13 Health Benefits of Blueberries for Your Eyes and Body
Blueberries are one of the most popular functional foods, and no list of superfoods is complete without them. But what does actual science have to say?
Blueberries are the fruits of the Vaccinium sect. Cyanococcus perennial flowering shrub. They're the most researched and most praised of all the berries for their high antioxidant content.
They come from either wild varieties (lowbush) or cultivated varieties (highbush). Lowbush blueberries tend to be smaller and more intensely colored—they also pack the most health benefits.
What Makes Blueberries So Healthy?
Blueberries are one of the richest known dietary sources of antioxidants, which protect our bodies from free radicals caused by cellular processes and environmental factors. Free radicals are associated with a host of diseases and eye health problems and are in part responsible for ageing.
The antioxidants in blueberries include flavonoids, a type of polyphenol. But it’s the anthocyanins in blueberries that have spread their fame.
Blueberries are the richest source of anthocyanins (387 to 487 mg per 100 grams) among all popular fruits consumed in the United States. Anthocyanins are flavonoids, powerful dark blue antioxidants that give blueberries their color.
Blueberries are also a rich in Vitamin C and Vitamin K. A 100-gram serving provides approximately 16% of the daily recommended value of Vitamin C and 24% of the daily recommended value of Vitamin K.
They also pack lots of manganese, which is essential for brain and nerve health. Manganese helps the body form connective tissues, is important for metabolism, and regulates the absorption of blood sugar and calcium.
Blueberries may be small, but they also pack 2.4 grams of fiber per 100-gram serving, or about 10% of the daily recommended intake.
Good to know: Wild, lowbush blueberries provide more antioxidants than cultivated highbush blueberries.
Brief History of Blueberries
Long before highbush blueberries were commercially cultivated, the First Nations peoples of Canada used wild blueberries medicinally and for food.
They would make blueberry syrup to cure coughing as well as blueberry pudding by mixing it with cornmeal and honey. They would also dry the fruit for use during winter.
The commercial varieties of blueberries commonly found in stores derive from species native to North America. Wild blueberries grow spontaneously in parts of Europe, Asia, and South America as well.
The early 1900s saw the first highbush blueberry to be commercially cultivated by USDA botanist Frederick Coville and farmer Elizabeth White.
Blueberries have seen a massive rise in popularity in North America in the last decades, not least because of the encouraging research on their health benefits. In the US alone, blueberry consumption has grown from around 6 ounces per person annually in 1970 to around 39 ounces per person in 2018.
Like other fruits considered superfoods in the West, blueberries are also being used in Traditional Chinese Medicine (TCM), where they are believed to eliminate toxins and expel heat and dampness.
TCM practitioners prescribe blueberries to improve and maintain stomach, bladder, and liver health. In TCM, liver health is closely connected to the eyes. TCM practitioners believe that if your liver is unhealthy then your eyes may become dry or blurry.
Today, commercially-grown blueberries can be either highbush varieties, which have a larger fruit; or lowbush or wild varieties that have smaller berries and have a more intense dark blue to purple color.
In the US, July is USDA’s National Blueberry Month when the blackberry harvest reaches its peak. The US is the leading producer of highbush blueberries while Canada produces most lowbush blueberries. Blueberries are the largest fruit crop produced in Canada, which shows how popular these fruits have become.
Top Health Benefits of Blueberries Backed by Science
Are the anthocyanins and other beneficial vitamins and compounds in blueberries really beneficial to health? Or is it all just hype? Let’s take a closer look at the available studies to see what science has to say about it.
1. Blueberries Protect the Retina from Oxidative Stress
The retina is especially vulnerable to oxidative stress from UV light, pollution, and other environmental factors. Ageing increases markers of oxidative stress and inflammation, which is one of the reasons many people develop vision problems as they grow older.
The very high content of antioxidants in blueberries makes these fruits ideal for boosting your resistance to oxidative stress.
2. Blueberries May Decrease Your Risk of Cataracts
A Finnish study involving over 10,000 participants associated a high flavonoid intake with a reduced risk of cataracts. Cataracts are the leading cause of treatable blindness around the world.
3. Blueberries May Reduce the Risk of Age-Related Macular Degeneration
A cohort study of women over 45 years of age associated blueberry consumption with a lower risk of age-related macular degeneration.
Another study found that anthocyanidins inhibit the growth of extra blood vessels which develop as macular degeneration advances.
