Fruit juice was once viewed as part of a healthy diet, but today it is often seen as supplying little more than a high dose of sugar. Increasingly, fruit juices are seen as junk foods, and consumption is falling. But, as we argue in our recently published paper, fruit juice should not be cut from our diets. Major reasons for not consuming fruit are that it involves effort and it is often inconvenient. But fruit juice avoids the problems of intact fruit while providing the same range of health-promoting chemicals.
Most of us have heard we should be eating five portions of fruit and vegetables a day. Yet several surveys have shown that few people meet this target. This is despite the Global Burden of Disease study concluding that a poor diet is responsible for one in five deaths and suggesting that greater health benefits might result from increasing consumption of whole grains, nuts, fruit and vegetables rather than concentrating on reducing the intake of sugar and fat.
Research has shown that drinking pure juice can be good for us. The Food4Me study, funded by the European Commission, revealed that lower weight was associated with a greater intake of fruits, vegetables and fruit juice. While a national nutritional survey in the US found that adults who drink pure juice were at a lower risk of obesity and had better insulin sensitivity.
Yet despite these benefits, several pressure groups and other organisations still suggest that juice should not be part of our diet. But their concerns rely on an analogy with sugar-sweetened fizzy drinks, and confusion over what a fruit juice actually is. The fear is that because fruit juice contains naturally occurring sugar, it increases the risk of obesity. Although fruit juice does contain sugar it should not be viewed as similar to sugar-containing drinks.
The term "fruit juice" includes drinks sweetened with sugar that contain little (if any) juice from fruit. Take Sunny Delight, for example. Thought to be a juice by many consumers, a 240ml serving contains 14 grams of sugar and only 13% fruit juice from concentrate. Fruit squashes and cordials meanwhile are a mixture of fruit pulp and sugar syrup. In contrast, pure fruit juice is just that, it has no added sugar.
Research has shown these drinks have very different effects on our bodies. A joint American and Chinese study of nearly 200,000 people found that drinking sugar-sweetened fruit juice increased the risk of diabetes, while drinking pure fruit juice did not. While another showed that while sugar-sweetened drinks increase the weight of children over six years, pure fruit does not.
Juices contain many health-promoting nutrients - such as vitamin C, polyphenols and carotenoids - that occur only to limited extents in sugar-sweetened drinks. Vitamin C, in particular, has been associated with reduced blood pressure, lower risk of heart disease and a better life expectancy for men.
Polyphenols - which gives fruit its red, purple and blue colours - have antioxidant, anti-inflammatory and anti-viral properties. A summary of 22 studies of flavonoids (a type of polyphenol) found that high intake cuts the risk of premature death by a quarter. And intake of anthocyanidins - another polyphenol - reduces the risk of developing diabetes.
Finally, carotenoids (responsible for orange, yellow and red colourings) have been associated with lower cancer risks. A summary of studies linked them with a lower risk of developing oral and laryngeal cancer. Similarly, greater levels of carotenoids in the blood have been related to a reduced rate of breast cancer.
Loss of fibre
But what about fibre? A second argument for not drinking juice is that it provides less dietary fibre than intact fruit. As the Mayo Clinic has pointed out, although fruit juice "contains most of the vitamins, minerals and plant chemicals (phytonutrients) found in the whole fruit ... healthy fiber is lost during most juicing".
Fibre helps to prevent diabetes, heart disease and some forms of cancer, but the Western diet doesn't provide enough. There is a view that if people don't drink juice, they will instead eat more intact fruit and the fibre that goes with it. But it's improbable that juice and intact fruit are often alternatives. If you stop drinking juice for breakfast you will replace it with another drink. We drink because we're thirsty not because we want to eat more fruit. The convenience of a drink allows consumption when it is impractical to eat fruit.
Nobody suggests that we should not eat meat or fish because they do not contain fibre. Instead, we look at the benefits of overall consumption - which is something we must start to do with fruit juice.
In 2017, an extensive survey of the benefits of fruit and vegetables found that the chances of premature death in those eating five to seven portions a day are 30% less than those eating none, or just one portion. As the health-promoting chemicals in intact fruit are also found in juice, it is unsurprising that this - and other studies - have found fruit juice beneficial to our health. This research also showed that drinking either citrus or other fruit juices was associated with a lower risk of coronary heart disease, stroke or death from any cause.
Although it should not be seen as an alternative to intact fruit, having a daily pure fruit juice is a simple way to increase intake of beneficial chemicals. As part of a healthy diet, pure juice should be viewed as a health food - not a junk food.
Author: David Benton - Professor of Psychology, Swansea University