Novel insights and practical strategies for health professionals to improve the uptake of plant-based diets in people with chronic kidney disease
Article information
Abstract
There has been a significant shift in dietary guidance in the past 5 years for people with chronic kidney disease. Multiple best practice guidelines in nephrology now include nutritional guidance that recommends the adoption of healthy dietary patterns with an emphasis on whole foods and diets with adequate fruit, vegetables, legumes, nuts, wholegrain bread and cereals, with minimal amounts of processed foods high in salt, sugar, and fat. While there is shortage of enthusiasm, from health professionals to adopt this new approach, there is a clear knowledge gap on how to get people to adopt plant-based diets. This is particularly apparent in settings where renal dietetic services are lacking. This manuscript, cowritten with consumers with lived experience of chronic kidney disease, outlines seven strategies to facilitate the adoption of plant-based diets and draws on evidence from the fields of marketing, implementation science, and behavior change. These strategies include paying attention to language, starting gradually and increasing variety, then transitioning to increasing vegetable portion size, focusing on adequacy, giving explicit guidance on how to reduce meat, remembering neophobia, and emphasizing the importance of individualized advice. Additional strategies from consumers include the need to address consumer fears about the adequacy of nutrient intake, focus on foods to enjoy not nutrients to restrict; provide advice on how to sensibly include favorite foods and make meals flavorsome and finally consider the adoption of plant-based diets as a spectrum to strive towards—with animal foods included at varying levels depending on food preferences, budget, cultural preferences.
Introduction
Chronic kidney disease (CKD) is the most common noncommunicable disease globally, and the absolute numbers of people with the condition exceed that of people with diabetes mellitus (DM), cardiovascular disease, cancer, and chronic respiratory disease [1]. Lifestyle modification and dietary manipulation are important strategies to delay the progression of CKD [2,3].
There is consistent epidemiological evidence supporting the health benefits of dietary patterns that are rich in fruits, vegetables, legumes, nuts and seeds, and whole grains, and lower in red meat, salt, and added sugars [4,5]. This includes a reduced incidence of CKD [6,7], progression of CKD [8], and mortality in people with CKD [9] who follow healthy dietary patterns. Evidence from the CORDIOPREV trial of a Mediterranean diet also suggests those with obesity and type 2 DM experienced a slower deterioration in kidney function compared to a low-fat diet [10]. Plant-based diets also have a lower climate footprint and are more sustainable [11]. These findings have resulted in a great deal of enthusiasm for the adoption of plant-based diets in people with CKD. Numerous clinical practice guidelines used for people with CKD also advocate explicitly for the adoption of plant-based diets [12,13] or more specifically for dietary patterns such as Mediterranean-style diets [4].
There are numerous challenges with the adoption of plant-based diets in CKD, not the least of which is a consistent definition. There is no consensus in the scientific literature on what a plant-based diet refers to [14]. This may vary from a vegan dietary pattern with the exclusion of animal products [15,16] to vegetarian dietary patterns with the inclusion of eggs and dairy to plant-dominant but omnivorous eating patterns [17]. In the context of CKD, a plant-dominant eating pattern (titled PLADO) has also been proposed as a strategy for the management of CKD. This definition is proposed as a flexible eating plan, administered by dietitians to achieve 0.6 to 0.8 g/kg protein per day and >50% of foods from plant-based sources [18]. Unfortunately, there is a global shortage of renal dietitians to assist with the education of this approach [19].
Other challenges regarding the adoption of plant-based diets in CKD relate to the increased load of dietary potassium and theoretical risk of hyperkalemia. However, no association has been found between plant food intake and hyperkalemia in CKD [20,21], and this may be related to the increased fiber content [18] and alkalinizing effects [22]. Other concerns regarding increased wholegrain, nut, and legume intake relate to the theoretical increase in phosphorus consumption from these foods. However, phosphorus is less bioavailable (<50%) as it is stored as phytate or phytic acid and is unable to be absorbed in the digestive tract efficiently due to the lack of phytase in humans [23].
The differing perspectives of consumers and clinicians also remain a challenge to the adoption of plant-based diets. For example, while many dietitians support the move to focus on whole foods and not nutrients, the support of the multidisciplinary team is perceived as critical [24] as well as adequate dietetic staffing to facilitate education and ongoing support [24,25]. Consumer taste preferences [26], cost, lack of understanding, and gender differences are also well-documented barriers to adopting plant-based diets [27]. In the context of CKD, while adherence rates to the renal diet are low [28], and consumers have expressed confusion regarding the complexity of the renal diet [29], there is evidence of enthusiasm to embrace dietary strategies that may retard the progression of the disease or retain good health [30,31] and a desire for dietetic guidance [32].
