Impact of Nutritional Counseling on Knowledge and Lifestyle Related to Immunity Among Academic University Staff in Lima (Peru) During the COVID-19 Pandemic

Introduction

The COVID-19 pandemic has triggered an unprecedented global health crisis, impacting millions of people worldwide, including those in Peru.¹ During this period, the critical role of the immune system in defending against the virus has been widely recognized, along with the importance of adopting healthy lifestyle habits to strengthen immune response.^2,3 Numerous studies have highlighted the impact of diet on the modulation of the immune system.^4–7 A healthy diet rich in essential nutrients, such as vitamins and minerals, has been shown to be crucial for maintaining optimal immune function, particularly in contexts like the COVID-19 pandemic.⁴ In fact, nutrients such as vitamin C, vitamin D, zinc, and iron play a crucial role in regulating both innate and adaptive immune responses.⁷ Additionally, a balanced diet that includes fruits, vegetables, whole grains, and high quality proteins has been shown to reduce susceptibility to infections and enhance the body’s ability to combat pathogens.⁵

Immunonutrition has gained significance as a key strategy for preventing and reducing the severity of respiratory infections.^5–7 The importance of promoting education on healthy eating habits has been emphasized as a complementary measure to enhance the population’s overall health.⁸ However, despite the growing scientific evidence, inconsistencies remain regarding the level of knowledge about healthy dietary practices and their impact on immunity. Por example, there is a tendency to underestimate the role of key foods and nutrients, such as fruits, vegetables, zinc, and omega-3 fatty acids, in modulating immune responses,⁹ with more emphasis often placed on trendy supplements rather than a balanced diet.¹⁰ In the context of university teachers, nutritional knowledge is particularly important, as they interact daily with students and play a crucial role in promoting healthy habits within their communities. However, previous studies have indicated that, overall, their level of nutrition knowledge is limited,¹¹ which can negatively affect their own health and hinder their ability to promote a healthy lifestyle in both their work environment and the broader community.

To date, nutrition counseling programs have proven to be effective in improving both nutrition knowledge and healthy lifestyle habits in diverse populations.^12,13 These interventions, typically involving educational sessions and personalized follow-ups, have successfully increased participants’ understanding of the importance of a balanced diet and its direct impact on health, particularly in the context of disease prevention.¹⁴ Nehme et al,¹⁵ in a study conducted among workers during the COVID-19 pandemic, demonstrated that nutritional counseling can significantly increase the consumption of foods rich in essential nutrients, such as proteins and other micronutrients, thereby contributing to improved overall health and greater awareness of the importance of nutrition for immunity. Similarly, a study conducted among primary school teachers found significant differences between pre- and post-test scores, indicating an increase in the teachers’ level of nutrition knowledge.¹²

Nutritional counseling not only enhances teachers’ knowledge but also equips them to more effectively transmit this knowledge to their students, fostering a positive impact on the entire school community.¹¹ However, the scientific literature on the implementation of nutritional counseling programs among educational personnel remains limited, highlighting the need for further research in this area. These programs have the potential to not only improve the individual health of educational workers, but also enhance their role as health promoters within educational institutions, fostering long-term positive changes in school communities.¹⁶ Educational personnel who lack a solid understanding of how healthy eating influences immunity may struggle to incorporate healthy eating practices into their daily routines, thereby reducing their ability to act as agents of change within the school environment,^17,18 which may, in turn, increase their susceptibility to infection and disease, especially during high-risk situations, similar to the COVID-19 pandemic. Therefore, there is a need for studies that assess the impact of nutritional counseling on this key group, in order to provide evidence supporting the development of targeted educational programs.

In the context of the COVID-19 pandemic, social distancing measures and mobility restrictions accelerated the adoption of digital solutions in various sectors, including nutrition.¹⁹ Nutrition tele-counseling, which utilizes virtual platforms to deliver nutritional guidance and education, has emerged as a vital tool for promoting healthy eating habits while ensuring the safety of participants.²⁰ This approach not only enhances accessibility to counseling programs by removing geographic barriers, but also provides participants with the flexibility to access information from home—an essential benefit during periods of confinement. Tele-counseling can be just as effective as face-to-face interventions in improving nutritional knowledge and promoting health-related behavioral changes, highlighting its relevance and applicability during health emergencies like the COVID-19 pandemic.¹⁹

The present study aims to evaluate the impact of nutritional tele-counseling on knowledge related to immunity and lifestyle among academic university staff in Lima, Peru, during the COVID-19 pandemic.

