acuity, faster recovery from photobleaching, and a reduction in NTG risk.