Supplemental calories improve essential fatty acid deficiency in cystic fibrosis patients

Fatty acid composition of plasma lipids was analyzed in malnourished cystic fibrosis patients undergoing 6 months of nutritional rehabilitation. There were three males and five females (mean age 15.1 yr); five patients had pancreatic insufficiency. Nutritional rehabilitation in seven of eight patients was accomplished by nocturnal nasogastric infusion of a high-carbohydrate semisynthetic diet, in addition to daily meals. One patient received high-energy food supplements as snacks in addition to regular meals. All patients were moderately to severely malnourished on entry to the study and showed significant improvement over the 6 months in (means +/- SE) energy intake (96 +/- 8.0 to 126 +/- 11% recommended daily allowance) and body composition (80 +/- 4 to 90 +/- 4% ideal body weight). Daily intakes of linoleic acid were not significantly different before or during nutritional rehabilitation either as an absolute amount (383 +/- 45 to 557 +/- 124 mg/kg/day) or as a percentage of total calories (4.50 +/- 0.40 to 4.73 +/- 0.14%). In comparison to the controls, the relative percentage of plasma cholesterol ester fatty acids of the CF patients on entry into the study showed a marked decrease of linoleic acid (52.7 +/- 1.0 versus 42.3 +/- 2.7%) with elevated palmitoleic (2.34 +/- 0.2 versus 5.64 +/- 0.7%) and oleic (18.7 +/- 1.0 versus 25.2 +/- 1.4%) acids; a pattern consistent with essential fatty acid deficiency. However, this pattern is not truly characteristic of a pure linoleic acid deficiency as the metabolites of linoleic acid were not decreased.(ABSTRACT TRUNCATED AT 250 WORDS)     

Correction of linoleic acid deficiency in cystic fibrosis

To identify evidence of essential fatty acid deficiency, we screened 64 patients with cystic fibrosis by analyzing total lipid extracts from plasma. Forty-three had an abnormal linoleate (18:2) level (less than 26%). Thirteen deficient patients (aged 10-24 yr) ingested for 1 yr 7% of their total calories as linoleate derived from a daily supplement of Microlipid. Five deficient patients (aged 10-37 yr) served as controls. Plasma and erythrocyte fatty acid composition were monitored by gas chromatography of total lipid extracts seven times during the twelve month period. Prostaglandins E2 and F2 alpha and their 15 keto 13, 14 dihydrometabolite, 6-keto F1 alpha, and thromboxane B2 were measured by radioimmunoassay. Sweat tests, oxygen saturation, growth indices, clinical severity scores, compliance, and possible side effects from taking Microlipid were followed. Results showed that oral supplementation with Microlipid can significantly increase plasma and erythrocytes % 18:2. One compliant patient died during the study and had normal tissue 18:2 levels. Nine of 13 patients gained more weight while taking Microlipid than in the previous year. No significant changes in sweat electrolytes, clinical scores, or oxygen saturation were found during the study year. Prostaglandin metabolites prostaglandin E2 showed an upward trend in supplemented patients, compared to controls. Prostaglandin F2 alpha remained unchanged over 1 yr but showed a trend significantly downward over the final 6 months in supplemented patients. We conclude that linoleate deficiency can be corrected with daily Microlipid supplements and that correction may alter prostaglandin metabolism.     

Effect on renal function of essential fatty acid supplementation in cystic fibrosis

Changes in renal hemodynamics, sodium homeostasis, renal acidifying capacity, and aldosterone excretion were studied before and after long-term intravenous essential fatty acid supplementation for a period of 3 years in 11 patients with cystic fibrosis. The mean (+/- SD) glomerular filtration rate was high at the start of the study (133 +/- 18 ml/min/1.73 m2 body surface area) and decreased significantly (p less than 0.05) to within normal values after 1 year of essential fatty acid supplementation. The urinary elimination of an oral sodium load initially was very low (3.6 +/- 2.5 mmol/hr/1.73 m2 body surface area vs control subjects' values of 7.9 +/- 2.0; p less than 0.001) and increased during treatment but was not normalized (p less than 0.05 vs control subjects' values). Free water clearance and distal tubular sodium delivery, which were significantly decreased before treatment (p less than 0.01 and p less than 0.001 vs control subjects' values, respectively) did not increase significantly. The mean urinary aldosterone excretion did not significantly differ from that in control subjects before and after treatment. The acidifying capacity was disturbed, indicating a low renal bicarbonate threshold, and was changed during treatment in only 2 of 10 patients. These data indicate that essential fatty acid deficiency may contribute to the renal disturbances in cystic fibrosis.     