In the developed world, macular degeneration is the leading cause of vision impairment in ageing populations.
4. Blueberries May Help Manage Glaucoma
The eye health benefits of blueberries don’t stop there. A study on patients suffering from glaucoma found that a daily intake of 50 mg of anthocyanin from black currants for 6 months improved ocular blood flow and visual field defects. A cross-over study also noted benefits to intraocular pressure.
More studies are needed to confirm these effects from blueberries, but given their high anthocyanin content, they likely have similar effects.
5. Blueberries May Reduce Eye Fatigue and Ocular Inflammation
A high anthocyanin intake may also reduce eye fatigue for people suffering from myopia by improving contrast sensitivity.
Blueberries may also reduce inflammation in eye tissues, which can be responsible for both short-term and serious long-term eye health problems.
Anthocyanins in blueberries support blood circulation and help to keep the delicate capillaries in the eyes healthy.
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6. Blueberries May Help Manage Diabetic Retinopathy
Blueberries could also help in the management of diabetic retinopathy, one of the more unpleasant complications of type 2 diabetes. They do this by slowing down the rate at which glucose enters the bloodstream.
7. Blueberries May Reduce Blood Pressure
Consuming 50 grams of blueberries per day may reduce blood pressure in overweight people, according to this study.
Other studies found a similar effect on postmenopausal women. Blueberries’ beneficial effects on reducing blood pressure are frequently noted in medical studies.
8. Blueberries Help Preserve Memory and Brain Function
Blueberries in one form or another have been associated with improvements in cell signaling and brain function in older individuals with mild cognitive impairment.
Another interesting study suggests that blueberries may help delay mental aging by 2.5 years. This finding is in keeping with the Chinese view of the blueberry as a longevity fruit.
9. Blueberries May Have Anti-Cancer Properties
Phytochemicals in blueberries have the potential to inhibit the growth of breast cancer cells. Another study supports the possible anti-cancer properties of polyphenols in blueberries.
Meanwhile, an animal study found that mice fed whole blueberry powder alongside a high-fat Western diet had smaller tumors and less metastasis. Blueberries may also play a role in preventing liver cancer.
10. Blueberries May Speed Up Muscle Recovery
Do you enjoy going to the gym or doing long runs? A small study on female athletes found that blueberry supplements speed up muscle recovery. This is linked to the anti-inflammatory and anti-oxidative effects of compounds found in blueberries.
11. Blueberries May Prevent Heart Disease
A high anthocyanin intake has also been linked to a significantly lower risk of heart disease in adult women. More studies are needed to further investigate this finding, but blueberries appear to be one of the healthiest fruits to eat if you want to keep your heart and circulatory system healthy.
In 2019, the American Heart Association has certified blueberries as a heart-healthy food.
12. Blueberries Promote Bone Health
A rich source of vitamin K, blueberries contribute to bone health. Vitamin K deficiency is linked to a higher risk of bone fractures.
13. Blueberries Promote Digestive Health
Last but not least, these delicious little fruits are good for the gut too. Dietary fiber plays an important role in the health of your intestines, and blueberries are a good source of fiber. You can get around 2.4 grams of dietary fiber from a 100-gram serving of blueberries.
How to Add Blueberries to Your Diet
Blueberries are one of the most versatile fruits around. To boot, they can be part of a low-cholesterol, heart-hearty, or diabetes diet.
We can’t blame you if you snack on them fresh. But there are many different ways you can use them whether they’re fresh, frozen, or dried. Let’s explore the most delicious and convenient ones.
Important: The outer layer of the blueberry contains almost all the anthocyanins, so you don’t want to throw it away!
Fresh Blueberries Uses
Fresh blueberries are the easiest to find in stores. Remember that larger fruits are highbush varieties while smaller ones tend to be lowbush. You can use either in lots of ways.
- Mash them to create a delicious breakfast spread—it’s great to start your day with a big dose of antioxidants.
- Add them to your morning breakfast cereals or oatmeal.
- Add to whole grain pancakes and waffles.
- Add them to muffins, pies, tarts, and other baked goods.
- Use them to top fruit cakes or vanilla cakes.
- Add them to green salads alongside nuts and seeds.
- Toss them into a fruit salad bowl with bananas and other berries.
- Make a blueberry topping for vanilla ice cream by cooking them with water and sugar—you can also use this topping for other desserts.
