Background & Objective : Head trauma is one of the most common causes of death in accidents and it is irreversible. More than 10000 cases of brain death occur annually in Iran and less than 10% of them are donors. That is why the number of organ transplantation in Iran is much lower than Europe and America. This study was conducted to investigate the attitude of 20-60 year-old citizens of Tehran about organ donation in brain death.

  Methods : This cross-sectional study was performed on 730 subjects (384 females and 346 males ( in 2000. The questionnaire and multi-stage sampling methods were used to collect data. The data were analyzed using SPSS and Chi-square tests.

  Results : about 44% of the subjects believed that the brain death is virtually irreversible and 93% of these subjects agreed with transplantation. 88% of those who agreed with transplantation accepted to fill out special donation forms. Humanitarian considerations and heavenly rewards were two main reasons mentioned by these people.

  Conclusions : According to this study, it is necessary to train people in order to increase their knowledge regarding brain death and create a positive attitude about organ donation. meanwhile passing some laws in this regard which are in accordance with Islam is recommended.

 Background & Objective: The prevalence of pediculosis in communities is one of the criteria for individual hygiene and one of the important diseases among students. Pediculosis capitis is very important in boarding schools. The aim of this study is to determine the prevalence of pediculosis capitis and relative factors among boarding school students.

 Methods: This study with a descriptive, analytic and cross - sectional method was performed upon 417 girl students from Ardabil boarding schools who were selected using systematic method. Pediculosis was diagnosed through direct observation by trained general practitioners. The data were collected using questionnaire and were analyzed by EPI 2000 and SPSS10.

 Results: 116 students (27.8%) complained about itching of scalp.41.2% of the students never took a shower in school and only 45.2% of them took a bath in school once a week or more. 74.3% of the students said that there was a bathroom in their school and about the accessibility of these bathrooms, 53 students (12.7%) had previous involvement with head lice. 21 cases (5%) had previous treatment of pediculosis capitis. 119 of the students (28.5%) suffered from head lice. There was a significant relationship among suffering from head lice and previous illness and existence of bath in home. No significant relationship was observed among this disease and sharing devices such as comb or head scarf in school or home. Prevalence of the disease among rural students was more common than urban ones.�

 Conclusions: some boarding school in Ardabil did not have enough hygienic facilities and the students of these schools were mostly from rural areas.

  Background & Objective : In order to prevent maternal mortality and morbidity, midwives should be able to implement community cares for women and their families. The aim of this study is to investigate midwives ’ knowledge, attitude and readiness to practice community oriented midwifery (COM).

  Methods : In this cross sectional study, all 280 midwives working in Kerman hospitals and health service centers were selected. The questioner for data collection had two parts. The first part intended to describe the characteristics of samples and the second part was used to evaluate midwives ’ knowledge, attitude, and readiness to practice community oriented midwifery. Correlation and chi - square tests were used to analyze the data.

  Results : Mean of knowledge score was 21.13 and 16.4% of the subjects had a good knowledge of COM. Mean of attitude score was 77.07 and 61.8% of the samples had a positive attitude towards COM. 79.2% of samples announced their readiness to practice COM.

  Conclusions : Based on the findings of this study it seems that the professional knowledge of midwives should be promoted, regarding COM.

  Background & Objective : Today, with changes in health care systems, most of the patients, receive occupational and special cares at home after being discharged from hospital . The aim of this study was to assess the effects of follow up on physical and emotional status of the patients with recent myocardial Infarction .

  Methods : This experimental study was done on 60 patients with acute myocardial infarction, who referred to Boali Hospital during 2000-2001.The patients were chosen randomly and were set in two different groups with 30 subjects in each group . Then, a home care program was designed for case group. but there was no intervention for control group . This home care program was completed and one week later the physical and emotional status of the patients in two groups were analyzed by Spilbergar and Beck tests and finally the results were compared in two groups using X² test.

  Results : The X² test showed that there is a significant difference between resting heart rate of two groups with P<0.05 but the difference among systolic and diastolic blood pressure, body weight, anxiety and depression was not statistically significant in two groups.

  Conclusions: Regarding the effects of follow-up on the physical and emotional status of the patients, nurses can improve the quality of the patienys life through active home - care and rehabilitation programs along with social supports.

