It is known that CD is a common form of malabsorption [52–54]. For the time being, lifelong rigorous GFD is the only available treatment effective in remitting the symptoms of CD [1, 2]. Nevertheless, symptoms can sometimes remain even though patients go on a GFD. Moreover, this dietary pattern can bring as a result an imbalanced proportion of macro and micronutrient ingestion in both minors and adults with CD [4, 55, 56]. Several reasons have been proposed to justify these results, such as the scarce nutritional education of this collective or the lack of a strict compliance to the diet [6, 32]. Thus, nutritional counseling and a regular follow up by RDN to celiac and gluten sensitive people have been proposed as key strategies for achieving successful results in both symptom deletion and dietary balance [6, 18] and, as a consequence, in the nutritional status and quality of life of this collective. In this regard, the present work is a pilot study, an initial approach, to design a specific nutritional intervention suitable for the coeliac community.
Studies in the literature usually show that celiac people at diagnosis commonly present lower BMI values than does the general population, apart from lower fat and muscle mass, and that these parameters are normalized on average, after commencement, over the next two years [57–59]. However, recently published works have observed that, in the last 30 years a changing pattern in the clinical presentation of celiac people has occurred, mainly in paediatric patients, and that weight loss, for example, is not as common a symptom as it was . Thus, recent research has also reported normal body weight and BMI values at diagnosis of CD [9, 61–65]. In the present work, most participants, adults and children, showed normal BMI, fat and muscle mass values at diagnosis indicating that their nutritional status was appropriate. Moreover, this remained unchanged 3 and 12 months after GFD commencement. This lack of changes after dietary treatment in celiac subjects with normal BMI values has also been described by other authors. Indeed, it has been proposed that following a GFD may have a beneficial effect on weight and body composition in patients whose BMI is out of its normal parameters [62–64, 66].
Biochemical parameters are also important when assessing the nutritional status of the celiac and gluten-sensitive collective. In the present study, all paediatric patients had normal biochemical parameters at the beginning of the study and all remained under normal ranges after 3 and 12 months on a GFD. These data are in accordance with the maintenance of normal body weight and composition observed for these subjects over the whole intervention. Only a fluctuation in fasting glucose was observed after 12 months among celiac children. These changes were also reflected in a recent study by Forchielli et al. , where authors described not only an increasing fasting glucose among celiac infants but also incremented HDL-c and decreased LDL-c values. However, it must be pointed out that the concentration of these parameters was maintained under normal ranges in both studies, and so no repercussion on celiac children´s health can be concluded. Among adult participants, celiac men had exceeded total cholesterol values at diagnosis, which is not borne out by the literature because, in general, celiac adults show lower total cholesterol values than the normal population at diagnosis [67, 68]. Moreover, this parameter was maintained unchanged after GFD treatment . Unfortunately, the small sample size of adult males in the present study and the lack of biochemical data collected in this group in vt3 and vt12 render this work not comparable with the other studies mentioned.
The dietary pattern of celiac people on GFD in published works indicate that even though energy consumption can adjust to energy waste, macronutrient distribution is not balanced. Protein and lipids (especially saturated ones) are usually consumed in excess among people following a GFD, and by contrast, carbohydrate consumption is low [5, 6, 70, 71]. It has to be considered that GFP have partly been blamed for this imbalance, for several reasons: the high price of GFP (source of carbohydrates) that make celiac sufferers avoid them ; cereals used in GFP manufacturing that are poorer in proteins and usually not whole grains [19, 73]; the use of fats and gums in their production in order to improve palatability , etc. In fact, our previous studies indicated these nutritional composition differences between GFP and their gluten-containing counterparts . Nevertheless, in the present study, all participants presented an imbalanced distribution of macronutrient at diagnosis, when GFP had not been consumed yet, and this was generally maintained until vt12. This fact would suggest that, apart from GFP consumption, there were other dietary factors that altered energy distribution, such as the dietary habits of the subjects.
