INTRODUCTION

Globally, unhealthy diets contribute to more deaths than any other risk factor and approximately 20% of all death scan be attributed to a suboptimal diet.1 Nutrition therefore plays a crucial role in the prevention and treatment of non-communicable diseases,2-4 which account for 89% and 88% of all deaths in the UK and USA, respectively.5, 6 In line with this, the UK's General Medical Council states that graduates should be able to discuss the role and impact of nutrition on health.7 In the USA, the Association of American Medical Colleges endorsed a bill in the US congress in 2019 to enhance nutrition education within medical school curricula, although this bill was not endorsed into legislation.8, 9 Nutrition is also of topical importance considering the significant role that diet plays in the development of many of the risk factors associated with severe COVID-19.10, 11

Despite acknowledgement of the importance of nutrition, there is still a significant under-representation of nutrition education in medical school curricula,12 which also appears to extend to postgraduate medical training.13 The most recent systematic review on this topic found that, regardless of country, setting or year of medical education, medical students report inadequate knowledge, skills and confidence to support patients in making sustainable dietary changes.14 Crowley et al.14 also found that, when initiatives are incorporated into curricula, their impact is modest as a result of the heterogeneity of approaches and lack of robust tools for evaluation, thus leading to recommendations to establish competencies as a means of benchmarking nutrition knowledge and skill. Identifying effective strategies to teach medical students about nutrition is therefore essential. Teaching methods recommended by a systematic review evaluating nutrition education interventions in health professionals included interprofessional learning (IPL) and interventions that place an emphasis on learners' personal health behaviours.15

The present study aimed to evaluate nutrition education interventions delivered to medical students published between 2015 and 2020 to assess recent efforts in this field subsequent to publication of the prior systematic review.15 Here, we define nutrition education as any educational experience related to the role of nutrition in health within the context of undergraduate medical education.

METHODS Search strategy

A rapid review of the literature was conducted using Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. A search (by PP) was conducted in Medline (via OvidSp), Scopus and ERIC (via EBSCOhost) (22/10/20) for relevant papers published from October 2015 to October 2020. This timeframe was chosen as an extension of a systematic review of nutrition education interventions conducted 5 years ago.15 The search terms used included (Medical student* or Medical school* or Medical undergraduate*) AND (Nutrition* education or Nutrition* intervention* or Nutrition* curricul* or Nutrition* training). The search terms used for each database are detailed in the Supporting information (Table S1). A forwards-citation search of the aforementioned systematic review was conducted15 and a backwards-citation search was conducted on a recent systematic review of nutrition in medical education.14

Study selection

The aim of the selection process was to identify any English-language empirical studies that quantitatively evaluated nutrition education interventions delivered to medical students. The inclusion and exclusion criteria used to determine eligibility are shown in Table 1. All citations were managed using EndNote Online (https://endnote.com). Duplicates were removed by hand.

Table 1. Inclusion/exclusion criteria Inclusion Exclusion Empirical study presenting quantitative data Not published in English Published within the past 5 years (October 2015–2020) Unable to isolate the outcomes of medical students from cohort Intervention delivered to undergraduate medical students Unable to isolate the outcomes of nutrition education intervention from a general lifestyle medicine intervention Delivers non-generalisable nutrition education of specific patient groups Unable to view full text Assessment alone was not considered as a nutrition education intervention Data extraction

Key information was extracted (by PP) from the included studies, identifying study design, intervention methods and modified Kirkpatrick's hierarchy score.16 Evaluating the effectiveness of nutrition education interventions is key in recognising their impact and shaping the development of future interventions. The Kirkpatrick model is a recognised method for ‘classifying the effectiveness of an intervention according to different educational outcomes’.16 The data extraction and descriptive statistics used were adapted from the previous systematic review on nutrition education interventions.15

Quality appraisal

The Medical Education Research Study Quality Instrument (MERSQI) was used to appraise the included studies.17 There was no MERSQI score cut-off for inclusion within the review. The total score was calculated as a percentage of points adjusting for non-applicable responses, giving a maximum score of 18.

RESULTS

In total, 178 papers were identified through the initial database search and 17 from citation chasing (Figure 1). After removing 69 duplicates, the remaining 126 papers were screened for eligibility based on the inclusion and exclusion criteria (Table 1) by assessing the title and/or abstract. Of these, 101 papers did not meet the inclusion criteria and were excluded. The full text of the remaining 25 papers was reviewed (by PP), of which 10 did not meet the inclusion criteria and were removed. The remaining 15 papers are evaluated in this review. A summary of the intervention descriptions, reported findings and MERSQI scores of the included papers is provided in Table 2.

