A total of 226 people participated in the study. After excluding those who did not complete the pre-and post-intervention questionnaires, did not attend the intervention, and/or were under the age of 18 and over the age of 65, 106 health professionals and 110 general population completed the study (Fig. 1). The mean age of participants was 29.49 ± 12.49 years. Most of the participants were female (84.7%). Among the participants, 25.5% were infected with COVID-19. A more significant percentage of the participants got vaccinated against COVID-19 (89.8%). Most of the health professionals were dietitians (34.9%) and midwives (32.1%). Most of general population had at least high school graduates (63.6%) (Table 1).
Table 1
Demographic Characteristics of the Participants (n = 216)
Characteristics | Health professionals (n = 106) | General population (n = 110) | Total (n = 216) |
Age (year) (Mean ± SD) | 25.29 ± 4.37 | 33.54 ± 15.99 | 29.49 ± 12.49 |
Gender (F/M, %) | 87.7/12.3 | 81.8/18.2 | 84.7/15.3 |
Infected with COVID-19 (n, %) | 23 (21.7) | 32 (29.1) | 55 (25.5) |
Vaccinated (n, %) | 98 (92.5) | 96 (87.3) | 194 (89.8) |
Profession (n, %) | | | |
Nurse | 28 (26.4) | -- | 28 (13) |
Dietitian | 37 (34.9) | -- | 37 (17.1) |
Midwife | 34 (32.1) | -- | 34 (15.7) |
Other | 7 (6.6) | -- | 7 (3.2) |
At least high school graduate (n, %) | 106 (100) | 70 (63.6) | 176 (81.5) |
Abbreviations; SD: standard deviation, F: Female, M: Male |
The knowledge about DS/HF in the prevention and treatment of COVID-19 of health professionals before (B) and after (A) intervention was shown in Table 2. The percentage of those who know that adequate-balance nutrition provides all vitamin-mineral needs increased from 76.4–91.5% after the intervention (p < 0.001). Similarly, the number of people who know that curcumin may interact with drugs given in the treatment of COVID-19 increased from 37.7–71.7% after the intervention (p < 0.001). Moreover, a significant improvement was observed in the percentage of knowledge about gingerol-COVID-19 drugs interactions (B:40.6%, A:71.7%; p < 0.001), and the relationship between vitamin D levels and COVID-19 (B:52.8%, A:81.1%; p < 0.001) after the intervention. Total knowledge scores of health professionals increased from 3.85 ± 1.60 to 5.51 ± 1.45 after the intervention (p = 0.000).
Table 2
Responses of the Health Professionals Before and After Intervention (n = 106)
Questions | Correct Answers | |
Before | After | p |
Q1- With adequate-balanced nutrition, a healthy individual can meet all their vitamin-mineral needs (n, %). | 81 (76.4) | 97 (91.5) | < 0.001* |
Q2- The use of curcumin may interfere with drugs used in COVID-19 and impair their effectiveness (n, %). | 40 (37.7) | 76 (71.7) | < 0.001* |
Q3- The use of gingerol may interact with drugs used in COVID-19 and impair their effectiveness (n, %). | 43 (40.6) | 76 (71.7) | < 0.001* |
Q4- Low vitamin D level is associated with COVID-19 (n, %). | 56 (52.8) | 86 (81.1) | < 0.001* |
Q5- Herbal foods can be recommended to everyone for the prevention of COVID-19 (n, %). | 76 (71.7) | 85 (80.2) | > 0.05 |
Q6- There is no single nutrient that can prevent or cure COVID-19 (n, %). | 102 (96.2) | 103 (97.2) | > 0.05 |
Q7- Multivitamin supplement may be recommended for individuals for the prevention of COVID-19 (n, %). | 10 (9.4) | 61 (57.5) | < 0.001* |
Total Scores (Mean + SD) | 3.85 ± 1.60 | 5.51 ± 1.45 | 0.000* |
Abbreviations; Q: Question; McNemar's test was used for categorical variables; Paired sample t-test was used for continuous variables; p < 0.05 is considered to be significant |
Table 3 presents the percentage of correct answers of general population to questions about nutrition and DS/HF in the prevention and treatment of COVID-19. The proportion of the participants who know a healthy individual with an adequate-balanced diet does not need to use DS, developed from 58.2–82.7% after the intervention (p < 0.001). The percentage of the participants who know those with diabetes (B:90%, A:98.2%, p = 0.012), hypertension (B:87.3%, A:98.2%, p < 0.001), and medication users (B:90.9%, A:99.1%; p = 0.012) should be careful when using DS/HF, improved significantly after the intervention. Among the questions related to COVID-19; the number of participants who know that adequate-balanced nutrition is effective in preventing COVID-19 increased significantly after the intervention (B:70%, A:86.4%, p = 0.004). Total knowledge scores of general population improved from 8.34 ± 1.45 to 9.39 ± 0.87 after the intervention (p = 0.000).
