Introduction
Healthy ageing is defined as ‘the process of developing and maintaining the functional capacity that enables well-being in older adults’(1). Although the consequences of the ageing process are visible in old age, risk factors that lead to health problems could be controlled and possibly prevented to achieve healthy ageing(Reference Kisling and Das2).
Enhancing healthy eating habits stands as one of the main preventive strategies to promote healthy ageing. Most dietary interventions have been focused on providing nutritional education based on calorie restriction(Reference Shlisky, Bloom and Beaudreault3). In addition, several dietary patterns, such as the Mediterranean diet(Reference Román, Jackson and Gadhi4) or other plant-based diets(Reference Rajaram, Jones and Lee5), have been shown to be beneficial for healthy ageing through different biological pathways(Reference Dominguez, Di Bella and Veronese6). However, achieving and maintaining adherence to healthy eating habits remains a major barrier to the achievement of healthy ageing(Reference Mills, White and Brown7).
Culinary medicine (CM) has been recognised as a novel strategy to modify dietary habits(Reference Asher, Shrewsbury and Bucher8), and has been defined as ‘a new evidence-based field of medicine that combines the art of food and cooking with the science of medicine’(Reference La Puma9). Although not associated with any particular dietary pattern, CM recommendations are usually based on plant-based healthy eating patterns, including the Mediterranean diet(Reference Mauriello and Artz10). This approach recognises culinary knowledge and skills as key resources for establishing and maintaining a healthy diet, but also for enjoying delicious food.
Despite the relevance of healthy ageing and CM, to our knowledge, no previous study has analysed the current scientific evidence on the effect of CM-based strategies to promote healthy ageing. Therefore, we aimed to review CM programmes aimed at promoting healthy ageing.
Material and methods
Selection criteria and search strategy (data source)
Inclusion criteria were CM programmes delivered to patients or healthy participants over the age of 40. CM programmes should include both nutritional and culinary education. In addition, only studies written in English or Spanish and published in the last 11 years (2011–2022) were included.
The literature search was conducted using the PubMed database from January 2011 to October 2022 (Fig. 1). The search strategy was carried out by combining the word ‘ageing’ with several terms related to culinary or nutrition: ‘ageing and culinary medicine’ OR ‘ageing and home cooking’ OR ‘ageing and culinary’ OR ‘ageing and healthy cooking’ OR ‘ageing and culinary nutrition’ OR ‘ageing and home food preparation’ OR ‘ageing and culinary education’ OR ‘ageing and culinary intervention’. To broaden the search and identify those studies that did not include the term ‘ageing’ but did include a dietary intervention, the following terms were used in isolation: (‘culinary medicine’), (‘home cooking’), (‘culinary nutrition’), (‘home food preparation’), (‘culinary education’).
Fig. 1. Data source.
Of the 537 articles initially retrieved, we excluded 456 articles that did not include a CM education programme (culinary-nutritional education). We additionally excluded seventy-four articles which were not delivered to people over 40 years of age, and therefore, seven studies met the inclusion criteria. After adding seven studies retrieved from two systematic reviews(Reference Reicks, Kocher and Reeder11,Reference Teggart, Ganann and Sihota12) , we finally selected fourteen culinary-nutritional interventions(Reference Diallo, Falls and Hicks13–Reference Moreau, Plourde and Hendrickson-Nelson25) (Fig. 1).
Data extraction and synthesis
Seven variables were selected on the basis of previous research studies(Reference Reicks, Kocher and Reeder11,Reference Murimi, Kanyi and Mupfudze26,Reference Owusu-Addo, Ofori-Asenso and Batchelor27) . These variables were extracted and analysed from each selected study (Fig. 2): health goal, study design, theoretical basis of the intervention, intervention duration, main outcomes, culinary intervention and the effectiveness of each intervention.
Fig. 2. Culinary medicine programmes: variables analysed and classification criteria.
Abbreviations: SMA, shared medical appointment; SCT, social cognitive theory; ELT, experiential learning theory.
*Non-excluding options
The health goals identified in each study were classified following the definitions provided by Kisling and colleagues(Reference Kisling and Das2), who distinguished different levels of prevention: primary prevention, secondary prevention, tertiary prevention and quaternary prevention. According to these authors, primary prevention aims to maintain a disease-free status in healthy individuals. Secondary prevention involves the early detection of disease and the treatment of these subclinical forms of the disease, if needed. Tertiary prevention focuses on the treatment of symptoms and sequelae of the disease during the clinical stage to minimise the severity of the disease. Finally, quaternary prevention aims to protect patients at risk of over-medicalisation from new medical interventions and to suggest ethically acceptable interventions(Reference Bentzen28). The health status of the study participants was also taken into account in the classification. Accordingly, in trials that included both healthy and sick participants, the health goal was classified as not well defined, and all potential stages of prevention were included.
Trial design referred to the number of arms included and the use of randomisation to assign interventions. We recorded whether the interventions were based on a theoretical framework and, if so, which theoretical model was applied. The duration of the intervention was classified into interventions lasting less than 5 months and those lasting 5 months or more, as previously established by Murimi and colleagues(Reference Murimi, Kanyi and Mupfudze26).
Outcomes were assessed according to criteria previously established by Reicks and colleagues(Reference Reicks, Kocher and Reeder11), who emphasised that the most common outcomes in this type of intervention are changes in dietary intake, psychosocial factors and health outcomes. The main outcomes were dietary outcomes, psychosocial outcomes and health-related outcomes. Dietary outcomes included energy and nutrient intakes, consumption of specific food groups, and eating patterns. Psychosocial outcomes included changes in behaviour, knowledge, confidence and attitudes. Finally, the assessment of health-related outcomes included anthropometric, physical activity and clinical outcomes.
In contrast to nutritional education, which has been extensively studied in dietary interventions, there is limited knowledge about culinary education. Therefore, three components of the culinary education intervention were extracted and analysed: first, the professional in charge of delivering the culinary education; second, the educational components used to deliver the culinary education; and third, the culinary curriculum developed in the intervention.
