What’s the deal with fish oil and cystic fibrosis?
Fish oil is used for several conditions including heart disease, reducing triglycerides (blood fats), diabetes, rheumatoid arthritis, ADHD, Crohn’s disease, cystic fibrosis and asthma. Studies have shown it may reduce blood pressure and be helpful in diabetes, rheumatoid arthritis, Crohn’s disease and cystic fibrosis, although better studies are needed.
The impaired digestion of fats in CF often leads to a deficiency of essential fatty acids (EFAs). This deficiency may in turn lead to a lowered immune function, which makes children with CF more susceptible to respiratory infection. EFA deficiency can be reversed by supplementation with corn oil (1 gram per 2.2 pounds [1 kg] body weight per day), safflower oil (1 gram per 2.2 pounds [1 kg] body weight per day), linoleic acid (7.7 grams per day), and eicosapentaenoic acid (EPA from fish oil) (2.7 grams per day). EPA supplementation was particularly effective. In a double-blind trial, six weeks of supplementation with 2.7 grams per day of EPA led to reduction in sputum and improvement in lung function in children with chronic respiratory infection due to CF.
When questioned, all the research team at the Sydney Children’s Hospital can tell us is that “Yes fish oil has been shown to be advantageous when used on mice…”. If you read the research to date there has been some evidence that fish oil can have a positive effect but like many parents of children with chronic illness, even if there’s no proof, should we be trying it anyway? Below is a quick summary of the mouse study:
Recently, a reversible fatty acid imbalance, i.e., elevated AA and low DHA that may underlie the chronic lung and pancreatic lesions of CF, was demonstrated in a mouse model of the human disease. Oral administration of high doses of DHA not only corrected the membrane lipid imbalance but also reversed the signs of CF in the affected mice. In addition to this theoretical basis for possible dietary therapeutic interventions, a recent Cochrane review concluded that, Regular n-3 supplements may provide some benefits for CF patients with relatively few adverse effects but cautioned that the evidence, so far, is insufficient to draw firm conclusions (8). Improvement of pulmonary function (e.g., FEV) has been observed in CF patients after 6-week to 8-month treatments with n-3 LCP including both EPA and DHA. The extent to which improvement was related to the combination of EPA and DHA versus DHA alone requires additional clarification, but recent observations suggest an independent effect of DHA. Effective doses of fish oil range from 4.5 to 5.3 g/d, providing 2.7 to 3.2 g/d of EPA and 1.8 to 2.1 g/d of DHA, but few other doses were evaluated.
And it seems that researchers at the University of Sydney agree that fish oil helps cystic fibrosis patients
NEW SOUTH WALES, AUSTRALIA. Researchers at the University of Sydney have found that daily supplementation with fish oil capsules alleviates many of the symptoms of cystic fibrosis. Cystic fibrosis is a serious, inherited childhood disease which involves a malfunctioning of the body’s mucus glands. An abnormally thick mucus is produced which clogs the lungs and results in breathing difficulties. Other symptoms include persistent cough and wheezing, repeated lung infections, and a failure to gain weight. Sixteen cystic fibrosis patients aged 12 to 26 took part in the experiment. Half the group received fish oil capsules providing 2.7 g of eicosapentaenoic acid (EPA) per day while the other half received identical olive oil capsules as a placebo. After six weeks of treatment the patients receiving EPA coughed up significantly less sputum, were breathing easier (both forced expiatory volume and vital capacity were up) and generally felt better. The Australian researchers believe that the EPA acts by modifying the role of leukotriene B4. Leukotriene B4 is thought to be the main culprit in the excessive inflammatory response to bacteria which characterizes cystic fibrosis.
Source: Lawrence, R. and Sorrell, T. Eicosapentaenoic acid in cystic fibrosis: evidence of a pathogenetic role for leukotriene B4. The Lancet, Vol. 342, August 21, 1993, pp. 465-69
And even though CFers have trouble with fat absorption; some [minor] research shows that CFers are able to successfully absorb omega-3s effectively by mouth.
Researchers at the State University of Gent set up an experiment to see if CF patients are able to absorb omega-3s effectively by mouth. The trial involved 9 CF patients (4 females and 5 males) ranging in age from 7 to 20 years. All had been diagnosed with pancreatic insufficiency and had poor fat absorption despite supplementing with pancreatic enzyme preparations. The patients were assigned to receive either 6 fish oil capsules per day for a month followed by 6 placebo capsules for a month or 6 placebo capsules daily for a month followed by 6 fish oil capsules daily for a month. Each fish oil capsule contained 335 mg of salmon oil and 165 mg of commercial soy lecithin and provided 152 mg of omega-3 fatty acids. The placebo capsules contained 500 mg of pharmaceutical-grade liquid paraffin.
The researchers found that the CF patients who took fish oil showed a marked increase in their phospholipid levels of eicosapentaenoic acid [EPA] (increase of 327%) and docosahexaenoic acid [DHA] (increase of 215%). The levels of EPA and DHA returned to baseline 2 weeks after discontinuing supplementation. The researchers also noted that patients with low initial levels of EPA showed the greatest increase in EPA levels after supplementation. They conclude that oral supplementation with fish oil and lecithin is effective in increasing the levels of omega-3 fatty acids especially EPA and DHA in cystic fibrosis patients.
