Heather Caswell, Nutrition Scientist, British Nutrition Foundation, High Holborn House, 52-54 High Holborn, London, WC1V 6RQ, UK. E-mail: email@example.com
Over recent years, consumers have shown an increasing interest in health and wellbeing, with many wanting food and drink products that are healthy and nutritious, yet fit in with busy lifestyles. Fruit juice is one beverage that has seen a dramatic increase in consumer purchasing since the 1970s, and is now consumed by nearly half the UK population. While the beneficial effects of consuming diets rich in fruit and vegetables are well documented, the specific health effects of consuming fruit juice are less so. Further, the role of fruit juice in conditions such as obesity has also recently come under scrutiny, due to questions over how liquid calories affect subsequent energy intake. Limitations in the literature in this area include a lack of studies looking at different types of fruit juices and their effects on health, as well as studies that differentiate fruit juice from fruit and vegetable intake. Consuming a diet rich in fruit and vegetables (to which fruit juice can count once towards the 5 A DAY target) can help to reduce an individual's risk of suffering from a variety of chronic diseases, and should therefore be encouraged.
Fruit juice is a popular choice of beverage, and the fruit juice market is one that has grown substantially over recent years (Mintel 2009). Indeed, recent research indicates that the market for fruit juice and juice drinks increased by 37% between 1999 and 2004, reaching £2.32 billion, with volume increasing by 26% over the same period to around 2.2 billion litres per year (Mintel 2009). Its rise in popularity may be due in part to an increase in interest in health and nutrition amongst consumers, but also to the fact that the ever-expanding fruit juice market now provides a range of different juice varieties catering for all tastes and needs (Mintel 2009).
This review will begin by looking at the many different juice products available to consumers, before looking at the role of juice in a balanced diet and its nutritional properties. The amount of fruit juice currently being consumed in the UK, and its contribution to nutrient intakes, will then be discussed. A summary of recent research into the impact of fruit juice consumption on health, both potential benefits and detrimental effects, will also be given. Finally, the environmental impact of juice production will briefly be considered.
Juice is a popular beverage amongst consumers, seen by many as a ‘healthy’ option, which is also ‘natural’ (Mintel 2008) and appeals to the busy individual wanting an easy way to get one of their 5 A DAY (see NHS 2009a).
While the juice market is one that is ever expanding, broadly speaking, juice can be divided into two categories:
Fruit juice is a drink consisting of 100% pure fruit juice, which typically contains no preservatives or other added ingredients [British Soft Drinks Association (BSDA 2009)]. Fruit juices can be classified as:
Freshly squeezed juices are produced by ‘squeezing’ the juice from the fruit of choice, which is then packaged and transported to the retailer usually within 24 hours. These juices often do not undergo any form of pasteurisation (see further discussion) and therefore typically have a very short shelf life (2–3 days) (BSDA 2009). However, they may undergo high-pressure treatment and/or modified-atmosphere packaging to increase their shelf life.
In the case of juices ‘from concentrate’, the juice is extracted from the fruit in exactly the same way as described previously. However, the extracted fruit juice is then concentrated (by evaporating the water naturally present in the juice) (BSDA 2009). This concentrate is often frozen before being transported to its destination, where water is added back to reconstitute the juice to 100% fruit juice (or alternatively, it can be used as an ingredient in a cordial/squash drink).
During production, fruit juices from concentrate are typically heat-treated, to ensure that any unwanted spoilage pathogens, including bacteria or moulds, are destroyed. The type of heat treatment the juice is subjected to affects the shelf life of the product:
These products are pasteurised by exposing them to a temperature of approximately 90°C for a short time period (10–20 seconds). They are then packaged into sterilised containers where the air is removed, so the products remain sterile. These products have a shelf life of approximately 6–9 months, but once opened must be stored in a chilled environment and consumed within the stated period of a few days. These products may be referred to as ‘ambient products’, as they do not require refrigeration during storage.
A lower temperature (70–75°C) is used in the pasteurisation of chilled products, which are again heat-treated for approximately 10–20 seconds. Refrigeration is required to reduce the risk of product spoilage, and products typically have a shelf life of 2–6 weeks. However, as with longer-life products, once opened, these beverages must be consumed within the period stated on pack.
Juice drinks are products which contain anything less than 100% pure fruit juice. The level of fruit juice contained in these drinks can be found in the ingredients panel, usually on the back of the pack. In reality, there are a vast range of products with differing percentages of fruit juice. These drinks may include those that are purchased in a ready-to-drink format, or those that are purchased as ‘cordial’, also known as dilutable drinks. These require dilution prior to consumption, and are typically diluted with approximately four parts water to one part cordial. Dilutable products may include products made with sugar, as well as low sugar options made with sweeteners.
A relatively new addition to this area is ‘high juice’ juice drinks. These products contain a higher percentage of juice than most other juice drinks, with products currently available containing up to 70% fruit juice.
Other juice options
Although not commonly consumed in the UK, fruit nectars are popular in many parts of Europe. Fruit juice nectars are defined as the fermentable but unfermented product obtained by the addition of water and sugar to fruit juice, concentrated fruit juice, fruit purée or concentrated fruit purée (or a mixture of these) (Jukes 1997). They typically consist of less than 100%, but more than 20%, fruit juice. In the US, the term nectar is one that is used for a diluted juice to denote a beverage that contains fruit juice or purée and water, and which may contain sweeteners (FDA 2009). These products will not be discussed further in this review.