Globally, the current intake of fruits and vegetables remains suboptimal. For example, fruit intake is estimated at 81.3 g/day [33] (optimal, ~300 g per day [33]), and vegetable intake is estimated at 186 g/day [34] (ideal, ≥400 g/day [33]). Nut intake remains very low in most developed nations with optimal intake recommended to be ~21 g/day [35] and actual intake estimated at 8.9 g/day [33]. Legume intake in developed nations is far more variable and intake ranges from 20.8 g daily in Canada to 26.1 g daily in Australia [36]. In Asian countries where the food is a staple of the cuisine, rates are also highly variable with intake in South Korea estimated at 28.5 g daily to 61.1 g day in Japan [36].
Given these challenges, it is important to examine strategies to promote the uptake of plant-based diets. The aim of this paper was to describe seven novel insights and evidence-based practical strategies from the fields of marketing, implementation science, and behavior change that may facilitate the adoption of plant-based diets in people with CKD.
Consider language
Prospect theory suggests that individuals value gains and losses differently and naturally prefer loss aversion [37]. When applied to the field of food choice this infers that labels such as vegetarian and vegan are terms defined by loss- loss of the inclusion of eggs, dairy, and other animal foods. In contrast, referring to a dietary pattern as ‘plant-based’ is thought to encourage consumers to focus on what is gained from this approach [38]. This gain-framing approach is also effective when encouraging behaviors relating to smoking reduction and physical activity [39].
A large field experiment in Denmark with more than 150,000 consumer decisions regarding menu selections examined this gain-framing approach [38]. Over 10 weeks, sales of menu items were tracked from a university menu with terms such as vegan, vegetarian, and plant-based used. In contrast to the expected results of prospect theory, the items labeled vegan and vegetarian were 24% more likely to sell than if labeled ‘plant-based.’ The authors speculate that this may be related to the unfamiliarity of consumers with the generic or unfamiliar phrase ‘plant-based.’ This was confirmed in other studies whereby a plant-based diet was considered equivalent in content by consumers to healthy diets and sustainable diets [40].
Given these unexpected findings, it may be more informative to examine the results of marketing interventions to promote plant-based diets. Several phrases are considered more effective at increasing consumer sales than using phrases such as plant-based, vegetarian, vegan, and healthy. These phrases relate to food provenance, flavor, look, and feel. For example, menu items labeled to identify provenance sell better and are said to be more evocative and positively associated with a culture, location, or setting [41]. Items such as Cuban black bean bowl, Indian chickpea curry, Mexican spiced scramble, or Cumberland veggie sausage and mash outsell items like black bean bowl, chickpea curry, or vegetarian sausage and mash [41]. Even simple phrasing connecting the food to where it is grown is also effective—such as garden salad or roasted field mushrooms [41]. Flavor-focused phrases are also preferred, such as spicy radish salad, fresh buttery roast corn, sweet spicy tofu, or zesty sweet potato and ginger soup [41–43]. Trials have demonstrated that taste-focused product labeling is more effective in boosting healthy food choices than the use of ‘healthy’ food labels [43,44].
Start by increasing vegetable variety
Vegetable consumption is intrinsic to good health [45]. Intake of vegetables can be improved using several strategies. Extending on the knowledge that increasing food variety leads to increased consumption [46], researchers tested two strategies to increase vegetable intake [47]. The first was a lunch meal with 600 g of vegetables arranged separately on a plate (broccoli, carrot, and snap peas) with 600 g of pasta. The alternative provided the same vegetables and pasta but with vegetables combined as a stir-fry mix. The results were that vegetables served as a varied mix resulted in significantly higher consumption at a meal (estimated at 48 g or one additional vegetable served consumed). The strategy may be more effective as it may prevent taste fatigue and development of satiety to one specific vegetable [47].
Then focus on increasing the portion size of one vegetable
Many leading health organizations globally suggest half the meal plate be filled with vegetables to achieve good health. This includes bodies such as KDIGO (Kidney Disease: Improving Global Outcomes) where the latest guidelines for DM and CKD [12] encourage an individualized diet high in vegetables, fruits, whole grains, legumes, plant-based proteins, unsaturated fats, and nuts; and small amounts of processed meats, refined carbohydrates, and sweetened beverages. To help achieve the desired proportion of vegetables at meals, Rolls et al. [48] used a randomized controlled trial design to test two methods exploring the strategic replacement of vegetables. In study one, the main meals consisted of meat, a grain, and three increasing serving sizes of broccoli (180 g, 270 g, and 360 g) [48]. In the second study, as the broccoli portion increased from 25%, 38%, and 50% of the plate, the meat and grain portions were decreased equally so that the total volume of food served did not change. The results were that both strategies (increasing portion size overall or replacing vegetables for one of the other meal components) can increase overall vegetable intake significantly [48]. However, when the intake of one vegetable increased without a consequent decrease in other meal components, there was an overall increase in food consumption and calories [48]. This suggests that non-starchy vegetables low in energy are best used for this approach.