  Background & Objective : Breast cancer is the most common type of cancer among women worldwide and accounts for the majority of their deaths due to the cancer. Hence, diagnosing its risk factors is of great importance. In this study the association between abortion and breast cancer risk was investigated.

  Methods : In this Case- Control study in Mashhad, 105 patients with confirmed breast cancer were compared with 105 healthy women who were living in their neighborhood and were the same age. A questionnaire including demographic information as well as same questions regarding the factors associated with conception and emphasising abortion were used to collect the data, which then were analyzed using SPSS ver 9.

  Results : the findings indicated a relationship between breast cancer and history of abortion, compared to women with no history of abortion (OR=2.09 95% CI=1.18- 3.69). Also there was a significant relationship between the frequency of abortion and breast cancer (P=0.008 ). but odds ratio was not higher among women whose age at first abortion was less than 20 years. Also abortion before first full- term pregnancy increased breast cancer risk (OR= 5.97 95% CI=1.18-19.6). But the age at the time of abortion did not have any effect on the breast cancer risk.

  Conclusions : The findings suggested that the risk of breast cancer has a positive relationship with frequency of abortion and the risk is even higher if the abortion occurs before the first full-term pregnancy. Thus, health interventions seem to be necessary in this regard.

  Background & Objective : Swallowing foreign bodies and their impaction in esophagus is common among children and proper diagnosis and treatment of this problem will decrease its complications. The objective of this study was to evaluate esophageal foreign bodies.

  Methods : 62 patients with complaining about foreign body ingestion were studied and factors such as age, sex, the kind of foreign body, the treatment done, its complications and the length of hospitalization were considered.

  Results : Of sixty- two patients, 30 were male and 32 were female. Coin was the most common foreign body in children (24 cases) while in adults bone (chicken or fish) was more common (19 cases). In the patients most of the foreign bodies were impacted in the upper esophagus at the cricopharengeal junction. In all patients except one case (in which endoscopic forceps was used to remove the foreign body) esophagoscopy was performed under general anesthesia to remove the impacted foreign bodies. Complication was seen in one case as bleeding.

 Conclusions: Since the esophageal foreign body is prevalent among children it is necessary to prevent it through offering adequate to parents.

 Background & Objective: Poster is a non-projector, visual, graphic and printed medium that is applied in various cases specially in health education. On the other hand, one of the health education experts task is evaluation of educational methods and media. Since few studies were performed on effectiveness of posters on knowledge of people, this study was designed to determine the percentage of people who looked at the posters in health centers and also to determine the level of knowledge attained from these posters located in different places of health centers.

 Methods: This was a semi-experimental study. The population was people who referred to Shahid Gannadi health center. Samples were selected by simple random method. The data were collected by a questionnaire. The posters were fixed in three places during three different stages and the collected data were analyzed.

 Results: The findings showed that from among these subjects, 18.8% in the first stage, 20.8% in the second stage and 61.2% in third stage observed the fixed posters. The probability of the poster to be seen near the doorway and examination room was equal (Odds Ratio=0.9) whereas the probability of the same posters to be seen in waiting hall was 7 times as much as the previously mentioned locations. The ANOVA indicated no significant difference between demographic variables (age, sex, marital status, ets) of study subjects and their knowledge scores.

 Conclusions: The study showed that People paid very little attention to fixed poster. Therefore, regarding the role of posters in increasing the knowledge level, several strategies should be employed to make people pay more attention to these posters. Following the accepted standards in preparation and fixation of posters and preparation of three dimensional boards for the posters in health care centers are suggested.

 Background & Objective: Stroke is a leading cause of death and disability worldwide. It is more common in men than in women, however more than half total stroke death occur in women. Several conditions and lifestyle factors have been well established as risk factors for stroke. The purpose of this study was to asses the magnitude of classic stroke risk factors and its pattern in women.

 Methods: A total of 62 patients with first-onset ischemic stroke were accrued from neurology unit of Alavi hospital during 2002 and compared with their age-matched controls from other units of same hospital. Information concerning potential risk factor exposure status was collected by structured questionnaire at interviews. Stroke risks were estimated by calculating the odds ratios.

 Results: Significantly increased risk of stroke was found among women with hypertension (OR=8.4 CI=3.7-1.8), current smoking (OR=4.2 CI=1.1-16), diabetes (OR=3.7 CI=1.4-9.7) and heart disease (OR=3.2 CI=1.2-8.4). Association of other factors (passive smoking, Hypercholestrolemia) with stroke was not significant.

