Death Risk and Use of Fish Oil Supplements
Pocobelli ,G. et al., Am. J. Clinical Nutr., 91: in press , 2010
Dept. of Epidemiology, School of Public Health, Univ.of Washington, Seattle, WA, USA
Since nutritional supplementation in capsule or tablet form is very common in older US adults, the present study was conducted to determine if the use of certain supplements may be associated with total mortality. One of the many supplements which was monitored in this study was fish oil containing DHA/EPA omega-3 fatty acids. A total of 77,719 participants (aged 50-76 years) from Washington State were followed for an average of 5 years. A ‘low-use’ category of supplementation was defined as using less than 4 days/week for less than 3 years during the 10 year period before baseline while ‘high-use’ was defined as a frequency of use for at least 4 or more times/week over a period of 3 or more years. After adjusting the results for numerous confounding factors including gender, age, smoking, physical activity, other factors, the overall death frequency (per 1000 person-years) was 17 % lower in the ‘high-use” category as compared to the non-users while the death frequency in the ‘low-use’ category was almost identical to the non-users.
The authors concluded that there was a ‘suggestion of a decreased risk for total mortality associated with a high intake of fish-oil supplements’ but the differences did not reach statistical significance.
Dr. Holub's Comments:
Since there has been published evidence from randomized controlled trials previously that fish oil supplementation was associated with a reduced risk for mortality from cardiovascular disease (Leon et al., Brit. Med. J., 337: a2932(2009)), it would have been particular interesting to determine if the different causes of mortality were related to the use of supplementation. Also, no information was available on the amount of DHA and/or EPA in the supplements as taken. It is well recognized that the amounts of DHA/EPA vary markedly across different brands and capsule sizes.