Focus on adequacy
The World Health Organization recommends consuming five servings (400 g of non-starchy vegetables and fruit per day) [49]. Ungar et al. [50] tested two different behavioral messages regarding intake in a three-armed randomized trial. The first message was to achieve adequacy and consume five servings per day (three servings of vegetables and two of fruit). The alternative intervention was to increase intake by ‘just one more serve,’ considered in marketing strategies to be a more realistic goal [51]. The control group was told to eat as usual. After education about serving sizes, the intervention group intake increased from 2.49 servings per day at baseline to 5.00 ± 0.7 servings at the end of the intervention (p = 0.04). In contrast, the ‘just one more’ group saw a nonsignificant increase from 2.45 servings at baseline to 3.41 ± 0.96 servings at the intervention end.
The translation of this advice to the CKD context may require some nuancing to this messaging. For example, for those with estimated glomerular filtration rate of <30 mL/min per 1.73 m2 and a history or predisposition for hyperkalemia, individualized advice remains important [22]. Outdated messaging that focuses on eliminating high-potassium fruit and vegetable choices such as tomatoes, potatoes, bananas, and oranges [52] should be amended. These fruits and vegetables can be included in the diet after education regarding appropriate portion size, elimination of foods with potassium additives, and adjustment of protein-rich foods such as meat, and chicken to an appropriate portion size as these also contain potassium.
Give guidance on how to reduce meat consumption
Per capita consumption of meat has been increasing for the past 50 years [53]. The top three leading consumers of meat are the United States (124 kg per person annually), Australia (122 kg per annum), and Argentina (109 kg per annum) [53]. Countries such as South Korea and Japan are markedly lower (66 kg [54] and 34 kg [55] per annum, respectively). Justification for eating meat includes the four ‘N’s: nice, natural, normal, and necessary [56]. Consumer market research into strategies to reduce meat intake suggests there are several distinct groups of consumers [57]. The major barrier to the adoption of plant-based diets among those who are considered high meat eaters was the perception that plant-based diets lack taste [58], and that plant-based diets are hard to prepare and cannot provide adequate protein [57,58]. Explicit instruction regarding the health effects of high meat intake appears to be especially effective at reducing consumption [59]. For example, ‘meat contributes to acidosis’ may be more effective messaging than generic calls to eat less meat [59]. Other evidence suggests multicomponent strategies like those that focus on skills to shop, prepare, and cook [60–62] are more effective than single-component interventions [63,64]. Understanding the motivation to move towards plant-based diets is also useful [65,66], with two distinct types of consumers: those who adopt the dietary pattern for ethical and sustainable reasons, and those who adopt plant-based eating for health reasons [67].
Do not forget neophobia
Despite the undeniable health benefits, strategies to increase legume intake are sparse [68]. Food neophobia, or a resistance to trying new foods contributes to the reluctance to eat less familiar types of legumes [68,69] as well as plant-based meat alternatives [62]. Effective strategies to increase legume intake despite the high prevalence of neophobia include starting intake with familiar forms. What is considered ‘familiar’ is context and culturally specific. In the United States, Australia, and the United Kingdom, this may include starting exposure with baked beans, peas, and peanuts. In the Mediterranean, this could be advocating for an increased intake and exposure to chickpeas, cannellini beans, and lentils. In Asian nations such as South Korea and Japan, this may be increasing the intake of soybeans, mung beans, or Adzuki beans [70]. Advice to improve digestibility, such as using canned versions is recommended to help ensure long-term sustainable intake [69]. In addition, remind consumers that increased flatulence is a common side effect. Once regular intake is established, encourage other forms of legume consumption such as legumes included in bakery products and flours, cereals, bars, pasta, and roasted forms. The addition of legumes to salads, soups, and as the focus of the meal is recommended [71]. Note caution with plant-based meat alternatives is needed as they may also be high in potassium additives [72] and excessive sodium.
Give individualized advice
There is clear evidence that individualized dietary advice is not just desired by people with CKD [30,32,73], but is also more effective [74] and delays time to dialysis [75]. Advice that is specific to the needs of the individual and their readiness to reduce meat intake [76] is more effective in improving dietary behaviors than ‘one size fits all’ population-based approaches [74]. This is particularly important given the high prevalence of multimorbidity in people with CKD [77]. Other strategies to assist people with CKD to improve diet quality include practical resources (cookbooks, apps, recipes, videos, handouts) [25,30], advice on how to prioritize multiple components of the diet, strategies to accommodate dietary needs on social outings, and methods to adapt family meals [25,32]. In addition, positively framed messages are critical to behavior change [39,78]. For example, ‘if you eat more vegetables, you will help improve your blood pressure’ is more effective than ‘eating too much salt will increase your blood pressure.’