Finally, the effectiveness of the programmes referred to whether statistically significant results were observed for the main outcome and the direction of the association.
Results
A total of fourteen CM intervention programmes conducted with people over the age of 40 were selected (Table 1)(Reference Diallo, Falls and Hicks13–Reference Moreau, Plourde and Hendrickson-Nelson25,Reference Shahar, Adznam and Lee29) .
Table 1. Culinary medicine studies reviewed
Abbreviations: n, sample size; RCT, randomized controlled trial; h, hour/s; CI, confidence interval; BMI, body mass index; SMA, shared medical appointment; HRQOL, health-related quality of life; BP, blood pressure; MNA, mini nutritional assessment; mm HG, millimetres of mercury; g, grams; CVD, cardiovascular disease; FINDRISC, finnish diabetes risk score; HDL, high density lipoprotein; LDL, low density lipoprotein.
The age of the participants ranged from 40 to 94 years old, and the sample size ranged from 21(Reference Schneeberger, Golubíc and Moore14) to 468 participants(Reference the, Barnett and Edlin24). Five CM programmes were conducted in the United States(Reference Diallo, Falls and Hicks13,Reference Schneeberger, Golubíc and Moore14,Reference Delichatsios, Hauser and Burgess16,Reference Peters, Contento and Kronenberg20,Reference Wunderlich, Bai and Piemonte23) , two in Japan(Reference Kwon, Yoshida and Yoshida17,Reference Kitaoka, Nagaoka and Matsuoka21) and the remainder in Ireland(Reference Power, Lee and Aspell15), the United Kingdom(Reference Penn, Ryan and White22), Italy(Reference Villarini, Lanari and Barchiesi18), New Zealand(Reference the, Barnett and Edlin24), Canada(Reference Moreau, Plourde and Hendrickson-Nelson25), China(Reference Chung and Chung19) and Malaysia(Reference Shahar, Adznam and Lee29). Three studies had a selection criterion based on gender, two of which included only women(Reference Kwon, Yoshida and Yoshida17,Reference Peters, Contento and Kronenberg20) and one only men(Reference Kitaoka, Nagaoka and Matsuoka21). With regard to the clinical condition of the participants, four studies included older adults at risk of social isolation or malnutrition(Reference Diallo, Falls and Hicks13,Reference Power, Lee and Aspell15,Reference Chung and Chung19,Reference Wunderlich, Bai and Piemonte23) , four studies included adults at risk of developing metabolic syndrome(Reference Villarini, Lanari and Barchiesi18,Reference Shahar, Adznam and Lee29) , cardiovascular disease (CVD)(Reference Delichatsios, Hauser and Burgess16) or type 2 diabetes(Reference Penn, Ryan and White22), one included patients with cancer(Reference Schneeberger, Golubíc and Moore14) and another included men with hypertension(Reference Kitaoka, Nagaoka and Matsuoka21). Finally, two trials were conducted in pre-frail adults(Reference Kwon, Yoshida and Yoshida17,Reference the, Barnett and Edlin24) and one in postmenopausal women(Reference Peters, Contento and Kronenberg20).
Variables analysed
Table 2 presents the analysis and characterisation of the seven variables selected for each study.
Table 2. Culinary medicine programmes measured following variables analysed.
Abbreviations: P1, primary prevention; P2, secondary prevention; RCT, randomized controlled trial; SSR, statistically significant results; CI, confidence interval; P3, tertiary prevention; SMA, shared medical appointment; BMI, body mass index; SCT, social cognitive theory; MNA, mini nutritional assessment; CVD, cardiovascular disease; ELT, experiential learning theory.
* p < 0·05;
** p < 0·01.
Health goal
The CM programmes were classified according to the level of prevention: primary, secondary, tertiary or quaternary prevention. Tertiary prevention was the most common(Reference Diallo, Falls and Hicks13,Reference Schneeberger, Golubíc and Moore14,Reference Delichatsios, Hauser and Burgess16–Reference Villarini, Lanari and Barchiesi18,Reference Kitaoka, Nagaoka and Matsuoka21,Reference Wunderlich, Bai and Piemonte23,Reference Shahar, Adznam and Lee29) , while only one study(Reference Peters, Contento and Kronenberg20) was classified as a primary prevention programme. There were five trials in which the stage of prevention was not well defined due to lack of information(Reference Power, Lee and Aspell15,Reference Chung and Chung19,Reference the, Barnett and Edlin24,Reference Moreau, Plourde and Hendrickson-Nelson25) or the inclusion of people with different clinical status(Reference Penn, Ryan and White22).
Study design
We found six studies with single arm(Reference Diallo, Falls and Hicks13,Reference Schneeberger, Golubíc and Moore14,Reference Delichatsios, Hauser and Burgess16,Reference Villarini, Lanari and Barchiesi18,Reference Penn, Ryan and White22,Reference Moreau, Plourde and Hendrickson-Nelson25) , six trials with two arms(Reference Power, Lee and Aspell15,Reference Chung and Chung19–Reference Kitaoka, Nagaoka and Matsuoka21,Reference Wunderlich, Bai and Piemonte23,Reference Shahar, Adznam and Lee29) , one trial(Reference Kwon, Yoshida and Yoshida17) with three study arms (one control group and two intervention groups) and one trial(Reference the, Barnett and Edlin24) with four arms (one control group and three intervention groups). Five of the trials with two or more arms(Reference Power, Lee and Aspell15,Reference Kwon, Yoshida and Yoshida17,Reference Chung and Chung19,Reference Peters, Contento and Kronenberg20,Reference the, Barnett and Edlin24) were randomised, while three trials(Reference Kitaoka, Nagaoka and Matsuoka21,Reference Wunderlich, Bai and Piemonte23,Reference Shahar, Adznam and Lee29) used a non-randomisation method to allocate participants to the different arms. In one of these studies(Reference Kitaoka, Nagaoka and Matsuoka21), the participants themselves chose to be included in the intervention or control group; in the study by Wunderlich and colleagues(Reference Wunderlich, Bai and Piemonte23), older adults at risk of social isolation were allocated to the congregate or home-delivered group according to their ability to travel; and in the trial by Shahar and colleagues(Reference Shahar, Adznam and Lee29), participants were allocated according to where they lived. Of the fourteen studies, four were pilot studies(Reference Power, Lee and Aspell15,Reference Delichatsios, Hauser and Burgess16,Reference Villarini, Lanari and Barchiesi18,Reference Penn, Ryan and White22) aimed to assess the feasibility of the interventions.