Materials and Methods

Design and Study Participants

A quasi-experimental, longitudinal, and prospective study was conducted, with the protocol approved by the research ethics committee of Clínica Avendaño (protocol code: 029–022-CIEI). Prior to the implementation of the online nutritional counseling program “Vida Sana - USIL”, which consisted of 16 educational sessions over 12 weeks, informed consent was obtained from all participants. The study was conducted in accordance with the ethical principles outlined in the 1975 Declaration of Helsinki and its subsequent amendments.

The study participants were staff members from Universidad San Ignacio de Loyola, a private university located in Lima, Peru. They attended the initial online session, where they were provided with all relevant information about the study. Those who expressed interest in participating completed a preliminary survey (pre-test). In addition, anthropometric measurements, including weight and height, were taken for each participant. These measurements had been assessed by the ‘Vida Sana - USIL’ program a few days prior to the start of the nutritional counseling.²¹

Sampling was not conducted due to the small population size. Instead, all individuals who met the selection criteria and agreed to participate were included. Initially, 47 collaborators were enrolled; however, 12 participants were lost during the 12-week nutritional counseling follow-up conducted between October and December 2022. As a result, 35 participants were included in the final analysis (see Figure 1).

Figure 1 Study design.

Implementation and Development of the “Vida Sana” Program

After obtaining authorization from the relevant university departments, a virtual meeting was held with all participants via the Zoom platform. During this session, the objective and procedures of the nutritional counseling study were explained, and informed consent was obtained. Participants were required to confirm their participation and send their signed consent forms via Email to the research team. The meeting also served to present the structure of the intervention and the role of the nutritionist, who was responsible for promoting and facilitating participation in the “Vida Sana” program.

Participants were invited to join a dedicated WhatsApp Messenger group, where they received ongoing communication, motivational content, and a secure link to complete the initial online survey via Google Forms. This baseline (pre-intervention) survey included questions to assess knowledge and lifestyle habits related to immunity. Importantly, participants did not receive feedback on their responses at this stage, in order to preserve the objectivity of the baseline measurement. The assessment process was fully standardized: all participants received the same questionnaire format, instructions, and delivery method, whether completed synchronously during the meeting or later via the provided link.

Following this, 16 weekly nutritional counseling sessions were delivered over the course of three months, each lasting 45 minutes. The sessions addressed topics related to healthy eating, immunity-supportive habits, and lifestyle changes. They were delivered virtually and included interactive components. At the end of each session, participants had the opportunity to ask questions and clarify any doubts about the content discussed.

Upon completion of the 16 sessions, participants were invited to complete the post-intervention survey, which contained the same set of questions as the initial survey. This allowed for a direct comparison of pre- and post-intervention scores to evaluate the impact of the nutritional counseling on participants’ knowledge and lifestyle behaviors related to immunity.

Training Resources and Tools

In preparation for the training sessions outlined in Table 1, the topics related to nutrition, immunity, healthy lifestyles, and the prevention of non-communicable diseases were developed by the lead researcher (a nutritionist) in collaboration with a multidisciplinary team of professionals in nutrition and public health. This collaborative approach ensured that the content was evidence-based, relevant to the context of the pandemic, and aligned with the objectives of the intervention.

Table 1 Nutritional Counseling Program to Improve Knowledge and Lifestyle

The sessions were delivered using Microsoft PowerPoint presentations and supported by interactive learning tools, such as Kahoot and Google Forms, which were used for feedback activities and to dynamically assess participants’ learning.

Within the WhatsApp group, participants had access to the full program schedule, including detailed information on the topics to be covered, session timings, and weekly activities. Supplementary materials—such as videos, guides, and recommendations on healthy eating and immunity-supportive lifestyle habits—were also shared to reinforce learning. This space encouraged participant interaction and facilitated ongoing engagement with the program. Additionally, recordings of each session were made available so participants could review the material at their own pace.

