Nutrition

n-3 fatty acids and cardiovascular disease. Breslow JL. Am J Clin Nutr. 2006 Jun;83(6 Suppl):1477S-1482S. Review. PMID: 16841857 The results of prospective cohort studies indicate that consuming fish or fish oil containing the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is associated with decreased cardiovascular death, whereas consumption of the vegetable oil-derived n-3 fatty acid {alpha}-linolenic acid is not as effective. Randomized control trials (RCTs) in the context of secondary prevention also indicate that the consumption of EPA plus DHA is protective at doses 3 g/d, EPA plus DHA can improve cardiovascular disease risk factors, including decreasing plasma triacylglycerols, blood pressure, platelet aggregation, and inflammation, while improving vascular reactivity. Mainly on the basis of the results of RCTs, the American Heart Association recommends that everyone eat oily fish twice per week and that those with coronary heart disease eat 1 g/d of EPA plus DHA from oily fish or supplements. Directions for future research include 1) RCTs to confirm the initial trials showing that EPA plus DHA decreases cardiovascular death and additional studies to determine whether this effect is due to EPA, DHA, or the combination; the dosage of the effective components; and whether the mechanism of action in humans is prevention of fatal arrhythmias. 2) Clinical studies to determine whether the reduction in cardiovascular disease risk factors is due to EPA, DHA, or the combination and the dosage of the effective components. 3) Clinical studies to determine whether vegetable oil-derived {alpha}-linolenic acid added to a diet enriched in n-6 fatty acids can effectively substitute for fish oil-derived EPA plus DHA.

Fish intake and risk of incident atrial fibrillation. Mozaffarian D, Psaty BM, Rimm EB, Lemaitre RN, Burke GL, Lyles MF, Lefkowitz D, Siscovick DS. Circulation. 2004 Jul 27;110(4):368-73. Epub 2004 Jul 19. PMID: 15262826 doi: 10.1161/01.CIR.0000138154.00779.A5 Conclusions- Among elderly adults, consumption of tuna or other broiled or baked fish, but not fried fish or fish sandwiches, is associated with lower incidence of AF. Fish intake may influence risk of this common cardiac arrhythmia.

Cardiac benefits of fish consumption may depend on the type of fish meal consumed: the Cardiovascular Health Study. Mozaffarian D, Lemaitre RN, Kuller LH, Burke GL, Tracy RP, Siscovick DS; Cardiovascular Health Study. Circulation. 2003 Mar 18;107(10):1372-7. PMID: 12642356 doi: 10.1161/01.CIR.0000055315.79177.16 Conclusions- Among adults aged >=65 years, modest consumption of tuna or other broiled or baked fish, but not fried fish or fish sandwiches, is associated with lower risk of IHD death, especially arrhythmic IHD death. Cardiac benefits of fish consumption may vary depending on the type of fish meal consumed.

Effect of fish oil on heart rate in humans: a meta-analysis of randomized controlled trials. Mozaffarian D, Geelen A, Brouwer IA, Geleijnse JM, Zock PL, Katan MB. Circulation. 2005 Sep 27;112(13):1945-52. Epub 2005 Sep 19. PMID: 16172267 doi: 10.1161/CIRCULATIONAHA.105.556886 Conclusions- In randomized controlled trials in humans, fish oil reduces HR, particularly in those with higher baseline HR or longer treatment duration. These findings provide firm evidence that fish oil consumption directly or indirectly affects cardiac electrophysiology in humans. Potential mechanisms such as effects on the sinus node, ventricular efficiency, or autonomic function deserve further investigation.

n-3 Fatty acids and cardiovascular disease: mechanisms underlying beneficial effects. Jung UJ, Torrejon C, Tighe AP, Deckelbaum RJ. Am J Clin Nutr. 2008 Jun;87(6):2003S-9S. PMID: 18541602 Dietary n-3 fatty acids, particularly eicosapentaenoic acid and docosahexaenoic acid, are important nutrients through the life cycle. Evidence from observational, clinical, animal, and in vitro studies indicates a beneficial role of n-3 fatty acids in the prevention and management of cardiovascular disease. Although the precise mechanisms are still unclear, clinical and preclinical studies indicate that the cardioprotective effects of n-3 fatty acids may be attributed to a number of distinct biological effects on lipid and lipoprotein metabolism, blood pressure, platelet function, arterial cholesterol delivery, vascular function, and inflammatory responses. Substantial evidence supports n-3 fatty acids as a practical, therapeutic adjuvant for promoting cardiovascular health and preventing and treating disease. n-3 Fatty acids modulate a number of important physiologic responses that can contribute to their cardioprotective effects. The multiple and complex mechanisms through which DHA and EPA exert their action appear to be distinct but also complementary. However, more studies are needed to quantify their protective effects and to define exact mechanisms of action.