Use of theoretical frameworks
Five out of the fourteen studies reported the theoretical framework used to achieve the behavioural outcomes. Specifically, the Social Medical Appointment (SMA) model, used in two studies(Reference Schneeberger, Golubíc and Moore14,Reference Delichatsios, Hauser and Burgess16) aimed to help patients identify and apply healthy self-care practices in group visits where individual patient medical problems were addressed. Social Cognitive Theory (SCT) was used in two studies(Reference Power, Lee and Aspell15,Reference Peters, Contento and Kronenberg20) and was based on improving self-efficacy as a tool to achieve health behaviour change. Finally, the study conducted by Penn and colleagues(Reference Penn, Ryan and White22) aimed to achieve behavioural change using Experiential Learning Theory (ELT), which involves ‘here and now’ experience, observation of its effects and subsequent reflection.
Intervention duration
Eight out of the fourteen trials(Reference Diallo, Falls and Hicks13–Reference Power, Lee and Aspell15,Reference Kwon, Yoshida and Yoshida17,Reference Chung and Chung19,Reference Penn, Ryan and White22,Reference the, Barnett and Edlin24,Reference Moreau, Plourde and Hendrickson-Nelson25) had an intervention period of less than 5 months, and five trials(Reference Villarini, Lanari and Barchiesi18,Reference Peters, Contento and Kronenberg20,Reference Kitaoka, Nagaoka and Matsuoka21,Reference Wunderlich, Bai and Piemonte23,Reference Shahar, Adznam and Lee29) had a duration of 5 months or more. The intervention period could not be determined in one study(Reference Delichatsios, Hauser and Burgess16), which only indicated that patients were invited to attend one or more monthly sessions offered in autumn and spring. Follow-up after the end of the intervention was reported in five trials(Reference Power, Lee and Aspell15,Reference Kwon, Yoshida and Yoshida17,Reference Chung and Chung19,Reference Penn, Ryan and White22,Reference the, Barnett and Edlin24) . The shortest follow-up period was 4 weeks(Reference Power, Lee and Aspell15), and the longest was 21·5 months(Reference the, Barnett and Edlin24).
Main outcomes
The outcomes measured were classified as dietary, psychosocial and health-related outcomes (Table 2). Of the seven studies that focused on dietary outcomes, one study measured changes in energy intake(Reference Power, Lee and Aspell15), and six(Reference Schneeberger, Golubíc and Moore14,Reference Villarini, Lanari and Barchiesi18,Reference Peters, Contento and Kronenberg20,Reference Kitaoka, Nagaoka and Matsuoka21,Reference Wunderlich, Bai and Piemonte23,Reference Moreau, Plourde and Hendrickson-Nelson25) assessed some characteristics related to dietary habits, such as alcohol consumption, meals eaten per day, fruit and vegetable consumption, or fat and fibre consumption. One of these six trials assessed the adherence to the prescribed dietary patterns(Reference Peters, Contento and Kronenberg20). Psychosocial outcomes were assessed in six studies(Reference Diallo, Falls and Hicks13–Reference Delichatsios, Hauser and Burgess16,Reference Chung and Chung19,Reference Moreau, Plourde and Hendrickson-Nelson25) , namely participation and attendance(Reference Diallo, Falls and Hicks13), perceived stress, patient activation, physical and mental quality of life(Reference Schneeberger, Golubíc and Moore14), food enjoyment and self-efficacy(Reference Power, Lee and Aspell15), patient satisfaction(Reference Delichatsios, Hauser and Burgess16,Reference Chung and Chung19) , participants’ perceived autonomy, knowledge about nutrition and health, and confidence in cooking and healthy eating(Reference Moreau, Plourde and Hendrickson-Nelson25). Eight trails assessed health-related outcomes: changes in anthropometric measures(Reference Schneeberger, Golubíc and Moore14,Reference Villarini, Lanari and Barchiesi18,Reference Shahar, Adznam and Lee29) , physical activity(Reference Villarini, Lanari and Barchiesi18,Reference Penn, Ryan and White22) and clinical outcomes(Reference Kwon, Yoshida and Yoshida17–Reference Chung and Chung19,Reference Kitaoka, Nagaoka and Matsuoka21,Reference the, Barnett and Edlin24,Reference Shahar, Adznam and Lee29) . Clinical outcomes included changes in physical and mental status(Reference Kwon, Yoshida and Yoshida17,Reference Chung and Chung19) , biochemical and physiological parameters(Reference Villarini, Lanari and Barchiesi18,Reference Kitaoka, Nagaoka and Matsuoka21,Reference Shahar, Adznam and Lee29) , quality of life (Health Related Quality of Life-HRQOL questionnaire)(Reference Kwon, Yoshida and Yoshida17), physical frailty status (The Frailty Scale)(Reference the, Barnett and Edlin24) and development of metabolic syndrome(Reference Villarini, Lanari and Barchiesi18).