 Conclusions: Hypertension, diabetes, current smoking and heart disease are major risk factors for stroke in women. Given that the majority of these factors are either correctable or modifiable, prevention strategies should be planned in accordance with this point in order to reduce the occurrence of stroke in women.

 Background & Objective: Self Confidence, is a continuous evaluation of an individual on himself. Hence it is important regarding the mental health and the personality balance. Due to the problems that low self-confidence brings about especially during the youth age and regarding the prevalence of this problem among adolescents, the present research was conducted in order to investigate the level of self-confidence among students.

 Methods: Self-confidence of 500 students was determined using Eysenck test. Multistage sampling was employed to select 7 out of 15 boys high schools randomly In each grade of study the required numbers were chosen randomly proportionate to the number of students in that grade. Scores more than 21 showed high self-confidence, 14-21 average and less than 14 indicated low confidence. To analyze the data, Chi- square and Mantel- Hanzel tests were used, with 95% significance.

 Results: 29.6% of students have had high self-confidence, 57.8% of them had average self-confidence while 12.6% of them had lower level of self-confidence. No significant relationship was seem among the rank of birth and the literacy of parents with the level of self-confidence. However there was a significant relationship between the number of siblings (P=0.0135) and study grade (P=0.0018) with the level of self-confidence. As a result, 11.5% of the students in the first grade, 6.6% in the second grade and 20.5% in the third grade had low self-confidence.

 Conclusion: The prevalence of�low self-confidence among third grade high school students, warns that they should be paid much attention by their parents and their school officials.

  Background & Objective : The fast population growth is one of the basic problems in Iran and using family planning devices has a remarkable role in decreasing it. The findings of researches carried out nationwide indicate the effectiveness of instruction in the application of family planning methods and devices. The objective of this study is determining the level of knowledge of 15-49 year-old women under Ardabil health and treatment center services.

  Methods : 138 qualified mothers were chosen randomly from among 15-49 year-old women under Ardabil health and treatment centers services. These subjects were selected from among 14 centers (10 mother from each center) and had secondary school level of education. This descriptive cross-sectional and prospective research was conducted by filling out the pre-planned questionnaire and preparing educational booklets and giving them to the mothers under the study as pretest and post-test procedures during the time span of December 2000 to May 2001.

  Results : No meaningful relationship was found between employment and utilizing family-planning devices. The results of Mc-Nemar test and t-test showed that statistically the instruction given with regard to the method of beginning to take anti-gestation pills, method of the intervals of taking the anti-gestation pills, taking measures at the time of forgetting to take anti-gestation pills, the preference of vasectomy to tobectomy, the interval between the injection of anti-gestation ampoules and the duration of IUD effectiveness before and after studying the manuals demonstrated a significant difference.

  Conclusions : Education plays an important role in increasing the knowledge level of the population under study and hence it improves their performance about family planning. So this instruction is recommended to be followed seriously.

  Background & Objective : Nutritionists have traditionally recognized breakfast as the most important meal of the day. The importance of eating breakfast is for growing and nutritional well being of children. While health habits such as eating breakfast, maintaining weight, and sleeping regularly are related to the longevity of adults, very little is known about the health habits of disadvantaged school-age children. This study set out to evaluate eating breakfast among adolescent girls and its relationship with body mass index, weight and nutrient intake.

  Methods : This descriptive cross-sectional study was done on 611 adolescent primary and secondary school girls (10-14 years old) in Ardabil. Anthropometric studies (height, weight, and MAC) and nutritional status (24 hour recall and food frequency) were done, and the students were asked about eating breakfast and other snacks. The collected data were analyzed using SPSS ver. 9 and Food Processor.

  Results : About 16.85% of girls had come to school without eating breakfast. BMI and body weight of these students were significantly more than those of girls who ate breakfast (P<0.05). On the other hand snack intake among the girls who did not use to eat breakfast was more than that among breakfast eaters (P<0.05). The amount of calorie, protein, thiamin, niacin, calcium and iron intake in breakfast-eating girls was more than those among non-eaters (P<0.05). The amount of folacin, riboflavin, calcium and zinc intake in non-eaters was less than recommended dietary allowance of WHO. The result of food frequency showed that the consumption of food such as protein different types of bread, potato, and legume among breakfast eaters was more than their consumption among non-eaters.

