Blueberries are packed with benefits for eye health, cancer prevention, and anti-aging. Eat this much to see the benefits.

Blueberries are not without their drawbacks. While they're best known for their eye health benefits, they're also known to help prevent colon cancer and improve memory. It can be difficult to gauge how much you should eat, so what's the optimal intake?

Blueberries were selected as one of the "World's 20 Superfoods" by Time magazine. Rich in powerful antioxidants like anthocyanins, polyphenols, and beta-carotene, they help prevent diseases caused by free radicals, such as heart disease, diabetes, obesity, and dyslipidemia. In particular, the antioxidant power of anthocyanins in blueberries is 2.5 times that of vitamin C and over six times that of tocopherol.

Anthocyanins are also beneficial for eye health, as they promote the resynthesis of rhodopsin, the purple pigment in the retina. Rhodopsin deficiency can lead to eye diseases, including fatigue. Anthocyanins also stimulate the connection between brain neurons, helping to improve memory. In fact, a study conducted at the University of Cincinnati College of Medicine on 47 elderly individuals found that anthocyanins in blueberries were beneficial in improving memory and activating brain function in older adults.

Blueberries are best eaten consistently over a long period of time. The effects of anthocyanins appear within 4 hours of consumption and disappear within 24 hours. It is better to eat blueberries once in a while than to eat large quantities occasionally. It is recommended to eat 20 to 30 pieces (40 to 80 g) per day for more than 3 months. Since the peel contains a lot of anthocyanins, it should be eaten with the peel.

When choosing blueberries, it's best to choose those grown organically or in pristine areas. Prolonged washing of blueberries in water will dissolve the water-soluble pigment anthocyanins. When ripe, they're bluish-black in color, while when unripe, they take on a reddish hue. Choose blueberries with bluish-black flesh.