Nutrition

AJCN July, 2006

[Why Am. Heart Association recommends LOTS of fish oil] n–3 Fatty acids and cardiovascular disease: navigating toward recommendations Am J Clin Nutr 2006 84: 1-2 ” Many studies in the scientific literature have shown a correlation between n–3 fatty acids (FAs) and cardiovascular disease (CVD), but translating the findings of these studies into intake recommendations for individuals and populations requires careful navigation. Two n–3 FAs, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are increasingly being recognized as important modulators of multiple biological pathways that affect health and disease (1-7). The essential n–3 FA precursor of EPA and DHA, -linolenic acid (ALA), is generally far less effective at inducing biological effects, in part because of its inefficient conversion to EPA and DHA in humans (8). Thus, maximal effects of n–3 FAs depend on the delivery of EPA and DHA rather than of ALA. EPA and DHA affect many pathways that could benefit CVD outcomes, including actions that lower blood concentrations of triacylglycerols, prevent thrombosis and cardiac arrhythmias, inhibit adverse inflammatory responses, and decrease platelet aggregation (7). EPA and DHA also reduce vascular smooth muscle hypertrophy, reduce endothelial dysfunction, and increase vascular reactivity and decrease cholesterol accumulation in the arterial wall (7). Surgically removed specimens from patients provided diets rich in EPA and DHA before undergoing carotid endarterectomy showed lower concentrations of inflammatory markers and other variables associated with plaque instability than did those from patients fed control diets (9)…they included only randomized controlled trials and prospective cohort studies that monitored patients for 1 y, and, in the case of the case-control studies, only those that actually documented intakes of fish oil and n–3 FAs. ..of particular importance is that no or very few complications were documented. In total, the evidence indicates that increased consumption of the n–3 FAs EPA and DHA, either through fish or supplements or both, reduced the rates of all-cause mortality, myocardial infarction, and sudden cardiac death. Evidence was strongest in secondary-prevention trials but was also present in primary-prevention studies…ALA has no or only weak beneficial effects on diminishing the risk of CVD…the American Heart Association and several international health agencies recommend intakes of 1 g EPA+DHA/d for patients with known CVD and of 4–500 mg EPA+DHA/d (2 servings of oily fish/wk) for those without CVD (16). Despite concern about toxins in fish, proper selection and preparation of fish results in a low risk from toxins (17, 18), especially when compared with low intakes of EPA and DHA (18). .. ”

[weight control essential to liver health] Nonalcoholic fatty liver, nonalcoholic steatohepatitis, ectopic fat, and the glycemic index Am J Clin Nutr 2006 84: 3-4. ” As the incidence of obesity in adults and children increases, so does the incidence of fatty liver disease. It has been estimated that 20% of adults have excess fat in the liver—ie, they have nonalcoholic fatty liver (NAFL). .. NAFL is one of the disorders of ectopic fat storage that has a strong association with insulin resistance. Fat is stored in hepatocytes and muscle fibers (intramyocellular fat), rather than in adipocytes. In addition to its common occurrence in obesity, NAFL is found in an extreme form in persons with lipodystrophy. Its frequency is increased by inactivity, and it is relatively common in persons with type 2 diabetes. Other than weight loss, effective treatment strategies for NAFL are not yet available…Intakes of total carbohydrate and fiber, glycemic index (GI), and glycemic load were measured from a semiquantitative food-frequency questionnaire… Some evidence exists that low-GI diets are beneficial to persons with type 2 diabetes (13). .. Low-GI diets have also been associated with lower serum concentrations of triacylglycerol (14) and C-reactive protein (15, 16)…”

[American Heart Association concludes at least 1,000IU vitamin D/day are recommended for optimal health] Estimation of optimal serum concentrations of 25-hydroxyvitamin D for multiple health outcomes Am J Clin Nutr 2006 84: 18-28. ” Recent evidence suggests that vitamin D intakes above current recommendations may be associated with better health outcomes. ..This review summarizes evidence from studies that evaluated thresholds for serum 25(OH)D concentrations in relation to bone mineral density (BMD), lower-extremity function, dental health, and risk of falls, fractures, and colorectal cancer. .. An intake for all adults of 1000 IU (40 µg) vitamin D (cholecalciferol)/d is needed to bring vitamin D concentrations in no less than 50% of the population up to 75 nmol/L. The implications of higher doses for the entire adult population should be addressed in future studies.”

[relaxation protects your heart]Lifestyle modifies obesity-associated risk of cardiovascular disease in a genetically homogeneous population Am J Clin Nutr 2006 84: 29-36 “Background: The association between obesity and cardiovascular disease risk differs across populations. Whether such differences in obesity-related risk factors exist within population groups of the same genetic origin but with differences in lifestyle remains to be determined…At any given level of obesity, Inuit residents in Greenland had lower blood pressure and lower concentrations of triacylglycerol and postchallenge plasma glucose and insulin than did the Inuit migrants in Denmark…Conclusions: The health risk associated with obesity clearly varies within groups of Inuit living in Greenland and Inuit migrants living in Denmark. The findings indicate that lifestyle factors modify the cardiovascular disease risk associated with obesity.”