Fruit smoothies are typically combinations of homogenised/crushed fruit and juice. Most single servings of commercially available fruit smoothies (typically 250 ml) contain at least one 80 g portion of whole fruit, as well as one portion of fruit juice (150 ml). Until very recently, despite the higher fruit content of many smoothies when compared to more traditional fruit juice products, they were still considered to only provide one serving of the 5 A DAY fruit and vegetable target (see further discussion). However, the Department of Health has recently revised this advice, which now states that any smoothie that contains at least 150 ml of fruit juice and at least 80 g of crushed fruit (or vegetable) pulp can claim up to a maximum of two portions of the 5 A DAY recommendation (NHS 2009b). Because of the difference between smoothies and fruit juice in terms of their nutritional properties and possible health benefits, smoothies are not covered in detail in this review, although they are touched upon briefly throughout. For a more in-depth overview of the potential health benefits of smoothies and their role in the diet, see Ruxton (2008).
Fruit juices with added ingredients
In addition to the more traditional fruit juice and juice drink varieties mentioned above, in recent years the fruit juice market has also seen the introduction of more ‘functional’ fruit juice products (‘functional foods being those that encompass potentially healthful products that may provide a health benefit beyond that provided by the traditional nutrients it contains’) with added ingredients. Some examples include: 100% orange juice fortified with plant sterols. Plant sterols are plant-derived cholesterol-lowering substances that have for some time been added to dairy foods (e.g. yogurts and yogurt drinks) and spreads (see Caswell et al. 2008). Also, orange juice enriched with longer-chain omega-3 fatty acids, docosahexeanoic acid (DHA) and eicosapentaenoic acid (EPA), naturally found in oily fish with proven health benefits. While this is one section of the fruit juice market that will no doubt increase over the coming years, the specific role/benefits of these products will not be discussed further in this review.
Market trends in fruit juice consumption
The fruit juice market is one that has grown substantially over the past 20–30 years, and this is reflected by a substantial increase in consumption (DEFRA 2007, 2009). In 2008, the fruit juice market was worth an estimated £3.2 billion (Mintel 2008). While the more traditional flavours of orange and apple juice still dominate the market (over 70%), consumer demand for ever more exotic flavours has seen the market diverge rapidly from its early beginnings in the 1970s (Mintel 2009). While products such as cranberry juice began to emerge during the early 1990s (The Grocer 1997), today new flavours are constantly being introduced. These beverages are not only targeted to satisfy consumer demand for taste, but are increasingly focused upon health and ‘naturalness’ (Reuters 2008).
As is suggested previously, this expansion has now moved beyond simply providing different flavours and types of juices, to providing juices enriched with vitamins and/or minerals, as well as various different ‘functional’ ingredients. Further, many drinks are now targeted at specific audiences, with a particular focus in recent years for a move towards providing ‘adult soft drink’ alternatives to alcohol. Indeed, this sector is one of the fastest growing sectors of the drinks market, driven by a preference for healthier drinks, changing attitudes towards alcohol consumption and a willingness to pay more for this type of product (Mintel 2006).
The role of fruit juice in a balanced diet
While the variety of different juice options presented above means a greater choice for consumers, it also represents a possible source of confusion as to the health benefits of the different types of drink on offer. For example, it may be particularly problematic trying to decide which count towards the government's 5 A DAY target, and which do not. It is therefore important that consumers can understand and correctly interpret the vast array of juice products available, so as to make an informed choice when selecting a juice product.
It is important to note that this review only discusses fruit juice and fruit juice drinks, and therefore no reference has been made to vegetable juices. However, these can also make a useful contribution to nutrient intakes, offer health benefits and count towards the 5 A DAY target.
A healthy balanced diet
Consuming a healthy, balanced diet is essential for general health, maintaining a healthy body weight and reducing the risk of a range of conditions, including heart disease, stroke, cancer, diabetes and osteoporosis (BNF 2007).
What is a healthy diet?
A healthy diet is one that is based on breads, rice, potatoes, pasta and other starchy foods, and is rich in fruits and vegetables. It will also include moderate amounts of milk and dairy foods, meat, fish, eggs, beans and other sources of non-dairy protein, and limited amounts of foods and drinks high in fat and/or sugar. Eating a variety of different foods is essential, as no one food can provide the body with all the nutrients it needs (BNF 2007).
In terms of fruit and vegetables, the UK Department of Health (DH) recommends that everyone should try to consume at least five servings of fruit of vegetables a day (5 A DAY), to help reduce the risk of diseases such as coronary heart disease and cancer (DH 2007). A portion of fruit or vegetables is approximately 80 g, which is, for example, one apple, a medium banana, three heaped tablespoons of cooked vegetables (e.g. peas, sweet corn) or two satsumas. For children, these portions will be slightly smaller, being approximately 40–60 g (or alternatively, what fits into the palm of a child's hand). It is important to remember that variety is essential, and we should aim to eat five different servings each day. In addition to fresh fruit, frozen, canned and dried also count, as does fruit juice. Indeed, in the 5 A DAY guidance, the Department of Health states that a 150 ml serving of fruit (or vegetable) juice counts as one portion. However, only one serving of juice per day can count, irrespective of how much is consumed. This is due to the fact that fruit juice contains very little fibre, even the freshly squeezed varieties and those containing ‘juicy bits’ (see Table 1). Further, the juicing process frees the sugars that are present naturally in fruit, which means that drinking juice frequently between meals may be damaging to teeth (DH 2007). Currently in the UK, the average intake of fruits and vegetables combined is just 2.8 portions per day (Henderson & Gregory 2002), and there is therefore an urgent need for the majority of people to increase their consumption. For those people who do not do so already, having fruit juice daily can help to achieve the 5 A DAY target.