What do consumers with chronic kidney disease think?
Recent survey results of more than 800 consumers with CKD from the United States, found that consumers were not confident in their ability to plan a balanced plant-based meal. Other barriers to adoption were family eating preferences, meal planning skills, food costs, and ease of cooking [25].
The consumer co-authors in this article also described some fears about the adoption of plant-based eating patterns. This included fears about getting adequate iron, omega-three fats, B12, and calcium and developing other nutritional deficiencies from insufficient protein. The ability of plant-based eating patterns to accommodate the changing nutrient needs of people with CKD was also a genuine fear voiced by consumers. Several consumer co-authors also noted that medicalization of the diet (being ‘prescribed’ a plant-based diet) invokes a sense of trepidation and wariness. Others reported that a prescribed diet can create a fear of being ‘othered’ or different and worried how this may impact social eating occasions or lead to being ostracized at social events.
Cost and access to fruits and vegetables also remain a challenge for many people with CKD [79–81]. Population modeling from Australia suggests that a 10% reduction in price for fruits and vegetables could result in a 14% increase in intake. Taxes on sugary foods and drinks were also found to increase fruit and vegetable intake [82]. Increased and ongoing promotion of the benefits of frozen and canned fruits and vegetables is needed as consumer awareness of their health benefits has been reported to be low [83]. Revision of consumer dietary information is needed as many remain outdated and discourage the eating of fruits, vegetables, legumes, and whole grains.
Suggestions from consumers about how to best market or describe the plant-based approach included:
• Taking an individualized multi-pronged (fun, educational, self-empowered, and supported) approach to build confidence.
• Focusing on foods to enjoy not nutrients to restrict.
• Remember to provide advice on how to sensibly include favorite foods and make meals flavorsome.
• Address fears about the impact of consuming high-potassium food staples such as potatoes, tomatoes, green leafy vegetables, and whole grains.
• Discussing adoption of plant-based diets as a spectrum to strive towards, with animal foods included at varying levels depending on food preferences, budget, and cultural preferences.
• Terminology matters. Instead of plant-dominant perhaps plant-centric is a more appealing term for some consumers which suggests some compromise and can enable visualization of food on a plate.
• Including education that describes explicit steps as part of the spectrum is preferred. This may start with advice to consumers to adopt a plant-forward approach, then transition to plant-centric, then vegetarian, then wholefood plant-based vegan.
• Progressive adoption at the right pace for each individual combined with fun/opportunity rather than judgment and labeling is desired. For example, any compromise that includes a reduction of meat consumption and processed foods with increased vegetable and fruit consumption is perceived by consumers as positive progress deserving of praise.
Other considerations noted by consumers that should be considered when providing advice about the adoption of plant-based diets include:
• Consider the additional challenges of accessing specialist renal dietetic advice. This may include a lack of access to renal dietitians as well as the cost of these services.
• Consider designing high-quality plain language written information for consumers on how to adopt plant-based diets that can be given by non-dietetic staff.
• Simple meal suggestions are needed for busy people who wish to follow this approach but need mealtime inspiration.
• Individualized advice is valued highly by consumers given the complexity of the CKD journey and the presence of other comorbidities.
• Education regarding the composition of commercial meat substitutes. These may be high in salt, potassium, or phosphorus additives.
• Consumers are confused by what appears to be unregulated and at times confusing labeling of ‘plant-based’ foods.
Summary
The focus of future dietary guidance regarding healthy eating will remain on optimal dietary patterns for good health and not nutrients [84]. To provide practical guidance to consumers with CKD, clinicians should pivot advice from a nutrient focus to providing food-based practical strategies to improve the adoption of plant-based diets. The seven strategies outlined in this article are summarized in Figure 1. Further research is needed to explore the impact of differing forms of messaging on the uptake of plant-based eating in people with CKD.
Notes
Conflicts of interest
All authors have no conflicts of interest to declare.
Acknowledgments
The author wishes to thank the organizing committee of the APCN KSN 2024 Congress and Dr. Tae-Hyun Yoo, Editor of Kidney Research and Clinical Practice for this invited article.
Data sharing statement
The data presented in this study are available from the corresponding author upon reasonable request.
Authors’ contributions
Conceptualization, Methodology: KL
Writing–original draft: All authors
Writing–review & editing: All authors
All authors read and approved the final manuscript.