Blueberries are a very popular, tasty fruit.
Known scientifically as Vaccinium ssp., they are closely related to cranberries, bilberries and huckleberries.
Blueberries are native to North America, but they are now grown commercially in the Americas and Europe ().
They are low in calories and incredibly healthy. Eating blueberries may benefit heart and brain health, as well as help regulate blood sugar levels.
Blueberries have a pleasant, sweet taste. They are often eaten fresh, but are sometimes frozen or juiced. They can be used in a variety of baked goods, jams, jellies and for flavorings.
Blueberries are small, around 5–16 millimeters, or 0.2–0.6 inches, in diameter. They range from blue to purple in color.
Different kinds of blueberries exist, so their appearance may vary slightly. The two most common varieties are highbush and lowbush blueberries.
One cup of blueberries (148 grams) contains 84 calories.
The table below contains information on the nutrients found in blueberries ():
Most of the carbs come from simple sugars like glucose and fructose, but they also contain some fiber.
Blueberries have a score of 53 on the glycemic index, which is relatively low ().
This means that blueberries should not cause major spikes in blood sugar levels and are considered to be safe for diabetics.
Dietary fiber is an important part of a healthy diet and may have protective effects against various diseases ().
One cup of blueberries contains 3.6 grams of fiber. In fact, around 16% of the carb content is in the form of fiber.
Bottom Line: Blueberries are mainly made up of carbs and water. They also contain a decent amount of fiber.
Blueberries are a good source of several vitamins and minerals.
- Vitamin K1: Blueberries are a good source of vitamin K1, which is also known as phylloquinone. Vitamin K1 is mostly involved in blood clotting, but may also benefit bone health ().
- Vitamin C: Also known as ascorbic acid, vitamin C is an antioxidant that is important for skin health and immune function ().
- Manganese: This essential mineral is required for normal amino acid, protein, lipid and carbohydrate metabolism ().
Blueberries also contain small amounts of vitamin E, vitamin B6 and copper.
Bottom Line: Blueberries are a good source of vitamin K1, vitamin C and manganese. They also contain vitamin E, vitamin B6 and copper, to a lesser extent.
Blueberries are rich in antioxidants and beneficial plant compounds. These include:
- Anthocyanins: These antioxidants give blueberries their color and may reduce the risk of heart disease (, , ).
- Quercetin: High intake of this flavonol has been linked with lower blood pressure and a reduced risk of heart disease (, ).
- Myricetin: This flavonol may have a number of health benefits, and has properties that may help prevent cancer and diabetes (, ).
Anthocyanins are the main antioxidant compounds found in blueberries. They belong to a large family of polyphenols called flavonoids.
Anthocyanins are believed to be responsible for many of the beneficial health effects of blueberries ().
More than 15 different anthocyanins have been detected in blueberries, but malvidin and delphinidin are the predominant compounds (, , ).
These anthocyanins seem to be concentrated in the skin. Therefore, the outer layer of the berry is the most valuable part ().
Bottom Line: Blueberries are rich in beneficial plant compounds and antioxidants, especially anthocyanins, which may account for many of their health benefits.
Blueberries may have benefits for heart, brain and blood sugar health.
Heart disease is the leading cause of death in the world ().
Studies have found a relationship between berries, or flavonoid-rich foods, and improved heart health (, ).
Some studies suggest that blueberries may have significant health benefits for people with high blood pressure, a major risk factor for heart disease (, ).
Blueberries may also inhibit oxidation of LDL cholesterol, a critical step in the heart disease process ().
An observational study of 93,600 nurses found that a high intake of anthocyanins was linked to a 32% lower risk of heart attacks ().
Bottom Line: Blueberries may decrease the risk of heart disease by lowering blood pressure and inhibiting oxidation of LDL cholesterol.
As the number of people over the age of 65 increases worldwide, so will age-related conditions and diseases.
Interestingly, a higher intake of flavonoid-rich foods has been associated with better brain function ().
Consuming blueberries may help prevent oxidative stress, which plays an important role in the aging process ().
Blueberries may also improve brain function directly. In one study, drinking blueberry juice every day for 12 weeks improved memory in 9 older adults with early memory decline ().
Another, six-year study found that blueberries and strawberries were linked to delays in brain aging by up to 2.5 years in older adults ().
Bottom Line: Several studies have shown that blueberries may play a role in brain health, delaying age-related decline and helping improve brain function.
Blood Sugar Control
The prevalence of type 2 diabetes is increasing rapidly worldwide ().
People with diabetes are sensitive to rapid changes in blood sugar, and need to be cautious when they eat foods rich in carbohydrates.
Blueberries contain moderate amounts of sugar, at 15 grams per cup.
They do not have adverse effects on blood sugar levels, which may be due to their high content of bioactive compounds.
Test tube studies suggest that the anthocyanins in blueberries can have beneficial effects on blood sugar control (, ).
Human studies have also shown promising results.
One study found that two blueberry smoothies a day for six weeks helped improve insulin sensitivity in obese people who were at a high risk of developing diabetes ().
Blueberries may also affect blood sugar levels directly after a high-carb meal by blocking certain digestive enzymes and reducing blood sugar spikes ().
Read this article for more on the health benefits of blueberries.
Bottom Line: Several studies indicate that blueberries may lower blood sugar levels and improve insulin sensitivity.
When eaten in moderation, blueberries do not have any known adverse effects in healthy individuals.
Allergy to blueberries does exist, but is extremely rare ().
Bottom Line: Blueberries are well tolerated when eaten in moderation, and allergy is very rare.
Blueberries are a popular, delicious fruit.
They are a good source of vitamin K1, vitamin C, manganese and several other beneficial plant compounds like anthocyanins.
Consuming blueberries on a regular basis may help prevent heart disease, improve brain health and help moderate blood sugar levels.