Blueberries are Low in Calories, But High in Nutrients
The blueberry is a flowering shrub that produces berries that are colored blue to purple, also known as blueberries.
It is strongly related to similar shrubs, such as those that produce cranberries and huckleberries.
Blueberries are small, around 5-16 millimeters (0.2-0.6 inches) in diameter, and have a flared crown at the end.
They are green in color at first, then change to blue-purple as they ripen.
These are the two most common types:
- Highbush blueberries are the most commonly grown species in the US.
- Lowbush blueberries are often referred to as “wild” blueberries. They are typically smaller and richer in some antioxidants.
This is what typical blueberries look like:
Blueberries are among the most nutrient dense berries. A 1 cup serving (148 grams) of blueberries contains (1, 2):
- Fiber: 4 grams.
- Vitamin C: 24% of the RDA.
- Vitamin K: 36% of the RDA.
- Manganese: 25% of the RDA.
- Then it contains small amounts of various other nutrients.
They are also about 85% water, and an entire cup contains only 84 calories, with 15 grams of carbohydrates.
Calorie for calorie, this makes them an excellent source of several important nutrients.
Blueberries are the King of Antioxidant Foods
Antioxidants are important.
They protect our bodies from damage by free radicals, unstable molecules that can damage cellular structures and contribute to aging and diseases like cancer (3, 4).
Blueberries are believed to contain the highestantioxidant capacity of ALL commonly consumed fruits and vegetables (5, 6, 7).
The main antioxidant compounds in blueberries belong to a large family of polyphenols, called flavonoids.
One group of flavonoids in particular, anthocyanins, is thought to be responsible for much of the beneficial health effects (8).
They have been shown to directly increase antioxidant levels inside the body (9, 10).
Bottom Line: Blueberries have the highest antioxidant capacity of all commonly consumed fruits and vegetables. Flavonoids appear to be the major antioxidant compounds.
Blueberries Reduce DNA Damage, Which May Help Protect Against Ageing and Cancer
Oxidative DNA damage is part of everyday life.
It is said to occur tens of thousands of times per day, in every single cell in the body (11).
DNA damage is part of the reason we grow older, and it also plays an important role in the development of diseases like cancer (12).
Because blueberries are high in antioxidants, they can help neutralize some of thefree radicals that cause damage to our DNA.
In one 4-week study, 168 participants were instructed to drink 1 liter (34 ounces) of a mixture of blueberry and apple juice, every day.
At the end of the study, oxidative DNA damage due to free radicals was reduced by 20% (13).
These findings have also been supported by smaller studies using either fresh or powdered blueberries (14, 15).
Bottom Line: Several studies have shown that blueberries and blueberry juice can protect against DNA damage, a leading driver of aging and cancer.
Blueberries Protect Cholesterol in The Blood From Becoming Damaged
Oxidative damage is not limited to our cells and DNA.
It is also problematic when our circulating LDLlipoproteins (the “bad” cholesterol) are oxidized.
In fact, oxidation of LDL is a crucial step in the heart disease process.
Fortunately for us, the antioxidants in blueberries are strongly linked to reduced levels of oxidized LDL (16).
A daily 50 gram serving of blueberries lowered LDL oxidation by 27% in obese participants, after a period of eight weeks (17).
Another study showed that 75 grams of blueberries with a main meal significantly reduced the oxidation of LDL lipoproteins (18).
Blueberries May Lower Blood Pressure
In one study, obese individuals at a high risk for heart disease noted a 4-6% reduction in blood pressure, after consuming 50 grams (1.7 ounces) of blueberries per day, for eight weeks (19).
Other studies have found similar effects, especially when looking at post-menopausal women (20, 21).
Given that high blood pressure is one of the leading drivers of heart attacks and strokes, the implications of this are potentially massive.
Blueberries May Help Prevent Heart Disease
Again, eating blueberries may lower blood pressure and oxidized LDL.
However, it’s important to realize that these are risk factors, not actual diseases.
What we really want to know is whether blueberries help prevent hard end points like heart attacks, which are the world’s biggest killer (22).
In a 2013 study on 93,600 nurses, eating plenty of anthocyanins (the main antioxidants in blueberries) was linked to a 32% lower risk of heart attacks (23).
This was an observational study, so it can not prove that the blueberries caused the reduction in risk, but it seems likely given the known beneficial effects on risk factors.