For optimum health benefits, the general advice is to aim for five servings of fruit and vegetables per day. That\u2019s the advice from governments and scientists alike \u2013 but let\u2019s face it: sometimes, it\u2019s hard to get \u2018em all in.<\/p>\n
For some, smoothies are the solution. They\u2019re a great way to slam down some nutrients in the morning: just collect up a whole bunch of produce, blend them all together, and drink it up. What could be healthier?\u00a0<\/p>\n
Well, we hate to be the bearers of bad news, but much like vitamin supplements<\/a>, this may be one \u201chealthy\u201d habit that\u2019s not as beneficial as you think. A study from 2023<\/a> found that, depending on exactly which ingredients you choose, some of the nutrients present in the fruit that goes into the beverage might end up going to waste once you drink it. And why? Because of the bananas.<\/p>\n \u201cWe were really surprised to see how quickly adding a single banana decreased the level of flavanols in the smoothie and the levels of flavanol absorbed in the body,\u201d Javier Ottaviani, director of the Core Laboratory of Mars Edge \u2013 part of Mars, Inc, who funded the study \u2013 and adjunct researcher at UC Davis, said in a statement<\/a> at the time.\u00a0<\/p>\n \u201cThis highlights how food preparation and combinations can affect the absorption of dietary compounds in foods,\u201d added Ottaviani, who was also lead author of the research.<\/p>\n So, what kind of damage are we talking here? Flavanols \u2013 you may also see them called flavan-3-ols or catechins \u2013 are chemical compounds present in foods like apples, pears, blueberries, blackberries, grapes, and cocoa (not chocolate<\/a>), and they\u2019re great for your heart and brain.\u00a0<\/p>\n \u201cPeople who eat a diet high in flavanol-rich foods may have better memory compared to those who have a low intake,\u201d noted Gunter Kuhnle, a Professor of Nutrition and Food Science at the University of Reading who was also on the study team, in a 2023 article<\/a>. \u201cA previous study also found that people with a low intake of flavanols were at higher risk of heart disease. Overall, there\u2019s convincing evidence that consuming enough flavanols has health benefits.\u201d<\/p>\n Unfortunately, many fruits and vegetables<\/a> also contain the flavanols\u2019 natural enemy: polyphenol oxidase, or PPO. You already know this compound, even if not by name \u2013 it\u2019s the chemical that causes sliced apples or bananas to go brown when they touch the air.<\/p>\n And, apparently, it also dramatically affects our bodies\u2019 ability to absorb flavanols. The researchers gave two groups of participants different flavanol-containing smoothies \u2013 one made with banana, which has a lot of PPO activity, and one made with mixed berries<\/a>, which don\u2019t. A third group, for control, took a simple flavanol capsule.<\/p>\n The results? The participants who drank the banana-based smoothie ended up with 84 percent lower flavanol levels in their plasma than those who took the capsule. The berry-based smoothie, in contrast, gave very similar results to the capsule \u2013 implying that the PPO-heavy banana had counteracted some important benefits of drinking the smoothie in the first place.<\/p>\n Of course, this isn\u2019t to say that bananas are bad \u2013 they\u2019re still a great option<\/a> for providing nutrients like potassium, fiber, vitamins, and antioxidants (plus, of course, some minor radioactivity<\/a>). And it\u2019s important to note that this study was pretty tiny, involving only eight participants, all of whom were \u201chealthy men\u201d, according to the report.<\/p>\n \u00a0<\/p>\n