Educación intercultural

2.6.1 Special diets

The importance of optimal nutrition and dietary manipulation, as an essential part of treatment, needs to be emphasized. Often it is not fully comprehended by families, leading to incomplete compliance with the prescribed diet. In fact, adhering to the special diets require a great deal of effort and adjustment, the diets are absolutely crucial to successful management of a considerable number of metabolic disorders. A special and specific diet is prescribed for each patient with a metabolic disorder that has dietary influences, for example, for patients with inborn errors of protein

metabolism (aminoacidopathies) the diet involves restricting the dietary intake of

protein to limit the intake of the amino acid/s (specific to each disorder) that cause the metabolic distress, and substituting this part of the diet with special formulas to provide essential nutrients which have been limited with the restricted diet (Clarke, 2002; and Walter & MacDonald, 2006).

Special diets often mean the difference between developmental disability and normal functioning of individuals with metabolic disorders (Brumm & Grant, 2010;

Cockburn & Clark, 1996; and Hoffmann, Helbling, Schadewaldt, & Wendel, 2006).

Children with metabolic disorders and their families need to comprehend the genetics of their particular disorders, the treatment of the disorder including the specific dietary restrictions, the reasons for these restrictions and how they work in preventing harmful effects of each disorder. It is important for families to know that the patients will be monitored through regular clinic visits and laboratory tests, be trained to take a blood sample, to adjust the diet to maintain metabolic control, and to handle social situations concerning food. This will help patients recognize that they can be effective individuals in society without compromising their health or being a burden on carers.

Nonetheless, compliance with these restricted diets is difficult, and tends to decrease around adolescence. Therefore identifying compliance barriers and learning how to help patients overcome them is an essential aspect of care (MacDonald, Gökmen-Ozel, van Rijn, & Burgard, 2010).

Effective nutritional programmes are in place to support and counsel patients and their families in most of the European countries and North America. They have regular clinic attendance, and when not able to attend patients are trained to send blood samples to their laboratories. Results are then given to the dietitians who can easily communicate these to the patients and families through the phone, and discuss the needed course of action, whether it is to continue with current diet or to implement changes in formula or food intake to improve blood levels. Having such systems in place and training patients and their families in dealing efficiently with them vastly improves the quality of care for each patient, and greatly helps patients and their families in dealing with their disorders. Nutrition counselling and education can be provided in many effective ways; it could be through one to one sessions or in group sessions, with the use of visual aids; such as posters; food models; videos; and stories and games for children (Bernstein et al., 2013; Schwandt et al., 1999; and Williams et

al., 1998). To be most effective education materials need to be adapted to suite the population they are intended for (Winkleby et al., 1997).

Fisch (2000) argued that “The effectiveness of our treatment is always in the shadow of the compliance of our patients” clearly elucidating how essential patient

compliance is to outcome. Many studies showed how non-compliance with diet and intake of prescribed protein substitute formulas negatively affect amino acid levels, IQ levels, and cause some vitamins and minerals deficiencies and decreases in bone mineral content (Chang, Gray, & O'Brien, 2000; Huijbregts et al., 2002; Przyrembel

& Bremer, 2000; and Robinson et al., 2000).

2.6.2 Formula compliance and vitamin and mineral needs

With all low or restricted protein diets there is a risk of deficiencies in some vitamins and minerals. Current research indicates particular deficiencies when the patients do not comply with their formula intake. Hanley et al (1996) followed 96 adolescents and young adults with PKU in their clinic in Canada; only 66% of them continued with their prescribed dietary therapy, and not all of those had good control or took their formula regularly. They tested 37 of their patients for several micronutrient deficiencies because the formula contains important supplements of vitamins and minerals that are lacking in the low phenylalanine diet, 12 (32%) of them had suboptimal levels of vitamin B12; five of those patients were off diet. They

recommend periodic monitoring of serum B12, red blood cell folate, and ferritin in adolescents and young adults with PKU, and additionally monitoring of

methylmalonic acid and homocysteine because they increase with lack of vitamin B12

and could be good indicators for early detection of B₁₂ deficiency (Hanley, Feigenbaum, Clarke, Schoonheyt, & Austin, 1996).