Data Collection Instruments

Knowledge Questionnaire on Immune-Related Nutrients

It was designed to assess participants’ knowledge of essential nutrients that support immune function. The questionnaire consisted of 8 items covering various categories of micronutrients, including vitamins (A, C, D, E), minerals (zinc, magnesium, iron), and omega-3, −6, and −9 fatty acids. Participants were asked to identify foods that contain these nutrients. The instrument was validated by four experts in nutrition and health sciences, who assessed its clarity, relevance, and appropriateness within the context of the study. The response options were dichotomous: “Yes” (knows the food containing the nutrient) and “No” (does not know). Each correct answer was awarded 1 point, while incorrect answers or lack of knowledge received 0 points. The total score reflected each participant’s level of knowledge regarding immunity-related nutrients. The internal consistency of the questionnaire was assessed using the Kuder-Richardson coefficient, yielding a value of 0.75, which indicates adequate reliability for the items measuring nutritional knowledge.

Immunity-Related Lifestyle Questionnaire

It was designed to gather information on dietary and behavioral habits that may affect the immune system. This questionnaire included 17 questions addressing the frequency of consumption of specific foods, such as whole grains, fruits, vegetables, nuts, legumes, protein-rich foods, and probiotic dairy products. In addition, it assessed lifestyle factors such as daily physical activity, water consumption, sleep duration, sun exposure, alcohol and tobacco use, and spiritual beliefs. The questionnaire was validated by a group of seven nutrition experts, who evaluated the relevance of the items and their alignment with the study’s objectives. The response options for most questions were based on the frequency of consumption or activity: “Never”, “Occasionally” (1 to 2 times per week), “Frequently” (3 to 5 times per week), and “Always” (every day). Each item was scored from 0 (for the least healthy responses) to 3 points (for the healthiest responses). The total score served as an indicator of the participants’ lifestyle in relation to immunity. The questionnaire had a Cronbach’s alpha coefficient of 0.71, indicating acceptable internal consistency.

Statistical Analysis

Descriptive analyses were performed for all study variables. Quantitative variables were summarized using measures of central tendency (mean, median) and dispersion (standard deviation, range), while categorical variables were presented as absolute frequencies and percentages.

To evaluate changes in food and nutrient knowledge scores and immunity-associated lifestyle scores before and after the intervention, the Wilcoxon signed-rank test was applied. This non-parametric test was selected due to the paired nature of the data and the non-normal distribution of the scores. For categorical variables derived from the classification of knowledge and lifestyle levels, the McNemar test was used to compare proportions between pre- and post-intervention measurements.

In addition, box plots were used to visualize the distribution of knowledge and lifestyle scores, and a scatterplot was employed to illustrate the correlation between both variables. Spearman’s rank correlation coefficient (rho) was used to assess the relationship between knowledge and lifestyle scores, given the ordinal and non-parametric nature of the data.

All analyses were conducted using SPSS version 17 (SPSS Inc., Chicago, IL, USA). A two-tailed significance level of 5% (p < 0.05) was used for all tests.

Results

A total of 35 participants aged between 25 and 64 years were included in the study. The majority belonged to the 30–59 age group (85.7%), followed by participants aged 60 years and older (8.6%) and those aged 18–29 (5.7%). The predominant gender was male (82.9%), and most participants were married (57.1%). According to body mass index (BMI), 54.3% of the participants were overweight, and 20% had grade 1 obesity. In terms of personal medical history, the most common condition was cardiovascular disease, specifically arterial hypertension (34.3%) (see Table 2).

Table 2 Sociodemographic Characteristics of the Participants (N = 35)

The study demonstrated a significant improvement in participants’ knowledge of foods rich in key nutrients for immunity following the nutritional intervention (see Table 3). Participants’ knowledge of foods containing vitamin A increased significantly (p = 0.007), as did their knowledge of foods rich in vitamin E (p < 0.001), vitamin D (p < 0.001), and vitamin C (p < 0.001). Similarly, a significant increase in knowledge about foods containing zinc (p < 0.001) and magnesium (p < 0.001) was observed. Additionally, knowledge levels regarding omega-3, −6, and −9 fatty acids rose from 37.1% to 91.4% (p < 0.001), while knowledge of iron-rich foods increased from 54.3% to 97.1% (p < 0.001).

Table 3 Knowledge of Foods and Nutrients Associated with Immunity

Table 4 illustrates a significant improvement in the participants’ overall knowledge score following the nutritional intervention. The mean overall score increased from 3.3 ± 1.9 before the intervention to 7.1 ± 1.5 after the intervention (p < 0.001), with the median rising from 3 (range 0–8) to 8 (range 2–8). Prior to the intervention, only 5.7% of participants were classified as having a high level of knowledge (score 7–8). After the intervention, only 5.7% remained at the low level (p < 0.001).