Table 3
Responses of General Population Before and After Intervention (n = 110)
Questions | Correct Answers |
| Before | After | p |
Q1- A healthy individual with an adequate-balanced diet does not need to use DS (n, %). | 64 (58.2) | 91 (82.7) | < 0.001* |
Q2- A healthy individual can meet all their vitamin-mineral needs with an adequate-balanced diet (n, %). | 78 (70.9) | 93 (84.5) | 0.009* |
Q3- Vitamins-minerals strengthen immunity (n, %). | 103 (93.6) | 106 (96.4) | > 0.05 |
Q4- Milk and its products are rich in protein (n, %). | 95 (86.4) | 107 (97.3) | < 0.001* |
Q5- Dietary supplements can become harmful to the body when consumed in excess amounts (n, %). | 104 (94.5) | 109 (99.1) | > 0.05 |
Q6- Those with diabetes should be careful when using DS/HF (n, %). | 99 (90.0) | 108 (98.2) | 0.012* |
Q7- Those with hypertension should be careful when using DS/HF (n, %). | 96 (87.3) | 108 (98.2) | < 0.001* |
Q8- Medication users should be careful when using DS/HF (n, %). | 100 (90.9) | 109 (99.1) | 0.012* |
Q9- Adequate and balanced nutrition is effective in preventing COVID-19 (n, %). | 77 (70.0) | 95 (86.4) | 0.004* |
Q10- There is no single nutrient that can prevent or cure COVID-19 (n, %). | 101 (91.8) | 105 (95.5) | > 0.05 |
Total Scores (Mean + SD) | 8.34 ± 1.45 | 9.39 ± 0.87 | 0.000* |
Abbreviations; Q: Question, DS: Dietary supplement, HF: Herbal Foods; McNemar's test was used for categorical variables; Paired sample t-test was used for continuous variables; p < 0.05 is considered to be significant |
For the prevention of COVID-19, there was a sharper decline in belief in vitamin C (B:93.4%, A:37.7%, p < 0.001) and vitamin D (B:89.6%, A:50%, p < 0.001) among health professionals after the intervention. Furthermore, the percentage of believers in zinc (B:69.8%, A:38.7%, p < 0.001), selenium (B:58.5%, A:39.6%, p = 0.018), omega-3 (B:81.1%, A:40.6%, p < 0.001), and HF including onion (B:78.3%, A:33%, p < 0.001), garlic (B:83%, A:36.8%, p < 0.001), and ginger (B:80.2%, A:41.5%, p < 0.001) decreased significantly. Among general population, the percentage of participants who believed that vitamin D (B:72.7%, A:40%, p < 0.001), and vitamin C (B:77.3%, A:41.8%, p < 0.001) effectiveness in the prevention of COVID-19 decreased significantly. Similar results were obtained for zinc (B:70%, A:34.5%, p < 0.001), selenium (B:56.4%, A:34.5%, p < 0.001), omega-3 (B:70.9%, A:46.4%, p < 0.001), and HF including ginger (B:80.9%, A:32.7%, p < 0.001) turmeric (B:74.5%, A:32.7%, p < 0.001), and propolis (B:78.2%, A:29.1%, p < 0.001) (Table 4).