Short-chain fatty acid absorption in patients with cystic fibrosis.

Patients with cystic fibrosis (CF) often exhibit malabsorption despite the use of supplemental pancreatic enzymes. Unabsorbed carbohydrates and amino acids can serve as substrates for large intestine anaerobic fermentation, thus increasing excretion of short-chain fatty acids (SCFA) in the feces. Nine patients with CF on regular pancreatic enzyme supplementations in the age range of 5-11 years and one older patient were studied. Three-day stool samples were collected, as were 72-h food records. Stools were analyzed for gross energy, total nitrogen, fat content, and SCFA concentration. A significant difference was found between CF and normal controls in total caloric excretion due to fat malabsorption. No significant difference was found between CF and normal controls in protein or SCFA excretion. Fat excretion as percentage of fat intake was significantly increased in CF patients: 35.3 +/- 10.2% versus 8.0 +/- 3.0%, respectively. These data suggest that carbohydrate supplementation could be more widely used to increase caloric intake in CF patients without causing secondary osmotic diarrhea.     

Intravenous linoleic acid supplementation in children with cystic fibrosis.

Ten children with CF in matched pairs were infused with either Intralipid or with 10% glucose on a double blind basis every other week for one year. Although statistically there was significantly greater gain in height and weight in the study year compared to the previous year only for the test group, both groups improved more than expected. Cumulative data analysis showed greater improvement for the Intralipid group (23 of a possible 45 points) compared to the glucose group (-2 points; P less than .02). This study indicates the need to better define the role of nutrition in the pathophysiology of CF. Meanwhile, it is recommended that all children with CF have plasma linoleic acid levels measured at least once yearly, and if levels are low, appropriate supplements should be given.     

Essential fatty acid deficiency in well nourished young cystic fibrosis patients

Essential fatty acid deficiency is well known in cystic fibrosis patients, but its pathogenesis remains unclear. It might be related to protein-energy malnutrition which is a common feature of cystic fibrosis or to some specific defects in fatty acid metabolism. To avoid the deleterious effects of protein-energy malnutrition, this study assesses the plasma phospholipid fatty acid pattern in well nourished young cystic fibrosis subjects. Sixteen cystic fibrosis subjects aged 6.6–20.0 years were studied and compared to 16 healthy controls matched for gender, age and nutritional status. Plasma phospholipids were separated by thin layer chromatography and phospholipid fatty acid pattern was determined by gas liquid chromatography. Anthropometry and dual-energy X-ray absorptiometry showed that lean body mass, fat-free mass and fat mass were similar in the two groups. Nutritional inquiry showed higher ingestion of macronutrients by cystic fibrosis subjects than by controls. Plasma phospholipid palmitoleic acid and eicosatrienoic acid were higher, and by contrast linoleic acid and docosahexaenoic acid were lower in cystic fibrosis subjects than in controls. The ratio linoleic acid/arachidonic acid was lower and the ratio eicosatrienoic acid/arachidonic acid was higher in cystic fibrosis subjects than in controls. Conclusion Essential fatty acid deficiency is present in young cystic fibrosis subjects in the absence of protein-energy malnutrition. It means that this deficiency is probably related to specific defects in fatty acid metabolism. Received: 1 December 1997 and in revised form: 3 July 1997 / Accepted 8 July 1997     

Abnormal fatty acid composition and impaired oxygen supply in cystic fibrosis patients.

Impaired oxygen supply and deteriorating health, in cystic fibrosis patients, correlates with abnormal changes in the fatty acid composition of blood lipids. As the proportion of oleates increases and that of linoleates decreases, erythrocyte membrane interference with the formation of intracellular oxyhemoglobin increases and arterial oxygen pressure decreases. The physical-chemical basis for these changes seems to be that oleic and linoleic acid differ in their ability to undergo reversible oxygenation in response to changes in oxygen pressure. The oxygen complex of linoleic acid dissociates at relatively high pressures, whereas that of oleic dissociates only at low pressures. Accordingly, excessive substitution of oleic for linoleic acid in membrane lipids would be expected to decrease the intracellular oxygen pressure to a level where hemoglobin oxygenation and any other oxygen-requiring processes would be impaired.     