Table 4 Level of Knowledge of Foods and Nutrients Associated with Immunity

The results presented in Table 5 indicate significant improvements in various eating habits and healthy behaviors following the intervention. A significant increase was observed in the daily consumption of cereals and whole grains (22.9% to 48.6%, p = 0.001), nuts (14.3% to 49.6%, p = 0.004), legumes (22.9% to 62.9%, p < 0.001), fruits and vegetables (20% to 77.1%, p < 0.001), as well as the number of glasses of water consumed per day (28.6% to 91.4%, p < 0.001). There was also a notable increase in the consumption of protein-rich foods, citrus fruits, red fruits, yogurt, and probiotics, as well as in the practice of daily physical activity (20% to 62.9%, p = 0.001).

Table 5 Frequency of Consumption and Lifestyles Associated with Immunity

Table 6 shows a significant improvement in the overall score and immunity-associated lifestyle categories following the intervention. The overall score increased significantly, from a mean of 4.3 ± 1.8 before the intervention to 11.3 ± 1.6 after the intervention (p < 0.001). The median also showed a notable increase, from 4 (range 1–8) to 12 (range 8–14). Regarding immunity-associated lifestyle, most participants were categorized as having a low lifestyle before the intervention (94.3%), whereas after the intervention, only 11.4% remained in this category. After the intervention, 71.4% of participants achieved an intermediate lifestyle (p < 0.001), and 17.2% reached a high lifestyle.

Table 6 Effect of the Intervention on the Overall Score and Immunity-Associated Lifestyle Categories Among Participants

Discussion

The COVID-19 pandemic introduced significant public health and educational challenges, emphasizing the need for intervention strategies that could be implemented remotely. Among these strategies, nutritional tele-counseling emerged as an effective tool for improving knowledge about health, immunity, and lifestyle habits across various populations.²² In educational institutions, where personnel face high work demands and stress, these interventions have played a crucial role in promoting healthy lifestyles. The present study evaluated the impact of nutritional tele-counseling on the staff of an educational institution during the pandemic, aiming to assess the knowledge gained about immunity and lifestyle habits. The results showed a significant improvement in both areas: the mean knowledge score increased from 3.3 ± 1.9 to 7.1 ± 1.5 (p < 0.001), and the lifestyle score rose from 4.3 ± 1.8 to 11.3 ± 1.6 (p < 0.001). These findings highlight the effectiveness of tele-counseling as a practical and scalable intervention in promoting immune-related education and healthy behaviors in academic settings.

In the current study, a statistically significant improvement was observed in participants’ knowledge of immunity-related nutrients (p < 0.001), with the percentage of participants at a high knowledge level increasing from 5.7% to 77.1%. This included knowledge about vitamins A, C, D, and E, as well as minerals such as zinc, iron, and magnesium. These findings suggest that nutritional tele-counseling can be an effective tool for promoting education about the importance of micronutrients in strengthening the immune system, particularly during a pandemic when immune health is a priority. This result aligns with a telehealth intervention study conducted on university teachers in Peru by Saintila et al,²³ in which the knowledge level scores on nutrition and healthy eating increased significantly. Similarly, findings from an E-Learning program for teachers have demonstrated an improvement in nutritional knowledge levels.²⁴ Knowledge of these nutrients can lead to better dietary decision-making and, consequently, a stronger immune response.

These micronutrients, along with omega-3, −6, and −9 fatty acids, have been shown to be essential for strengthening the immune system.²⁵ For example, vitamin A helps maintain the integrity of epithelial barriers and regulates lymphocyte response, while vitamin C functions as an antioxidant and stimulates interferon production.⁷ Vitamin D modulates both innate and adaptive immunity, preventing inflammatory overactivation, and vitamin E protects immune cells from oxidative stress.²⁵ Among minerals, zinc is crucial for lymphocyte function and has antiviral effects, while iron is essential for immune cell proliferation and macrophage metabolism.⁷ Magnesium, on the other hand, plays a role in the activation of T lymphocytes, making it indispensable for an adequate immune response.²⁶ Omega-3, −6, and −9 fatty acids are essential for strengthening the immune system due to their role in modulating the inflammatory response and supporting immune cell function. As a result, these nutrients are crucial for maintaining immune system functionality and protecting the body against infections, including SARS-CoV-2.^25,27