Table 1. Nutritional information for juice, per 150 ml as consumed
Energy (kcal) (EAR = 1940 kcal/day (women), 2550 kcal/day (men))
Total sugars (g)
Fibre (NSP) (g) (RNI = 18 g/day)
Vitamin C (mg) (RNI = 40 mg/day)
Count as one of 5 A DAY?
Source: figures are based on averages of manufacturers data.
ND: data not available.
EAR (Estimated Average Requirement): the average amount of energy required by UK adults.
RNI (Reference Nutrient Intake): the amount of a nutrient that is enough to meet the needs of the majority of the population.
NB – all figures are approximates, and may vary depending upon the different brands of products.
100% freshly squeezed orange juice (not from concentrate) – chilled product
Pure orange juice from concentrate, unsweetened (ready to drink) – ambient product
Pure orange juice from concentrate with bits – ambient product
Pure pineapple juice from concentrate – ambient product
Carbonated apple juice from concentrate (100%) – ambient product
100% pure squeezed orange and mango juice – chilled product
Fruit juice drinks
Orange and mango juice drink (70% pressed juice and 30% sparkling water)
Cranberry juice drink (25% cranberry juice from concentrate) – ambient product
45 (vitamin C added to juice)
Concentrated blackcurrant juice drink (contains 22% juice). Requires dilution prior to consumption (values given for juice after dilution using 30 ml of cordial, as diluted with 1 part cordial: 4 parts water)
60 (vitamin C added to cordial)
Blackcurrant squash from concentrate (10%). No added sugar, contains sweeteners. Requires dilution prior to consumption (values given for juice after dilution using 30 mL of cordial, as diluted with 1 part cordial: 4 parts water)
Still orange juice drink from concentrate (12%) (ready to drink)
Orange and mango juice drink (ready to drink, fruit juice from concentrate – orange (12.4%), lemon (5.4%), passion fruit (1.5%), mango puree (0.7%).
Mango and Passion fruit smoothie
Most countries around the world promote the importance of eating more fruit and vegetables (see Painter et al. 2002), but the detail of the message varies. For example, New Zealand focuses on the importance of eating a variety of fruit and vegetables, with the message ‘eat your colours everyday – 5+ a day the colour way’(5+ a day 2009). In the US, recommendations on fruit and vegetable intake are based upon the age, sex and physical activity levels of an individual, and recommendations are given as cup sizes, rather than portion sizes (http://www.mypyramid.gov).
The nutrient composition of fruit juice
The information presented in Table 1 allows for comparison of the nutritional profile of different fruit juice/juice drink varieties. One of the most striking observations relates to freshly squeezed fruit juice and fruit juice ‘from concentrate’. It is a common consumer (mis-) perception that 100% freshly squeezed juice varieties are healthier than ‘from concentrate’ products (Reuters 2008). However, from the data presented, it can be seen that there is actually little difference in terms of nutritional value between the two. The chilled/freshly squeezed products presented have similar energy, sugar and fibre concentrations to the concentrated varieties, and both count towards an individual's 5 A DAY. It would, however, be interesting to see if any difference exists between these products in terms of other nutritional components, such as antioxidants and phytochemicals, an area where research is currently lacking.
As can also be seen from Table 1, the energy content of fruit juices and juice drinks varies quite widely, ranging from the lower energy (artificially sweetened) cordial drinks (providing 1.8 kcal/100 ml) to the relatively high energy fruit juices and juice drinks. An average 200 ml serving of fruit juice (the suggested on-pack serving size) would provide approximately 100 kcal of energy, similar to the amount provided by some non-juice beverages, such as semi-skimmed milk or cola (Table 2), but considerably more than unsweetened tea or coffee. The relatively high energy content of fruit juice (derived from sugars naturally present in the fruit) may be one reason why fruit juice consumption has been linked with concerns over weight gain. However, as discussed more fully later, a recent review of the evidence has concluded that 100% fruit juice consumption does not appear to be associated with weight status or the likelihood of being overweight in childhood (O'Neil & Nicklas 2008).
Table 2. Nutritional information for non-fruit juice beverages, per 150 ml as consumed
Coffee, instant, made with water and semi-skimmed milk
The sugar content of fruit juice and juice drinks is also variable. Food labelling legislation requires a declaration of total sugars content on pack, but in the UK there is no dietary reference value for total sugars intake. However, a reference value of no more than 10% of total energy (E) intake does exist for non-milk extrinsic sugars (NMES). NMES refers to those sugars that are not part of the cellular structure of foods, or those that are added to foods during processing or preparation (DH 1991). The definition includes the phrase ‘non-milk’, as sugars found in milk (e.g. lactose) are extrinsic, but are not included as part of this 10% total energy recommendation. Using the estimated daily energy requirement of women (2000 kcal) as a guide, this translates to approximately 50 g/day of NMES (DH 1991). Using similar principles, the Institute of Grocery Distribution (IGD) has suggested a Guideline Daily Amount (GDA) value for total sugars for labelling purposes of 90 g/day (IGD 2005). Average intakes of NMES currently exceed the 10% energy level and intakes are particularly high in a number of population groups, for example young adults (aged 19–24 years) and children (Gregory & Lowe 2000; Henderson & Gregory 2002). In fresh fruit, the sugars present are contained within the cell structure (intrinsic sugars); however, the juicing process releases these sugars and so they are categorised as non-milk extrinsic sugars (NMES). It is therefore assumed, when discussing the sugar content of fruit juice, that 100% of the sugars present contribute towards NMES intake.