n-3 fatty acids and gene expression. Deckelbaum RJ, Worgall TS, Seo T. Am J Clin Nutr. 2006 Jun;83(6 Suppl):1520S-1525S. Review. Erratum in: Am J Clin Nutr. 2006 Oct;84(4):949. PMID: 16841862 Accumulating evidence in both humans and animal models clearly indicates that a group of very-long-chain polyunsaturated fatty acids, the n-3 fatty acids (or omega-3), have distinct and important bioactive properties compared with other groups of fatty acids. n-3 Fatty acids are known to reduce many risk factors associated with several diseases, such as cardiovascular diseases, diabetes, and cancer. The mechanisms whereby n-3 fatty acids affect gene expression are complex and involve multiple processes. As examples, n-3 fatty acids regulate 2 groups of transcription factors, such as sterol-regulatory-element binding proteins and peroxisome proliferator-activated receptors, that are critical for modulating the expression of genes controlling both systemic and tissue-specific lipid homeostasis. Modulation of specific genes by n-3 fatty acids and cross-talk between these genes are responsible for many effects of n-3 fatty acids.

Quantitative analysis of the benefits and risks of consuming farmed and wild salmon. Foran JA, Good DH, Carpenter DO, Hamilton MC, Knuth BA, Schwager SJ. J Nutr. 2005 Nov;135(11):2639-43. PMID: 16251623 Contaminants in farmed Atlantic and wild Pacific salmon raise important questions about the competing health benefits and risks of fish consumption. A benefit-risk analysis was conducted to compare quantitatively the cancer and noncancer risks of exposure to organic contaminants in salmon with the (n-3) fatty acid-associated health benefits of salmon consumption. Recommended levels of (n-3) fatty acid intake, as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), may be achieved by consuming farmed or wild salmon while maintaining an acceptable level of noncarcinogenic risk. However, the recommended level of EPA+DHA intake cannot be achieved solely from farmed or wild salmon while maintaining an acceptable level of carcinogenic risk. Although the benefit-risk ratio for carcinogens and noncarcinogens is significantly greater for wild Pacific salmon than for farmed Atlantic salmon as a group, the ratio for some subgroups of farmed salmon is on par with the ratio for wild salmon. This analysis suggests that risk of exposure to contaminants in farmed and wild salmon is partially offset by the fatty acid-associated health benefits. However, young children, women of child-bearing age, pregnant women, and nursing mothers not at significant risk for sudden cardiac death associated with CHD but concerned with health impairments such as reduction in IQ and other cognitive and behavioral effects, can minimize contaminant exposure by choosing the least contaminated wild salmon or by selecting other sources of (n-3) fatty acids.

(NaturalNews) After menopause, women are at increased risk for the bone-weakening condition known as osteoporosis. And women who are diabetic have an even greater chance of developing the disorder. But now comes research from Egyptian scientists that suggests flaxseed oil could be a natural way to protect bone health. The new study, recently published in the International Journal of Food Safety, Nutrition and Public Health, concludes that flaxseed oil has a beneficial effect on bone mineral density and reduces markers associated with osteoporosis. Bottom line: supplementing the diet with flaxseed oil could markedly reduce the risk of osteoporosis and be of particular benefit to post-menopausal and diabetic women. Scientist Mer Harvi and colleagues at the National Research Center in Cairo, Egypt, investigated the impact of diabetes on bone health. Then in laboratory studies they evaluated how flaxseed oil added to the diet could delay the onset of osteoporosis.

