While its classification leaves it considered as something that is likely safe for most people, there are a few different blueberry juice side effects that have the potential to affect you. You should familiarize yourself with these possible risks before eating the fruit or drinking its juice.

Salicylate

Raw blueberries and blueberry juice have relatively high levels of salicylate, which is similar in nature to aspirin and comes from salicylic acid. Much like aspirin, salicylate is known to cause stomach irritation and upset in some individuals. However, even if you are prone to salicylate-induced stomach irritation, you will likely find that small amounts of the fruit and its juice are still enjoyable without noticeable ill effects.

Diabetes

Most types of blueberries will not have a negative effect on blood sugar levels. However, there are a few types that can lower your blood sugar levels, and even interfere with diabetes medication and insulin if you are an individual with diabetes. It is recommended that you carefully monitor your blood sugar if you have diabetes and plan on consuming blueberries or blueberry juice.

Tannins

Blueberries contain relatively small amounts of tannins – the same chemical compound that gives coffee its bitter taste – and can cause stomach upset in sensitive individuals. If you consume large amounts of tannins, you are also at a greater risk of liver or kidney damage.

Surgery

Because blueberries and blueberry juice can affect blood sugar levels, this can create difficulty in moderating proper blood sugar levels throughout and after surgery. If you have a surgery planned, it is recommended that you avoid blueberries for at least two weeks beforehand.

Although there are several possible blueberry juice side effects that have negative repercussions, it is still generally considered that blueberries are a safe and healthy fruit. As with all foods, pay attention to your body’s reactions to fruits you digest, and you will likely have nothing to worry about.