Culinary intervention
A chef was involved in the intervention in two of the trials analysed(Reference Schneeberger, Golubíc and Moore14,Reference Delichatsios, Hauser and Burgess16) , although in one of them(Reference Delichatsios, Hauser and Burgess16) former physicians or other researchers took responsibility for training in cases where a chef was not available (Table 2). In seven trials(Reference Power, Lee and Aspell15,Reference Kwon, Yoshida and Yoshida17,Reference Chung and Chung19,Reference Kitaoka, Nagaoka and Matsuoka21–Reference Wunderlich, Bai and Piemonte23,Reference Moreau, Plourde and Hendrickson-Nelson25) the culinary intervention was delivered by a physician, nutritionist, dietitian or other research staff, while in five trials(Reference Diallo, Falls and Hicks13,Reference Villarini, Lanari and Barchiesi18,Reference Peters, Contento and Kronenberg20,Reference the, Barnett and Edlin24,Reference Shahar, Adznam and Lee29) no information was given about the professionals involved.
Twelve trials(Reference Diallo, Falls and Hicks13–Reference Kwon, Yoshida and Yoshida17,Reference Chung and Chung19–Reference Moreau, Plourde and Hendrickson-Nelson25) included at least two educational components (cooking classes, hands-on cooking or other incentives), while two trials included a single educational component (cooking classes)(Reference Villarini, Lanari and Barchiesi18,Reference Shahar, Adznam and Lee29) . Cooking classes or demonstrations were provided in nine studies(Reference Schneeberger, Golubíc and Moore14,Reference Delichatsios, Hauser and Burgess16–Reference Peters, Contento and Kronenberg20,Reference Penn, Ryan and White22,Reference Wunderlich, Bai and Piemonte23,Reference Shahar, Adznam and Lee29) , while hands-on cooking experience, namely experiential learning in which participants cooked as part of the intervention, was provided in seven studies(Reference Diallo, Falls and Hicks13,Reference Power, Lee and Aspell15,Reference Kwon, Yoshida and Yoshida17,Reference Peters, Contento and Kronenberg20,Reference Kitaoka, Nagaoka and Matsuoka21,Reference the, Barnett and Edlin24,Reference Moreau, Plourde and Hendrickson-Nelson25) . Examples of incentives included the provision of cooking instructions through videos, guidebooks and recipes(Reference Power, Lee and Aspell15,Reference Kwon, Yoshida and Yoshida17,Reference Chung and Chung19,Reference Kitaoka, Nagaoka and Matsuoka21,Reference Penn, Ryan and White22,Reference Moreau, Plourde and Hendrickson-Nelson25) . In addition, free delivery of food(Reference Diallo, Falls and Hicks13,Reference Power, Lee and Aspell15,Reference Chung and Chung19,Reference Wunderlich, Bai and Piemonte23) , individual culinary and nutritional counselling(Reference Peters, Contento and Kronenberg20,Reference Kitaoka, Nagaoka and Matsuoka21,Reference Wunderlich, Bai and Piemonte23) , and tasting(Reference Schneeberger, Golubíc and Moore14,Reference Delichatsios, Hauser and Burgess16,Reference Kwon, Yoshida and Yoshida17,Reference Peters, Contento and Kronenberg20,Reference the, Barnett and Edlin24) were offered as incentives.
The curriculum of each study includes the total number of teaching classes delivered, the frequency of delivery and the total number of teaching hours. The full curriculum delivered was found in nine studies(Reference Schneeberger, Golubíc and Moore14,Reference Power, Lee and Aspell15,Reference Kwon, Yoshida and Yoshida17,Reference Kitaoka, Nagaoka and Matsuoka21–Reference Moreau, Plourde and Hendrickson-Nelson25,Reference Shahar, Adznam and Lee29) , while five studies(Reference Diallo, Falls and Hicks13,Reference Delichatsios, Hauser and Burgess16,Reference Villarini, Lanari and Barchiesi18–Reference Peters, Contento and Kronenberg20) did not report the number of teaching hours delivered, the total number of teaching classes or the intervention period. The lowest number of classes delivered was one session(Reference Shahar, Adznam and Lee29) and the highest was twenty-four sessions(Reference Peters, Contento and Kronenberg20). The most common frequency of classes was one session per week(Reference Diallo, Falls and Hicks13,Reference Power, Lee and Aspell15,Reference Kwon, Yoshida and Yoshida17,Reference Chung and Chung19,Reference Peters, Contento and Kronenberg20,Reference the, Barnett and Edlin24,Reference Moreau, Plourde and Hendrickson-Nelson25) , while the lowest frequency was one session in 6 months(Reference Shahar, Adznam and Lee29). The total number of hours provided during the intervention could be obtained in nine studies(Reference Schneeberger, Golubíc and Moore14,Reference Power, Lee and Aspell15,Reference Kwon, Yoshida and Yoshida17,Reference Kitaoka, Nagaoka and Matsuoka21–Reference Moreau, Plourde and Hendrickson-Nelson25,Reference Shahar, Adznam and Lee29) , with the lowest being 1·5 h(Reference Shahar, Adznam and Lee29) and the highest being 24–36 h(Reference Kwon, Yoshida and Yoshida17).
Efficacy of the CM programmes
In terms of the effectiveness of the CM programmes analysed, three studies(Reference Diallo, Falls and Hicks13,Reference Delichatsios, Hauser and Burgess16,Reference Penn, Ryan and White22) found no statistically significant results, while eleven studies(Reference Schneeberger, Golubíc and Moore14,Reference Power, Lee and Aspell15,Reference Kwon, Yoshida and Yoshida17–Reference Kitaoka, Nagaoka and Matsuoka21,Reference Wunderlich, Bai and Piemonte23–Reference Moreau, Plourde and Hendrickson-Nelson25,Reference Shahar, Adznam and Lee29) found statistically significant results.
