Brenda Garrett

Omega-3 Fatty Acid Blood Levels Clinical Significance and Controversy

The relationship of fish and dietary omega-3 fatty acids and cardiovascular disease (CVD) has been investigated in numerous studies and comprehensive reviews and recommendations exist, but guidance on blood concentrations is missing.1–4 Some prospective fish oil treatment investigations report a significant reduction in CVD events but others do not.5–7 A recent meta-analysis did not find a statistically significant relationship between omega-3 consumption and CVD mortality, but it failed to take into account the implications of variability in individual blood levels of omega-3 fatty acids.8 Blood levels of omega-3 fatty acids can be influenced by dietary intake of omega-3 fatty acids and intake with oral supplements. The Multiple Risk Factor Intervention Trial reported in 1995 that serum omega-3 fatty acids blood levels were inversely correlated with coronary heart disease (CHD).9 An association of dietary sources of nonfried fish and blood levels of eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) were reported in the Atherosclerosis Risk In Communities (ARIC) investigation and the Multi-Ethnic Study of Atherosclerosis (MESA) investigations.10,11 Blood levels of dietary omega-3 fatty acids can vary based on geography and diet habits. For example, Japanese living in Japan have higher blood omega-3 fatty acid levels than whites living in Pennsylvania and Japanese Americans living in Honolulu. The lower 5th percentile of blood omega-3 fatty acids in the Japanese living in Japan is higher than the mean levels in whites and Japanese Americans even though total fat is comparable.12 The purpose of this review is to explore insight derived from clinical investigations reporting blood or plasma levels of omega-3 fatty acids and the relationship to CHD risk that may shed light on the fish oil controversy. A National Library of Medicine PubMed search was conducted with the key words omega-3, …

Omega-3 Fatty Acid Blood Levels Clinical Significance Update

ABSTRACTThe potential benefit of fish oil (omega-3 fatty acids) consumption to reduce cardiovascular disease (CVD) risk remains controversial. Some investigations report reduced CVD risk associated with fish or fish oil consumption while others report no benefit. This controversy is in part resolved when consideration is given to omega-3 blood levels in relation to CVD risk as well as blood levels achieved in clinical trials of omega-3 supplementation and CVD benefit. There is a wide variation in omega-3 blood levels achieved between individuals in response to a given dose of an omega-3 supplement. Many studies tested a daily dose of 1 gram omega-3 supplementation. The individual variation in blood omega-3 levels achieved in response to a fixed daily dose helps to explain why some individuals may obtain CVD protection benefit while others do not due to failure to achieve a therapeutic threshold. Recent development of a population range in a United States population helps to provide clinical guidance since population omega-3 blood level ranges may vary due to environmental and genetic reasons. Omega-3 supplementation may also be of benefit in reducing the adverse impact of air pollution on CVD risk.

Genetic Testing for Early Detection of Individuals at Risk of Coronary Heart Disease and Monitoring Response to Therapy: Challenges and Promises

Coronary heart disease (CHD) often presents suddenly with little warning. Traditional risk factors are inadequate to identify the asymptomatic high-risk individuals. Early identification of patients with subclinical coronary artery disease using noninvasive imaging modalities would allow the early adoption of aggressive preventative interventions. Currently, it is impractical to screen the entire population with noninvasive coronary imaging tools. The use of relatively simple and inexpensive genetic markers of increased CHD risk can identify a population subgroup in which benefit of atherosclerotic imaging modalities would be increased despite nominal cost and radiation exposure. Additionally, genetic markers are fixed and need only be measured once in a patient’s lifetime, can help guide therapy selection, and may be of utility in family counseling.

Firefighters, heart disease, and aspects of insulin resistance: the FEMA Firefighter Heart Disease Prevention study.

Objective: To determine the association of cardiovascular risk markers with noninvasive imaging of atherosclerosis in firefighters. Methods: Cross-sectional investigation of subclinical atherosclerosis with metabolic, work related, and life-style variables in 296 professional firefighters. Results: Calcified coronary atherosclerosis (CAC), carotid arterial intimal thickness (CIMT), and electrocardiogram provided independent CVD assessments. Homeostatic Model Assessment (HOMA) concentrations were related to heart-rate-corrected QT (QTc) (slope ± SE: 2.16 ± 65, P = 0.001), average common CIMT (0.019 ± 0.005 mm, P = 0.0005), and total CAC lesions (0.269 ± 0.116, P = 0.02). Stepwise linear regression selected fasting insulin as the strongest predictor for QTc, HOMA as the strongest predictor of average CIMT, and fasting glucose as the strongest predictor of total coronary lesion number and score. Conclusion: Firemens HOMA and fasting insulin and glucose concentrations were significantly associated with three measures of CVD. Aspects of insulin resistance are related to CVD risk among firefighters.