Another study reported that 77% of the adult PKU patients in their sample, who are off diet, had biochemical signs of vitamin B₁₂ deficiency (Hvas, Nexo, & Nielsen, 2006). They have also measured their vitamin B₆ intake through food diaries and found that 71% of the patients get less than the recommended intake. Vitamin B₆ is found in beans, meat, poultry, fish and some fruits and vegetables, but mainly in high protein foods. The authors recommend daily vitamin supplementation for PKU

patients who are off diet and continued dietary management throughout adult life (Hvas et al., 2006).

Robinson and colleagues (2000) found that vitamin B₁₂ is adequately supplied within the formula or additional supplements for adolescents and adults with PKU on a strict diet, while patients on a relaxed or unrestricted diet had inadequate intake of vitamin B₁₂. This was due to their tendency to avoid animal protein because they either find the taste unpleasant or because they recognize it is harmful to them and try to avoid it.

Vugteveen et al (2011) has shown that patients who were continuously treated and have been taking their formula have been found to have functional vitamin B₁₂ deficiency, which is defined by the authors as an increase of methylmalonic acid levels even if vitamin B12 levels were normal. They recommend yearly monitoring of serum methylmalonic acid levels in PKU patients to detect B12 deficiency in the earliest stages. The researchers speculate that finding more vitamin B12 deficiencies in PKU patients could be due to lower bioavailability of B12 from the protein substitute formula and due to taking the formula less than three times a day; increased intake of B12 in one meal reduces its availability (Vugteveen et al., 2011). The main dietary source of B12 is animal protein. Untreated vitamin B12 deficiency may lead to a wide range of psychiatric and neurologic problems, some irreversible, in addition to the risk of macrocytic anaemia (Hvas et al., 2006; and Robinson et al., 2000).

Several studies report high incidence of iron deficiency in patients with PKU despite being compliant with the diet and the protein substitute formulas; all patients in these studies had an adequate iron intake within the recommended level (Acosta et al., 2004; Acosta, 1996; Arnold, Kirby, Preston, & Blakely, 2001; Bodley, Austin, Hanley, Clarke, & Zlotkin, 1993; Miranda da Cruz, Seidler, & Widhalm, 1993; and Tavil et al., 2006). The researchers questioned the bioavailability of iron through the protein substitute formula and called for further research. Iron deficiency could affect growth levels and cause cognitive, motor, and behavioural disturbances, therefore the researchers recommended regular monitoring of complete blood counts, haemoglobin, and ferritin for early assessment of any deficiency. One of the previous studies gave iron supplements (5 mg elemental Fe/kg daily) for 4 months to the patients with low iron levels, the patients benefited from this treatment and showed improved levels (Miranda da Cruz et al., 1993).

Only one study looked at vitamin A levels for patients with PKU (Acosta, 1996). All patients had intakes of vitamin A greater than the recommended dietary allowance for age but the plasma retinol concentrations for 48% of them were in the marginal or deficient range. Again the bioavailability of vitamin A from the formula was questioned and further research is warranted.

A few studies looked at selenium levels in patients with PKU and found that high percentages of the patients had low plasma selenium levels, but the patients didn’t present any selenium deficiency symptoms (Barretto et al., 2008; Jochum et al., 1997;

and MacDonald et al., 2004). This was explained by the low level of selenium in some of the formulas or due to noncompliance with the formula intake. In addition to selenium deficiency Barretto and colleagues found that 37.5% of their patients had below normal levels of erythrocyte zinc even though their intake of zinc was more than the dietary recommended intake. Dietary fibre and phytate content of grains, nuts, and legumes may reduce the bioavailability of zinc by forming insoluble complexes with zinc (Barretto et al., 2008).

Low bone mineralization has been reported in older children with PKU and associated with high levels of blood phenylalanine (Adamczyk et al., 2011; Al-Qadreh et al., 1998; and McMurry, Chan, Leonard, & Ernst, 1992). In all of these studies older children and adolescents who were not compliant with the PKU diet and formula intake had significantly lower bone mineral density than compliant patients and normally developing children. This puts the non-compliant patients at increased risk of not reaching the optimum bone mineral content increasing their risk for fractures and adult osteoporosis. Furthermore, Adamczyk and colleagues (2011) reported that non-compliant patients had significantly lower muscle mass than compliant patients.

The researchers recommended continuous dietary compliance with good blood phenylalanine control to protect the bone mineral development of patients with PKU and to reduce the risk of abnormalities in the fat and muscle tissues (Adamczyk et al., 2011; Al-Qadreh et al., 1998; and McMurry et al., 1992).