The main outcomes in the three studies that failed to demonstrate beneficial effects were participation in the CM programme(Reference Diallo, Falls and Hicks13), patient satisfaction with the sessions(Reference Delichatsios, Hauser and Burgess16), and amount and type of physical activity level(Reference Penn, Ryan and White22). These studies shared three common characteristics. First, the duration of the intervention was not reported(Reference Delichatsios, Hauser and Burgess16) or was less than 5 months(Reference Diallo, Falls and Hicks13,Reference Penn, Ryan and White22) ; second, the design involved a single group(Reference Diallo, Falls and Hicks13,Reference Delichatsios, Hauser and Burgess16,Reference Penn, Ryan and White22) ; and third, only one outcome was measured(Reference Diallo, Falls and Hicks13,Reference Delichatsios, Hauser and Burgess16,Reference Penn, Ryan and White22) .
Among the eleven trials with statistically significant results, six(Reference Schneeberger, Golubíc and Moore14,Reference Power, Lee and Aspell15,Reference Peters, Contento and Kronenberg20,Reference Kitaoka, Nagaoka and Matsuoka21,Reference Wunderlich, Bai and Piemonte23,Reference Moreau, Plourde and Hendrickson-Nelson25) found significant improvements in dietary outcomes, two(Reference Power, Lee and Aspell15,Reference Moreau, Plourde and Hendrickson-Nelson25) in psychosocial outcomes, and seven trials(Reference Schneeberger, Golubíc and Moore14,Reference Kwon, Yoshida and Yoshida17–Reference Chung and Chung19,Reference Kitaoka, Nagaoka and Matsuoka21,Reference the, Barnett and Edlin24,Reference Shahar, Adznam and Lee29) reported statistically significant results for at least one health-related outcome. Four trials achieved significant results in more than one outcome: two trials found significant improvements in both dietary and psychosocial outcomes(Reference Power, Lee and Aspell15,Reference Moreau, Plourde and Hendrickson-Nelson25) , and two trials found significant improvements in both dietary and health outcomes(Reference Schneeberger, Golubíc and Moore14,Reference Kitaoka, Nagaoka and Matsuoka21) .
Six trials reported significant improvements in dietary outcomes such as energy intake(Reference Power, Lee and Aspell15), fat intake(Reference Schneeberger, Golubíc and Moore14), salt consumption(Reference Kitaoka, Nagaoka and Matsuoka21), alcohol consumption(Reference Wunderlich, Bai and Piemonte23), food group consumption(Reference Peters, Contento and Kronenberg20,Reference Kitaoka, Nagaoka and Matsuoka21,Reference Moreau, Plourde and Hendrickson-Nelson25) , water, milk and soy drink intake(Reference Moreau, Plourde and Hendrickson-Nelson25), and adherence to healthy dietary patterns(Reference Peters, Contento and Kronenberg20). Three of these trials used theoretical frameworks(Reference Schneeberger, Golubíc and Moore14,Reference Power, Lee and Aspell15,Reference Peters, Contento and Kronenberg20) . A single-arm study(Reference Schneeberger, Golubíc and Moore14) reported a reduction in weekly fat intake in breast cancer survivors after 14 weeks of intervention. A randomised controlled trial (RCT)(Reference Power, Lee and Aspell15) that measured changes in energy intake found a significant reduction in female participants in the treatment group after 8 weeks of intervention, with a significant interaction between time, condition and sex. In the former study, the intervention group received a weekly visitor to cook together, in contrast to the control group, which only received a guidebook and recipes. A 1-year RCT(Reference Peters, Contento and Kronenberg20) reported an improvement in food consumption in both intervention groups (whole-food group, moderate-fat group), which was translated into improved adherence to healthy eating patterns. Improvements in whole grain, fruit, vegetable, water, milk and soy drink consumption were observed in a single-arm trial after one weekly session for 8 weeks(Reference Moreau, Plourde and Hendrickson-Nelson25). A 5-month non-RCT(Reference Kitaoka, Nagaoka and Matsuoka21) reduced salt consumption by reducing high-salt foods, such as Japanese noodle soup. Significant results were observed not only from pre- to post-assessment in the intervention group, but also between the intervention and control groups. Finally, a reduction in alcohol consumption was reported in congregate meals group after a 2-year nutrition education and counselling intervention(Reference Wunderlich, Bai and Piemonte23).
An 8-week RCT(Reference Power, Lee and Aspell15) using the SCT model as a behaviour change tool showed statistically significant improvements in psychosocial outcomes, demonstrating improvements in food enjoyment and self-efficacy. Meanwhile, a single-arm study(Reference Moreau, Plourde and Hendrickson-Nelson25) achieved significant improvements in knowledge about nutrition and health and confidence in cooking and healthy eating, providing a weak significant association between these two variables (knowledge and confidence), also finding that increased confidence in healthy eating was a predictor of desired dietary habits.