Fruit juices and juice products also contain vitamin C, unlike many non-juice beverages, and therefore can be considered as a good vehicle through which to ensure individuals are getting a sufficient amount of this nutrient. However, it is interesting to note the wide variation in the vitamin C content of various juices. From the data presented earlier, it can be seen that orange juice provides the most naturally occurring vitamin C out of all the products listed, with both the freshly squeezed and ‘from concentrated’ products providing a similar amount. While cranberry juice drink is also a good source of vitamin C, it must be noted that vitamin C has been added to this product during production, and therefore this high level is not solely because of the vitamin C present naturally in the product. However, studies that have assessed the bioavailability of vitamin C from natural versus synthetic sources seem to indicate no differences in absorption between the two (Nelson et al. 1975; Mangels et al. 1993). Consumers can therefore be confident of getting similar benefits in terms of vitamin C content from drinking such a product compared to consuming a product naturally containing vitamin C. In contrast to this, juice drink products provide substantially less vitamin C, highlighting the need for consumers to read the labels of juice products, to select the one that best meets their needs.
Further, the data show that fruit juice and juice drinks provide very little, if any, dietary fibre. Dietary fibre is the non-digestible part of plant foods, which is found naturally in a variety of foods including fruits, vegetables, cereals and pulses. Fibre comprises a range of substances with overlapping properties (Buttriss & Stokes 2008), one of which is cholesterol reduction, and high fibre intakes (especially so-called soluble or viscous types of fibre) can therefore help protect against heart disease. Fibre is also important for normal bowel functioning. The recommended daily intake in the UK for adults is 18 g of dietary fibre when measured by the Englyst method [which measures the non-starch polysaccharides (NSP) content of food stuffs]. However, most UK adults fail to reach this target, with a national average of just 15.2 g per day for men and 12.6 g for women (Henderson & Gregory 2002). The figures presented in Table 1 documenting the low fibre levels found in most fruit juice drinks support the guidelines set by the Department of Health, that fruit juice should only count once towards the 5'A DAY target, and highlight the fact that fruit juice should not be seen as a dietary substitute for fresh fruit. Of note is the higher amount of fibre provided by smoothies, which is due to the fact that, unlike fruit juice, smoothies contain crushed fruit and/or vegetables (Ruxton 2008).
As shown in Table 1, 150 ml of fruit juice (including carbonated varieties) counts once towards the 5 A DAY target. Further, some ‘high juice’ juice drinks may also count, provided enough of the juice is consumed (e.g. a serving of 220 ml of 70% juice would count as one of the 5 A DAY). While the majority of cordials and juice drinks do not count towards this target, they still provide a similar amount of energy to fruit juice, as well as a similar amount of sugar. It is for this reason that many healthy eating guidelines state that, if individuals consume fruit juice-based beverages, they should try to opt for 100% juice varieties (Byers et al. 2002).
Fruit juice in the UK diet
How much is being consumed?
National food surveys have been carried out in the UK since the 1940s and give an indication of the types and quantities of foods being consumed by UK households each year. The quantity of fruit juice purchased in UK households from 1975 to present is shown in Figure 1.
As can be seen from this data, there was a large increase in the purchasing of fruit juice between 1975 and the early 1990s, when purchasing increased nearly eightfold. However, since the mid to late 1990s, fruit juice purchases have largely plateaued. Although there does not appear to be any one reason for this lack of expansion of the market, it has been speculated that competition from alternative beverages may be one cause (The Grocer 2001), and that extending consumption beyond breakfast has proved challenging (Mintel 2008). The vast array of different juice drink products currently available on the market also means that increasing the consumption of pure fruit juices remains difficult for manufacturers (Mintel 2008). It must be noted that currently, data from the National Food Survey of UK household food purchases is only available until 2007; it would be interesting to see if juice purchasing, particularly of the more luxury items, has suffered in the recent economic climate. Recent data seem to suggest that this may indeed be the case (see Fig. 2, Nielsen 2009). It would also be interesting to see the impact that these changes have had upon nutrient intakes of the population, particularly vitamin C intake.
The National Diet and Nutrition survey is a rolling dietary survey that gathers information about the diets and nutritional status of the UK population. Data from this survey can be used to identify the percentage of the UK population who consume fruit juice, as well as the mean amount of juice they consume. It can also be used to identify the percentage contribution of fruit juice to nutrient intakes of different population sub-groups. As can be seen in Table 3, fruit juice appears to be a popular choice of beverage among young people and adults, with nearly half of both men and women from these age groups reporting consuming fruit juice. While approximately one third of young children and older women consume juice, only 12% of older adult men reported consuming fruit juice. In terms of the amount of fruit juice consumed, young people reported consuming the most, at an average of 903 ml/week (boys) and 825 ml/week (girls). When looking at the information presented in Figure 1 and Table 3, it is important to note that the data presented in Figure 1 is based on an average of all the households sampled in the survey, and therefore may take into account households who never purchase juice. Further, this data reflects purchases, rather than actual consumption, and it cannot be guaranteed that all the juice purchased was consumed. In contrast, the NDNS data in Table 3 comes from weighed food diaries of fruit juice consumers, and therefore gives a more accurate indication of how much fruit juice people who drink juice are actually consuming. Although there are limitations with such surveys, such as misreporting of food intakes (see Macdiarmid & Blundell 1998), these figures are some of the most accurate currently available for the UK population.
