Olés for Omega-3s
- A randomised interventional trial of -3-polyunsaturated fatty acids on endothelial function and disease activity in systemic lupus erythematosus
Annals of the Rheumatic Diseases, Volume 67, Number 6, June 2008, pp. 841-848
- Leukocyte numbers and function in subjects eating n-3 enriched foods: selective depression of natural killer cell levels
Arthritis Research & Therapy, Volume 10, Issue 3, R57, May 14, 2008
What is the topic?
Omega-3 polyunsaturated oils found in fish have been proven to help lower risk for heart disease. This could be relevant to lupus since there is a known increased risk for heart disease in people with lupus.
What did the researchers hope to learn?
Two groups of researchers studied the various effects of omega-3 fish oils in people. The first group, from Northern Ireland, wanted to see if taking low-dose supplements of omega-3 oils had any effect on lupus disease activity, and if the oils provide protection for lupus patients against cardiovascular disease (heart disease, stroke, or hardening of the arteries). The second team of researchers, from Australia, focused their attention on how omega-3 fatty acids affected white blood cells (leukocytes) of the immune system.
Who was studied?
The Irish researchers had 60 lupus patients in their study, who were recruited from a database of more than 350 lupus patients throughout Northern Ireland. None of the 60 patients had diabetes, high blood pressure, or a history of previous heart, kidney, or liver disease, and they couldn’t be taking more than 10 mg of steroids daily -- all of which are known to be risk factors for heart disease and could complicate the findings. The Australian research group studied 44 healthy adults, ranging in ages from 23 to 63 years old.
How were the studies conducted?
The Irish researchers divided their study patients into two groups of 30; one group was given pills that contained a daily dose of 3 grams of fish oil, while the other group got pills (placebo) that looked the same but contained olive oil instead of fish oil, so that the calories of the two different pills would be about the same. Neither the patients nor the research team knew which patients received the active pills or which ones got placebo. This made their study "double-blind" and "placebo-controlled," which is the gold standard when it comes to research methods. The patients took their pills for 24 weeks, and underwent clinical exams and had blood drawn at the beginning, middle, and end of the 24-week study period. The clinical exams included a measurement of blood flow called flow-mediated dilation (FMD), which has been used as a way to determine how well blood vessels are functioning. The researchers compared changes in the lupus disease activity scores and in FMD between the two groups to see if the fish oil had any effect.
The Australian group also conducted their research as a double-blind, placebo-controlled study. One group of study participants had a diet of regular processed foods, while the other group ate the same foods enriched with omega-3 oils. The groups were asked to eat at least 8 portions of the study-supplied prepared foods daily, which would amount to a dose of 1 gram of omega-3 oils for those receiving the supplemented products. After six months, the researchers checked the numbers and functions of certain types of immune cells of the two groups, and the level of omega-3 type proteins in the blood.
What did the researchers find?
In the Northern Ireland study, lupus disease activity, especially in the skin and joints was significantly reduced in the patients who received the fish oil supplements, at both the 12-week and 24-week follow-up periods. No such reduction was seen in the lupus disease activity of the patients who got the placebo. There were also changes in the blood platelets of the patients who took the fish oil supplements, with an increase in proteins that are considered anti-inflammatory and a decrease in proteins that promote inflammation; these changes were not evident in the group that took placebo. The fish oil group showed an increase in FMD, which the researchers took as a sign that the omega-3 oils were helping the cells in the blood vessel walls to remain healthy.
At the end of their six-month study period, the Australian researchers found the total number of immune cells were significantly lower in the group that ate the fish-oil enriched foods as compared to the other group. This reduction was related to the level of omega-3 type proteins found in the platelets. The researchers also showed that there was a significant reduction in the numbers of NK (natural killer) cells in the blood of those who ate fish oil enriched foods. The primary role of NK cells it is to attack and kill foreign invaders; however, in autoimmune diseases, NK cells can cause adverse inflammation. The researchers also noted an increase in the production of a molecule called leukotriene (LT) among the supplemented-food group. Although LT usually promotes inflammation, there are some indications that increased LT production can also protect tissue from inflammatory damage.
What were the limitations of the studies?
With their blinding and placebo controls, both studies were well-designed to gather usable data. However, the study populations, being from Northern Ireland and from Australia, were in all likelihood made up primarily of Caucasians. Larger studies that include people of different genetic backgrounds will be needed before it would be clear that fish oil supplements have value for all lupus patients. As for the Australian study, although the findings are encouraging, it was conducted with only healthy volunteers, and it is fair to wonder whether the same outcomes would be seen with lupus patients.
What do the results mean for you?
Both of these studies support the possible value of adding fish, or fish oil supplements, to the diet. The Northern Ireland study suggested that the addition of even small doses of omega-3 oils led to improvement in lupus symptoms. And since other studies have shown that omega-3s are protective against heart disease, this may have special significance for lupus patients, who are at increased risk for hardening of the arteries and other cardiovascular disease that may develop slowly without any visible symptoms. Furthermore, both studies used low doses of omega-3 oils, either in pills or added to food, either of which could be easily accommodated without major changes in food preparation or menu planning. As with any dietary change, people with lupus who are thinking about taking omega-3 fish oil supplements should first discuss the plan with their doctor.