Preferred Reporting Items for Systematic reviews and Meta-Analyses diagram

Table 2. Summarising of the 15 included studies Study Author (year) Country Intervention description Compulsory or elective Study design and participants Type of instructor Setting Method of intervention Duration Content areas covered Improved outcomes (Kirkpatrick hierarchya) MERSQI Score/18

Baute et al. (2017)

USA18

Pilot intervention of a student-led evidence-based lecture series Elective

Single group post-test only.

Clinical medical students (n = 65)

Medical student Classroom

Lecture

Student-led peer-assisted learning

5 h Not reported Satisfaction1 7.2

Berz et al. (2020)

USA19

Interprofessional nutrition session Elective

Single group pre-test and post-test

Fourth year medical students (n = 42)

Dietitian

Physician

Classroom

Lecture

Interprofessional

Workshop

90-min

Basic science nutrition

Dietary counselling

Diet history taking

Attitudes

Knowledge

Clinical skills (2b)

12.6

Broad et al. (2018)

UK20

Pilot intervention of a 6-week nutrition course with a student-led school-based teaching component Elective

Single group pre-test and post-test

Final-year medical students (n = 15)

Dietitian

Manager

Pharmacist

Physician

Psychologist

Classroom

School

Lecture

Student-led service learningb

Workshop

11 h

MDietary counselling

Specific patient population

Knowledge (2b) 12

Cavuoto Petrizzo (2020)

USA21

Interprofessional nutrition workshop integrated within the pre-clinical curricula Required

Single group pre-test and post-test

Pre-clinical medical students (n = 63)

Dietitian

Physician

Classroom

Interprofessional

Workshop

2 h

Basic nutrition science

Dietary counselling

Diet history taking

Satisfaction

Attitudes (2a)

12.6 Nonrandomized, 2 group Pre-clinical medical students (n = 197) Behaviour (3) 15

Coppoolse (2020)

The Netherlands22

10-week lifestyle and nutrition course Elective

Single group pre-test and post-test

Non-randomized, 2 group

Medical students (all years) (n = 118)

Dietitian

Nutritionist

Psychologist

Classroom Lecture 25 h Specific patient population Knowledge (2b) 13.2

Flynn et al. (2019)

USA23

4-week plant-based cooking program Elective

Single group pre-test and post-test

First and second year medical students (n = 43)

Not reported Kitchen Cooking session 2 h

Dietary patterns

Learner's health behaviour

Knowledge

Learner's health behaviour (3)

13.2

Jacob et al. (2016)

USA24

Pilot intervention of a 1-day culinary cooking laboratory for first-year medical students Compulsory Single group post-test only First year medical students (n = 90) Student dietitian Kitchen

Case-based discussion

Cooking session Interprofessional

6 h

Basic nutrition science

Culinary medicine

Dietary counselling

Satisfaction (1) 9.6

Monlezun et al. (2018)

USA25

Multisite cohort study of students from 20 medical schools over 5 years Elective

Single group pre-test and post-test

Non-randomised, 2 group

Medical students (all years) (n = 3248)

Not reported

Classroom

Kitchen

Online

Cooking session Problem based learning 28 h

Basic nutrition science

Culinary medicine

Specific patient population

Knowledge

Learner's health behaviour (3)

13.8

Mota et al. (2020)

Portugal26

Nutrition and metabolism curricula unit for first year medical students Compulsory Single group pre-test and post-test Pre-clinical medical students (n = 310) Dietitian Classroom

Case-based discussion

Problem based learning

75 h

Basic nutrition science

Population health

Specific patient populations

Attitudes

Knowledge

Learner's health behaviour (3)

13.2

Pang et al. (2019)

USA27

6-week culinary medicine course for second year medical students Elective

Single group pre-test and post-test

Second year medical students (n = 15)

Chef Dietitian

Physician

Kitchen

Case-based discussion

Lecture Cooking session

Interprofessional

15 h

Culinary medicine

Specific patient populations

Attitudes

Knowledge (2b)

13.8

Ramsetty et al. (2020)

USA28

Pilot intervention of case-based nutrition education session via video conferencing Compulsory

Single group pre-test and post-test

Third year medical students (n = 58)

Not reported Online Case-based discussion 2 h

Dietary counselling

Specific patient populations

Attitudes (2a) 8.4

Ring et al. (2018)

USA29

Pilot intervention combining didactics, culinary sessions with a student-led school-based teaching component Elective

Single group pre-test and post-test

First and second year medical students (n = 21)

Chef

Classroom

Kitchen

School

Lecture Cooking session Student-led service learning 15 h plus student-led component (not reported)

Basic nutrition science

Culinary medicine

Dietary counselling

Population health

Specific patient populations

Attitudes

Learner's health behaviour (3)

11.4

Ronecker et al.