Table 3. Mean consumption of fruit juice (ml per week) by those classed as fruit juice consumers, and the percentage of the total population classed as consumers
Contribution to nutrient intakes in the UK population
Carbohydrate (including fructose and glucose) is the main macronutrient in fruit juice. Fruit juice also contains a wide variety of micronutrients, most notably vitamin C, but also folate, beta carotene, potassium and polyphenols (O'Neil & Nicklas 2008). Table 4 shows the contribution of 100% fruit juice to a selection of nutrient intakes in the UK population, based on the current level of consumption.
Table 4. Percentage contribution of fruit juice to nutrient intakes in the UK population
As shown in Table 4, fruit juice makes a significant contribution to the vitamin C intakes of both men and women of all ages, but most notably older teenagers (15–18 years of age). It is of interest that today, fruits, vegetables and fruit juices are the main dietary sources of vitamin C. However, during the war period, when fruit was in short supply and fruit juice was, to all extents and purposes, non-existent, potatoes were in fact the main vitamin C source in the diet. However, once rationing ceased, potato consumption decreased, and consumption of fruit, as well as fruit juice, rose, bringing average vitamin C intakes up from 51 mg/day in 1940 to 59 mg/day in 2000 (data from NFS). In addition to vitamin C, it must be noted that fruit juice also contributes to population intakes of other vitamins, including folate, although this contribution is a lot less than the contribution to vitamin C intakes (NDNS data).
While fruit juice can be seen to be a beneficial addition to the diet, it does not contribute to the fibre intakes of the population at any age, owing to the very small amounts of fibre present, even in the freshly squeezed varieties (see Table 1). While the data presented in Tables 1 and 2 suggest that, when compared to non-soft drink options, such as water and milk, fruit juice is relatively high in sugar, its contribution to total NMES intake in the diet is fairly low. As the data show, at a population level, it appears that, on average, less than 10% of NMES intake in all age groups comes from fruit juice. This suggests that concerns about its high sugar content contributing to population NMES intake may be unjustified, as it appears that the majority of NMES intake at all ages come from other dietary sources. In terms of concerns over the high energy content of fruit juice, when compared to other drinks, it can be seen that it is providing on average just 1% of energy intake in adults, and less than 0.5% in the older adults age group.
Fruit juice and health
This section provides an overview of evidence from studies investigating the impact of fruit juice on health. This overview was compiled by examining published studies identified from databases such as PubMed. It is in no way a systematic review of the evidence, but provides a summary of recent research conducted in this area.
It is widely recognised that fruit and vegetable consumption is associated with good health. Although the precise reasons for this still elude researchers, the health benefits provided by these foods are largely thought to stem from their micronutrient content, and also plant bioactives. Plant bioactives or phytochemicals are non-nutritive constituents of plant foods with anticipated health-promoting/beneficial effects (Margetts & Buttriss 2003; Gry et al. 2007). These compounds include carotenoids, flavonoids and other phenolic compounds that have been suggested to play a role in protecting against conditions such as cardiovascular disease (CVD) and cancer (Visioli et al. 2000; Johnson 2007). Initially it was assumed that the mechanisms underpinning these effects were related to the antioxidant properties of such bioactive substances and the antioxidant nutrients (e.g. vitamin C) available in these foods, but it is now recognised that the mechanisms are more complex than this [see Jackson (2003) for a detailed overview]. The health-promoting effects of fruits and vegetables are probably due to a variety of factors, such as the low energy density of these foods.
The bulk of the available literature on the health effects of plant foods concerns fruits and vegetables per se, but some information is also available for juices. Outlined below is a summary of the literature describing the health effects of consuming fruit juice.
Associations between juice consumption and healthier dietary habits
Many of the studies looking at the health benefits of fruit juice consumption focus on its ability to promote a better nutrient intake in consumers versus non-consumers, and indicate that people who consume fruit juice tend to have healthier overall dietary habits than those who do not. In one such study, fruit juice consumption and total nutrient intake was assessed in a cohort of 3618 children aged 2–11 years. The study found that, compared to those children who did not consume fruit juice, those who consumed more than 170 ml of fruit juice daily had significantly higher intakes of total carbohydrate, vitamins C and B6, folate, potassium, magnesium and iron, and significantly lower intakes of total and saturated fat and added sugar. The children also consumed significantly more servings of fruit and vegetables compared to non-juice consumers (Nicklas et al. 2008). However, the study failed to report any association with socio-economic status, and did not report if this confounder was controlled for, highlighting a potential drawback in the methodology. This association between juice consumption and healthy lifestyle habits has also been observed by Schulz et al. (2005), who identified better weight control in adults consuming fruit juice (although it was not stated if this was 100% juice) as part of a diet that was also rich in wholegrain bread, fruits and raw vegetables, and lower in high-fat foods. This supports previous findings suggesting fruit juice consumption is a marker of healthier dietary habits.
Some studies have highlighted possible detrimental effects associated with fruit juice consumption, such as a possible increase in risk of obesity and short stature in children who consume juice. For example, in a cross-sectional study involving a US cohort of 168 healthy children aged 2 (n = 94) and 5 (n = 74) years, consumption of 340 ml per day of fruit juice was found to be associated with obesity (Dennison et al. 1997). However, it must be noted that this amount of juice both far exceeds that recommended as counting towards the 5 A DAY target (150 ml), and average consumption in the UK (Table 3).
In recent years, there has been interest in the potential effect that energy consumed as so-called ‘liquid calories’ has on weight control, with suggestions that energy from liquids is less satiating then energy from solids (see Benelam 2009). This interest has stemmed from the observation that an increase in the consumption of sugared beverages parallels the rising obesity levels seen in many countries. The theory behind the association between weight gain and beverage consumption is that sugar-containing beverages are less satiating than solid foods providing the same amount of energy, and hence can lead to over-consumption of energy compared to needs (DiMeglio & Mattes 2000). The WHO technical report on diet and chronic disease (2003) specifically noted that the energy contained in fluids was not well detected by the body, such that energy compensation (the adjustment of energy intakes provoked by the ingestion of a given food stimulus) at subsequent eating occasions does not occur (WHO 2003). However, evidence to support this is inconsistent and it may actually be the mode of consumption (i.e. whether the liquid is perceived to be a food or drink) that influences its effect on satiety [see Benelam (2009) for an overview].
Evidence looking specifically at the role of fruit juice and juice drinks on weight control has produced seemingly conflicting results (see Drewnowski & Bellisle 2007 for a summary). In one recent study, O'Neil and Nicklas (2008) reviewed the current evidence on the impact of fruit juice consumption on weight gain. The review considered the results from nine cross-sectional and 12 longitudinal studies that had all assessed the relationship between 100% fruit juice consumption and weight control in children and adolescents. These studies varied in size, with many being large-scale (involving 3000+ participants). The different studies also comprised a range of ages of children (2 to 19 years). The study concluded that, based on current evidence, 100% fruit juice consumption was associated with better nutrient intake but was not associated with weight status or the likelihood of being overweight in childhood. Many studies have also considered the impact of sugar-sweetened beverages, including fruit juice drinks, on weight gain. In one study of 136 Australian children, intake of cordial at age 7.7 years was found to be associated with an increase in Body Mass Index (BMI) at a mean age of 13 years (Tam et al. 2006). However, it must be noted that no information was given as to whether possible confounders were controlled for in this study. In contrast, a secondary analysis of data from the National Health and Nutrition Examination Survey 1999–2002 (a study that was included in the review by O'Neil and Nicklas (2008), but which also looked at fruit juice drinks as well as fruit juice), found no association between fruit juice intake and weight. This analysis assessed the impact of fruit juice intake, including 100% juice varieties as well as juice drinks (defined as any sweetened fruit juice, fruit-flavoured drink, or drink that contained fruit juice in part) of 1572 2–5-year-old children on BMI. No association was found between BMI and 100% fruit juice consumption, or with intake of fruit juice drinks (O'Connor et al. 2006).
Although there is currently much debate as to the impact of intrinsic versus added sugars in this context, it should be noted that the nutrition and energy content of different sugars is identical (i.e. 3.75 kcal/g).
CVD and cancer
The protective effects of consuming fruit and vegetables on CVD and cancer risk are well documented (see Margetts & Buttriss 2003; Stanner et al. 2004). Evidence in this area has come from large-scale cohorts followed over many years. For example, Bazzano et al. (2002) found subjects who consumed more than three servings of fruit and vegetables per day had a 42% reduction in stroke mortality and a 27% reduction in risk of CVD mortality compared to those who consumed less than one serving per day. In a meta-analysis of cohort studies, Dauchet et al. (2006) reported that the risk of coronary heart disease (CHD) is reduced by 4% for each additional serving of fruit and vegetable per day and by 7% for fruit intake. In terms of fruit and vegetables and cancer risk, a large review conducted in the early 1990s found that fruits and vegetables had a significant protective effect against a variety of forms of cancer (Block et al. 1992). Furthermore, the World Cancer Research Fund/American Institute for Cancer Research expert report on diet and cancer concluded that vegetables and fruits may protect against a range of cancers including mouth, stomach and bowel cancer, leading the report to recommend that people should try to eat more (WCRF/AICR 2007).
More specifically, the benefits of consuming fruit juice on CVD and cancer risk have also been described. In a review looking at the potential role played by fruit juice in preventing these conditions, Ruxton et al. (2006) searched MEDLINE and the Cochrane library for studies which assessed the impact of consumption of pure fruit juice on CVD and cancer. Evidence was assessed from 37 studies relating to fruit juice consumption and CVD, ranging in size from small-scale studies with ten participants to large-scale cohorts, such as the Nurses Health Study (over 71 000 participants), and including studies with both healthy subjects and participants with health problems (e.g. hypertension, impaired glucose tolerance). To assess the effects of fruit juice on cancer, 11 studies were examined, which looked at outcomes such as breast cancer risk, risk of renal cell carcinoma, and DNA damage. The review found convincing evidence from epidemiological and clinical studies that pure fruit juice reduces CHD risk via a number of probable mechanisms; however evidence documenting the protective effect of fruit juice on cancer risk was not as strong (Ruxton et al. 2006).
A further intervention study has shown a reduction in oxidative cell damage (involved in the pathogenesis of atherosclerosis, cancer and diabetes) and an increase in blood glutathione levels (an antioxidant) after consumption of mixed red berry juice (Weisel et al. 2006). In this study, 18 male subjects and 9 controls consumed 700 ml of either mixed berry juice or a corresponding polyphenol-depleted juice, respectively, on a daily basis for a four-week period. Subjects consuming the juice saw a decrease in oxidative DNA damage (P < 0.0005) and an increase in glutathione status (P < 0.05) when compared with controls. Finally, fruit juice consumption, specifically citrus fruit juices, has also been associated with protection against ischemic stroke (RR 0.75 for an increment of one serving per day) in a very large cohort involving over 100 000 subjects from the Nurses' Health Study and the Health Professional's Study (Joshipura et al. 1999).
