RESUMEN
Epidemiologic studies and clinical trials have demonstrated that the unique fatty acid profile of nuts beneficially affects serum lipids/lipoproteins, reducing cardiovascular disease (CVD) risk. Nuts are low in SFA and high in PUFA and monounsaturated fatty acids (MUFA). Macadamia nuts are a rich source of MUFA. A randomized, crossover, controlled feeding study (5-wk diet periods) compared a Macadamia nut-rich diet [42.5 g (1.5 ounces)/8.79 MJ (2100 kcal)] [MAC; 33% total fat (7% SFA, 18% MUFA, 5% PUFA)] vs. an average American diet [AAD; 33% total fat (13% SFA, 11% MUFA, 5% PUFA)] on the lipid/lipoprotein profile of mildly hypercholesterolemic (n = 25; 15 female, 10 male) subjects. Serum concentrations of total cholesterol (TC) and LDL cholesterol (LDL-C) following the MAC (4.94 +/- 0.17 mmol/L, 3.14 +/- 0.14 mmol/L) were lower than the AAD (5.45 +/- 0.17 mmol/L, 3.44 +/- 0.14 mmol/L; P < 0.05). The serum non-HDL cholesterol (HDL-C) concentration and the ratios of TC:HDL-C and LDL-C:HDL-C were reduced following consumption of the MAC diet (3.83 +/- 0.17, 4.60 +/- 0.24, and 2.91 +/- 0.17, respectively) compared with the AAD (4.26 +/- 0.17, 4.89 +/- 0.24, and 3.09 +/- 0.18, respectively; P < 0.05). There was no change in serum triglyceride concentration. Thus, macadamia nuts can be included in a heart-healthy dietary pattern that reduces lipid/lipoprotein CVD risk factors. Nuts as an isocaloric substitute for high SFA foods increase the proportion of unsaturated fatty acids and decrease SFA, thereby lowering CVD risk.
Asunto(s)
Colesterol/sangre , Dieta , Alimentos , Hipercolesterolemia/dietoterapia , Macadamia , Adulto , Anciano , Estudios Cruzados , Femenino , Humanos , Hipercolesterolemia/sangre , Masculino , Persona de Mediana EdadRESUMEN
Human, animal, and in vitro research indicates a beneficial effect of appropriate amounts of omega-3 (n-3) polyunsaturated fatty acids (PUFA) on bone health. This is the first controlled feeding study in humans to evaluate the effect of dietary plant-derived n-3 PUFA on bone turnover, assessed by serum concentrations of N-telopeptides (NTx) and bone-specific alkaline phosphatase (BSAP). Subjects (n = 23) consumed each diet for 6 weeks in a randomized, 3-period crossover design: 1) Average American Diet (AAD; [34% total fat, 13% saturated fatty acids (SFA), 13% monounsaturated fatty acids (MUFA), 9% PUFA (7.7% LA, 0.8% ALA)]), 2) Linoleic Acid Diet (LA; [37% total fat, 9% SFA, 12% MUFA, 16% PUFA (12.6% LA, 3.6% ALA)]), and 3) alpha-Linolenic Acid Diet (ALA; [38% total fat, 8% SFA, 12% MUFA, 17% PUFA (10.5% LA, 6.5% ALA)]). Walnuts and flaxseed oil were the predominant sources of ALA. NTx levels were significantly lower following the ALA diet (13.20 +/- 1.21 nM BCE), relative to the AAD (15.59 +/- 1.21 nM BCE) (p < 0.05). Mean NTx level following the LA diet was 13.80 +/- 1.21 nM BCE. There was no change in levels of BSAP across the three diets. Concentrations of NTx were positively correlated with the pro-inflammatory cytokine TNFalpha for all three diets. The results indicate that plant sources of dietary n-3 PUFA may have a protective effect on bone metabolism via a decrease in bone resorption in the presence of consistent levels of bone formation.
Asunto(s)
Biomarcadores/sangre , Resorción Ósea/tratamiento farmacológico , Grasas Insaturadas en la Dieta/administración & dosificación , Ácidos Grasos Omega-3/administración & dosificación , Fosfatasa Alcalina/sangre , Índice de Masa Corporal , Colágeno Tipo I/sangre , Estudios Cruzados , Método Doble Ciego , Ácidos Grasos/sangre , Femenino , Humanos , Ácido Linoleico/administración & dosificación , Masculino , Persona de Mediana Edad , Péptidos/sangre , Factor de Necrosis Tumoral alfa/análisis , Ácido alfa-Linolénico/administración & dosificaciónRESUMEN
Tree nuts have a fatty acid profile that favourably affects blood lipids and lipoproteins. They are low in saturated fat and high in unsaturated fatty acids and are rich sources of other nutrients. An extensive database consistently shows total and LDL cholesterol-lowering effects of diets low in saturated fat and cholesterol and high in unsaturated fat provided by a variety of tree nuts. Collectively, a summary of studies conducted to date shows that tree nuts reduce LDL cholesterol by 3-19 % compared with Western and lower-fat diets. Nuts also contain many nutrients and bioactive compounds that appear to contribute to the favourable effects on lipids and lipoproteins--these include plant sterols, dietary fibre and antioxidants. Because of their unique nutrient profile, nuts can be part of a diet that features multiple heart-healthy foods resulting in a cholesterol lowering response that surpasses that of cholesterol-lowering diets typically used to reduce CVD risk.
