BOTTOM LINE:The antioxidants in blueberries have been shown to protect LDL lipoproteins (the "bad" cholesterol) from oxidative damage, a crucial step in the pathway towards heart disease.
In fact, oxidation of LDL is a crucial step in the heart disease process.
5. Blueberries May Lower Blood Pressure
Blueberries appear to have significant benefits for people with high blood pressure, a major risk factor for some of the world's leading killers.
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 ( 18).
Other studies have found similar effects, especially when looking at post-menopausal women (19, 20).
Given that high blood pressure is one of the leading drivers of heart attacks and strokes, the implications of this are potentially massive.
Regular blueberry intake has been shown to lower blood pressure in numerous studies.
6. 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 (21).
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 (22).
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.
There is some evidence that regular blueberry consumption can help prevent heart attacks.
7. Blueberries Can Help Maintain Brain Function and Improve Memory
Oxidative stress can accelerate the brain's aging process, having negative effects on brain function.
According to animal studies, the antioxidants in blueberries tend to accumulate in areas of the brain that are essential for intelligence (23, 24).
They appear to directly interact with aging neurons, leading to improvements in cell signalling.
Human studies have also shown promising results.
In one of these studies, 9 elderly participants with mild cognitive impairment consumed blueberry juice every day. After 12 weeks, they had seen improvements in several markers of brain function (25).
A six year study of 16,010 elderly participants found that blueberries and strawberries were linked to delays in cognitive aging by up to 2.5 years (26).
The antioxidants in blueberries seem to have benefits for the brain, helping to improve brain function and delaying age-related decline.
8. Anthocyanins in Blueberries Can Have Anti-Diabetic Effects
Blueberries are moderate in sugar when compared to other fruits.
One cup contains 15 grams, which is equivalent to a small apple or large orange. However, the bioactive compounds in blueberries appear to outweigh any negative impact of the sugar when it comes to blood sugar control.
Research suggests that anthocyanins in blueberries can have beneficial effects on insulin sensitivity and glucose metabolism. These anti-diabetic effects have been shown with both blueberry juice and extract (27, 28, 29).
In a study of 32 obese subjects with insulin resistance, a blueberry smoothie caused major improvements in insulin sensitivity (30).
Improved insulin sensitivity should lower the risk of metabolic syndrome and type 2 diabetes, which are currently some of the world's biggest health problems.
Several studies have shown that blueberries have anti-diabetic effects, helping to improve insulin sensitivity and lower blood sugar levels.
9. Substances in Them May Help Fight Urinary Tract Infections
Urinary tract infections are a common problem in women. It is well known that cranberry juice can help prevent these types of infections.
Blueberries are highly related to cranberries, and contain many of the same active substances as cranberry juice (31).
These substances are called anti-adhesives, and help prevent bacteria like E. coli from binding to the wall of the bladder.
Blueberries haven't been studied much for this purpose, but chances are that they have similar effects as cranberries (32).
Like cranberries, blueberries contain substances that can prevent certain bacteria from binding to the wall of the urinary bladder. This may be useful in preventing urinary tract infections.
10. Blueberries May Help Reduce Muscle Damage After Strenuous Exercise
Strenuous exercise can lead to muscle soreness and fatigue.
This is driven, in part, by local inflammation and oxidative stress in the muscle tissue (33).
Blueberry supplementation may reduce the damage that occurs at the molecular level, minimizing soreness and reduction in muscle performance.
In a small study of 10 female athletes, blueberries accelerated muscle recovery after strenuous leg exercises (34).
Take Home Message
It is clear that blueberries are incredibly healthy and nutritious.
The fact that they are sweet, colorful, and can be enjoyed both fresh and frozen, is just a tasty bonus.