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Effects of daily almond consumption on cardiometabolic risk and abdominal adiposity in healthy adults with elevated LDL-cholesterol: a randomized controlled trial.
Berryman, CE, West, SG, Fleming, JA, Bordi, PL, Kris-Etherton, PM
Journal of the American Heart Association. 2015;4(1):e000993
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Research has shown that almond consumption has a positive impact on cardiovascular risk factors and markers for inflammation. The aim of this randomised controlled trial was to compare a cholesterol lowering diet with almonds (1.5oz./day) with the same diet but substituting almonds with a calorie-matched food (i.e. a muffin) in a controlled-feeding setting. The study concluded that almonds reduce non high density lipoproteins, low-density lipoproteins and central adiposity in healthy individuals. The researchers suggest that it is likely to be almonds unique fatty acid profile and in particular, oleic acid that offers these cardiovascular protective effects. It recommended a daily intake of 1.5oz of almonds to replace high carbohydrate snacks.
Abstract
BACKGROUND Evidence consistently shows that almond consumption beneficially affects lipids and lipoproteins. Almonds, however, have not been evaluated in a controlled-feeding setting using a diet design with only a single, calorie-matched food substitution to assess their specific effects on cardiometabolic risk factors. METHODS AND RESULTS In a randomized, 2-period (6 week/period), crossover, controlled-feeding study of 48 individuals with elevated LDL-C (149±3 mg/dL), a cholesterol-lowering diet with almonds (1.5 oz. of almonds/day) was compared to an identical diet with an isocaloric muffin substitution (no almonds/day). Differences in the nutrient profiles of the control (58% CHO, 15% PRO, 26% total fat) and almond (51% CHO, 16% PRO, 32% total fat) diets were due to nutrients inherent to each snack; diets did not differ in saturated fat or cholesterol. The almond diet, compared with the control diet, decreased non-HDL-C (-6.9±2.4 mg/dL; P=0.01) and LDL-C (-5.3±1.9 mg/dL; P=0.01); furthermore, the control diet decreased HDL-C (-1.7±0.6 mg/dL; P<0.01). Almond consumption also reduced abdominal fat (-0.07±0.03 kg; P=0.02) and leg fat (-0.12±0.05 kg; P=0.02), despite no differences in total body weight. CONCLUSIONS Almonds reduced non-HDL-C, LDL-C, and central adiposity, important risk factors for cardiometabolic dysfunction, while maintaining HDL-C concentrations. Therefore, daily consumption of almonds (1.5 oz.), substituted for a high-carbohydrate snack, may be a simple dietary strategy to prevent the onset of cardiometabolic diseases in healthy individuals. CLINICAL TRIAL REGISTRATION URL www.clinicaltrials.gov; Unique Identifier: NCT01101230.
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Weight loss with a low-carbohydrate, Mediterranean, or low-fat diet.
Shai, I, Schwarzfuchs, D, Henkin, Y, Shahar, DR, Witkow, S, Greenberg, I, Golan, R, Fraser, D, Bolotin, A, Vardi, H, et al
The New England journal of medicine. 2008;359(3):229-41
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Most trials comparing the effectiveness of weight-loss regimes are carried out over short durations. This trial explored the effectiveness of three dietary protocols (low carbohydrate, Mediterranean diet and low fat) on weight loss over 2 years. The study randomly allocated 322 moderately obese subjects to one of the three dietary regimes. The mean weight loss for the 272 people completing the study after 2 years was significantly different between the groups; 3.3kg for the low fat group, 4.6kg for the Mediterranean diet group and 5.5kg for the low carbohydrate group. Diabetic subjects in the Mediterranean group achieved more favourable fasting blood sugar and insulin levels compared to the low fat group. The low carbohydrate group achieved the most favourable outcomes in terms of their lipid profiles compared to the other groups. The authors concluded that the Mediterranean diet and low carbohydrate diets may be effective alternatives to low fat regimes; they achieved weight-loss and also some metabolic benefits.
Abstract
BACKGROUND Trials comparing the effectiveness and safety of weight-loss diets are frequently limited by short follow-up times and high dropout rates. METHODS In this 2-year trial, we randomly assigned 322 moderately obese subjects (mean age, 52 years; mean body-mass index [the weight in kilograms divided by the square of the height in meters], 31; male sex, 86%) to one of three diets: low-fat, restricted-calorie; Mediterranean, restricted-calorie; or low-carbohydrate, non-restricted-calorie. RESULTS The rate of adherence to a study diet was 95.4% at 1 year and 84.6% at 2 years. The Mediterranean-diet group consumed the largest amounts of dietary fiber and had the highest ratio of monounsaturated to saturated fat (P<0.05 for all comparisons among treatment groups). The low-carbohydrate group consumed the smallest amount of carbohydrates and the largest amounts of fat, protein, and cholesterol and had the highest percentage of participants with detectable urinary ketones (P<0.05 for all comparisons among treatment groups). The mean weight loss was 2.9 kg for the low-fat group, 4.4 kg for the Mediterranean-diet group, and 4.7 kg for the low-carbohydrate group (P<0.001 for the interaction between diet group and time); among the 272 participants who completed the intervention, the mean weight losses were 3.3 kg, 4.6 kg, and 5.5 kg, respectively. The relative reduction in the ratio of total cholesterol to high-density lipoprotein cholesterol was 20% in the low-carbohydrate group and 12% in the low-fat group (P=0.01). Among the 36 subjects with diabetes, changes in fasting plasma glucose and insulin levels were more favorable among those assigned to the Mediterranean diet than among those assigned to the low-fat diet (P<0.001 for the interaction among diabetes and Mediterranean diet and time with respect to fasting glucose levels). CONCLUSIONS Mediterranean and low-carbohydrate diets may be effective alternatives to low-fat diets. The more favorable effects on lipids (with the low-carbohydrate diet) and on glycemic control (with the Mediterranean diet) suggest that personal preferences and metabolic considerations might inform individualized tailoring of dietary interventions. (ClinicalTrials.gov number, NCT00160108.)