Asunto(s)
Lípidos/sangre , Nueces/química , Carya/química , Colesterol/sangre , Ensayos Clínicos como Asunto , Humanos , Juglans/química , Lipoproteínas/química , Macadamia/química , Pistacia/química , Prunus/químicaRESUMEN
Saturated fat reduction is a primary goal for decreasing the risk of cardiovascular disease. In a recent epidemiologic study, a low-fat diet high in saturated fat (10.6%-16.0% energy) was associated with less progression of coronary atherosclerosis, whereas carbohydrate intake (67% energy) was associated with a greater degree of progression in postmenopausal women.
Asunto(s)
Enfermedades Cardiovasculares/sangre , Grasas Insaturadas en la Dieta/administración & dosificación , Grasas de la Dieta/administración & dosificación , Ácidos Grasos/sangre , Factores de Edad , Enfermedades Cardiovasculares/epidemiología , Enfermedades Cardiovasculares/metabolismo , Carbohidratos de la Dieta/administración & dosificación , Grasas de la Dieta/efectos adversos , Progresión de la Enfermedad , Femenino , Humanos , Masculino , Factores SexualesRESUMEN
The dietary recommendations made for carbohydrate intake by many organizations/agencies have changed over time. Early recommendations were based on the need to ensure dietary sufficiency and focused on meeting micronutrient intake requirements. Because carbohydrate-containing foods are a rich source of micronutrients, starches, grains, fruits, and vegetables became the foundation of dietary guidance, including the base of the US Department of Agriculture's Food Guide Pyramid. Dietary sufficiency recommendations were followed by recommendations to reduce cholesterol levels and the risk for cardiovascular disease; reduction in total fat (and hence saturated fat) predominated. Beginning in the 1970s, carbohydrates were recommended as the preferred substitute for fat by the American Heart Association and others to achieve the recommended successive reductions in total fat and low-density lipoprotein cholesterol (LDL-C). Additional research on fats and fatty acids found that monounsaturated fatty acids could serve as an alternative substitution for saturated fats, providing equivalent lowering of LDL-C without concomitant reductions in high-density lipoprotein cholesterol and increases in triglycerides witnessed when carbohydrates replace saturated fat. This research led to a sharper focus in the guidelines in the 1990s toward restricting saturated fat and liberalizing a range of intake of total fat. Higher-fat diets, still low in saturated fatty acids, became alternative strategies to lower-fat diets. As the population has become increasingly overweight and obese, the emergence of the metabolic syndrome and its associated disruptions in glucose and lipid metabolism has led to reconsiderations of the role of carbohydrate-containing foods in the American diet. Consequently, a review of the evidence for and against high-carbohydrate diets is important to put this controversy into perspective. The current dietary recommendations for carbohydrate intake are supported by the evidence.
Asunto(s)
Carbohidratos de la Dieta/administración & dosificación , Carbohidratos de la Dieta/clasificación , Política Nutricional/tendencias , HumanosRESUMEN
Individual FA have diverse biological effects, some of which affect the risk of cardiovascular disease (CVD). In the context of food-based dietary guidance designed to reduce CVD risk, fat and FA recommendations focus on reducing saturated FA (SFA) and trans FA (TFA), and ensuring an adequate intake of unsaturated FA. Because stearic acid shares many physical properties with the other long-chain SFA but has different physiological effects, it is being evaluated as a substitute for TFA in food manufacturing. For stearic acid to become the primary replacement for TFA, it is essential that its physical properties and biological effects be well understood.
