Why bother to take vitamins?

The first clear description of ‘fibrocystic disease of the pancreas’ or Cystic Fibrosis (CF) came in the late 1930s and evidence of vitamin A deficiency was reported in 10 of 49 patients as early as 1939. Indeed, this paper recommended ‘generous dosages’ of vitamin A for these patients. Biochemical evidence of fat-soluble vitamin deficiency occurs early in infants diagnosed with CF by newborn screening. Sokol et al. reported the fat-soluble vitamin status of 36 infants diagnosed by newborn screening between 1984 and 1987 with the initial evaluation being undertaken at around sevenweeks of age. Therewas an inverse correlation between three-day faecal fat excretion and serum α-tocopherol levels (vitamin E). Twenty-one percent of patients had low vitamin A levels, 35% low vitamin D, 38% low vitamin E and vitamin E:lipid ratio though none had an elevated PIVKA-II (protein induced by vitamin K absence or antagonism) – one indicator of vitamin K deficiency. Introduction of pancreatic enzyme replacement therapy, and standard fat-soluble vitamin supplementation corrected vitamin A and D status at 6 and 12 months of age. However, 10% of patients remained vitamin E deficient. Feranchak et al. reported that 44 of 96 (45.8%) infants diagnosed by newborn screening between 1984 and 1997 had a deficiency of one or more of the fat-soluble vitamins by 4–8 weeks of age. Vitamin A deficiency occurred in 29% of patients, vitamin D deficiency in 22.5% and vitamin E deficiency in 22.8%. Bines et al. reported low serum retinol in 20 out of 39 (51%) infants and low α-tocopherol in nine of 38 (24%) infants diagnosed by newborn screening between 1991 and 1994. These studies are supported by more contemporaneous data. Neville and Ranganathan reported 58 infants diagnosed by newborn screening between 2001 and 2006. Median age of diagnosis was 1 month (range 0–3 months). Vitamin D deficiency was described in 11 of 30 infants (37%), vitamin E deficiency in seven of 45 (16%) and vitamin A deficiency 27 of 45 (60%). Vitamin A and E levels were significantly lower in pancreatic insufficient patients. Vitamin A and E status was significantly correlated with pancreatic status though there was no significant correlation with pancreatic status and vitamin D deficiency. Why bother to take vitamins? Firstly, because at the time of diagnosis of CF there is clear biochemical evidence of vitamin A deficiency in up to 60% of infants and vitamin D and E deficiency in up to 37% and 38%, respectively. Untreated, the incidence of biochemical and later clinical vitamin deficiencies will increase. Most people with CF are at risk of fat-soluble vitamin deficiencies due to fat malabsorption and maldigestion as a consequence of pancreatic insufficiency and bile salt deficiency. Patients treated with pancreatic enzyme replacement therapy may still experience refractory steatorrhoea due to enzyme inactivation as a consequence of high intestinal pH, small bowel bacterial overgrowth, the presence of a mucus barrier lining the intestine, short gut syndrome due to previous bowel resection and CF-related liver disease. Adherence rates are difficult to assess but non-adherence to pancreatic enzyme replacement is commonly reported and contributes to malabsorption. We know that some patients do not bother to take their prescribed vitamins as adherence rates in people with CF of 47% of the recommended vitamin prescription have been reported. Modi et al. compared different methods of assessing adherence to vitamin therapy. Adherence was variable and ranged DECLARATIONS