Following the intervention, whole grain consumption increased significantly (p < 0.001), with the proportion of participants reporting frequent intake rising from 5.7% to 71.4%. These findings suggest that nutritional tele-counseling is not only effective in increasing knowledge of nutrients but also in promoting positive changes in eating habits, such as incorporating fiber-rich foods and nutrients essential for immune and overall health. Similarly, an intervention study demonstrated that intensive nutrition education is associated with increased whole grain consumption,²⁸ which has been linked to improved digestive health, better regulation of body weight, and a reduced risk of chronic diseases such as type 2 diabetes and cardiovascular disease.²⁹

Whole grains have anti-inflammatory and antioxidant properties that may contribute to improved immune function, reinforcing the importance of including these foods as part of a balanced diet.^30,31 These beneficial effects are partly due to their high content of dietary fiber, phenolic compounds, and other phytochemicals, which act as potent antioxidants, neutralizing free radicals and reducing oxidative stress in the body.^30,31 Additionally, whole grains are rich in essential fatty acids, B vitamins, and minerals such as zinc and magnesium, all of which are important for proper immune function.³² The fiber in whole grains also positively impacts intestinal health by promoting the growth of beneficial bacteria in the microbiome, which strengthens the intestinal barrier and enhances the immune response.³³ This mechanism is crucial, as a healthy gut is one of the body’s primary defenses against pathogens. Modulating the gut microbiome through the consumption of whole grains could reduce systemic inflammation and enhance innate immunity.³⁴ Finally, bioactive compounds present in whole grains, such as beta-glucans, have been shown to activate immune cells, including natural killer cells and macrophages, which optimizes the body’s ability to fight infection.³⁵ This underscores the importance of promoting whole grain consumption, not only for digestive health but also as a key ally in strengthening the immune system.³⁶

The post-test results also indicated a statistically significant increase (p < 0.001) in the consumption of fruits, vegetables, and legumes, with the majority of participants reporting frequent intake after the program. This finding aligns with the results of an intervention study involving trained teachers, which demonstrated an increase in fruit and vegetable consumption among participants.³⁷ Similarly, an intervention aimed at changing the work environment to promote fruit and vegetable consumption found a positive increase in fruit and vegetable intake among a group of Brazilian workers after the program’s implementation.³⁸ The findings of our study are particularly relevant, as these food groups are rich in vitamins, minerals, antioxidants, and bioactive compounds that play an essential role in maintaining a robust immune system.³⁹ Citrus fruits, for example, are a rich source of vitamin C, which acts as an antioxidant to protect immune cells from oxidative damage and enhance lymphocyte function, contributing to a stronger response to viral and bacterial infections.⁴⁰

Similarly, red fruits such as strawberries and blackberries contain anthocyanins and other polyphenols that not only possess antioxidant properties but have also been shown to reduce chronic inflammation and enhance immune function.⁴¹ These properties help protect the body from free radical damage and support the activity of immune cells, such as macrophages.⁴⁰ Vegetables, particularly leafy greens, are rich in vitamins A, C, and E, as well as minerals such as magnesium and iron, which are essential for the proliferation and maturation of immune cells.⁷ Legumes, on the other hand, provide high-quality protein and fiber, which improve intestinal health by strengthening the intestinal barrier and, in turn, enhancing innate immunity.⁴² These results suggest that the program not only enhanced participants’ nutritional knowledge but also promoted tangible dietary behavior changes, which could contribute to improved infection resilience and overall health.

