69 research outputs found
Polyunsaturated fatty acids for the primary and secondary prevention of cardiovascular disease
Background: Evidence on the health effects of total polyunsaturated fatty acids (PUFA) is equivocal. Fish oils are rich in omega-3 PUFA and plant oils in omega-6 PUFA. Evidence suggests increasing PUFA-rich foods, supplements or supplemented foods can reduce serum cholesterol, but may increase body weight, so overall cardiovascular effects are unclear. Objectives: To assess effects of increasing PUFA intake on cardiovascular disease (CVD) and all-cause mortality in adults. Search method: We searched CENTRAL, MEDLINE and Embase to April 2017 and ClinicalTrials.com and World Health Organization International Clinical Trials Registry Platform to September 2016, without language restrictions. We checked trials included in relevant systematic reviews. Selection criteria: We included randomised controlled trials (RCTs) comparing higher with lower PUFA intakes in adults with or without CVD that assessed effects over ≥12 months. We included full-text, abstracts, trials registry entries and unpublished data. Outcomes were all-cause mortality, CVD mortality and events, risk factors (blood lipids, adiposity, blood pressure), and adverse events. We excluded trials where we could not separate effects of PUFA intake from other dietary, lifestyle or medication interventions. Data collection and analysis: Two authors independently screened titles/abstracts, assessed trials for inclusion, extracted data, and assessed risk of bias. We wrote to authors of included studies for further data. Meta-analyses used random-effects analysis, sensitivity analyses included fixed-effects and limiting to low summary risk of bias. We assessed GRADE quality of evidence. Main result: We included 49 RCTs randomising 24,272 participants, with duration of one to eight years. Twelve included trials were at low summary risk of bias, 33 recruited participants without cardiovascular disease. Baseline PUFA intake was unclear in most trials, but 3.9% to 8% of total energy intake where reported. Most trials gave supplemental capsules, but eight gave dietary advice, eight gave supplemental foods such as nuts or margarine, and three used a combination of methods to increase PUFA. Increasing PUFA intake probably has little or no effect on all-cause mortality (risk 3.4% vs 3.3% in primary prevention, 11.7% vs 11.5% in secondary prevention, risk ratio (RR) 0.98, 95% confidence interval (CI) 0.89 to 1.07, 24 trials in 19290 participants), but probably reduces risk of CVD events from 5.8% to 4.9% in primary prevention, 23.3% to 20.8% in secondary prevention (RR 0.89, 95% CI 0.79 to 1.01, 20 trials in 17,073 participants), both moderate quality evidence. Increasing PUFA may reduce risk of CHD events from 13.4% to 7.1% primary prevention, 14.3% to 13.7% secondary prevention (RR 0.87, 95% CI 0.72 to 1.06, 15 trials, 10,076 participants), CHD death (5.2% to 4.4% primary prevention, 6.8% to 6.1% secondary prevention, RR 0.91, 95% CI 0.78 to 1.06, 9 trials, 8810 participants) and may slightly reduce stroke risk (2.1% to 1.5% primary prevention, RR 0.91, 95% CI 0.58 to 1.44, 11 trials, 14,742 participants), but has little or no effect on cardiovascular mortality (RR 1.02, 95% CI 0.82 to 1.26, I2 31%, 16 trials, 15,107 participants) all low quality evidence. Effects of increasing PUFA on major adverse cardiac and cerebrovascular events and atrial fibrillation are unclear as evidence is of very low quality. Event outcomes were all downgraded for indirectness, as most events occurred in men in westernised countries. Increasing PUFA intake reduces total cholesterol (MD -0.12 mmol/L, 95% CI -0.23 to -0.02, I2 79%, 8072 participants, 26 trials) and probably decreases triglycerides (TG, MD -0.12 mmol/L, 95% CI -0.20 to -0.04, I2 50%, 3905 participants, 20 trials), but has little or no effect on HDL (MD -0.01 mmol/L, 95% CI -0.02 to 0.01, I2 0%, 4674 participants, 18 trials) and LDL (MD -0.01 mmol/L, 95% CI -0.09 to 0.06, I2 44%, 3362 participants, 15 trials). Increasing PUFA probably causes slight weight gain (MD 0.76 kg, 95% CI 0.34 to 1.19, I2 59%, 7100 participants, 12 trials). Effects of increasing PUFA on serious adverse events such as pulmonary embolism and bleeding are unclear as the evidence is of very low quality. Authors' conclusions: Increasing PUFA intake probably reduces risk of CVD events, may reduce risk of CHD events and CHD mortality,and may slightly reduce stroke risk, but has little or no effect on all-cause or CVD mortality. The mechanism may be via lipid reduction, but increasing PUFA probably slightly increases weight
Reduction in saturated fat intake for cardiovascular disease