USA (2019)30

Didactic curriculum with a 6-8-week student-led family coaching program Elective

Single group pre-test and post-test

First and second year medical students (n = 25)

Dietitian

Physician

Classroom

Communityc

Lecture Student-led service learning 7 h plus student-led component (not reported)

Specific patient populations

Population health

Attitudes

Knowledge (2b)

12.6 Rothman et al. (2020) USA31 Pilot intervention culinary sessions with disease specific case-based discussions with a student-led school-based teaching component Elective

Single group pre-test and post-test

Fourth year medical students (n = 30)

Dietitian

Physician

Classroom

Kitchen

School

Cooking session

Case-based discussion

Patient experience

Student-led service learning

16 h plus student-led component (not reported

Basic nutrition science

Culinary medicine

Specific patient populations

Attitudes (2a) 8.4 Shafto et al. (2016) USA32 Pilot intervention combining didactic and culinary sessions Elective

Single group pre-test and post-test

Medical students (all years) (n = 17)

Chef

Physician

Kitchen

Cooking session

Lecture

18 h

Basic nutrition science

Dietary patterns

Culinary medicine

Attitudes (2a) 10.2 aModified Kirkpatrick levels based on Best Evidence in Medical Education: (1) learners' views on the intervention, (2a) learners' attitudes toward the intervention, (2b) learners' improved knowledge or skills, (3) learners' behaviour change, (4a) delivery of care or (4b) patient outcomes. bService-learning: Students teaching members of the community. cCommunity: Outside of the institution or school setting.

Most (n = 12) of the studies were conducted in the USA, with the remaining from the UK,20 the Netherlands22 and Portugal.26 Four of the interventions were required,21, 24, 26, 28 whereas the rest were elective (optional). Five of these interventions were described as pilot studies.18, 20, 29, 31, 32 The median number of participants was 51, ranging from 1520 to 3248.25 Interventions either allowed students of all year groups to participate22, 25, 32 or were specific to year19, 20, 24, 27, 28, 31 and clinical groups.18, 21, 23, 26, 29, 30 The median duration of all the interventions was 11 h, ranging from 90 min19 to 75 h.26 However, three studies did not report the length of the student-led component of the course.29-31

Content areas and teaching methods

Nine of the interventions addressed specific patient populations. For example, Coppoolse et al.22 implemented a 10-week elective course involving 25 experts hosting lectures covering a different topic related to nutrition and disease over 25 h. Lectures included ‘nutrition and diabetes’, ‘nutrition and cancer’ and ‘nutrition and cardiovascular disease’. Nine interventions included basic nutrition science; for example, Mota et al.26 delivered a nutrition and metabolism required curricula unit for first year students. Contents included metabolic pathways, micro- and macronutrients, and regulation of food intake. Culinary medicine was utilised in seven studies.23-25, 27, 29, 31, 32 Dietary counselling was covered in six of the identified interventions.19-21, 24, 28, 29 Most of the studies incorporated a combination of content areas. For example, Jacob et al.24 delivered a single day culinary laboratory where students had to identify certain micro- and macronutrients that would benefit a patient case study and consider the metabolic pathways and food sources for these nutrients before cooking a tailored recipe. No studies reported the use of national or standardised guidance to inform the learning objectives of the interventions.

A range of teaching methods were used. Five studies incorporated a student-led component where medical students taught each other,18 school children18, 25, 26 or families30 about nutrition. One study used a student-led evidence-based nutrition lecture series involving a total of five peer taught lectures.18 A survey found that 93% (n = 14) of students agreed with the statement: ‘I like the peer teaching aspect of this lecture series and think it is an effective way to learn’. Ronecker et al.30 developed a didactic curriculum with a 6-8-week student-led family coaching program. This involved a 7-h coaching and nutrition training course followed by weekly meetings with at-risk children and their families. Similarly, Ring et al.29 involved both a teaching and service component, where medical students taught school children about healthy eating after a nutrition training course involving a combination of didactics and culinary medicine. Students reported increased confidence in nutrition and obesity counselling after the course (p < 0.001).

Four interventions were explicit in harnessing IPL as part of the teaching methods.19, 21, 24, 27 One study developed an interprofessional nutrition workshop that was jointly facilitated by registered dietitians who ‘provided experience and critical content’ for the session.21 Additionally, student dietitians participated in the planning and facilitation of the experiential culinary laboratory of Jacob et al.24 The results of a questionnaire used to evaluate medical student's attitudes towards the culinary laboratory found that the participants rated the knowledge of the student dietitians highly and above their own (p < 0.001).24 Other teaching methods used include cooking sessions,23-25, 27, 29, 31, 32 lectures18-20, 22, 27, 29, 30, 32 and case-based discussions.24, 26-28, 31

Instructors varied and with some involving a combination of professions, including dietitians,19-22, 24, 26, 27, 30, 31 physicians,20, 21, 27, 31, 32 chefs,27, 29,