Fish intake is associated with a reduced progression of coronary artery atherosclerosis in postmenopausal women with coronary artery disease. Erkkilä AT, Lichtenstein AH, Mozaffarian D, Herrington DM. Am J Clin Nutr. 2004 Sep;80(3):626-32. PMID: 15321802 Conclusions: Consumption of fish is associated with a significantly reduced progression of coronary artery atherosclerosis in women with coronary artery disease.

The effect of select nutrients on serum high-density lipoprotein cholesterol and apolipoprotein A-I levels. Mooradian AD, Haas MJ, Wong NC. Endocr Rev. 2006 Feb;27(1):2-16. Epub 2005 Oct 21. Review. PMID: 16243964 One of the factors contributing to the increased risk of developing premature atherosclerosis is low plasma concentrations of high-density lipoprotein (HDL) cholesterol (HDLc). Multiple potential mechanisms account for the cardioprotective effects of HDL and its main protein apolipoprotein A-I (apo A-I). The low plasma concentrations of HDL could be the result of increased fractional clearance and reduced expression of apo A-I. To this end, nutrients play an important role in modulating the fractional clearance rate, as well as the rate of apo A-I gene expression. Because medical nutrition therapy constitutes the cornerstone of management of dyslipidemias, it is essential to understand the mechanisms underlying the changes in HDL level in response to alterations in dietary intake. In this review, we will discuss the effect of select nutrients on serum HDLc and apo A-I levels. Specifically, we will review the literature on the effect of carbohydrates, fatty acids, and ketones, as well as some of the nutrient-related metabolites, such as glucosamine and the prostanoids, on apo A-I gene expression. Because there are multiple mechanisms involved in the regulation of serum HDLc levels, changes in gene transcription do not necessarily correlate with clinical observations on serum levels of HDLc.

Fish consumption and the 30-year risk of fatal myocardial infarction. Daviglus ML, Stamler J, Orencia AJ, Dyer AR, Liu K, Greenland P, Walsh MK, Morris D, Shekelle RB. N Engl J Med. 1997 Apr 10;336(15):1046-53. PMID: 9091800 Conclusions These data show an inverse association between fish consumption and death from coronary heart disease, especially nonsudden death from myocardial infarction.

Mercury, fish oils, and the risk of myocardial infarction. Guallar E, Sanz-Gallardo MI, van't Veer P, Bode P, Aro A, Gómez-Aracena J, Kark JD, Riemersma RA, Martín-Moreno JM, Kok FJ; Heavy Metals and Myocardial Infarction Study Group. N Engl J Med. 2002 Nov 28;347(22):1747-54. PMID: 12456850 Conclusions The toenail mercury level was directly associated with the risk of myocardial infarction, and the adipose-tissue DHA level was inversely associated with the risk. High mercury content may diminish the cardioprotective effect of fish intake.

Mercury and the risk of coronary heart disease in men. Yoshizawa K, Rimm EB, Morris JS, Spate VL, Hsieh CC, Spiegelman D, Stampfer MJ, Willett WC. N Engl J Med. 2002 Nov 28;347(22):1755-60. PMID: 12456851 Conclusions Our findings do not support an association between total mercury exposure and the risk of coronary heart disease, but a weak relation cannot be ruled out.

Antioxidant Supplementation in Atherosclerosis Prevention (ASAP) study: a randomized trial of the effect of vitamins E and C on 3-year progression of carotid atherosclerosis. Salonen JT, Nyyssönen K, Salonen R, Lakka HM, Kaikkonen J, Porkkala-Sarataho E, Voutilainen S, Lakka TA, Rissanen T, Leskinen L, Tuomainen TP, Valkonen VP, Ristonmaa U, Poulsen HE. J Intern Med. 2000 Nov;248(5):377-86. PMID: 11123502 DOI: 10.1046/j.1365-2796.2000.00752.x Conclusions. Our study shows that a combined supplementation with reasonable doses of both vitamin E and slow-release vitamin C can retard the progression of common carotid atherosclerosis in men. This may imply benefits with regard to other atherosclerosis-based events.