Of the seven trials(Reference Schneeberger, Golubíc and Moore14,Reference Kwon, Yoshida and Yoshida17–Reference Chung and Chung19,Reference Kitaoka, Nagaoka and Matsuoka21,Reference the, Barnett and Edlin24,Reference Shahar, Adznam and Lee29) that reported statistically significant results for health outcomes, five(Reference Kwon, Yoshida and Yoshida17,Reference Chung and Chung19,Reference Kitaoka, Nagaoka and Matsuoka21,Reference the, Barnett and Edlin24,Reference Shahar, Adznam and Lee29) included at least two groups, and the duration of three trials(Reference Villarini, Lanari and Barchiesi18,Reference Kitaoka, Nagaoka and Matsuoka21,Reference Shahar, Adznam and Lee29) was 5 months or longer. In particular, two single-arm trials(Reference Schneeberger, Golubíc and Moore14,Reference Villarini, Lanari and Barchiesi18) showed statistically significant reductions in body mass index (BMI)(Reference Schneeberger, Golubíc and Moore14,Reference Villarini, Lanari and Barchiesi18) and fat and lean body mass(Reference Schneeberger, Golubíc and Moore14) after CM intervention. In addition, a 6-month non-RCT(Reference Shahar, Adznam and Lee29) reported significant reductions in waist circumference and body weight for women in the intervention group. Five trials(Reference Kwon, Yoshida and Yoshida17–Reference Chung and Chung19,Reference Kitaoka, Nagaoka and Matsuoka21,Reference Shahar, Adznam and Lee29) reported statistically significant results for biochemical and physiological parameters, physical and mental status, and medical outcomes. Regarding biochemical parameters, a single-arm study(Reference Villarini, Lanari and Barchiesi18) reported a significant reduction in total cholesterol after the intervention, and a 6-month non-RCT(Reference Shahar, Adznam and Lee29) reported a beneficial effect of the intervention on total cholesterol in men, while a 5-month non-RCT(Reference Kitaoka, Nagaoka and Matsuoka21) observed a greater reduction in the sodium-to-potassium excretion ratio in the intervention group than in the control group after the intervention, also showing a significant reduction in low-density lipoprotein (LDL) cholesterol and blood pressure in the treatment group after the intervention. A 3-week RCT(Reference Chung and Chung19) reported a significant improvement in nutritional status, as assessed by the Mini Nutritional Assessment (MNA) form, in the group that received 3 d of free food samples per week, compared with the control group that received only 1 d of food samples per week. In terms of physical performance, changes in handgrip strength, a predictor of sarcopenia, and physical frailty were reported. A three-arm RCT(Reference Kwon, Yoshida and Yoshida17) reported a significant improvement in handgrip strength in the exercise intervention group from baseline to post-intervention assessment, while the exercise nutrition group showed a significant reduction in this parameter from post-intervention to follow-up assessment. Physical frailty was assessed using the Fried Frailty Score, a five-question screening tool suitable for clinicians to identify frailty, with a reduction in the score indicating an improvement in the patient’s physical status. A four-arm RCT(Reference the, Barnett and Edlin24) showed a significant reduction in the Fried Frailty Score in the exercise group at post-intervention follow-up. In addition, participants in the group that received both culinary-nutritional and exercise education were more likely to be robust at the end of the programme than those in the control group(Reference the, Barnett and Edlin24). The three-arm study(Reference Kwon, Yoshida and Yoshida17) reported significant changes in quality of life from baseline to post-intervention assessment: the exercise-nutrition group reported significant improvements in role physical, bodily pain, role emotional and physical components; and the exercise group reported significant improvements in mental health. Finally, a significant reduction in bodily pain was observed in all groups from post-intervention to follow-up assessment, while the exercise group also showed a significant reduction in physical functioning, role physical, vitality, role emotional, and physical and mental components.
In the studies with positive results, participants were recruited mainly through media campaigns(Reference Power, Lee and Aspell15,Reference Peters, Contento and Kronenberg20,Reference Kitaoka, Nagaoka and Matsuoka21) , social/community centres(Reference Power, Lee and Aspell15,Reference Wunderlich, Bai and Piemonte23,Reference Shahar, Adznam and Lee29) and health professionals or health organisations(Reference Schneeberger, Golubíc and Moore14,Reference Power, Lee and Aspell15,Reference Kwon, Yoshida and Yoshida17–Reference Chung and Chung19,Reference Kitaoka, Nagaoka and Matsuoka21,Reference the, Barnett and Edlin24,Reference Moreau, Plourde and Hendrickson-Nelson25) . Regarding the retention methods used, most CM programmes analysed in this review did not report details about this. Some studies provided a close follow-up by contacting participants who missed a session to arrange a make-up session(Reference Peters, Contento and Kronenberg20) or to encourage regular attendance(Reference Villarini, Lanari and Barchiesi18). In addition, the implementation of theoretical frameworks is likely to have worked as an undirected method of retaining participants in three studies(Reference Schneeberger, Golubíc and Moore14,Reference Power, Lee and Aspell15,Reference Peters, Contento and Kronenberg20) . Specifically, Schneeberger and colleagues(Reference Schneeberger, Golubíc and Moore14) included a health coach in all visits, Peters and colleagues(Reference Peters, Contento and Kronenberg20) developed behavioural sessions to motivate participants, and Power and colleagues(Reference Power, Lee and Aspell15) used a trained volunteer to go to participants’ homes for vicarious learning (learning by observing others). Other retention methods were the use of a trained facilitator(Reference the, Barnett and Edlin24), covering transport costs(Reference the, Barnett and Edlin24) or using a reinforcement method(Reference Shahar, Adznam and Lee29), although in the latter study(Reference Shahar, Adznam and Lee29) the authors did not specify the method of reinforcement used.
Discussion
This comprehensive review has analysed fourteen culinary-nutritional trials to promote healthy ageing (40–94 years old). Most of these trials found a significant outcome related to healthy ageing. Interestingly, longer intervention durations (5 months or more) and study designs involving two or more groups appeared to be critical factors associated with the observation of significant results. The classification of the studies according to the stages of prevention showed that although the prevalence of tertiary prevention in the studies analysed was high (eight out of fourteen), there were also a few studies (three out of fourteen) that included healthy participants without associated chronic diseases. This highlights the potential of CM in enhancing the wellbeing of participants through preventive interventions in addition to disease treatment. On the other hand, although few authors have identified theoretical frameworks as a success factor in healthy ageing interventions(Reference Owusu-Addo, Ofori-Asenso and Batchelor27), most CM programmes did not refer to this issue as a factor influencing the effectiveness of the intervention.
