Triglycerides, Statins and Docosahexaenoic Acid (DHA)

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Triglycerides, Statins and Docosahexaenoic Acid (DHA)

http://www.vitasearch.com/CP/experts/BJMeyerAT04-28-07.htm

Barbara J. Meyer, Ph.D.

School of Health Sciences

University of Wollongong

Wollongong, NSW, 2522, Australia

+61 2 4221 3459 / +61 2 4221 3486 (FAX)

bmeyer@...

" Dose-Dependent Effects of Docosahexaenoic Acid Supplementation

On Blood Lipids in Statin-Treated Hyperlipidaemic Subjects, "

Lipids, 2007; 42(2): 109-15. 45177 (6/2007)

Kirk Hamilton: Can you please share with us your educational

background and current position?

Barbara J. Meyer: I have a BSc (Hons) degree and a Ph.D. from the

Department of Medicine, Monash University, Clayton, , Australia.

I am currently an Associate Professor, School of Health Sciences,

University of Wollongong, NSW Australia.

KH: What got you interested in studying the role of docosahexaenoic

acid (DHA) and lipid lowering in subjects on statins with elevated

triglycerides?

BJM: We have had a long standing interest in the area of omega-3

polyunsaturated fatty acids and cardiovascular disease. In the past,

studies had been conducted in people with elevated plasma lipid levels,

treated by statins, but these trials used EPA rich fish oil capsules. As

DHA may be important for heart health (reducing cardiac arrhythmias) and

had also been shown to lower plasma triglycerides in people not on

statin therapy, we wanted to know if combined statin therapy with DHA

could improve their plasma lipid status. Furthermore, people on statin

therapy, still had persistent hypertriglyceridaemia and hence we thought

that DHA may benefit such people. We also wanted to know the required

dose for this specific population, hence the dose response of DHA.

KH: Is it the DHA or EPA component of fish oil that is lipid

modulating? Or, are they both equal in their lipid altering capabilities?

BJM: Both EPA and DHA are effective in lowering plasma triglycerides in

hyperlipidaemic people already on statin therapy.

KH: Where did you come up with a dose of 4 and 8 gms/d of tuna oil?

How much DHA was in those doses? How were they taken? With meals or away

from meals? In a single dose or divided dose?

BJM: We wanted to conduct a dose response as previous research had

focused on one dose only. We wanted to determine if a lower dose still

had triglyceride lowering effects compared to higher doses. 4g DHA-rich

tuna oil per day provided a little over 1g of DHA per day (1.08g) while

8g DHA-rich tuna oil per day provided a little over 2g per day (2.16g).

The reason why we chose 1g and 2g DHA is that 1g DHA (or EPA) is enough

to cause a hypotriglyceridaemic effect in people with

hypertriglyceridaemia who are not on lipid lowering medications such as

a statin. So we wanted to see if 1g DHA was enough to reduce plasma

triglycerides in people already on statin treatment. The capsules were

taken either in the morning or the evening or throughout the day. It was

left up to the study participant to determine what suited them and their

lifestyle. We did advise them to take these capsules prior to a meal,

whether it be breakfast, lunch and/or dinner, but it was not mandatory

that they did so. It was up to the study volunteers as to whether they

consumed the capsules in one go or throughout the day, as it did not

matter, just as long as they consumed the required amount per day.

KH: Can you tell us about your study and the basic results?

BJM: The study was a double-blinded, random placebo controlled trial

and consisted of 45 hyperlipidaemic subjects who were already on stable

statin treatment for at least 3 months and who had persistent

hypertriglyceridaemia. The study subjects were randomly assigned to one

of three groups: placebo (olive oil), low DHA (1g DHA per day) or high

DHA (2g DHA per day), to determine a dose response to DHA. Plasma

samples were collected after 3 and 6 months of intervention in 40

subjects who completed the trial. Plasma triglycerides were reduced by

27% by 2g DHA dose whereas the 1g DHA dose was not effective. This

reduction in plasma triglycerides was achieved within 3 months and

sustained for 6 months. Even though plasma total cholesterol was already

well controlled by the statin treatment, there was a further dose

dependent reduction in cholesterol with DHA supplementation and this was

reflected primarily in the reduction in VLDL-cholesterol. These results

demonstrate that 2g DHA-rich tuna oil can lower plasma triglycerides and

total cholesterol in people already on statin therapy, while the 1g dose

was not high enough. These lipid reductions were achieved within 3

months of DHA supplementation and sustained by 6 months. Hence fish oil

in addition to statin therapy may be preferable to drug combinations for

the treatment of combined hyperlipidaemia.

KH: Where there any side effects with the DHA supplementation? How

was the patient compliance?

BJM: There were no reports of any side effects in our study. Patient

compliance was excellent as shown by their respective changes in

erythrocyte fatty acid (DHA) levels.

KH: What is DHA’s most significant lipid modulating characteristic?

BJM: DHA is able to lower plasma triglycerides in people with

hypertriglyceridaemia and in people already on statin therapy. Some

studies have also shown this hypotriglyceridaemic effect in people with

normal plasma triglyceride levels (Weber, P and Raederstorff, D.

Nutrition Metabolism & Cardiovascular Diseases 2000;10(1):28-37). Some

studies also show a small, but significant rise in HDL-cholesterol

levels ( TR et al. Metabolism 2004:53(6);749-754).

KH: Who is a candidate for DHA therapy? What type of cardiovascular

disease patient?

BJM: In my view, the general Australian population is not consuming

enough DHA and any increase in consumption of foods containing DHA would

be good for all Australians (Meyer BJ et al. Lipids 2003:38;391-398;

Howe PRC et al. Nutrition. 2006 Jan;22(1):47-53). The Japanese consume

approximately 1.6g per day of omega-3 polyunsaturated fatty acids

(PUFA), whilst Australians are only consuming 0.25g per day.

KH: Do statins have any adverse effects on fatty acid metabolism,

especially of the omega-3 family?

BJM: As far as I am aware, statins do not have any adverse effects on

fatty acid metabolism or specifically on omega-3 fatty acid metabolism.

KH: Do you have any other further comments you would like to share?

BJM: Taking fish oils (either EPA-rich or DHA-rich, approximately 2g

per day) in combination with a statin may be preferable to combinations

of drugs currently prescribed for mixed hyperlipidaemia as there are

fewer side effects associated with omega-3 PUFA supplementation.

--

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