Source: Christophe, Armand, et al. Increase of long chain omega-3 fatty acids in the major serum lipid classes of patients with cystic fibrosis. Ann Nutr Metab, Vol. 36, 1992, pp. 304-12
Taking too much fish oil may increase triglyceride levels which can be harmful. Some studies have also shown that although Cfers don’t absorb as much essential fatty acids as non-Cfers, that high tyriglycerides may still occur.
A DGReview of :“Abnormal lipid concentrations in cystic fibrosis”
American Journal of Clinical Nutrition, 06/11/2002
By Mark Pownall
High levels of triglycerides in the blood are common in cystic fibrosis, questioning the traditional belief that lipid levels were not of concern in this group of patients.
The clinical significance of the findings may become more important as modern treatments result in patients with cystic fibrosis living longer, the researchers behind the study say.
The researchers, from the University of Minnesota in the United States, measured the fasting lipid profiles in 192 patients with cystic fibrosis. The patients also had an oral glucose tolerance test.
The CF patients of all ages had higher triacylglycerol and lower total cholesterol concentrations than the means of the US population. Thirty three of the patients (16 percent) had hypertriglyceridaemia, while eight had elevated cholesterol. levels.
Most of the patients had only hypertriglyceridaemia; only three had both high triglycerides and high cholesterol in their plasma samples.
There was no obvious correlation to other biochemical measurements. Lipid levels were not linked to body mass index, weight, glucose tolerance, the area under the curve or glucose or insulin, nor glycated hemoglobin levels.
There was also no link established with cystic fibrosis genotype, use of systemic steroids, blood pressure, liver enzymes, CV-reactive protein or pulmonary functio
In the face of all these negative findings, the researchers suggest that the hypertriglyceridaemia seen in cystic fibrosis patients may be related to a chronic low-grade inflammation or to a dietary macronutrient imbalance with an excess absorption of simple carbohydrate compared to fat.
The researchers say it is uncertain whether the lipid abnormalities are related to a risk of cardiovascular disease in the CF population.
Am J Clin Nutr 2002; 75: 1005-1011. “Abnormal lipid concentrations in cystic fibrosis”
So what are triglycerides?
Source: American Heart
Triglycerides are the chemical form in which most fat exists in food as well as in the body. They’re also present in blood plasma and, in association with cholesterol, form the plasma lipids.
Triglycerides in plasma are derived from fats eaten in foods or made in the body from other energy sources like carbohydrates. Calories ingested in a meal and not used immediately by tissues are converted to triglycerides and transported to fat cells to be stored. Hormones regulate the release of triglycerides from fat tissue so they meet the body’s needs for energy between meals.
How is an excess of triglycerides harmful?
Excess triglycerides in plasma is called hypertriglyceridemia. It’s linked to the occurrence of coronary artery disease in some people. Elevated triglycerides may be a consequence of other disease, such as untreated diabetes mellitus. Like cholesterol, increases in triglyceride levels can be detected by plasma measurements. These measurements should be made after an overnight food and alcohol fast.
So as parents what we want to know is – what does all this mean? Should we be giving our CF kids more fish oil? If so, how much more? How much is too much? And how much is enough? The above research suggests that effective doses of fish oil range from 4.5 to 5.3 g/d, providing 2.7 to 3.2 g/d of EPA and 1.8 to 2.1 g/d of DHA, but few other doses were evaluated.
The reality is that our doctors don’t know how much fish oil we should be giving our kids but understandably, will err on the side of caution. The question for me as a parent is, how harmful are larger doses of fish oil if I choose to follow the research and up the dosage? Should I be testing my child for high triglyceride levels? Is the dose he is currently on even high enough?
My son is 2 years old and currently on 4 x Metagenics EPHA / DHA capsules daily which deliver 500mg of triglycerides daily [165 mg EPA and 110 mg DHA] per capsule. If I can find anyone to give me advice on this I’ll update the site and let you know.>
Additional info on therapeutic dosages:
Typical dosages of fish oil are 3 g to 9 g daily, but this is not the upper limit. In one study, participants ingested 60 g daily. The most important omega-3 fatty acids found in fish oil are called eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). In order to match the dosage used in several major studies, you should take enough fish oil to supply about 2 g to 3 g of EPA (2,000 mg to 3,500 mg) and about 1.0 g to 2.5 g of DHA daily (1,000 mg to 2,500 mg). Far higher doses have been used in some studies; conversely, one study found blood-pressure lowering effects with a very low daily dosage of DHA—0.7 g.238
DHA and EPA are not identical and might not have identical effects. Some evidence hints that DHA may be more effective than EPA for thinning the blood 176 and reducing blood pressure.105 The reverse may be true for reducing triglyceride levels, but study results are conflicting.160-165, 235
Some manufacturers add vitamin E to fish oil capsules to keep the oil from becoming rancid. Another method is to remove all the oxygen from the capsule. If possible, purchase fish oil products certified as free of significant levels of mercury, toxic organochlorines, and PCBs (see Safety Issues). Flaxseed oil also contains omega-3 fatty acids, although of a different kind. It has been suggested as a less smelly substitute for fish oil. However, it is far from clear whether flaxseed oil is therapeutically equivalent to fish oil.1,200. Studies to date suggest it is not.
The USA National Cholesterol Education Program guidelines for triglycerides are: