The study by Collin et al. makes an important contribution to the still scarce and inconsistent discussion on the potential health impact of fruit juices: in this cohort of US adults, each additional dose of approximately 330 ml/day of fruit juice was associated with a 24% increased risk of all-cause mortality; there is no causality, this evidence is "only" suggestive of an association, and the study has limitations such as the small number of deaths associated with coronary heart disease, and the need for a larger number of participants and a longer study period. Even so, the dissemination of these results is accompanied by a message urging moderate consumption of fruit juices.
To be able to separate the effects of different fruit juices from other processed fruit products, or to examine risks and potential benefits, much needs to be done, starting with epidemiological studies that should specifically measure exposure to different products and compare them with each other and with the effects resulting from the consumption of whole fruit.
We recognize that it is not easy, due to the richness of varieties and constant innovation in fruit processing, such as: refrigerated and presented whole, in pieces or in pulp (with or without the addition of juices), dehydrated, freeze-dried, in purees, in jams or preserves, even in juices with or without the addition of sugar or sweeteners, and varying in the different fruits that constitute them; as such, properties such as texture, phytochemical and nutritional composition differ (raspberry, blueberry, orange or apple juices, for example, are far from being the same as each other…), or the presence of sweeteners.
And this last aspect of sweetener use gains extraordinary prominence with this month's article by Higgins and Mattes (the latter marking the beginning of work on the impact of different fluids, such as soups, on appetite), in the AJCN, where we begin to observe the consequences that the choice of one sweetener, and not another, can have on the body weight of overweight individuals. Revolutionary in knowledge.
In this study, the addition of saccharin (but not the other 3 sweeteners tested) led to weight gain, and as such, the possibility that a sweet taste without energy value can lead to weight gain is now recognized; as such, a boundary is established beyond which sweeteners may no longer be seen as a globally identical entity in relation to this area of health.
Another surprising result: sucralose, one of the four sweeteners tested, contributed to weight loss, and this new finding raises questions about its potential future role in the existing chemical arsenal against excess weight. However, it is important not to forget the importance of sweet taste as a powerful psychobiological phenomenon so well illustrated in John Blundell's "satiety cascade," which drives us to seek and consume food.
In its canned form, high consumption is indicated as potentially increasing the risk of mortality. Therefore, a delicate balance is needed, where the type of processing, "dose," genetic and metabolic vulnerability, coupled with an inadequate lifestyle of the studied populations, may also be key to accommodating different results between studies. It's important to remember that higher or moderate consumption of fruit juices, or interventions to increase their intake in controlled trials, have already been associated with lower risks of mortality and cardiovascular disease (and a decrease in diastolic blood pressure), and specifically with 100% juices, a decrease in metabolic syndrome and obesity; however, there are also studies that describe a higher risk of weight gain and insulin resistance with high consumption of 100% fruit juices.
Regarding the high or greater consumption of 100% juices, in the review by Fardet et al., to be published next June in Nutrition Reviews, higher intake was not significantly associated with: CVD (nor systolic blood pressure); glycemia/insulinemia; total cholesterol and HDL-C; nor cancers – total, colon and breast. It is important to highlight, for breast cancer, that fruit consumed in its natural state during adolescence showed a protective role, which gives it a prominent place.
Unfortunately, in interpreting these effects, in addition to the traditional limitations in studies dealing with human nutrition, such as follow-up times, sample size, and the validity of different measurement methods, there is also a lack of information on the different access to healthcare depending on the population (so important in mortality studies…) and there are concerns about the possibility of residual confounding.
No less important in the study by Collin et al., are the results found regarding the intake of sugary drinks (where regulation through taxation, reformulation, and marketing control attempts to address consumption), in which for each additional serving of sugary drinks, the risk of mortality increases by 11%. Added to this is the threat we found in our study of Portuguese children, namely that these drinks may be part of a dietary pattern that also includes fast food and sugary foods, associated with more screen time, less sleep, and lower maternal education, which does not help.
In conclusion, and considering the studies mentioned: eating whole fruit seems to have more protective evidence against the occurrence of metabolic dysregulation or the risk of chronic diseases than consuming it in the form of juices; and sweetened fruit juices and canned fruit seem to offer less protection than 100% juices.
Studies/learn more at:
Collin et al. Association of Sugary Beverage Consumption With Mortality Risk in US Adults: A Secondary Analysis of Data From the REGARDS Study. JAMA Netw Open. 2019 May 3;2(5):e193121
https://jamanetwork.com/…/fullarticle/10.1001/jamanetworkop…
Fardet et al. Association between consumption of fruit or processed fruit and chronic diseases and their risk factors: a systematic review of meta-analyses. Nutr Rev. 2019
https://doi.org/10.1093/nutrit/nuz004
Higgins & Mattes. A randomized controlled trial contrasting the effects of 4 low-calorie sweeteners and sucrose on body weight in adults with overweight or obesity. Am J Clin Nutr. 2019 May 1;109(5):1288-1301
https://doi.org/10.1093/ajcn/nqy381
Moreira et al. Food patterns according to sociodemographics, physical activity, sleeping and obesity in Portuguese children. Int J Environ Res Public Health. 2010 Mar;7(3):1121-38
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2872303/
Author's note:
The content above is intended for educational purposes and to promote scientific discussion within the higher education system in health sciences, and should not be used to replace public health recommendations or those of healthcare professionals, particularly in dietary advice or treatment.
