Higher levels of omega-3 fatty acids may decrease the risk of dementia, improve survival in older people, and protect against the damage from pollution.
Researchers from Norway and France reported the results of their prospective studies in the American Journal of Clinical Nutrition, which showed that higher levels of omega-3 fatty acids, particularly EPA (eicosapentaenoic acid), may benefit mortality rates and cognitive function.
In the Norwegian study, Morten Lindberg from the Norwegian University of Science and Technology in Trondheim and co-workers recruited 254 frail, elderly patients and measured dietary intakes of omega-3 fatty acids using plasma phospholipid concentrations of EPA.
Over the course of three years of follow-up, the researchers found that people with the lowest average plasma phospholipid EPA concentrations were about 40 per cent more likely to die, compared to people with higher levels.
In the French study, Cecilia Samieri from Inserm (U897) in Bordeaux and co-workers followed the 1214 non-demented participants in the Three-City Study from Bordeaux. Over the course of four years, 65 of the participants developed dementia, state the researchers.
Comparing blood levels of EPA, DHA (docosahexaenoic acid), and total omega-3 levels, the researchers found that only higher blood levels of EPA were associated with a 31 per cent lower incidence of dementia.
A third study published in the same journal reported however that supplementation of older people with high dose omega-3 did not affect mood or well-being.
The third study, led by Ondine van de Rest from Wageningen University, was a 26-week double-blind, placebo-controlled trial with 302 volunteers. The 65-year old subjects were randomly assigned to consume high dose omega-3 (1800 mg/d EPA plus DHA), lower dose omega-3 (400 mg/d EPA plus DHA), or placebo.
While plasma concentrations of the fatty acids did increase according to the omega-3 dose, this was not associated with any significant change in the mental well-being of the volunteers in any of the groups.
Putting the studies into context, William Harris from Sanford Research at the University of South Dakota commented in an accompanying editorial: “Together, these findings suggest that dietary habits that include higher versus lower intakes of long-chain omega-3 fatty acids may bring certain health benefits that short-term supplementation cannot provide.”
Source: American Journal of Clinical Nutrition, Vol. 88, pages 706-713, 714-721, 722-729.
Protection against smog damage
An international team of researchers reported that fish oil supplements may protect the heart against certain damaging effects of air pollution.
Writing in the journal Environmental Health Perspectives, lead author Isabelle Romieu from the Mexican National Institute of Public Health reported that the supplements may counter the detrimental affects to the heart caused by exposure to high levels of particulates from vehicle exhaust and industrial emissions.
The supplements were also found to increase the activity of certain protective antioxidant enzymes in the body, such as copper/zinc (Cu/Zn) superoxide dismutase (SOD), manganese SOD, and glutathione peroxidase (GSH-Px). Air pollution is reported to inhibit the action of the enzymes.
While the researchers studied the effects of fish oil and soy oil supplements, the greater protective effects were observed following fish oil supplementation, which the researchers said could be due to the different fatty acid profile of the two supplements: fish oil contains EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), while soy oil contains ALA (alpha-linolenic acid).
“This is the first study to evaluate the impact of supplementation with omega-3 polyunsaturated fatty acids on biomarkers of response to oxidative stimuli related to air pollution exposure among individuals in a non-controlled environment,” wrote Romieu
Source: Environmental Health Perspectives, Vol. 116, pp. 1237-1242