Asunto(s)
Enfermedades Cardiovasculares/prevención & control , Grasas de la Dieta/farmacología , Ácidos Esteáricos/farmacología , Grasas de la Dieta/administración & dosificación , Grasas de la Dieta/metabolismo , Digestión , Ingestión de Alimentos , Humanos , Absorción Intestinal , Factores de Riesgo , Ácidos Esteáricos/administración & dosificación , Ácidos Esteáricos/metabolismo , Triglicéridos/químicaRESUMEN
OBJECTIVE: To evaluate the diet quality of free-living men, women, and children choosing peanuts and peanut products. DESIGN: Using data reported in the Continuing Survey of Food Intake by Individuals and Diet and Health Knowledge Survey (CSFII/DHKS) from 1994-1996, food codes were used to sort respondents by use or nonuse of peanuts. SUBJECTS: A nationally representative sample of 4,751 men, 4,572 women, and 4,939 children (boys and girls, 2-19 yrs) who completed 2-day intake records. MEASURES OF OUTCOME: The two-sample t test was used to analyze differences between peanut users and nonusers for energy, nutrient intakes, Health Eating Index (HEI) scores, and body mass index (BMI). RESULTS: Peanut users (24% of CSFII/DHKS) had higher intakes (p < 0.001) of protein, total fat, polyunsaturated fat (PUFA), monounsaturated fat, (MUFA) (p < 0.01), fiber, vitamin A, vitamin E, folate, calcium, magnesium, zinc, and iron. Percent of energy from saturated fat was not significantly different for men, women or girls and was slightly lower (p < 0.01) for boys. Dietary cholesterol of peanut users was lower for all population groups; this decrease was significant for both men (p < 0.01) and children (p < 0.001). The HEI was calculated as a measure of overall nutrient profile of the diets and was significantly greater for peanut users (men 61.4, women, 65.1, children 66.8) compared to nonusers (men 59.9, women 64.1, children 64.7) for men (p = 0.0074) and children (p < 0.001). Energy intake was significantly higher in all population groups of peanut users (p < 0.001; boys: p < 0.01); however mean BMI for peanut users was lower for all gender/age categories (women: p < 0.05; children: p < 0.001). CONCLUSIONS: These results demonstrate improved diet quality of peanut users, indicated by the higher intake of the micronutrients vitamin A, vitamin E, folate, calcium, magnesium, zinc, and iron and dietary fiber, and by the lower intake of saturated fat and cholesterol. Despite a higher energy intake over a two-day period, peanut consumption was not associated with a higher BMI.
Asunto(s)
Arachis , Dieta/normas , Grasas de la Dieta/administración & dosificación , Micronutrientes/administración & dosificación , Vitaminas/administración & dosificación , Adolescente , Adulto , Índice de Masa Corporal , Niño , Preescolar , Registros de Dieta , Encuestas sobre Dietas , Fibras de la Dieta/administración & dosificación , Ingestión de Energía , Femenino , Humanos , Masculino , Recuerdo Mental , Política Nutricional , Estados UnidosRESUMEN
"Bioactive compounds" are extranutritional constituents that typically occur in small quantities in foods. They are being intensively studied to evaluate their effects on health. The impetus sparking this scientific inquiry was the result of many epidemiologic studies that have shown protective effects of plant-based diets on cardiovascular disease (CVD) and cancer. Many bioactive compounds have been discovered. These compounds vary widely in chemical structure and function and are grouped accordingly. Phenolic compounds, including their subcategory, flavonoids, are present in all plants and have been studied extensively in cereals, legumes, nuts, olive oil, vegetables, fruits, tea, and red wine. Many phenolic compounds have antioxidant properties, and some studies have demonstrated favorable effects on thrombosis and tumorogenesis and promotion. Although some epidemiologic studies have reported protective associations between flavonoids or other phenolics and CVD and cancer, other studies have not found these associations. Various phytoestrogens are present in soy, but also in flaxseed oil, whole grains, fruits, and vegetables. They have antioxidant properties, and some studies demonstrated favorable effects on other CVD risk factors, and in animal and cell culture models of cancer. However, because phytoestrogens act both as partial estrogen agonists and antagonists, their effects on cancer are likely complex. Hydroxytyrosol, one of many phenolics in olives and olive oil, is a potent antioxidant. Resveratrol, found in nuts and red wine, has antioxidant, antithrombotic, and anti-inflammatory properties, and inhibits carcinogenesis. Lycopene, a potent antioxidant carotenoid in tomatoes and other fruits, is thought to protect against prostate and other cancers, and inhibits tumor cell growth in animals. Organosulfur compounds in garlic and onions, isothiocyanates in cruciferous vegetables, and monoterpenes in citrus fruits, cherries, and herbs have anticarcinogenic actions in experimental models, as well as cardioprotective effects. In summary, numerous bioactive compounds appear to have beneficial health effects. Much scientific research needs to be conducted before we can begin to make science-based dietary recommendations. Despite this, there is sufficient evidence to recommend consuming food sources rich in bioactive compounds. From a practical perspective, this translates to recommending a diet rich in a variety of fruits, vegetables, whole grains, legumes, oils, and nuts.