Tue Jul 2

Can you drink your fruit and vegetables? How does juice compare to the whole food?

Written by: Emma Beckett, Adjunct Senior Lecturer, Nutrition, Dietetics & Food Innovation - School of Health Sciences, UNSW Sydney

Do you struggle to eat your fruits and vegetables? You are not alone. Less than 5% of Australians eat the recommended serves of fresh produce each day ^[1] (with 44% eating enough fruit but only 6% eating the recommended vegetables).

Adults should aim to eat ^[2] at least five serves of vegetables (or roughly 375 grams) and two serves of fruit (about 300 grams) each day. Fruits and vegetables help keep us healthy because they have lots of nutrients (vitamins, minerals and fibre) and health-promoting bioactive compounds (substances not technically essential but which have health benefits) without having many calories.

So, if you are having trouble eating the rainbow ^[3], you might be wondering – is it OK to drink your fruits and vegetables instead in a juice or smoothie? Like everything in nutrition, the answer is all about context.

It might help overcome barriers

Common reasons for not eating enough fruits and vegetables are preferences, habits, perishability, cost, availability, time and poor cooking skills ^[4]. Drinking your fruits and vegetables in juices or smoothies can help overcome some of these barriers.

Juicing or blending ^[5] can help disguise tastes you don’t like, like bitterness in vegetables. And it can blitz imperfections such as bruises or soft spots. Preparation doesn’t take much skill or time, particularly if you just have to pour store-bought juice from the bottle. Treating for food safety and shipping time does change the make up of juices slightly, but unsweetened juices still remain significant sources of nutrients ^[6] and beneficial bioactives ^[7].

Juicing can extend shelf life ^[8] and reduce the cost of nutrients. In fact, when researchers looked at the density of nutrients relative to the costs of common foods, fruit juice was the top performer ^[9].

So, drinking my fruits and veggies counts as a serve, right?

How juice is positioned in healthy eating recommendations is a bit confusing. The Australian Dietary Guidelines ^[10] include 100% fruit juice with fruit but vegetable juice isn’t mentioned. This is likely because vegetable juices weren’t as common in 2013 when the guidelines were last revised.

The guidelines ^[11] also warn against having juice too often or in too high amounts. This appears to be based on the logic that juice is similar, but not quite as good as, whole fruit. Juice has lower levels of fibre compared to fruits, with fibre important for gut health, heart health and promoting feelings of fullness. Juice and smoothies also release the sugar from the fruit’s other structures, making them “free”. The World Health Organization recommends ^[12] we limit free sugars for good health.

But fruit and vegetables are more than just the sum of their parts. When we take a “reductionist ^[13]” approach to nutrition, foods and drinks are judged based on assumptions made about limited features such as sugar content or specific vitamins.

But these features might not have the impact we logically assume because of the complexity of foods and people. When humans eat varied and complex diets, we don’t necessarily need to be concerned that some foods are lower in fibre than others. Juice can retain the nutrients and bioactive compounds of fruit and vegetables and even add more because parts of the fruit we don’t normally eat, like the skin, can be included.

Juicing or blending might mean you eat different parts of the fruit or vegetable. flyingv3/Shutterstock ^[14]

So, it is healthy then?

A recent umbrella review of meta-analyses ^[15] (a type of research ^[16] that combines data from multiple studies of multiple outcomes into one paper looked at the relationship between 100% juice and a range of health outcomes.

Most of the evidence showed juice had a neutral impact on health (meaning no impact) or a positive one. Pure 100% juice was linked to improved heart health and inflammatory markers and wasn’t clearly linked to weight gain, multiple cancer types or metabolic markers (such as blood sugar levels).

Some health risks linked to drinking juice were reported ^[17]: death from heart disease, prostate cancer and diabetes risk. But the risks were all reported in observational studies ^[18], where researchers look at data from groups of people collected over time. These are not controlled and do not record consumption in the moment. So other drinks people think of as 100% fruit juice (such as sugar-sweetened juices or cordials) might accidentally be counted as 100% fruit juice. These types of studies are not good at showing the direct causes of illness or death.

What about my teeth?

The common belief juice damages teeth might not stack up. Studies that show juice damages teeth often lump 100% juice in with sweetened drinks ^[19]. Or they use model systems like fake mouths that don’t match ^[20] how people drinks juice in real life. Some use extreme scenarios ^[21] like sipping on large volumes of drink frequently over long periods of time.

Juice is acidic and does contain sugars, but it is possible proper oral hygiene, including rinsing, cleaning ^[22] and using straws can mitigate these risks.

Again, reducing juice to its acid level misses the rest of the story, including the nutrients and bioactives contained in juice that are beneficial to oral health ^[23].

groups of women outside drinking orange juice in cups

Juice might be more convenient and could replace less healthy drinks. PintoArt/Shutterstock ^[24]

So, what should I do?

Comparing whole fruit (a food) to juice (a drink) can be problematic. They serve different culinary purposes, so aren’t really interchangeable.

The Australian Guide to Healthy Eating recommends water as the preferred beverage ^[25] but this assumes you are getting all your essential nutrients from eating.

Where juice fits in your diet depends on what you are eating and what other drinks it is replacing. Juice might replace water in the context of a “perfect” diet. Or juice might replace alcohol or sugary soft drinks ^[26] and make the relative benefits look very different.

On balance

Whether you want to eat your fruits and vegetables or drink them comes down to what works for you, how it fits into the context of your diet and your life.

Smoothies and juices aren’t a silver bullet, and there is no evidence they work as a “cleanse” or detox ^[27]. But, with society’s low levels of fruit and vegetable eating, having the option to access nutrients and bioactives in a cheap, easy and tasty way shouldn’t be discouraged either.