Current Atherosclerosis Reports

Harris, William

doi: 10.1007/s11883-010-0129-0pmid: 20697847

Geleijnse, Johanna; Goede, Janette; Brouwer, Ingeborg

doi: 10.1007/s11883-010-0137-0pmid: 20814766

There is a large body of scientific evidence that has been confirmed in randomized controlled trials indicating a cardioprotective effect for omega-3 fatty acids from fish. For alpha-linolenic acid (ALA), which is the omega-3 fatty acid from plants, the relation to cardiovascular health is less clear. We reviewed the recent literature on dietary ALA intake, ALA tissue concentrations, and cardiovascular health in humans. Short-term trials (6–12 weeks) in generally healthy participants mostly showed no or inconsistent effects of ALA intake (1.2–3.6 g/d) on blood lipids, low-density lipoprotein oxidation, lipoprotein(a), and apolipoproteins A-I and B. Studies of ALA in relation to inflammatory markers and glucose metabolism yielded conflicting results. With regard to clinical cardiovascular outcomes, there is observational evidence for a protective effect against nonfatal myocardial infarction. However, no protective associations were observed between ALA status and risk of heart failure, atrial fibrillation, and sudden death. Findings from long-term trials of ALA supplementation are awaited to answer the question whether food-based or higher doses of ALA could be important for cardiovascular health in cardiac patients and the general population.

Harris, Kristina; Kris-Etherton, Penny

doi: 10.1007/s11883-010-0136-1pmid: 20820954

Characterizing which types of carbohydrates, including whole grains, reduce the risk for coronary heart disease (CHD) is challenging. Whole grains are characterized as being high in resistant carbohydrates as compared with refined grains, meaning they typically are high in fiber, nutrients, and bound antioxidants. Whole grain intake consistently has been associated with improved cardiovascular disease outcomes, but also with healthy lifestyles, in large observational studies. Intervention studies that assess the effects of whole grains on biomarkers for CHD have mixed results. Due to the varying nutrient compositions of different whole grains, each could potentially affect CHD risk via different mechanisms. Whole grains high in viscous fiber (oats, barley) decrease serum low-density lipoprotein cholesterol and blood pressure and improve glucose and insulin responses. Grains high in insoluble fiber (wheat) moderately lower glucose and blood pressure but also have a prebiotic effect. Obesity is inversely related to whole grain intake, but intervention studies with whole grains have not produced weight loss. Visceral fat, however, may be affected favorably. Grain processing improves palatability and can have varying effects on nutrition (e.g., the process of milling and grinding flour increases glucose availability and decreases phytochemical content whereas thermal processing increases available antioxidants). Understanding how individual grains, in both natural and processed states, affect CHD risk can inform nutrition recommendations and policies and ultimately benefit public health.

Fernandez, Maria; Calle, Mariana

doi: 10.1007/s11883-010-0130-7pmid: 20683785

The perceived association between dietary cholesterol (DC) and risk for coronary heart disease (CHD) has resulted in recommendations of no more than 300 mg/d for healthy persons in the United States. These dietary recommendations proposed in the 1960s had little scientific evidence other than the known association between saturated fat and cholesterol and animal studies where cholesterol was fed in amounts far exceeding normal intakes. In contrast, European countries, Asian countries, and Canada do not have an upper limit for DC. Further, current epidemiologic data have clearly demonstrated that increasing concentrations of DC are not correlated with increased risk for CHD. Clinical studies have shown that even if DC may increase plasma low-density lipoprotein (LDL) cholesterol in certain individuals (hyper-responders), this is always accompanied by increases in high-density lipoprotein (HDL) cholesterol, so the LDL/HDL cholesterol ratio is maintained. More importantly, DC reduces circulating levels of small, dense LDL particles, a well-defined risk factor for CHD. This article presents recent evidence from human studies documenting the lack of effect of DC on CHD risk, suggesting that guidelines for DC should be revisited.

Siri-Tarino, Patty; Sun, Qi; Hu, Frank; Krauss, Ronald

doi: 10.1007/s11883-010-0131-6pmid: 20711693

Despite the well-established observation that substitution of saturated fats for carbohydrates or unsaturated fats increases low-density lipoprotein (LDL) cholesterol in humans and animal models, the relationship of saturated fat intake to risk for atherosclerotic cardiovascular disease in humans remains controversial. A critical question is what macronutrient should be used to replace saturated fat. Substituting polyunsaturated fat for saturated fat reduces LDL cholesterol and the total cholesterol to high-density lipoprotein cholesterol ratio. However, replacement of saturated fat by carbohydrates, particularly refined carbohydrates and added sugars, increases levels of triglyceride and small LDL particles and reduces high-density lipoprotein cholesterol, effects that are of particular concern in the context of the increased prevalence of obesity and insulin resistance. Epidemiologic studies and randomized clinical trials have provided consistent evidence that replacing saturated fat with polyunsaturated fat, but not carbohydrates, is beneficial for coronary heart disease. Therefore, dietary recommendations should emphasize substitution of polyunsaturated fat and minimally processed grains for saturated fat.