Table 4
Attitudes of Participants on the Effectiveness of Dietary Supplements/Herbal Foods in the prevention and treatment of COVID-19 Before and After Intervention (n = 216)
Dietary supplements / Herbal foods | Prevention from COVID-19 |
Health professionals (n, %) (n = 106) | General population (n, %) (n = 110) |
Before | After | p | Before | After | p |
Vitamin C | 99 (93.4) | 40 (37.7) | < 0.001* | 85 (77.3) | 46 (41.8) | < 0.001* |
Vitamin D | 95 (89.6) | 53 (50.0) | < 0.001* | 80 (72.7) | 44 (40.0) | < 0.001* |
Zinc | 74 (69.8) | 41 (38.7) | < 0.001* | 77 (70.0) | 38 (34.5) | < 0.001* |
Selenium | 62 (58.5) | 42 (39.6) | 0.018* | 62 (56.4) | 38 (34.5) | < 0.001* |
Omega-3 | 86 (81.1) | 43 (40.6) | < 0.001* | 78 (70.9) | 51 (46.4) | < 0.001* |
Onion | 83 (78.3) | 35 (33.0) | < 0.001* | 83 (75.5) | 36 (32.7) | < 0.001* |
Garlic | 88 (83.0) | 39 (36.8) | < 0.001* | 86 (78.2) | 35 (31.8) | < 0.001* |
Ginger | 85 (80.2) | 44 (41.5) | < 0.001* | 89 (80.9) | 36 (32.7) | < 0.001* |
Turmeric | 83 (78.3) | 41 (38.7) | < 0.001* | 82 (74.5) | 36 (32.7) | < 0.001* |
Propolis | 81 (76.4) | 42 (39.6) | < 0.001* | 86 (78.2) | 32 (29.1) | < 0.001* |
Dietary supplements / Herbal foods | Treatment of COVID-19 |
Health professionals (n, %) (n = 106) | General population (n, %) (n = 110) |
Before | After | p | Before | After | p |
Vitamin C | 80 (75.5) | 19 (17.9) | < 0.001* | 84 (76.4) | 34 (30.9) | < 0.001* |
Vitamin D | 80 (75.5) | 27 (25.5) | < 0.001* | 81 (73.6) | 34 (30.9) | < 0.001* |
Zinc | 56 (52.8) | 18 (17.0) | < 0.001* | 74 (67.3) | 23 (20.9) | < 0.001* |
Selenium | 50 (47.2) | 21 (19.8) | < 0.001* | 57 (51.8) | 24 (21.8) | < 0.001* |
Omega-3 | 65 (61.3) | 23 (21.7) | < 0.001* | 78 (70.9) | 43 (39.1) | < 0.001* |
Onion | 55 (51.9) | 14 (13.2) | < 0.001* | 76 (69.1) | 29 (26.4) | < 0.001* |
Garlic | 61 (57.5) | 16 (15.1) | < 0.001* | 79 (71.8) | 28 (25.5) | < 0.001* |
Ginger | 57 (53.8) | 29 (27.4) | < 0.001* | 81 (73.6) | 29 (26.4) | < 0.001* |
Turmeric | 51 (48.1) | 28 (26.4) | < 0.001* | 76 (69.1) | 29 (26.4) | < 0.001* |
Propolis | 54 (50.9) | 17 (16.0) | < 0.001* | 77 (70.0) | 26 (23.6) | < 0.001* |
McNemar's test was used for analysis; *p < 0.05 is considered to be significant
The percentage of those who agreed that vitamin C is effective in the treatment of COVID-19 decreased both among health professionals (B:75.5%, A:17.9%, p < 0.001) and general population (B:76.4%, A:30.9%, p < 0.001). Similarly, beliefs in vitamin D decreased significantly among both health professionals (B:75.5%, A:25.5, p < 0.001) and general population (B:73.6, A:30.9, p < 0.001). Among health professionals, beliefs in zinc (B:52.8%, A:17%, p < 0.001), selenium (B:47.2%, A:19.8, p < 0.001), and omega-3 (B:61.3%, A:21.7, p < 0.001) also declined significantly after the intervention. In a similar way, beliefs in HF including onion (B:51.9%, A:13.2%, p < 0.001), turmeric (B:48.1%, A:26.4%, p < 0.001), and propolis (B:50.9%, A:16%, p < 0.001) decreased significantly. For general population, beliefs in zinc (B:67.3%, A:20.9%, p < 0.001), selenium (B:51.8%, A:21.8%, p < 0.001), omega-3 (B:70.9%, A:39.1%, p < 0.001), garlic (B:71.8%, A:25.5%, p < 0.001), ginger (B:73.6%, A:26.4%, p < 0.001), and propolis (B:70%, A:23.6%, p < 0.001) declined significantly after the intervention (Table 4).