Health effects of specific fruit juices
Despite the fact that there are many different varieties of fruit juices available, there is actually relatively little difference between them in terms of the nutrients they provide (Table 1). However, plant bioactive composition and profile can vary greatly between fruits, due partly to the wide variety of colours, a direct result of some of these components, such as carotenoids and anthocyanins (Saltmarsh et al. 2003). The available evidence which describes the potential benefits of certain different types of fruit juice is summarised below.
Cranberry juice has long been associated with the treatment of urinary tract infections (UTIs). A recent Cochrane review looked at the effectiveness of cranberry juice in preventing UTIs in susceptible populations (including infants, pregnant women and the elderly). The review found cranberry juice may decrease the number of symptomatic UTIs over a 12-month period, particularly in those women with recurrent UTIs (Jepson & Craig 2008). Despite this, the European Food Safety Authority (EFSA), which is currently reviewing potential health claims to be allowed on food and drink products, recently rejected an application for the use of a claim supporting the role of cranberry juice in reducing the risk of UTIs in women (specifically by inhibition of the adhesion of certain bacteria in the urinary tract).The panel concluded that the evidence provided in support of this claim was not sufficient to allow such an on-pack health claim to be made (EFSA 2009).
Frequent consumption of grape juice (rich in a variety of flavanoids) has been associated with improved endothelial function within the lining of blood vessels. In a study investigating the effect of consuming purple grape juice on endothelial function in 15 patients with coronary artery disease, it was shown that consumption of juice for 14 days improved flow-mediated vasodilation and reduced LDL-susceptibility to oxidation (Stein et al. 1999). Further studies have also shown grape juice consumption to reduce platelet aggregation (associated with atherosclerotic disease development) (Keevil et al. 2000; Freedman et al. 2001), although it must be noted that both of these trials used small numbers (10 and 20 subjects respectively) of healthy subjects.
The effects upon health of blackcurrant juice have also been studied. In a group of 48 patients with peripheral artery disease, a daily combination of blackcurrant juice and orange juice (250 ml of each) was shown to reduce markers of inflammation, when compared with subjects who were given a reference beverage with a similar amount of carbohydrate but no bioactive components (Dalgard et al. 2009).
While there are some suggestions in the literature that specific fruit juices may have roles in promoting health, the evidence to demonstrate the underpinning mechanisms is largely absent. Vitamin C, present in citrus juices and those from berries in particular, is often recommended in the popular press as helping to banish cold and flu symptoms. However, a recent Cochrane review assessed the available evidence of the role of vitamin C supplementation (at doses of at least 200 mg per day or more) on symptoms of the common cold. Contrary to popular belief, evidence from 30 different studies, involving a total of 11 350 participants, showed that regular supplementation with vitamin C had no effect on the incidence of cold symptoms in the general population, although it may reduce the severity and intensity of common cold symptoms slightly. However, the magnitude of this effect was so small that its clinical usefulness is doubtful. Despite this, it may have a beneficial role for those under conditions of extreme physical or cold stress (such as marathon runners or skiers) (Hemiläet al. 2007). However, it must be kept in mind that it has repeatedly been shown that the results of supplement trials of specific nutrients are often not comparable to the effects shown when physiological levels of a nutrient are consumed via the diet. One of the reasons for this is likely to be because foods and drinks (e.g. juices) contain many additional components not found in a supplement. The detailed effects of most of these compounds on health are still not known, and there is also the possibility that they may interact in a positive manner with nutrients such as vitamin C at levels available in foods.
Dental caries (tooth decay) are caused by the progressive destruction of the teeth by acid produced by bacteria on the tooth surface. These bacteria produce acid by fermenting sugars found in foods, which decreases the pH at the tooth surface and causes demineralisation of the tooth enamel. Over time, these acids are gradually neutralised by saliva, and when the pH of the mouth rises to its original level, remineralisation of the tooth occurs using calcium and other minerals present in saliva. When food and drinks containing sugar are consumed frequently throughout the day, there is little time for this remineralisation process to occur, and tooth decay results.
As stated, the sugar in fruit juice and juice drinks is present as NMES, and therefore fruit juice and juice drinks have a much greater cariogenic potential than whole fruits, which are not associated with the production of dental caries (Moynihan & Petersen 2004).
Of particular concern with regards to the cariogenic potential of fruit juices are situations where young children are given juices in bottles or sip cups, causing the juice to be in contact with the teeth for a prolonged period of time. Current evidence indicates that a high frequency of sugar consumption is more damaging in terms of caries development than the total amount of sugar consumed at any one time (Moynihan 2005), so this practise is thought to be associated with an increase in caries risk (Tinanoff & Palmer 2000). A number of studies have examined the impact of fruit juice and juice drinks on tooth decay. For example, the association between dental caries and beverage consumption was assessed in a cohort of 642 US children who were tracked in a longitudinal study from the ages of 1–7 years. The authors found that consumption of fruit juice was associated with increased caries risk; however, the effect of fruit juice on caries risk was not as great as that seen with other beverages, such as soda (Marshall et al. 2003). This finding is also supported by a recent study by Lim et al. (2008). In this study, the cariogenicity of soft drinks, compared to water and fruit juice, was tested in a cohort of over 350 3–5 year olds. They found that children who consumed more soft drinks, relative to milk and fruit juice, were at a greater risk of developing dental caries as they grew older.