Degirolamo, Chiara; Rudel, Lawrence

doi: 10.1007/s11883-010-0133-4pmid: 20725810

Dietary interventions have been consistently proposed as a part of a comprehensive strategy to lower the incidence and severity of coronary heart disease (CHD), in the process providing long-term cardioprotection. Replacement of dietary saturated fatty acids (SFA) with higher intakes of monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) has been reported to be inversely associated with risk of CHD. The observed lower incidence of CHD among populations consuming a Mediterranean-type diet, mainly enriched in MUFA from olive oil, has long supported the belief that MUFA are an optimal substitution for SFA. However, both epidemiologic and interventional studies suggest that although substituting MUFA-rich foods for SFA-rich foods in the diet can potentially lower total plasma cholesterol concentrations, this substitution does not lower the extent of coronary artery atherosclerosis. In addition, although recent evidence suggests that the source of MUFA (animal fat vs vegetable oils) may differentially influence the correlation between MUFA intake and CHD mortality, animal studies suggest that neither source is cardioprotective.

Ros, Emilio; Tapsell, Linda; Sabaté, Joan

doi: 10.1007/s11883-010-0132-5pmid: 20820955

Nuts are nutrient-dense foods with complex matrices rich in unsaturated fatty acids and other bioactive compounds, such as L-arginine, fiber, minerals, tocopherols, phytosterols, and polyphenols. By virtue of their unique composition, nuts are likely to beneficially impact heart health. Epidemiologic studies have associated nut consumption with a reduced incidence of coronary heart disease in both genders and diabetes in women. Limited evidence also suggests beneficial effects on hypertension and inflammation. Interventional studies consistently show that nut intake has a cholesterol-lowering effect and there is emerging evidence of beneficial effects on oxidative stress, inflammation, and vascular reactivity. Blood pressure, visceral adiposity, and glycemic control also appear to be positively influenced by frequent nut consumption without evidence of undue weight gain. Berries are another plant food rich in bioactive phytochemicals, particularly flavonoids, for which there is increasing evidence of benefits on cardiometabolic risk that are linked to their potent antioxidant power.

Mas, Emilie; Mori, Trevor

doi: 10.1007/s11883-010-0134-3pmid: 20725809

Statins lower cholesterol by inhibiting 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, the rate-limiting enzyme in the biosynthesis of cholesterol. However, severe adverse events, including myalgias and rhabdomyolysis, have been reported with statin treatment. Different mechanisms have been proposed to explain statin-induced myopathy, including reduction of mevalonate pathway products, induction of apoptosis, mitochondrial dysfunction, and genetic predisposition. A decrease in coenzyme Q10 (CoQ), a product of the mevalonate pathway, could contribute to statin induced myopathy. This article reviews the clinical and biochemical features of statin-induced myopathy, the inter-relationship between statins and the concentration of CoQ in plasma and tissues, and whether there is a role for supplementation with CoQ to attenuate statin-induced myopathy.

Park, Kyong; Mozaffarian, Dariush

doi: 10.1007/s11883-010-0138-zpmid: 20820953

Fish consumption is associated with lower risk of cardiovascular disease. Some fish species also contain methylmercury, which may increase cardiovascular risk, as well as selenium, a trace element that could counter the effects of methylmercury or have beneficial effects itself. These potentially conflicting effects have created public confusion about the risks and benefits of fish consumption in adults. We examined the evidence for cardiovascular effects of fish consumption, particularly effects of marine omega-3 fatty acids, methylmercury, and selenium. Compelling evidence indicates that modest fish consumption substantially reduces cardiovascular risk, in particular cardiac mortality, related at least partly to benefits of omega-3 fatty acids. In contrast, observational studies and (for selenium) clinical trials demonstrate mixed and inconclusive results for cardiovascular effects of methylmercury and selenium. Net health benefits of overall fish consumption in adults are clear. Quantitative risk-benefit analyses of cardiovascular effects of consuming specific fish species, based on joint contents of fatty acids, methylmercury, and selenium, cannot currently be performed until the cardiovascular effects of methylmercury and selenium are established.

Fernandez, Stanley; Boden, William

doi: 10.1007/s11883-010-0135-2pmid: 20845088

There is a continuing debate regarding the most effective strategy for treating stable ischemic heart disease (SIHD). Conflicting data have emerged from several small, randomized controlled trials and meta-analyses regarding the benefits of early revascularization in SIHD. Two recent multicenter, randomized trials, the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial and the Bypass Angioplasty Revascularization Investigation in Type 2 Diabetes (BARI-2D) trial, compared two management strategies in SIHD—an initial conservative approach with optimal medical therapy (OMT) versus a strategy of early revascularization in combination with OMT. COURAGE randomized SIHD patients who were candidates for percutaneous coronary intervention (PCI) to either a strategy of early PCI in combination with OMT or OMT alone, whereas BARI-2D randomized diabetic patients with coronary artery disease to either early revascularization (PCI or coronary artery bypass surgery [CABG]) versus OMT. This review examines the principal findings of these trials, with discussion of their strengths, limitations, and applicability to the general population. The results support the hypothesis that in patients with SIHD, early revascularization with PCI in combination with OMT is not superior to OMT alone in reducing mortality and other major cardiovascular events. Subset analysis from BARI-2D did suggest that early CABG, although it did not reduce mortality, significantly reduced the rate of nonfatal myocardial infarction compared with an initial OMT approach. Based on these data, the majority of patients with SIHD should be managed initially with medical therapy, a strategy that is also the most cost effective. Revascularization can be considered for patients with severe or refractory symptoms despite a trial of medical therapy. For diabetic patients who have extensive coronary artery disease, early revascularization with CABG may be reasonable.