The duration of most trials included in our review was less than 5 months. Interestingly, all CM interventions conducted for 5 months or more achieved statistically significant results in various outcomes, including dietary(Reference Peters, Contento and Kronenberg20,Reference Kitaoka, Nagaoka and Matsuoka21,Reference Wunderlich, Bai and Piemonte23) and clinical outcomes(Reference Villarini, Lanari and Barchiesi18,Reference Kitaoka, Nagaoka and Matsuoka21,Reference Shahar, Adznam and Lee29) . This finding is consistent with the findings of Murimi and colleagues(Reference Murimi, Kanyi and Mupfudze26), who showed that an intervention of 5 months or more was an important factor associated with the effectiveness of dietary interventions after conducting a systematic review of forty-five studies that included dietary education interventions(Reference Reicks, Kocher and Reeder11). Of the eleven trials that reported statistically significant results, eight(Reference Power, Lee and Aspell15,Reference Kwon, Yoshida and Yoshida17,Reference Chung and Chung19–Reference Kitaoka, Nagaoka and Matsuoka21,Reference Wunderlich, Bai and Piemonte23,Reference the, Barnett and Edlin24,Reference Shahar, Adznam and Lee29) included at least two groups. In these eight trials, participants made positive changes in their eating habits(Reference Power, Lee and Aspell15,Reference Peters, Contento and Kronenberg20,Reference Kitaoka, Nagaoka and Matsuoka21,Reference Wunderlich, Bai and Piemonte23) , and attitudes towards food(Reference Power, Lee and Aspell15), and reported improvements in some clinical outcomes(Reference Kwon, Yoshida and Yoshida17,Reference Chung and Chung19,Reference Kitaoka, Nagaoka and Matsuoka21,Reference the, Barnett and Edlin24,Reference Shahar, Adznam and Lee29) , such as reductions in LDL-cholesterol(Reference Kitaoka, Nagaoka and Matsuoka21). In conclusion, the results observed in our review suggest that the inclusion of multiple arms and the duration of the intervention should be well defined in the design of future CM programmes.
In the studies included in our review, the culinary intervention was usually led by physicians, nutritionists, dietitians or other research staff members. A low presence of chefs as educators was stated. This finding contrasts with the fact that chefs are the professionals who have the knowledge and the skills to deliver culinary education(Reference Asher, Shrewsbury and Bucher30). In addition, we were not able to identify the person responsible for the culinary education in a large number of the studies analysed, as has been previously reported in adult cooking intervention studies(Reference Reicks, Kocher and Reeder11). These issues indicate that the culinary educator should be better justified in the CM programmes.
Evaluations of the type of culinary intervention showed a frequent use of cooking classes and hands-on cooking experience as educational components. Alpaugh and colleagues(Reference Alpaugh, Pope and Trubek31) reported similar effects when comparing an active (hands-on cooking) and passive (chef demonstrations) culinary intervention. The location of the cooking classes varied across the CM programmes. For example, three(Reference Schneeberger, Golubíc and Moore14,Reference Peters, Contento and Kronenberg20,Reference Moreau, Plourde and Hendrickson-Nelson25) out of the eleven trials with positive results delivered the cooking classes in a community kitchen, one culinary intervention(Reference Kwon, Yoshida and Yoshida17) used a classroom in a research centre, and one(Reference Power, Lee and Aspell15) was delivered in participants’ homes. In addition, one culinary intervention(Reference Chung and Chung19) provided cooking classes using a digital format. Similar to other aspects of culinary interventions, many studies did not specify the location of the cooking classes(Reference Villarini, Lanari and Barchiesi18,Reference Kitaoka, Nagaoka and Matsuoka21,Reference Wunderlich, Bai and Piemonte23,Reference the, Barnett and Edlin24,Reference Shahar, Adznam and Lee29) , and this lack of information limits the assessment of the importance of location on the effectiveness of these CM programmes. In this sense, the COVID-19 pandemic forced the delivery of virtual CM courses, but it also demonstrated the flexibility and viability of this approach for participants who would not have attended in person if they live far away(Reference Newman, Yan and Messiah32). Therefore, virtual delivery of cooking classes can be considered as an alternative or complementary activity to face-to-face interventions when designing CM programmes.
Several studies(Reference Diallo, Falls and Hicks13–Reference Kwon, Yoshida and Yoshida17,Reference Chung and Chung19–Reference Moreau, Plourde and Hendrickson-Nelson25) included other educational components as an incentive to improve the effectiveness of the interventions. For example, the delivery of food may be an interesting method to improve the nutritional status of low-income communities and older adults living alone(Reference Power, Lee and Aspell15,Reference Chung and Chung19,Reference Wunderlich, Bai and Piemonte23) . Specifically, in the studies by Power and colleagues(Reference Power, Lee and Aspell15) and Chung and colleagues(Reference Chung and Chung19), raw food was delivered to participants to be cooked, whereas in the studies by Wunderlich and colleagues(Reference Wunderlich, Bai and Piemonte23) and Diallo and colleagues(Reference Diallo, Falls and Hicks13), participants were offered an already cooked meal. These CM programmes were successful in achieving significant reductions in energy intake(Reference Power, Lee and Aspell15) and alcohol consumption(Reference Wunderlich, Bai and Piemonte23), as well as significant improvements in food enjoyment, self-efficacy(Reference Power, Lee and Aspell15) and nutritional status(Reference Chung and Chung19). Another component used as an incentive was the provision of individualised advice to participants. This strategy has been used to improve health outcomes in nutritional education programmes(Reference De Toro-Martín, Arsenault and Després33), highlighting the power of personalisation as a teaching tool. In the study by Peters and colleagues(Reference Peters, Contento and Kronenberg20), behavioural sessions were developed with individual goals and action plans. In the study by Kitaoka and colleagues(Reference Kitaoka, Nagaoka and Matsuoka21), participants received individualised feedback, reinforcement and problem-solving strategies based on information obtained from monitoring their diet. Finally, in the study by Wunderlich and colleagues(Reference Wunderlich, Bai and Piemonte23), participants were encouraged to call the dietitian for individual counselling. Despite the different ways in which individualised counselling was implemented(Reference Peters, Contento and Kronenberg20,Reference Kitaoka, Nagaoka and Matsuoka21,Reference Wunderlich, Bai and Piemonte23) , those interventions that provided personalised or tailored counselling were successful in changing participants’ dietary behaviour and improving their adherence to healthy dietary patterns; and in some cases, these changes were translated into significant improvements in biochemical and physiological parameters(Reference Kitaoka, Nagaoka and Matsuoka21). In this sense, personalised advice could be an interesting educational tool in culinary interventions and should therefore be considered in the design of future CM programmes.