[trans-fats and palm oil hazardous] Palm and partially hydrogenated soybean oils adversely alter lipoprotein profiles compared with soybean and canola oils in moderately hyperlipidemic subjects Am J Clin Nutr 2006 84: 54-62 “Background: Partially hydrogenated fat has an unfavorable effect on cardiovascular disease risk. Palm oil is a potential substitute because of favorable physical characteristics…Conclusion: Palm and partially hydrogenated soybean oils, compared with soybean and canola oils, adversely altered the lipoprotein profile in moderately hyperlipidemic subjects without significantly affecting HDL intravascular processing markers.”

[chili pepper/spice very beneficial against diabetes, etc.] Effects of chili consumption on postprandial glucose, insulin, and energy metabolism Am J Clin Nutr 2006 84: 63-69 ” the consumption of chili-containing meals increases energy expenditure and fat oxidation, which may help to reduce obesity and related disorders…Conclusion: Regular consumption of chili may attenuate postprandial hyperinsulinemia.” [that otherwise can lead to diabetes] [A low GI diet, not a low carb diet, reduces long-term illness]Relations of glycemic index and glycemic load with plasma oxidative stress markers Am J Clin Nutr 2006 84: 70-76 “Background: Recent data suggest that acute hyperglycemia may increase in vivo free radical production. This increased production has been implicated in many disease processes…Conclusions: Chronic consumption of high-GI foods may lead to chronically high oxidative stress. A low-GI diet, not a low-carbohydrate diet, appears to be beneficial in reducing oxidative stress.”

[why choline is now a vitamin] Choline deficiency increases lymphocyte apoptosis and DNA damage in humans Am J Clin Nutr 2006 84: 88-94 “Background: Whereas deficiency of the essential nutrient choline is associated with DNA damage and apoptosis in cell and rodent models, it has not been shown in humans…Conclusions: A choline-deficient diet increased DNA damage in humans. Subjects in whom these diets induced liver or muscle dysfunction also had higher rates of apoptosis in their peripheral lymphocytes than did subjects who did not develop organ dysfunction. Assessment of DNA damage and apoptosis in lymphocytes appears to be a clinically useful measure in humans (such as those receiving parenteral nutrition) in whom choline deficiency is suspected. ”

[Great tables listing best fruits and vegetables] Content of redox-active compounds (ie, antioxidants) in foods consumed in the United States Am J Clin Nutr 2006 84: 95-135 “Background: Supplements containing ascorbic acid, -tocopherol, or ß-carotene do not protect against oxidative stress–related diseases in most randomized intervention trials. We suggest that other redox-active phytochemicals may be more effective and that a combination of different redox-active compounds (ie, antioxidants or reductants) may be needed for proper protection against oxidative damage. Objective: We aimed to generate a ranked food table with values for total content of redox-active compounds to test this alternative antioxidant hypothesis. Design: An assay that measures the total concentration of redox-active compounds above a certain cutoff reduction potential was used to analyze 1113 food samples obtained from the US Department of Agriculture National Food and Nutrient Analysis Program.” [Roc’s note: as education essay explains at this site, other antioxidants described here trap free radicals of different energy levels, and direct them through fat-soluble vitamin E and water-soluble vitamin C to inactivate the radicals. Thus, you need plenty of vitamins C and E everywhere, and a diet rich in fruits and vegetables to provide the diversity of antioxidants (hundreds at least) that are essential to optimal health.] [fishoil reduces inflammation/C-reactive protein] Dietary long-chain n–3 fatty acids of marine origin and serum C-reactive protein concentrations are associated in a population with a diet rich in marine products Am J Clin Nutr 2006 84: 223-229 “…few studies have evaluated the relations between serum CRP concentrations and consumption of n–3 PUFAs derived from marine products in populations with a diet rich in marine products. Therefore, it is still unclear whether a greater consumption of n–3 PUFAs is associated with lower serum CRP concentrations…Conclusions: Greater intake of n–3 PUFAs derived from marine products, as measured with a self-administered questionnaire, was independently related to a lower prevalence of high CRP concentrations in this older Japanese population with a diet rich in marine products. Our findings suggest that even very high intakes of n–3 PUFAs may lower serum CRP concentrations.”

[Try to know your birthweight situation] Combined effects of dietary fat and birth weight on serum cholesterol concentrations: the Hertfordshire Cohort Study Am J Clin Nutr 2006 84: 237-244 “Background: Blood cholesterol responses to the manipulation of dietary fat vary widely between persons. ..Conclusion: The adverse effects of high intakes of total and saturated fat on serum cholesterol concentrations in men may be confined to those with lower birth weights.”

Concentrated red grape juice exerts antioxidant, hypolipidemic, and antiinflammatory effects in both hemodialysis patients and healthy subjects Am J Clin Nutr 2006 84: 252-262 “…Objective: The aim of the study was to study the effects of dietary supplementation with concentrated red grape juice (RGJ), a source of polyphenols, on lipoprotein profile, antioxidant capacity, LDL oxidation, and inflammatory biomarkers. ..Conclusion: Dietary supplementation with concentrated RGJ improves the lipoprotein profile, reduces plasma concentrations of inflammatory biomarkers and oxidized LDL, and may favor a reduction in cardiovascular disease risk.”