Regarding protein-rich food consumption, the study also showed a statistically significant improvement after the intervention (p < 0.001), suggesting that participants became more aware of the importance of proteins in supporting immune function. This aligns with previous studies showing that educational interventions can raise awareness of the importance of protein in the diet, leading to increased consumption.⁴³ Similarly, a study demonstrated an increase in protein intake following the implementation of a nutritional counseling program that emphasized the importance of protein in the diet, utilizing digital support tools.⁴⁴ Proteins are essential for the proper functioning of the immune system, as they provide the amino acids needed for the synthesis of antibodies, enzymes, and other key immune molecules, such as cytokines and immune cell receptors.⁴⁵

Additionally, proteins support the repair and regeneration of body tissues, contribute to the maintenance of muscle mass, and are involved in numerous enzymatic and hormonal processes that regulate metabolism and immune defense.⁴⁶ A sufficient intake of high-quality protein can also enhance vaccine responses and reduce susceptibility to infections.⁴⁷ In the context of immune challenges such as the COVID-19 pandemic, adequate protein consumption is especially important for maintaining resilience and promoting recovery.⁴⁵

Moreover, protein-rich foods such as legumes, nuts, fish, lean meats, and dairy products contain essential micronutrients like zinc and iron, which support immune function.⁴⁸ Increased consumption of these foods may have positively impacted participants’ immune health, particularly in the context of strengthening the immune response to viral infections, as observed during the COVID-19 pandemic.⁴⁵ These results highlight the program’s effectiveness not only in enhancing nutritional knowledge but also in fostering changes in dietary habits, which can directly impact overall health and immune system responsiveness.

A statistically significant increase (p < 0.001) was also observed in the proportion of participants engaging in at least 30 minutes of daily physical activity after the intervention. This has important implications for their overall health and physical well-being. Regular physical activity is strongly associated with numerous health benefits, including improved cardiovascular function, body weight management, enhanced immune system strength, and a reduced risk of chronic diseases such as type 2 diabetes and heart disease.⁴⁹ This finding suggests that the program not only enhanced nutritional knowledge but also encouraged positive changes in participants’ physical activity habits, which could lead to significant improvements in their long-term quality of life. Similarly, a previous mHealth intervention program demonstrated that personalized education and counseling on the importance of physical activity, combined with telephone support, led to a sustained increase in regular exercise among participants.⁵⁰ This type of intervention not only helps individuals incorporate exercise into their daily routines but also reinforces personal motivation and enhances overall quality of life. For example, an online workplace exercise intervention during the COVID-19 pandemic revealed that participants significantly improved their perception of quality of life, particularly in the pain domain, leading to an overall improvement in their health status.⁵¹ Therefore, the results of the present study highlight the importance of incorporating physical activity components into nutritional counseling programs to maximize health benefits.

Finally, the percentage of people consuming alcoholic beverages increased significantly, a concerning finding given the context of the COVID-19 pandemic. Stress, social isolation, and economic uncertainty during the pandemic contributed to a global rise in alcohol consumption, as reported in several studies.⁵² The rise in alcohol consumption may be linked to the need to relieve emotional stress and anxiety caused by confinement and social restrictions, factors that led many individuals to adopt unhealthy habits as a coping mechanism.⁵³ This increase in alcohol consumption has negative implications for both the immune system and overall health of the participants.⁵⁴ Excessive alcohol consumption weakens the immune system, increases susceptibility to infections, and can counteract the benefits of other dietary and lifestyle improvements, such as increased consumption of nutrient-rich foods and regular physical activity.⁵⁵ These results highlight the importance of addressing stress management and promoting healthy habits in a holistic manner within intervention programs during crisis situations, such as a pandemic. Additionally, it is crucial to incorporate education on the risks of alcohol consumption, especially during times when mental well-being may be compromised.

In addition to the main outcomes discussed previously, the study revealed significant changes in other lifestyle variables that are often overlooked but are equally essential for overall well-being and immune health. For instance, daily water intake increased substantially from 28.6% to 91.4% of participants (p < 0.001), underscoring the effectiveness of the program in promoting hydration—an essential factor in metabolic and immune functions. Similarly, the percentage of participants engaging in at least 30 minutes of daily physical activity rose from 20% to 62.9% (p = 0.001), confirming that the intervention not only improved nutritional knowledge but also encouraged more active lifestyles. Conversely, no significant change was observed in sun exposure habits (p = 0.5), despite its relevance for vitamin D synthesis and immune modulation. This may be attributed to external limitations such as urban infrastructure, work routines, or pandemic restrictions.

Moreover, although a slight increase in the proportion of participants reporting more than eight hours of sleep was observed (from 71.1% to 82.9%), this was not statistically significant (p = 0.727). Quality and duration of sleep are known to affect immune function and mental health, suggesting that future programs should include more targeted strategies to promote sleep hygiene.

