The underlying nutritional claim (that frozen blueberries retain, and in some cases contain slightly higher measurable, anthocyanin levels than fresh) has real support in peer-reviewed literature. Research shows that the concentration of antioxidants called anthocyanins in frozen blueberries increases after freezing. A South Dakota State University study is frequently cited: freezing blueberries increases their concentration of anthocyanins, a type of antioxidant. During the freezing process, ice crystals disrupt the structure of blueberries, making the anthocyanins more accessible/extractable. Separately, blueberries are frozen soon after they are picked, "they are equal in quality to fresh," Plumb explained. She analyzed the anthocyanin content of blueberries frozen for one, three and five months and found no decrease . The Lohachoompol 2004 study similarly found frozen blueberries retained anthocyanin content comparable to fresh even after months of storage.

The health-effects portion of the claim is supported by review-level evidence. Epidemiological studies have suggested an association between anthocyanin intake and improved cardiovascular risk, type 2 diabetes and myocardial infarct. Clinical studies using anthocyanins have shown a significant decrease in inflammation markers and oxidative stress . A 2024 systematic review concluded there is evidence for a positive effect of anthocyanins on cognition and insight into the relevance of endothelial function.