  Conclusions : This study indicated that eating breakfast can provide adequate calorie and nutrients but its omission can not only lead to lower calorie and nutrients intake but also have an unfavorable effect on food habit and weight of the students.

 Background & Objective: Tuberculosis is a diseases which is severely threatening the individuals health and is spreading quickly. Moreover, the appearance of new strains resistant to drugs has complicated the issue. Since there is no information available regarding the present drug-resistance situation of patients suffering from tuberculosis in Mashhad, this study was conducted to determine the prevalence of this resistance in this city.

 Methods: To determine prevalence of anti-tuberculosis drug resistance in Mashhad, drug sensitivity of 75 M. tuberculosis strains isolated from patients with pulmonary and extra-pulmonary tuberculosis from 20 Feb. 2002 to 20 Aug. 2002 was studied using the indirect proportion method. Every strain was tested against Rifampicin (RMP), Isoniazid (INH), Ethambutol (ETM), and Streptomycin (STM). Medical records of the patients were reviewed. Patients with no or less than 1 month treatment were defined as new cases and those previously treated for more than 1 month were defined as previously treated cases.

 Results: Of 75 isolates, 70(93.33%) were from new and 5(6.66%) from previously treated cases. 68 patients (90.66%) were suffering from pulmonary and 7(9.33%) from extra-pulmonary tuberculosis. Of 75 isolates, 23(36%) were resistant to at least one anti-tuberculosis drug. The highest rate of resistance was observed to streptomycin. Three of the 75 strains (4%) were resistant to all four drugs. 1.43% and 40% of strains isolated from newly and previously treated patients respectively were multidrug resistant.

 Conclusions: In this study new cases with MDR-TB were less prevalent compared to other studies. Most drug resistance and MDR-TB were associated with previous treatment. Continual evaluation of drug resistance following DOTS implementation seems to be necessary.

  Background and Objective : Today, laparoscopic surgeries, because of reducing postoperative complications, are increasingly developing. Intraperitoneal insufflations of CO2_�and systemic absorption of it during laparoscopy results in hypercarbia. Using N₂O during maintenance of anesthesia in these patients can enhance hypercarbia. This is because N₂O increases the volume of pneumoperitoneum. This study was performed to determine the effect of N₂O in enhancing hypercarbia during laparoscopy.

  Methods : Sixty Patients, with physical status I or II, undergoing outpatient diagnostic gynecologic laparoscopy according to ASA (American Society of Anesthesiology) scaling took part in this clinical and single blind trial, and were randomly divided in to two groups, each with 30 patients. In all patients, general anesthesia with end tracheal intubation was administered. The technique of anesthesia and ventilation were the same in all patients. Only, during the maintenance of anesthesia, N₂O was not administered to group I (control) of patients, but in group II (case), patients received N₂O, in 50% concentration in oxygen. The variables under study were evaluated and recorded at certain times and finally the data were analyzed using chi-square test, student t-test and EPI-5_�software.

  Results : There was no significant difference between two groups in terms of demographic data, homodynamic variables (heart rate, mean arterial pressure, and electrocardiogram changes), oxygen saturation, and the use of any additional analgesic drug (instead of N₂O in group I). Comparing the End tidal CO₂ (Etco₂) in two groups indicated that Etco₂ increases in those patients who used N₂O during maintenance of anesthesia (p=0.02).

  Conclusions : With regard to significant difference between two groups in the enhancement of intraoperative hypercarbia (although it was not associated with homodynamic changes in this study), it is better not to use N₂O in general anesthesia for laparoscopic procedures.

  Background & Objective : Even though the medical sciences have developed increasingly, ectopic pregnancy is still an important cause of maternal mortality. Despite many researches on medical therapy of ectopic pregnancy (EP), surgery is still the first management of patients with EP. Most of these patients have become pregnant for the first time and keeping their fertility in the future is very important. Surgery especially salpangectomy can do nothing to keep this fertility. It seems that efficacy of medical therapy of EP, especially in Iran is unknown. This research was conducted to determine the efficacy of medical therapy of EP with Methotrexate in some patients.