To help reduce the risk of suffering from dental caries, while also benefiting from the health benefits offered by fruit juices, the British Dental Health Foundation suggests that people should try and consume fruit juice at meal times, or if consuming juice between meal times, to dilute it with water. Further, brushing teeth after consuming acidic foods or drinks (such as fruit juice) can cause permanent damage to teeth due to erosion of the tooth enamel. It is therefore advised to either brush teeth before a meal, to allow the fluoride in toothpaste to coat the teeth and protect them; or alternatively to wait until an hour after eating or drinking acidic foods before brushing, in order for the saliva in the mouth to have time to neutralise the acids (British Dental Health Foundation 2005).
Environmental impact of fruit juice
Fruit juices are a popular choice of drink among health conscious consumers, offering an easy and quick way to get one of their 5 A DAY. However, with consumers demanding ever more exotic flavours, which they often expect to be ‘fresh’ at the time of purchase, the environmental impact of this industry must be considered. The type of juice (i.e. concentrate versus fresh), as well as the flavour, both play a role in the impact that juice production has on the environment.
As already stated, juices ‘from concentrate’ are produced by evaporating the water from the extracted fruit juice in the place of production (British Soft Drinks Association 2009). Once these juices have been made into a concentrate, they can be frozen and shipped to their destination, where they are then reconstituted. In comparison, consumer demand for freshly squeezed juice means these products often must reach stores within a day of being pulped, and therefore air travel is required. As air travel has the greater impact on carbon dioxide emissions, opting for these fresh juices could be seen as a less environmentally friendly option. Further, concentrated juices can be more efficiently transported than fresh varieties, due to their very nature (i.e. there is less liquid to transport). In addition to these factors, another consideration is that fresh juice requires transportation via a chilled distribution chain, right from the point of production to the point of purchase. Once at the point of purchase, it again also requires chilling by the retail outlet and again in the home prior to consumption. This is in contrast to concentrated varieties, which can usually be stored at ambient temperatures once packaged until opened. All these factors can be seen to impact upon an individuals ‘carbon footprint’, which specifically relates to the amount of greenhouse gases produced in our day-to-day lives through burning fossil fuels for e.g. electricity, as well as processes such as food production (Carbon Footprint 2009). This has lead to heightened interest over recent years in trying to reduce the carbon footprint of the diet, both by thinking about the transportation method of foods, while also considering the foods we eat on a daily basis (Science Daily 2008).
In addition to the impact of fresh versus concentrated juice, the type of fruit juice also has an impact on the environment. Orange juice has traditionally been the most popular flavour of fruit juice, and to this day remains one of the most common choices amongst consumers (BBC 2005). While this option may not be seen as particularly exotic, the two largest producers of orange juice are Brazil and Florida, whose combined production accounts for 90% of the world's supply (FAO 2009). Further, as more exotic flavours are brought to the fruit juice market to satisfy consumer thirst for premium drinks, e.g. pomegranate, the need for juice to be transported by air from a variety of locations around the world will no doubt increase. The environmentally conscious consumer may therefore wish to opt for juices produced closer to home to minimise the impact that this is having on the environment. It is, however, appreciated that this may be difficult, with some manufacturers failing to include such information on their products. Further, where claims such as ‘produced in the UK’ are made on-pack, this can simply mean that the final product has been made in the UK, and does not necessarily mean that all the ingredients are from the UK. While manufacturers who state such information on pack are required to ensure this information is accurate, to prevent misleading consumers (FSA 2009), it appears that actually identifying the source of all the ingredients used to produce a product is difficult, and suggests that further regulations may be needed to allow consumers to make environmentally friendly purchases.
As can be seen from the information presented above, fruit juice can have a place in a healthy, balanced diet, both in terms of providing individuals with one serving of their recommended 5 A DAY, as well as making an important contribution to vitamin C intakes. In addition to fruit juice, new juice drinks are now also emerging with enhanced nutritional properties, including products with added ingredients as well as ‘healthier’ fruit juice drinks (e.g. high juice drinks). Consuming a diet rich in fruits and vegetables, to which fruit juice can contribute one serving, as part of a healthy balanced diet may also help to reduce the risk of suffering from a variety of chronic diseases, including cardiovascular disease and cancer.
While the market for fruit juice continues to expand, providing consumers with a vast array of juice products to choose from, it is important that consumers can understand the varying nutritional properties that the different varieties may provide, and opt for the healthier choices. Looking at the evidence presented here, it can be seen that 100% fruit juice varieties provide the most natural vitamin C, and are favourable compared with many juice drink varieties, which can often contain the same amount of energy and sugar, but do not count as one of the 5 A DAY. This observation is reflected in the American Cancer Society Guidelines on Nutrition and Physical Activity for Cancer Prevention, which recommend that individuals should always opt for 100% juice if they consume fruit or vegetable juices (Byers et al. 2002). Further, despite the common consumer mis-conception that freshly squeezed varieties of 100% juice are healthier than those ‘from concentrate’, this does not actually appear to be the case. In the current economic climate, this may therefore provide consumers with a cheaper, more environmentally friendly option to help them achieve one of their 5 A DAY.
Finally, while fruit juice consumption may be a useful way to help the population consume more fruit and achieve sufficient vitamin C intakes, it must be remembered that fruit juices, unlike fresh fruit, do not contribute to fibre intakes, and are also a source of NMES. Consumption must therefore not be to the detriment of fresh varieties of fruit and vegetables, but rather as an additional way to ensure the consumption of a healthy, balanced diet. Further, the frequency of intake between meals should also be limited.
Conflict of interest
The Foundation has received financial support from GlaxoSmithKline in the production of this review. However, the views expressed are independent and GlaxoSmithKline have not been involved in writing or shaping the contents of this paper.