Relationships between pulmonary function and plasma fatty acid levels in cystic fibrosis patients

Nineteen patients with cystic fibrosis (CF) were studied to determine whether plasma fatty acids correlated with severity of their lung disease as assessed by pulmonary function testing. Results were compared with 19 normal subjects of similar age and sex. Linoleic acid content of all lipid fractions was significantly lower in CF patients than controls including cholesterol ester fraction (CF 31%, control 50%, p less than 0.001), triglyceride fraction (7.6 to 16.6%, p less than 0.001), and phospholipid fraction (13.9 to 21.7%, p less than 0.001). Mean 20:3 omega 9/20:4 omega 6 ratio for CF patients was higher in all lipid classes and was suggestive of essential fatty acid deficiency. Correlations were found to exist between most pulmonary function parameters and fatty acids of plasma phospholipids but not any other lipid class. Positive correlations were found between all ventilatory tests and total omega 3 polyunsaturated fatty acids and also 22:5 omega 3 and 22:6 omega 3. There was no correlation between total saturated fatty acids, total monounsaturates, total omega 6 fatty acids, or triene/tetraene ratios and pulmonary function. Positive correlations were found between pulmonary function parameters and certain omega 6 polyunsaturates including 20:4 and 22:4 but not 18:2.     

Energy expenditure of patients with cystic fibrosis

Resting energy expenditure was measured by open-circuit indirect calorimetry in 71 patients, aged 8.9 to 35.5 years, with cystic fibrosis who had no recent history of acute lung infection. Pulmonary function and nutritional status were studied simultaneously. In most patients, resting energy expenditure was above normal (range 95% to 153% of predicted values for age, sex, and weight as derived from the Harris Benedict equations), and was negatively correlated with pulmonary function (P less than 0.01) and nutritional status (P less than 0.01) when expressed as a percentage of body fat. Pulmonary status was positively correlated with nutritional status (P less than 0.01). We conclude that resting energy expenditure in patients with cystic fibrosis exceeds normal values and that the increase correlates with a deterioration in lung function and nutritional status.     

Prospective study of fatty acid supplementation over 3 years in patients with cystic fibrosis

Intravenous fatty acid supplementation (10% Intralipid, 10 ml/kg body weight) was given to 10 patients with cystic fibrosis (CF), in intervals for 3 years. One year of intensive treatment with supplementation every fortnight was followed by 1 year of intermission and then 1 year of the same treatment given for 2 days every 2 months. Compared with matched CF patients, the clinical course, evaluated by Shwachmann scoring, showed less deterioration in the treated group, especially during the year of intensive treatment. Single parameters, such as pulmonary function tests, pulmonary X-ray films, clinical infections, bacterial growth of sputa, and sweat electrolyte concentration, showed no differences. It is concluded that if there is any benefit of this kind of treatment in CF, it has to be very intensive. At present, the psychological stress involved in repeated parenteral administrations over long periods prevents its use in clinical routine.     

Essential fatty acid deficiency in relation to genotype in patients with cystic fibrosis.

OBJECTIVE: To determine if the serum phospholipid fatty acid pattern in patients with cystic fibrosis (CF) was related to the major cystic fibrosis transmembrane conductance regulator gene mutations. METHODS: Patients with CF (n = 110) aged 3 months to 56 years were studied. Serum samples were analyzed for phospholipid fatty acid with gas-liquid chromatography, and cystic fibrosis transmembrane conductance regulator mutations were determined with standard methods. RESULTS: Patients with CF had significantly lower molar percentages of linoleic acid and docosahexaenoic acid in the serum phospholipid than healthy controls (mean +/- standard deviation, 20.3 +/- 4.5 and 2.6 +/- 0.9 vs 22.4 +/- 2.2 and 3.1 +/- 0.7, respectively; P <.001). Palmitoleic and oleic acids were significantly increased (P <.001) but arachidonic acid was not different from controls. Homozygotes for DeltaF508 and heterozygotes/homozygotes for 394delTT showed significantly lower concentrations of linoleic acid and docosahexaenoic acid than the other groups. Low values were not correlated to anthropometric data or lung function. Patients with pancreatic insufficiency showed similar differences to those with sufficient pancreatic function, reflecting the different genotypes. CONCLUSION: Serum concentrations of linoleic acid and docosahexaenoic acid were significantly lower in patients with severe cystic fibrosis transmembrane conductance regulator mutations, suggesting an association between the basic defect and abnormal essential fatty acid metabolism in CF patients.     