 Methods: In a prospective uncontrolled clinical trial study 26 patients with EP were hospitalized in Yazd Madar hospital. Six of them did not have any indications of medical therapy and were treated surgically.20 patients were treated with Methotrexate considering all the requirements. These patients received Methotrexate 1mg/kg daily. For the prevention of side effects, folinic acid with a dose of 0.1 Methotrexate was given. The efficacy of treatment was determined afterwards with the serial measuring of serum level. The data were analyzed using Chi-Square test and SPSS software.

 Results: The average age of these patients was 27.19 years and most of them had spotting as a symptom. They had been married for 6.9 years on average and most of these patients (42.3%) were experiencing their first pregnancy. Fourteen patients (53.8%) had a history of infertility and 26.9% had a history of abortion. 50% had experienced a previous abdominal surgery. Four patients had recurrent EP and the average of gestational age at the time of diagnosis was 6.2 weeks. Finally fifteen patients (75%) were treated successfully. Four out of five patients, who had a failed medical treatment, had a serum level higher than 1000 IU/L. Five out of eight patients, (62.5%) who were followed, experienced normal intrauterine pregnancy after one year of treatment.

 Conclusions: Medical therapy of Ectopic pregnancy with Methotrexate seems to be safe and effective but when serum level exceeds 1000 IU/L it is less likely to succeed.

 Background & Objective: The quality of services given to emergency patients at a hospital as well as these patients ’ satisfaction of the services is an index of overall services in that hospital. This study is an attempt to evaluate the degree of satisfaction among the patients referring to the emergency rooms of the hospital of Ardabil University of Medical Sciences during fall and winter 2000.

 Methods: In this cross-sectional prospective study, 600 emergency patients referring to emergency rooms of Alavi, Fatemi, Buali and Aliasghar hospitals were selected. They filled a questionnaire. The data were analyzed by SPSS software.

 Results: The findings indicated that 78.1% of the whole subjects were generally satisfied with the services. The greatest degree of satisfaction belonged to specialty services (93.8%) and the physicians ’ and nurses ’ contact (92.3% and 91.8% respectively). The least degree of satisfaction belonged to hospital charges (40.2%), and unavailability of non-emergency drugs in hospital pharmacy (42.9%).

 Conclusions: According to the results of this study the medical centers need to offer more coverage of national health insurance services. Furthermore it seems necessary to equip these emergency rooms with round the clock pharmacies and provide the required drugs.

  Background & Objective : When a cesarean is necessary, it can be a life-saving technique for both mother and infant. In recent twenty years, the cesarean childbirth rate has increased dramatically. Moreover a cesarean costs nearly twice as much as a vaginal birth. The world Health organization states that a cesarean rate greater than 10-15% cannot be justified. The aim of this study was to determine the cesarean rates and its indications in social security hospital of Ardabil.

 Methods: In this cross-sectional study was conducted all of the deliveries (both cesarean and normal delivery) in Ardabil social security hospital were investigated using a questionnaire including the characteristics of indication. The data were analyzed using SPSS software.

  Results : 45.4% of the deliveries were done using cesarean and 54.6% of them with a normal procedure. 55.8% of all the cesareans had an accepted indication. 44.2% of cesareans were controversial or elective, 22.7% were repeated cesarean, 8.4% were breech presentation and 2.3% were golden baby and 10.8% of the cesareans did not have a clear indication.

 Conclusions: The cesarean section rates in this study were higher than world rates. As a result the rising cesarean birth rate must be stopped and reversed with health interventions.

 Background & Objective: Dependence on substance or addiction is a psychological disturbance. This is referred to as substance abuse in psychological classifications and is the second most common psychological disturbance. On the other hand depression is an instance of disturbance, which is observed among the victims of substance abuse. This study set out to evaluate the effectiveness of Cognitive-Behavior Therapy (CBT) of depression among patients with substance abuse.

 Methods: Using experimental method, 28 men and women (23-35 years, normal IQ) with substance abuse were randomly selected according to DSMIV criteria. These subjects had been under anti-addiction medication for two years, without adequate control, and were divided into two groups. The two groups received the following treatments for 6 weeks: 1- Cognitive Behavior Therapy. 2- No specific psychological treatment (control group). Two instruments were used to collect data namely Beck Depression Inventory (BDI) to evaluate depression and demographic forms to record the information.