- Make blueberry jam in a saucepan that you can enjoy throughout all seasons. You’ll only need sugar and a bit of lemon juice.
- Blend them into a purple-blue smoothie with Greek yogurt and other fruits.
- Blend with blackberries and orange juice into a deliciously healthy fresh juice.
Frozen Blueberries Uses
Blueberries harvested when ripe and quickly frozen retain their health benefits. Take them out of the freezer a few hours before eating and let them defrost at room temperature. Or defrost them in the fridge overnight.
- Make a quick summer-cooling smoothie—no defrosting needed.
- Use frozen blueberries to make a delicious blueberry coconut ice cream with bananas and refrigerated coconut cream.
- Eat them with whipped cream.
- Make yogurt ice cream by simply putting some into low-fat yogurt.
- Add them to oatmeal—no thawing needed.
- Make blueberry sauce for main dishes or desserts—it cooks better with frozen blueberries. You’ll need a bit of sugar and lemon juice and water.
- Use them as ice-cube replacements—throw frozen blueberries into sparkling water.
Dried Blueberries Uses
You can also enjoy blueberries dried. Have a supply of them tucked away in your pantry for when you run out of fresh berries.
- Mix them into homemade granola bars.
- Bake them into desserts.
- Throw some into homemade bagel dough.
- Mix with nuts and seeds to create a health-boosting trail mix or after-gym snack.
- Cook with balsamic vinegar and water to make a delicious sauce for lamb or duck stakes.
When to Avoid Blueberries
As we’ve seen, blueberries are a rich source of Vitamin K. This vitamin helps to make some of the proteins the body needs for blood clotting.
Suddenly increasing or decreasing your intake of blueberries can affect levels of Vitamin K in your body. This doesn’t mean you can’t eat blueberries if you’re taking blood thinners. But it’s best to discuss this with your doctor and not overheat blueberries and related products.
How to Grow Blueberries in the Garden
Growing blueberries at home is a great way to eat more of them more often. Highbush blueberries are the easiest to grow. You’ll find many cultivars adapted to your region. You can generally find them at your local gardening center or in online stores.
Blueberry plants grow slowly. Bare-root plants 2 to 3 years old are easier to grow compared to growing blueberries from seed. They will also yield fruit sooner. You can grow blueberries in the soil or in a container.
Good to know before you start: Blueberries grow best in acidic soil with a pH between 4 and 5. It’s best to test the soil and add peat moss or granulated sulfur several months before planting to amend it if needed.
The best time to plant blueberry bushes is in early spring. Grow at least two different varieties to help the plant cross-pollinate.
- Plant your blueberry bush in a sunny spot away from trees and sheltered from the wind. A bit of shade won’t hurt the plant, but too much will stunt its growth.
- Plant multiple bushes in a patch. You can plant them in rows, spacing them around 3-5 feet apart depending on the size of the variety you choose. Make sure to leave enough room for harvesting between rows.
- Don’t plant them more than half an inch below ground. Plants grown in a container can go as much as one inch deeper.
- Water well after planting and then water regularly. The soil should be kept moist but not soggy.
- You can use a balanced fertilizer one year after planting. Keep in mind that yellow leaves are more likely to be the result of iron deficiency caused by a high pH rather than a lack of fertilizer.
- You can sacrifice the blossoms of the plant in the first year to redirect energy into the plant becoming better established. You can then prune plants after the 4th year in early spring or late winter.
- Be patient. While you may enjoy a bit of a harvest in the first year, the plant will need several years to produce mature harvests. Mature harvests can be bountiful, with a single bush producing 7 to 8 kilograms of fruit during the summer.
- You can also grow blueberry bushes in a container with drainage holes. Make sure to pick a potting mix fit for plants that love acid soil. You can also add mulch to maintain moisture. During winter, cover the container with straw or move it to a sheltered area.
Tip: Birds love blueberries at least as much as humans, so you may have to protect the plant with bird netting.
Add Some Healthy Blue to Your Menu
Blueberries are one of the more accessible superfoods. And with so many ways to use them, adding them to your everyday menu shouldn’t be too difficult.
Remember: you’re more likely to enjoy their health benefits if you eat them regularly.
Another easy way to incorporate them into your diet is to use a supplement that mixes blueberry extracts with other powerful fruits and plants. This way you can enjoy the eye health benefits of blueberries alongside their more general health benefits.
The best part? Blueberries are delicious, and you’ll enjoy every little one. Healthy foods never tasted better!