Linoleic acid absorption from lipid supplements in patients with cystic fibrosis with pancreatic insufficiency and in control subjects

To determine the relative role of malabsorption as the cause of decreased linoleic acid in blood and tissue lipids of patients with cystic fibrosis (CF) and pancreatic insufficiency, the increase in plasma linoleic acid was determined after ingestion of various lipid supplements. CF patients with documented pancreatic insufficiency and normal control subjects were given each of four different lipid supplements on separate days (a minimum of 3 days apart). The supplements were commercial safflower oil, Microlipid, Captex 810D, and Captex 810B. Fasting subjects consumed 36 g of lipid in a milk shake containing 15 g of protein and 45 g of carbohydrate. Plasma samples obtained at 0, 2, 4, 6, and 8 h after the meal showed that CF patients absorbed linoleic acid from all of the lipid preparations tested when administered with their regular dose of pancreatic enzyme supplement. The mean maximal increase in percent plasma linoleic acid in CF patients was not different from controls after ingestion of safflower oil, Microlipid, and Captex 810B. With Captex 810D the CF patients had a significantly higher increase in percent plasma linoleic acid than controls, 6.75% vs. 2.27%, respectively, at 2 h (p less than 0.01), and 11.10% vs. 4.65% at 8 h (p less than 0.01). The CF patients also appeared to absorb the Captex products faster than controls, suggesting that presence of medium chain length fatty acids in these structured lipids facilitated their utilization by CF patients. The results indicate that malabsorption alone cannot account for the inadequate or marginal essential fatty acid status of CF patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Energy and respiratory metabolism in cystic fibrosis: the influence of carbohydrate content of nutritional supplements

The basal energy expenditure (BEE) in a group of adolescent and young adult patients with cystic fibrosis (CF) with mild lung disease was 97 +/- 6% of that predicted by the Harris-Benedict equation (which estimates BEE by age, sex, height, and weight). The BEE of a group with more severe lung disease was 117 +/- 5% of that predicted by the Harris-Benedict equation, due primarily to a 14% greater oxygen consumption (VO2) and 24% greater CO2 production (VCO2) compared with milder lung disease (p less than 0.05). The measured BEE in the patients with mild lung disease correlated well with the predicted BEE, but variably underestimated that of patients with more advanced lung disease. The influence of low carbohydrate (Pulmocare) and higher carbohydrate (Instant Breakfast) nutritional supplements on the energy and pulmonary metabolism was compared in 10 malnourished CF patients with moderate to severe lung disease. Their BEE before ingesting the supplements was 120% of that predicted by the Harris-Benedict equation. Their VCO2 increased 9-19% for the 3 h after ingesting 500 kcal/M2 of Pulmocare, and 25-30% after ingesting Instant Breakfast (p less than 0.05). The respiratory quotient (RQ) was significantly greater for Instant Breakfast than Pulmocare. The minute ventilation (VE) rose 10-13% for the 3 h after ingesting Pulmocare, versus 27-31% after ingesting Instant Breakfast, but the difference was not significant. The metabolic expenditure rose 13-16% for the 3 h after ingesting both formulas. We concluded that CF patients have increasing difficulty maintaining their nutrition as their pulmonary disease progresses, in part because of a 17-20% increase in their BEE.(ABSTRACT TRUNCATED AT 250 WORDS)     

A therapeutic trial of fatty acid supplementation in cystic fibrosis.

Seven children with cystic fibrosis (CF) have been treated for at least one year with intravenously administered soya oil emulsion. In all, an improvement of at least one biochemical abnormality in character with the disease appeared. The children's clinical course remains benign. This course is remarkably better than that of other children with CF treated without Intralipid in Auckland in the same period, though a placebo effect cannot be discounted. It is postulated that intravenous supplementation with essential fatty acid in CF may in turn partially correct an error of metabolism of prostaglandins present in the disease.     

Vitamin status in treated patients with cystic fibrosis.

The water-soluble (B1, B2, B6, C, folic acid) and fat-soluble vitamin (A, carotene, E, and D) status of 36 patients with cystic fibrosis was assessed and compared with a control group of 21 age-matched normal children. Twenty-seven of the patients were receiving vitamin supplements (except folic acid and vitamin E) at the time of investigation. Vitamin B1, B2, and B6 status was adequate in all patients, and there was little evidence of folic acid deficiency. Vitamin C stores might not have been adequate in some of these patients, despite daily supplements with 50 mg of the vitamin. Steatorrhoea, often severe, was present in most of them. Serum carotene and vitamin E concentrations were low in over 90% of patients and were related to the severity of steatorrhoea. Vitamin A was low in over 40% of the patients despite daily vitamin supplements of 4000 IU and correlated with the serum retinol-binding protein level. Serum 25-OH cholecalciferol was low in some patients whether or not they were receiving a daily supplement of 400 IU vitamin D. In a short-term supplementation trial with water-miscible preparations of vitamin A and E in 14 patients, the serum levels of both vitamins responded well to 2 weeks of treatment with 50 mg vitamin E and 4000 IU vitamin A. Except for serum vitamin A, which was lowest in patients with the poorest clinical grading, the other vitamins were not influenced by the clinical grade of the patients.