 Results: The data were analyzed using repeated measurements including a pretest and two posttests. In pretest, according to scores of both groups from Beck test, there was a severe depression among the subjects. However in the second and third posttests these scores fell significantly. The intra-group and inter-group tests showed that these reduction in scores was related to the intra-group differences.

 Conclusions: CBT has had an important role in treatment of depression among patients with substance abuse. Psychological intervention was able to help them change their cognition by decreasing depression and enable them to have a more positive belief in controlling themselves against dependency. It seems that taking psychologically team-approach (both theoretically and practically) about control strategies and treatment of depression in patients with substance abuse can deeply improve their life style as well as their individual and social relations.

 Background & Objective: Despite all improvements in diagnosis and treatment, one third of patients with Myocardial infarction lose their life. Different studies have shown that cardiac arrhythmia are the most common cause of death in MI, and cardiac blocks are one of the important groups of these arrhythmia, which are effective in prognosis, duration of hospitalization and hospital mortality of the patients.

  Methods : In this study, 630 patients with AMI, who were admitted in CCU of Bou-Ali hospital in Ardabil from January 1998 to January 2001 were studied and the data were callected with the help of questionnaires and secondary data analysis method. The data were analyzed with statistical methods.

  Results : 9.4% of cases in this study had AV block and 30.2% had bundle branch block. 40.5% of men and 37.6% of women had at least one kind of block(in AV node or bundle branch), but no significant relation was found between sex and these blocks. Also, 62% of in-hospital mortalities of patients with AMI were in association with blocks (AV or bundle branch) and only 38% of mortalities were without blocks. This showed a meaningful relation between hospital mortality and these kinds of blocks (p <0.05 ).

 Conclusions: The total frequency of AV and bundle branch blocks due to AMI, was 39.6% which is similar to other studies, but what is remarkable in this study, is the higher prevalence of bundle branch blocks due to AMI.

  Background & Objective : Despite the ever increasing use of oral contraceptives there is uncertainty about the stroke risk associated with their use. Some cases of pulmonary Emboli and stroke have been reported among women taking these pills. The present research was conducted to investigate the relationship between taking contraceptive pills and the risk of ischemic stroke.

  Methods : In a case-control study, women with definite ischemic stroke were selected from Alavi Hospital in Ardabil who had no prior stroke. The control group was age-matched ( ± 3years) to cases and were selected from other wards of the same hospital. A questionnaire was administered to elicit information about prior exposure to various risk factors, including the oral contraceptive pill (OCP). The data were analyzed by SPSS software (Ver. 12) and statistical methods such as chi-square, multivariate regression and ANOVA. The risk factor were estimated by odds ratio.

 Results: OCP consumption was associated with an increased risk of ischemic stroke (OR=5.4 95% CI=1.1-5.3), and after adjustment for other risk factors of stroke it was OR=2.7 (95% CI=0. 95-7.2) with p=0.05.

 Conclusions: According to this study there was weak evidence for an association between ischemic stroke and OCP consumption. Extended studies are needed to clarify the relationship between risk of stroke and the present/ past use of OCP.

 Background & Objective: Nutritional status of individuals and community are influenced by different factors. Investigating nutrition and food problems as well as determining dietary pattern play a crucial role in determining nutrition programs and policies, preventing food deficiency, improving nutrition level and preventing malnutrition diseases. The aim of this study was to determine calorie and nutrients intake, food habit and dietary pattern in rural areas of Ardabil.

 Methods: In this cross-sectional study 250 families from 15 rural areas of Ardabil were selected using simple random method. Nutrition status of all the individuals was studied using 24 hour recall and food frequency. Data were analyzed using SPSS and Food processor.

 Results: This study showed that intake of some nutrients (Zinc, Selenium, Folic acid and Vitamin B₂) in the subjects were significantly less than Recommended Dietary Allowance (RDA) of WHO (P<0.001), but intake of protein, iron and calcium was more than the RDA of WHO (P<0.001). Calorie intake of 20% of rural people was less than 75% of RDA(mostly seen among men). The findings of food frequency showed that main foods of rural individuals in Ardabil were local bread (Lavash), potato, egg, milk, biscuit, yogurt, garlic, onion, vegetable fat, butter and tomato.

 Conclusions: This study showed unsuitable intake of some nutrients. In order to improve the nutritional status of these people, regular intake of different groups of foods should be instructed.