BACKGROUND: Reducing saturated fat reduces serum cholesterol, but effects on other intermediate outcomes may be less clear. Additionally, it is unclear whether the energy from saturated fats eliminated from the diet are more helpfully replaced by polyunsaturated fats, monounsaturated fats, carbohydrate or protein. OBJECTIVES: To assess the effect of reducing saturated fat intake and replacing it with carbohydrate (CHO), polyunsaturated (PUFA), monounsaturated fat (MUFA) and/or protein on mortality and cardiovascular morbidity, using all available randomised clinical trials. SEARCH METHODS: We updated our searches of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid) and Embase (Ovid) on 15 October 2019, and searched Clinicaltrials.gov and WHO International Clinical Trials Registry Platform (ICTRP) on 17 October 2019. SELECTION CRITERIA: Included trials fulfilled the following criteria: 1) randomised; 2) intention to reduce saturated fat intake OR intention to alter dietary fats and achieving a reduction in saturated fat; 3) compared with higher saturated fat intake or usual diet; 4) not multifactorial; 5) in adult humans with or without cardiovascular disease (but not acutely ill, pregnant or breastfeeding); 6) intervention duration at least 24 months; 7) mortality or cardiovascular morbidity data available. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed inclusion, extracted study data and assessed risk of bias. We performed random-effects meta-analyses, meta-regression, subgrouping, sensitivity analyses, funnel plots and GRADE assessment. MAIN RESULTS: We included 15 randomised controlled trials (RCTs) (16 comparisons, ~59,000 participants), that used a variety of interventions from providing all food to advice on reducing saturated fat. The included long-term trials suggested that reducing dietary saturated fat reduced the risk of combined cardiovascular events by 21% (risk ratio (RR) 0.79; 95% confidence interval (CI) 0.66 to 0.93, 11 trials, 53,300 participants of whom 8% had a cardiovascular event, I² = 65%, GRADE moderate-quality evidence). Meta-regression suggested that greater reductions in saturated fat (reflected in greater reductions in serum cholesterol) resulted in greater reductions in risk of CVD events, explaining most heterogeneity between trials. The number needed to treat for an additional beneficial outcome (NNTB) was 56 in primary prevention trials, so 56 people need to reduce their saturated fat intake for ~four years for one person to avoid experiencing a CVD event. In secondary prevention trials, the NNTB was 32. Subgrouping did not suggest significant differences between replacement of saturated fat calories with polyunsaturated fat or carbohydrate, and data on replacement with monounsaturated fat and protein was very limited. We found little or no effect of reducing saturated fat on all-cause mortality (RR 0.96; 95% CI 0.90 to 1.03; 11 trials, 55,858 participants) or cardiovascular mortality (RR 0.95; 95% CI 0.80 to 1.12, 10 trials, 53,421 participants), both with GRADE moderate-quality evidence. There was little or no effect of reducing saturated fats on non-fatal myocardial infarction (RR 0.97, 95% CI 0.87 to 1.07) or CHD mortality (RR 0.97, 95% CI 0.82 to 1.16, both low-quality evidence), but effects on total (fatal or non-fatal) myocardial infarction, stroke and CHD events (fatal or non-fatal) were all unclear as the evidence was of very low quality. There was little or no effect on cancer mortality, cancer diagnoses, diabetes diagnosis, HDL cholesterol, serum triglycerides or blood pressure, and small reductions in weight, serum total cholesterol, LDL cholesterol and BMI. There was no evidence of harmful effects of reducing saturated fat intakes. AUTHORS' CONCLUSIONS: The findings of this updated review suggest that reducing saturated fat intake for at least two years causes a potentially important reduction in combined cardiovascular events. Replacing the energy from saturated fat with polyunsaturated fat or carbohydrate appear to be useful strategies, while effects of replacement with monounsaturated fat are unclear. The reduction in combined cardiovascular events resulting from reducing saturated fat did not alter by study duration, sex or baseline level of cardiovascular risk, but greater reduction in saturated fat caused greater reductions in cardiovascular events
Mummies and dental health in the ancient Ilo valley, southern Peru
In the very arid climate of southern Peru, archaeological remains, including many human burials, are extremely well preserved. Study of the teeth of mummified people from different cultural groups and time periods is beginning to provide evidence of diet and disease among the ancient inhabitants of the Ilo valley between the foot-hills of the Andes and the desert coast
Famine, the Black Death, and health in fourteenth-century London
In the first half of the fourteenth century two catastrophes struck the population of Europe: the Great Famine and the Black Death. The latter has been extensively studied, but much less is known about the biological effects of the Great Famine. A large assemblage of skeletal remains from one of the Black Death burial grounds, the Royal Mint cemetery in London, provides a unique opportunity to investigate these effects by analyzing the teeth of individuals who survived the famine but died during the Black Death
Mammal bones and teeth : an introductory guide to methods of identification /
Includes bibliographical references (page 59) and index.Bones and their identification -- Size and variation -- Antlers -- Horn cores -- Cranial bones -- Teeth -- Tooth sockets -- Mandible -- Vertebrae -- Ribs -- Scapula -- Humerus -- Radius-Ulna -- Innominate bone -- Femur -- Tibia-fibula -- Carpals -- Tarsals -- Bovid and cervid metapodials -- Horse metapodials -- Metapodials of cats, dogs, pigs and humans -- Phalanges
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