By contrast, fiber intake among adult men at diagnosis and at vt3 was appropriate. Women and children consumed low amounts of this nutrient at diagnosis, but the GFD made women and children increase fiber consumption by vt3, and it was maintained in vt12. This could be due to the fact that fibre content does not differ between GFP and their homologues as much as macronutrient content does. In fact, it has been recently described that specially glutenfree breads can contain even more fibre than those containing gluten, suggesting that the food industry is making efforts to raise the content of this nutrient in GFP [74–76] .
All these dietary imbalances observed among participants were linked to their dietary habits. In fact, imbalances remained unchanged across the whole study. According to the literature [4, 9, 55, 56, 65, 77], poor consumption of cereal, fruits, vegetables and oils was observed in all groups of participants. By contrast, meat was consumed in excess, which could be linked to the greater contribution of saturated fats in the diet at diagnosis. In fact, a positive correlation between both parameters was observed among celiac children at diagnosis (p = 0.02). Likewise, this nutrient consumption decreased slightly among children at vt3 and vt12, as did meat consumption. In the light of the above, giving dietary advice after vt0 and the followup in vt3 and vt12 did not change participants’ dietary pattern in our study. Thus, it can be stated that, in general, the dietary advice received by participants had little impact on their dietary profile improvement.
Even though dietary imbalances are observed frequently among people following a GFD, just as they are among the general population [4, 55], the introduction of a GFD is recommended for the partial or total elimination of symptoms [1, 78, 79]. Nevertheless, the period required for symptom remission varies between individuals [80, 81] and there is a small proportion of patients that continues suffering from symptoms even though they follow a GFD [81, 82]. In the present study, an amelioration of gastrointestinal symptoms in the first three months was observed among children, which was probably due to the motivation of starting the intervention and thus to a complete initial adherence to the diet. However, after this period a return of symptoms was observed in vt12, which indicated the probable relaxation of this collective in strictly following the GFD. In fact, dietitians suspected a lower dietary adherence at vt12 on face-to-face interviews among child participants. The literature also indicates that dietary adherence to GFD can decrease with the duration of treatments [83, 84] and the higher the adherence, the more effective the GFD is in resolving symptoms [85, 86]. Symptoms reported by adult participants did not change during the intervention indicating that concern about both the diet and symptom presence was not as important for children as it was for adults. Unfortunately, dietary adherence among the participants was not collected in the present study. In this respect, Silvester et al. have shown that almost all patients with CD only manage to maintain a diet which is reduced in gluten but not totally gluten-free . Thus, these data suggest that a continuous follow up of patients is necessary for ensuring the total adherence to the diet and for obtaining its beneficial results in symptom absence not only in the short term, but also in the long term.
Considering all the above mentioned it is clear that correct personalized dietary counseling, nutritional education and a continuous follow-up of celiac and gluten sensitive patients performed by RDN is crucial for obtaining positive results. The lack of changes viewed in the present study indicates that the intervention may not have been the most appropriate. In an attempt to find a simple form of counseling, which is not too stressful for the patient and is feasible for healthcare personnel, patients were given personalized dietary advice through individualized reports by e-mail, which probably resulted in a lack of complete adherence, disinformation or failing to grasp the guidelines. It also appears that reports did not capture the interest of the participants. Although they had the option of requesting personalized consultations, most of them did not. Furthermore, the loss of participants in the study was substantial. For successful results, a continuous and more frequent monitoring as well as patient nutrition education should be carried out while applying a more effective methodology, namely: face-to-face intervention, regular phone calls, WhatsApp and mail attention, Internet forums, workshops and other educational tools for patient empowerment. Bearing this in mind, this study represents a pilot experience devoted to a second improved intervention study, which will start in the near future in order to achieve better outcomes.
The main limitation of the present study was the high number of participants that failed to continue with the study during the follow up and the consequent lack of data at vt3 and vt12. Thus, a second improved study, as well as any further interventions aimed to improve GFD in celiac people, must overcome this limitation. Moreover, it would be interesting to analyse vitamin and mineral consumption and to detect the main difficulties in following a safe and balanced GFD. However, it is worth highlighting the long period in which participants were monitored in the present study, as well as the amount of data collected about the evolution of their nutritional status and dietary habits. It is also noteworthy that this study provides relevant information about decisive aspects that future interventions should address.