The evaluation of the culinary training revealed a great variability in the frequency of classes taught during the interventions. For example, while Diallo and colleagues(Reference Schneeberger, Golubíc and Moore14) included one weekly cooking session over 8 weeks, Wunderlich and colleagues(Reference Wunderlich, Bai and Piemonte23) included four sessions per year. Interestingly, a review published by Owusu-Addo and colleagues(Reference Owusu-Addo, Ofori-Asenso and Batchelor27) found an association between the number of sessions and improved intervention fidelity and programme impact on older adults(Reference Owusu-Addo, Ofori-Asenso and Batchelor27). In line with this, the follow-up by Peters and colleagues(Reference Peters, Contento and Kronenberg20) found significant changes in the first four months of the intervention when the sessions’ frequency was higher (one session per week) compared to the following months of the study (one or two sessions per month). However, only nine studies identified in our review(Reference Schneeberger, Golubíc and Moore14,Reference Power, Lee and Aspell15,Reference Kwon, Yoshida and Yoshida17,Reference Kitaoka, Nagaoka and Matsuoka21–Reference Moreau, Plourde and Hendrickson-Nelson25,Reference Shahar, Adznam and Lee29) provided full details of the number, frequency and hours of classes offered. More information on culinary curricula is needed to adequately assess the effectiveness of CM interventions.
The CM programmes were more successful in achieving dietary and health outcomes than psychosocial outcomes. This could be explained by the findings previously demonstrated by Farmer and colleagues(Reference Farmer, Touchton-Leonard and Ross34) that, although cooking interventions have a positive impact on psychosocial outcomes, the evidence is limited and scarce, partly due to the use of non-validated research instruments(Reference Farmer, Touchton-Leonard and Ross34). Furthermore, psychosocial outcomes were mostly related to dietary and health issues, such as dietary behaviour or perceived stress of participants, and only one(Reference Moreau, Plourde and Hendrickson-Nelson25) of the studies analysing psychosocial outcomes assessed culinary knowledge or behaviour related to cooking. In this context, there is a great opportunity to improve the methods used to assess psychosocial outcomes and support the need to develop a larger study that analyses the impact of a culinary intervention developed by a chef with a well-defined frequency of cooking classes on psychosocial outcomes. Although improving dietary habits should be one of the main objectives of culinary and nutritional interventions(Reference Hasan, Thompson and Almasri35), only half of the studies analysed recorded dietary outcomes, which were then translated into small dietary changes. In this sense, Garcia and colleagues(Reference Garcia, Reardon and Mcdonald36) showed that cooking interventions led to little change in fruit and vegetable consumption and had low effectiveness in modifying dietary behaviour(Reference Garcia, Reardon and Mcdonald36). On the other hand, health-related outcomes included changes in a wide range of parameters, including anthropometric measurements, physical activity and clinical outcomes. Although positive results were obtained, the changes achieved were small. In fact, none of the CM programmes achieved a significant improvement in physical activity, although this was the main outcome in two lifestyle interventions(Reference Villarini, Lanari and Barchiesi18,Reference Penn, Ryan and White22) . Culinary interventions remained successful in improving healthy dietary intake(Reference Hasan, Thompson and Almasri35) and health-related outcomes(Reference Reicks, Kocher and Reeder11), but one of the key points for achieving the greatest changes in dietary intake and health-related outcomes probably depends on improving the design of CM programmes. Furthermore, in the context of healthy ageing, the scientific literature has recently highlighted the need to assess the ageing process and how healthy ageing interventions modify the ageing process(Reference Campisi, Kapahi and Lithgow37). In particular, the measurement of biomarkers of ageing has been suggested as a promising strategy for evaluating healthy ageing interventions(Reference Campisi, Kapahi and Lithgow37).
Limitations
Two major limitations of the present review should be mentioned. First, potential CM studies published before the last 11 years were not included in this review, although the concept of CM is new and we believe that the likelihood of excluding a relevant study is low. Second, we excluded seventy-four published studies where the participant profile was outside the scope of the review. Although the excluded studies described some positive effects on dietary, health or psychosocial outcomes(Reference Pritlove, Capone and Kita38–Reference Adam, Young-Wolff and Konar51), the participant profiles of these seventy-four studies included twenty-three trials with adult participants aged less than 40 years, six trials with children or adolescents, seven trials with parents or families, eight trials with health professionals, twenty-three trials with medical or health students, one trial with both doctors and patients, and six trials in which the age of participants was not well defined.
Conclusions
Our review has shown that CM intervention programmes can be a powerful tool to promote healthy ageing in the adult population. The duration of the intervention and the study design emerged as key determinants influencing the effectiveness of the interventions. Furthermore, other factors such as the inclusion of culinary outcomes, the optimisation of the culinary curriculum, the participation of a chef and adding several educational components (cooking classes, hands-on cooking, individual counselling, among others) could contribute to better health outcomes in ageing individuals. By considering these factors, CM programmes have the potential to significantly enhance the wellbeing and health status of ageing individuals, fostering a healthier and more vibrant ageing process.
Acknowledgements
We acknowledge the Basque Government for its support of the project and for providing Jara Domper with ‘Ayudas de formación a personal investigador y tecnólogo en el entorno científico-tecnológico y empresarial del sector agropesquero y alimentario vasco’.
Conflict of interest
None.
Authorship
J.D. participated in the conception and design of the study, performed the critical review of the current literature and the assessment and wrote the first draft of the manuscript. M.R.C. and U.E. developed the concept and design of this study and supervised the analysis of the results and the writing of the manuscript, Lu.G., Le.G. and V.D. contributed to the critical analysis of the results and to the writing of the manuscript. All included authors were involved in the review and subsequent approval of the final version of the manuscript.
