Blueberries are a very popular, tasty fruit native to North America but grown commercially across the Americas and Europe (1).

They’re low in calories and incredibly healthy, potentially regulating blood sugar levels and aiding heart and brain health.

Often marketed as a superfood, blueberries are an excellent source of several vitamins, beneficial plant compounds, and antioxidants ().

This article reviews blueberries, including their nutrition and benefits.

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As a member of the heather family (Vaccinium ssp.), blueberries are closely related to cranberries, bilberries, and huckleberries.

These small, round berries are about 0.2–0.6 inches (5–16 mm) in diameter, and their color can range from blue to purple.

Different kinds of blueberries exist, so their appearance may vary slightly. The two most common varieties are highbush and lowbush blueberries.

Blueberries have a pleasant, sweet taste. They’re often eaten fresh but may also be frozen or juiced. They can be used in a variety of baked goods, jams, and jellies, as well as for flavorings.

SUMMARY Blueberries are small, round, purple or blue berries belonging to the heather family. Highbush and lowbush blueberries are the two most common varieties.

Blueberries are low in calories and fat yet provide decent amounts of healthy fiber.

A 3.5-ounce (100-gram) serving of raw blueberries has ():

  • Calories: 57
  • Water: 84%
  • Protein: 0.7 grams
  • Carbs: 14.5 grams
  • Sugar: 10 grams
  • Fiber: 2.4 grams
  • Fat: 0.3 grams

Carbs

Blueberries primarily consist of 14% carbs, 84% water, and small amounts of protein and fat.

Most of the carbs come from simple sugars like glucose and fructose, but blueberries also contain some fiber.

These berries have a score of 53 on the glycemic index (GI), which measures how quickly certain foods raise blood sugar levels (4).

As this score is relatively low, blueberries should not cause major spikes in blood sugar and are considered safe for people with diabetes.

Fiber

Dietary fiber is an important part of a healthy diet and may have protective effects against various diseases ().

One cup (148 grams) of blueberries provides 3.6 grams of fiber. In fact, around 16% of the carb content in these berries comes in the form of fiber.

SUMMARY Blueberries are low in calories and fat. They’re mainly made up of carbs and water but also contain a decent amount of fiber.

Blueberries are a good source of several vitamins and minerals, including:

  • Vitamin K1. This nutrient 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 important for skin health and immune function ().
  • Manganese. This essential mineral is needed for normal amino acid, protein, lipid, and carbohydrate metabolism ().

Blueberries also contain small amounts of vitamin E, vitamin B6, and copper.

SUMMARY Blueberries are a good source of manganese and vitamins C and K1. They also provide small amounts of copper, as well as vitamins E and B6.

Blueberries are rich in antioxidants and beneficial plant compounds, including:

  • Anthocyanins. These antioxidants give blueberries their color and may reduce your risk of heart disease (, , ).
  • Quercetin. High intake of this flavonol has been linked to lower blood pressure and a reduced risk of heart disease (, ).
  • Myricetin. This flavonol may have a number of health benefits, such as helping prevent cancer and diabetes (, ).

Anthocyanins

Anthocyanins are the main antioxidant compounds in blueberries.

They belong to a large family of polyphenols called flavonoids, which are believed to be responsible for many of the beneficial effects of blueberries ().

More than 15 different anthocyanins have been detected in blueberries, with malvidin and delphinidin being the predominant compounds (, , ).

These anthocyanins seem to be concentrated in the skin of the fruit. Therefore, the outer layer of the berry is the most nutritious part (18).

SUMMARY 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 your heart, brain, and blood sugar.

Heart Health

Heart disease is the leading cause of death worldwide ().

Studies note a relationship between berries — or flavonoid-rich foods — and improved heart health (, ).

Some research suggests that blueberries may have significant health benefits for people with high blood pressure, a major risk factor for heart disease (, ).

These berries may also inhibit the oxidation of LDL (bad) cholesterol — a critical step in the heart disease process ().

An observational study in 93,600 nurses found that a high intake of anthocyanins was linked to a 32% lower risk of heart attacks ().

Brain Health

As the number of people older than 65 increases worldwide, so will age-related conditions and diseases.

Interestingly, a higher intake of flavonoid-rich foods like blueberries has been associated with better brain function ().

Eating blueberries may prevent oxidative stress — which plays an important role in the aging process ().

These berries may also improve brain function directly. In one 12-week study, drinking blueberry juice daily improved memory in 9 older adults with early memory decline ().

Another, six-year study in older adults found that blueberries and strawberries were linked to delays in brain aging by up to two and a half years ().

Blood Sugar Control

The prevalence of type 2 diabetes is increasing steadily worldwide ().

People with diabetes are sensitive to rapid changes in blood sugar and need to be cautious when they eat foods rich in carbs.

Blueberries contain moderate amounts of sugar — or 15 grams per cup (148 grams).

However, they don’t 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 shown promising results as well.

One six-week study found that two blueberry smoothies daily 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 ().

SUMMARY Blueberries may decrease your risk of heart disease, boost brain health, 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 ().

SUMMARY Blueberries are well tolerated when eaten in moderation, and allergy is very rare.

Blueberries are a popular, delicious fruit.

They’re a good source of vitamin K1, vitamin C, manganese, and several other beneficial plant compounds like anthocyanins.

Eating blueberries on a regular basis may prevent heart disease, improve brain health, and help moderate blood sugar levels.