Regarding health risk behaviors, smoking habits remained largely unchanged (p = 0.503), highlighting the need to include specific content and follow-up mechanisms aimed at reducing tobacco consumption. In contrast, alcohol intake increased significantly during the study period (from 11.4% to 37.1%, p = 0.004), likely reflecting the psychosocial impacts of the COVID-19 pandemic rather than the program’s influence. This reinforces the importance of integrating emotional regulation and stress management components in health promotion programs.

Finally, an interesting finding emerged in the domain of spirituality. Although the proportion of participants who agreed with the statement “God positively influences my life” remained unchanged at 82.9%, the shift was statistically significant (p < 0.001), possibly reflecting increased introspection or spiritual reaffirmation during the intervention period. These findings suggest that spirituality may play a meaningful role in shaping health behaviors and emotional resilience, particularly during times of crisis.

Limitations and Recommendations for Future Research

This study presents several limitations that should be considered when interpreting the findings. First, the absence of a control group limits the ability to make causal inferences. Without a comparison group, it is not possible to determine whether the observed improvements in nutritional knowledge, dietary habits, and physical activity were solely due to the intervention or influenced by other external factors, such as pandemic-related lifestyle changes. Future research should incorporate randomized controlled designs to more accurately evaluate the effectiveness of nutritional tele-counseling.

Second, data collection relied on self-reported measures, which may introduce recall and social desirability biases. Participants might have over- or under-reported behaviors such as food intake or physical activity. To address this, future studies should include objective measures where feasible (eg, wearable devices for physical activity tracking or food diaries validated by nutritionists).

Third, while the questionnaires used were validated by content experts and showed acceptable internal consistency, they were not standardized tools recognized at national or international levels. This may limit the comparability of results across studies. It is recommended that future research conduct full psychometric evaluations of the instruments, including pilot testing, factor analysis, and cross-cultural adaptation processes, to ensure broader applicability and reliability.

Fourth, the sample size and specificity of the population (academic staff from a single private university in Lima, Peru) limit the generalizability of the findings. Broader studies should be conducted with larger, more heterogeneous samples from multiple institutions, including both public and private sectors, and across different regions of the country. This would help assess whether the effects of the intervention are consistent across various sociodemographic and occupational groups.

Lastly, future studies could benefit from exploring the long-term impact of nutritional tele-counseling, including follow-up assessments months after the intervention to evaluate the sustainability of behavior changes. Moreover, integrating additional components such as stress management, alcohol reduction strategies, and sleep hygiene education could enhance the holistic impact of future programs.

Public Health Implications

The public health implications of this study are significant, especially in the context of the COVID-19 pandemic, which has underscored the importance of maintaining optimal immune health and adopting healthy lifestyles. The findings suggest that nutritional tele-counseling can serve as an accessible and effective tool for educating individuals about the importance of nutrition and physical activity, while promoting positive changes in health-related behaviors. This type of intervention can be implemented on a large scale, particularly during health crises when access to in-person services may be limited.

Increased consumption of foods rich in vitamins, minerals, protein, and fiber, along with more regular physical activity, has the potential to reduce the incidence of chronic diseases such as obesity, type 2 diabetes, and cardiovascular disease, which place a considerable burden on public health systems. Additionally, promoting a balanced diet alongside increased physical activity can strengthen the immune system, enabling the population to better cope with viral infections and other diseases.

However, the increase in alcohol consumption observed in this study presents a challenge for public health policies, as its abuse can negate the benefits of healthy habits. This underscores the need for more comprehensive interventions that address both nutrition and other critical factors such as stress management and harmful substance use. En general, the results of this study support the use of tele-counseling as a preventive and health promotion strategy that can be adapted to diverse populations and contexts, helping to reduce the burden of lifestyle-related diseases and strengthen public health more broadly.

Conclusion

This study demonstrated that nutritional tele-counseling is an effective tool for enhancing immunity knowledge and promoting healthier lifestyle habits among the staff of an educational institution during the COVID-19 pandemic. Participants showed a significant increase in the consumption of foods rich in essential nutrients for the immune system, such as vitamins and minerals, along with a higher intake of fruits, vegetables, whole grains, and protein-rich foods. Additionally, there was an increase in regular physical activity, which has important implications for overall health and well-being. However, the rise in alcohol consumption highlights the need to integrate stress management strategies and promote healthy habits in a more comprehensive manner in future interventions.