Six-year effect of combined vitamin C and E supplementation on atherosclerotic progression: the Antioxidant Supplementation in Atherosclerosis Prevention (ASAP) Study. Salonen RM, Nyyssönen K, Kaikkonen J, Porkkala-Sarataho E, Voutilainen S, Rissanen TH, Tuomainen TP, Valkonen VP, Ristonmaa U, Lakka HM, Vanharanta M, Salonen JT, Poulsen HE; Antioxidant Supplementation in Atherosclerosis Prevention Study. Circulation. 2003 Feb 25;107(7):947-53. PMID: 12600905 doi: 10.1161/01.CIR.0000050626.25057.51 Conclusions- These data replicate our 3-year findings confirming that the supplementation with combination of vitamin E and slow-release vitamin C slows down atherosclerotic progression in hypercholesterolemic persons.

Dark chocolate consumption increases HDL cholesterol concentration and chocolate fatty acids may inhibit lipid peroxidation in healthy humans. Mursu J, Voutilainen S, Nurmi T, Rissanen TH, Virtanen JK, Kaikkonen J, Nyyssönen K, Salonen JT. Free Radic Biol Med. 2004 Nov 1;37(9):1351-9. PMID: 15454274 doi:10.1016/j.freeradbiomed.2004.06.002 Cocoa polyphenols may increase the concentration of HDL cholesterol, whereas chocolate fatty acids may modify the fatty acid composition of LDL and make it more resistant to oxidative damage.

Mercury, fish oils, and risk of acute coronary events and cardiovascular disease, coronary heart disease, and all-cause mortality in men in eastern Finland. Virtanen JK, Voutilainen S, Rissanen TH, Mursu J, Tuomainen TP, Korhonen MJ, Valkonen VP, Seppänen K, Laukkanen JA, Salonen JT. Arterioscler Thromb Vasc Biol. 2005 Jan;25(1):228-33. Epub 2004 Nov 11. PMID: 15539625 doi: 10.1161/01.ATV.0000150040.20950.61 Conclusions- High content of mercury in hair may be a risk factor for acute coronary events and CVD, CHD, and all-cause mortality in middle-aged eastern Finnish men. Mercury may also attenuate the protective effects of fish on cardiovascular health. Mercury may increase the risk of cardiovascular diseases. In this study, high mercury content in hair increased the risk of cardiovascular morbidity and mortality in middle-aged Finnish men and attenuated the beneficial effects of fish oils on cardiovascular health. Regular consumption of fish with high mercury content should be avoided.

Glycemic index, glycemic load, and the risk of acute myocardial infarction in Finnish men: The Kuopio Ischaemic Heart Disease Risk Factor Study. Mursu J, Virtanen JK, Rissanen TH, Tuomainen TP, Nykänen I, Laukkanen JA, Kortelainen R, Voutilainen S. Nutr Metab Cardiovasc Dis. 2009 Oct 14. [Epub ahead of print] PMID: 19836217 doi:10.1016/j.numecd.2009.08.001 Conclusions Our results suggest that both high dietary GI and GL are associated with increased risk of AMI among overweight and GL possibly among less physically active men.

High dietary methionine intake increases the risk of acute coronary events in middle-aged men. Virtanen JK, Voutilainen S, Rissanen TH, Happonen P, Mursu J, Laukkanen JA, Poulsen H, Lakka TA, Salonen JT. Nutr Metab Cardiovasc Dis. 2006 Mar;16(2):113-20. Epub 2005 Nov 2. PMID: 16487911 doi:10.1016/j.numecd.2005.05.005 Conclusions The main finding of this study is that long-term, moderately high dietary methionine intake may increase the risk of acute coronary events in middle-aged Finnish men free of prior CHD. More prospective research is needed to confirm the role of dietary methionine in the development of CVD, and whether its effects are independent of homocysteine.

Fish consumption and risk of subclinical brain abnormalities on MRI in older adults. Virtanen JK, Siscovick DS, Longstreth WT Jr, Kuller LH, Mozaffarian D. Neurology. 2008 Aug 5;71(6):439-46. PMID: 18678827 doi: 10.1212/01.wnl.0000324414.12665.b0 Conclusions: Among older adults, modest consumption of tuna/other fish, but not fried fish, was associated with lower prevalence of subclinical infarcts and white matter abnormalities on MRI examinations. Our results add to prior evidence that suggest that dietary intake of fish with higher eicosapentaenoic acid and docosahexaenoic acid content, and not fried fish intake, may have clinically important health benefits