Highlights from ISSFAL 2006
The International Society for the Study of Fatty Acids and Lipids (ISSFAL) held its biennial meeting in Cairns, Australia, July 23-28. Over 400 scientists, health professionals, educators and others interested in fatty acids and lipids attended. Highlights included:
Cardiovascular Health
- Lowering blood cholesterol may not reduce cardiac mortality. Two presenters analyzed published data from the U.S. and Japan, concluding that cholesterol-lowering may have no effect on mortality in primary prevention.
- Heart muscle concentrates DHA, whereas atherosclerotic lesions accumulate EPA. EPA-fed animals had fewer lesions, smaller lipid deposits, less macrophage infiltration and thicker fibrous caps on lesions, all of which were associated with less severe and more stable atherosclerosis. Carotid plaque also accumulates more EPA than DHA.
- Carriers of the apoE genotype respond to EPA and DHA with reduced triglycerides, but those having the apoE4 allele had less triglyceride lowering and higher LDL levels compared with those having the apoE3 allele. This suggests that carriers of the apoE4 allele may be less responsive to some of the cardiac effects of long-chain omega-3 fatty acids (n-3 LC-PUFAs).
Maternal and Infant Health
- Population-based evidence suggests that breast milk trans fatty acids are inversely related to n-3 LC-PUFA concentrations and may interfere with their availability to the infant. Maternal smoking also appears to adversely affect n-3 PUFA metabolism in fetal development.
- More sensitive measures of cognitive development in infants and toddlers than widely used global assessments are needed. Assessments such as distractibility can be measured before age 3, but more complex executive functions such as card sorting on two dimensions (e.g., color and object) cannot be reliably assessed until the frontal cortex has accumulated sufficient DHA.
- Nine-month old infants of mothers supplemented with 200 mg of DHA from 24 weeks of gestation until delivery had significantly improved problem-solving compared with infants of placebo-supplemented mothers..
- Children with attention-deficit hyperactivity disorder not taking medication were supplemented with high EPA-fish oil for 15 weeks. There were significant improvements in scores for inattention, hyperactivity and impulsivity in the fish oil, but not the placebo-supplemented group..
Brain Composition and Function
- Measures of the metabolic loss of AA and DHA in rat brain, which is equivalent to the daily need for these PUFAs, suggest a requirement for AA and DHA of about 4:1. Deprivation of n-3 LC-PUFAs did not increase the conversion of ALA to DHA in rat brain, but did so in the liver. Animals deficient in n-3 LC-PUFAs increased the half-life and reduced the loss of DHA compared with control animals. Deficiency of n-3 LC-PUFAs increased phospholipase A2 activity, suggesting an upregulation of AA metabolism. Some mental disorders are treated with drugs that alter AA metabolism in ways which mimic the effects of n-3 LC-PUFA deficiency.
- n-3 LC-PUFA deficiency reduces phosphatidylserine in neuronal membranes, whereas provision of DHA increases its synthesis from phosphatidylcholine and phosphatidylethanolamine. Reduced phosphatidylserine diminishes cell signaling at the membrane, thereby compromising neuronal cell survival. DHA also prevents neuronal cell apoptosis and promotes neurite growth.
- Current levels of DHA supplementation of infant formula may be inadequate. Term baboon infants fed formula supplemented with 3 times the DHA level (0.96% by wt) added to US infant formula had significantly increased DHA concentration in the precentral gyrus compared with those fed the approved amount (0.32% by wt).
Clinical Conditions
- An observational study examined the relationship between postpartum depression, n-3 PUFA status at 12 weeks gestation and behavioral problems in the offspring at 5-7 years of age. Children’s behavior scores were associated with maternal depression scores and life-stress events, but not maternal n-3 PUFA status. Low maternal n-3 status was related to more behavioral problems in boys, but not in girls.
- n-3 PUFA-deficient diets were associated with increased intraocular pressure in aging, the underlying cause of glaucoma. Animals fed sufficient n-3 PUFAs had no increase in intraocular pressure as they aged.
- Transgenic mice (fat-1 mice) able to convert n-6 to n-3 LC-PUFAs provide a model for studying alterations in the concentrations of these fatty acid families. Fat-1 mice have significantly reduced development and growth of melanoma tumors, increased production of anti-inflammatory resolvins, reduced colon cancer, increased mammary gland n-3 PUFAs and enhanced anti-inflammatory activity compared with wild-type mice.
SOURCE: PUFA Newsletter
Ω