Fruit and vegetable juices are often considered an excellent alternative to whole food, practical to carry with you, tasty and, it is believed, also healthy, so much so that many chapters and pages of books and magazines that promote wellness are dedicated to recipes of smoothies and centrifuges. But is it really so? Can fruit and vegetable juices be included without problems in a healthy and balanced diet? We try to clarify based, as always, on the most recent and interesting scientific studies.
The difference between juices and soft drinks
First of all, it should be specified that there is a big difference between fruit, vegetable or mixed juices and soft drinks, often rich in sugars, colorings and sweeteners. In this article, we will refer to juices as drinks obtained by extraction or pressing of the liquid naturally contained in fruit and vegetables. Juices of this type can be made fresh at home, and it is the best choice, or purchased ready-made in shops and supermarkets, in these cases it is good to read the label and avoid drinks with added sugars and sweeteners. Once this premise is made, fruit and vegetable juices differ from soft drinks, such as sugary tea and sugary juices, sports drinks or effervescent drinks. In fact, fruit juices have a composition that is closest to the fruit or vegetable from which they are made, providing vitamins, minerals and antioxidants, which are instead absent in soft drinks (Ruxton et al, Nutrients, 2021). So let's try to understand in more detail which healthy substances are contained in juices.
Juices, a source of vitamins and minerals
Fruit and vegetable juices, as mentioned, provide vitamins and minerals that are easily assimilated by the body. Studies have shown that drinking orange juice every day for three weeks increased vitamin C levels by almost 60%, folate by 45% and carotenoids by 22% (Ruxton et al, Nutrients, 2021). But each juice has its own characteristics, let's find out more. Apple juice provides chlorogenic acid, quercetin and catechins, which are antioxidant substances, orange juice contains hesperidin, narirutin and carotenoids, other substances with anticancer and anti-aging action, and if the orange is red then we find in its juice also anthocyanins, substances with a powerful anti-free radical action. Grape, cherry and berry juices are a source of anthocyanins and pomegranate juice provides ellagitannins. Carrot juice provides potassium and vitamin C, beetroot juice provides nitrates, which help keep blood pressure under control, and tomato juice contains lycopene, a powerful anticancer agent, and minerals (Zheng et al, Int J Mol Sci, 2017). Pineapple juice provides manganese and vitamins C and group B (Khomich et al, Vopr Pitan, 2022).
Therefore, fruit and vegetable juices play an important role when it comes to supplying the body with antioxidants, vitamins and minerals (Ruxton et al, Nutrients, 2021).
Fruit and vegetable juices and heart health
Sugary drinks are associated with an increased risk of developing obesity and type 2 diabetes, with possible damage to the cardiovascular system. Instead, fruit and vegetable juices do not have this association (Ruxton et al, Nutrients, 2021). Additionally, studies have shown that moderate juice consumption has no impact on fasting blood sugar and insulin resistance (Ruxton et al, Nutrients, 2021). The consumption of fruit and vegetable juices is instead associated with a lower risk of heart attack and stroke, it is believed for the contribution of potassium, vitamin C, folate and polyphenols (Ruxton et al, Nutrients, 2021). In particular, some juices that have shown an interesting cardioprotective action are blood orange juice, which improves the functionality of the endothelium, which is the inner lining of blood vessels and the heart, blackcurrant and grapefruit juices, which counteract the rigidity of blood vessels, and pomegranate juice, which has an antithrombotic action (Zheng et al, Int J Mol Sci, 2017).
Fruit and vegetable juices and inflammation
Juices can help counteract chronic inflammation. For example, pomegranate juice significantly reduces indicators of inflammation (Ruxton et al, Nutrients, 2021). Tomato juice, being rich in lycopene, is also an aid against chronic inflammation, as well as prune and peach juice, which have been shown to be useful in cases of inflammation induced by obesity (Zheng et al, Int J Mol Sci, 2017). Cloudy apple juice, but not filtered apple juice, helps reduce bad LDL cholesterol (Zhang et al, Nutrients, 2022).
Fruit and vegetable juices and microbiota
Thanks to their contribution in antioxidants, juices protect the microbiota and support the proliferation of good bacteria. As a consequence, studies have shown that juices, by acting on the microbiota, counteract weight gain, but also inflammation and protect the heart (Henning et al, Sci Rep, 2017). As a particular example, cherry juice has been able to restore the microbiota altered by a diet high in fat and sugar and has increased the production of short-chain fatty acids, which are substances produced by good intestinal bacteria and which have anti-inflammatory action (Wang et al, Food Function, 2023).
Fruit and vegetable juices and the brain
Studies have shown that those who drink a fruit and vegetable juice rich in polyphenols at least three times a week have a lower risk of developing Alzheimer's, it is believed due to the neuroprotective action of the antioxidant substances (Dai et al, Am J Med, 2006).
Better juices or whole fruit?
As we have seen, fruit and vegetable juices have a composition very similar to that of whole fruit or vegetable, they are practical to take with you, tasty and healthy. Indeed, in some cases the antioxidant substances contained in the juices are even more easily assimilated than those of the whole fruit. As is the case with the orange, in which hesperidin and narirutin are more easily assimilated when the juice is taken and less when the whole fruit is consumed, it is believed due to the presence of fibers in the whole fruit that inhibit absorption (Ruxton et al , Nutrients, 2021). Juices can therefore be considered part of a healthy and varied diet, which, in any case, should always also include whole fruit and vegetables. In fact, whole fruits and vegetables provide fibers, which are missing, or present in smaller quantities, in juices (Ruxton et al, Nutrients, 2021). The fibers help reduce the absorption of sugars and fats, stimulate intestinal function and satiate. Juices, on the other hand, are less satiating and this could lead to a greater consumption of food and a consequent greater intake of energy, with an increased risk of developing diabetes and obesity (Zheng et al, Int J Mol Sci, 2017). If we choose juices that have not been filtered and that contain pulp we can increase the intake of fibers (Khomich et al, Vopr Pitan, 2022).
Then, it is also important to choose juices without added sugar or sweeteners, which could increase the risk of obesity (Zheng et al, Int J Mol Sci, 2017). Finally, it must be said that it is definitely not a good healthy choice to think about replacing a meal with fruit and vegetable juices. In fact, these drinks, while providing vitamins, minerals and antioxidants, are low in fibre, which is important for our well-being, and in proteins and fats, which are also essential for health.