Saturated Fat and Cardiometabolic Risk Factors, Coronary Heart Disease, Stroke, and Diabetes: A Fresh Look at the Evidence

Dietary and policy recommendations frequently focus on reducing saturated fatty acid consumption for improving cardiometabolic health, based largely on ecologic and animal studies. Recent advances in nutritional science now allow assessment of critical questions about health effects of saturated fatty acids (SFA). We reviewed the evidence from randomized controlled trials (RCTs) of lipid and non-lipid risk factors, prospective cohort studies of disease endpoints, and RCTs of disease endpoints for cardiometabolic effects of SFA consumption in humans, including whether effects vary depending on specific SFA chain-length; on the replacement nutrient; or on disease outcomes evaluated. Compared with carbohydrate, the TC:HDL-C ratio is nonsignificantly affected by consumption of myristic or palmitic acid, is nonsignificantly decreased by stearic acid, and is significantly decreased by lauric acid. However, insufficient evidence exists for different chain-length-specific effects on other risk pathways or, more importantly, disease endpoints. Based on consistent evidence from human studies, replacing SFA with polyunsaturated fat modestly lowers coronary heart disease risk, with ~10% risk reduction for a 5% energy substitution; whereas replacing SFA with carbohydrate has no benefit and replacing SFA with monounsaturated fat has uncertain effects. Evidence for the effects of SFA consumption on vascular function, insulin resistance, diabetes, and stroke is mixed, with many studies showing no clear effects, highlighting a need for further investigation of these endpoints. Public health emphasis on reducing SFA consumption without considering the replacement nutrient or, more importantly, the many other food-based risk factors for cardiometabolic disease is unlikely to produce substantial intended benefits

Processing of meats and cardiovascular risk: time to focus on preservatives

Dietary guidelines emphasize selecting lean (low-fat) meats to reduce saturated fat and cholesterol, but growing evidence suggests that health effects may relate to other ingredients, such as sodium, heme iron, or L-carnitine. Understanding how meats influence health, and on which nutrients this relationship depends, is essential to advise consumer choices, set guidelines, and inform food reformulations. A recent study published in BMC Medicine involving 448,568 participants in 10 European countries, provides important evidence in this regard. After multivariate adjustment, intake of unprocessed red meat was not significantly associated with total or cause-specific mortality; conversely, intake of processed meat was associated with a 30% higher rate of cardiovascular disease (CVD) (per 50 g/day, relative risk 1.30, 95% confidence interval 1.17 to 1.45) and also higher cancer mortality. These findings are consistent with our previous meta-analysis, based on smaller studies, showing strong associations of processed meats, but not unprocessed meats, with CVD. Preservatives are the notable difference; the calculated blood-pressure effects of sodium differences (around 400% higher in processed meats) explain most of the observed higher risk. Although unprocessed red meats seem to be relatively neutral for CVD, healthier choices are available, including fish, nuts, legumes, fruits, and vegetables. Public-health guidance should prioritize avoidance of processed meats, including the low-fat deli meats currently marketed as healthy choices, and the food industry should substantially reduce sodium and other preservatives in processed meats. See related research article here http://www.biomedcentral.com/1741-7015/11/63

Assessing global dietary habits: a comparison of national estimates from the FAO and the Global Dietary Database.

BACKGROUND: Accurate data on dietary habits are crucial for understanding impacts on disease and informing policy priorities. Nation-specific food balance sheets from the United Nations FAO provided the only available global dietary estimates but with uncertain validity. OBJECTIVES: We investigated how FAO estimates compared with nationally representative, individual-based dietary surveys from the Global Dietary Database (GDD) and developed calibration equations to improve the validity of FAO data to estimate dietary intakes. DESIGN: FAO estimates were matched to GDD data for 113 countries across the following 9 major dietary metrics for 30 y of data (1980-2009): fruit, vegetables, beans and legumes, nuts and seeds, whole grains, red and processed meats, fish and seafood, milk, and total energy. Both absolute and percentage differences in FAO and GDD mean estimates were evaluated. Linear regression was used to evaluate whether FAO estimates predicted GDD dietary intakes and whether this prediction varied according to age, sex, region, and time. Calibration equations were developed to adjust FAO estimates to approximate national dietary surveys validated by using randomly split data sets. RESULTS: For most food groups, FAO estimates substantially overestimated individual-based dietary intakes by 74.5% (vegetables) and 270% (whole grains) while underestimating beans and legumes (-50%) and nuts and seeds (-29%) (P < 0.05 for each). In multivariate regressions, these overestimations and underestimations for each dietary factor further varied by age, sex, region, and time (P < 0.001 for each). Split-data set calibration models, which accounted for country-level covariates and other sources of heterogeneity, effectively adjusted FAO estimates to approximate estimates from national survey data (r = 0.47-0.80) with small SEs of prediction (generally 1-5 g/d). CONCLUSIONS: For all food groups and total energy, FAO estimates substantially exceeded or underestimated individual-based national surveys of individual intakes with significant variation depending on age, sex, region, and time. Calibration models effectively adjusted the comprehensive, widely accessible FAO data to facilitate a more-accurate estimation of individual-level dietary intakes nationally and by age and sex.Supported by a grant from the Bill & Melinda Gates Foundation (Global Dietary Habits among Women, Price and Income Elasticities, and Validity of Food Balance Sheets; to LCDG, SH, RM, PS and DM) and the Medical Research Council Epidemiology Unit Core Support (MC_UU_12015/5; to FI).This is the final version of the article. It first appeared from the American Society for Nutrition via http://dx.doi.org/10.3945/​ajcn.114.08740

Global, regional, and national consumption levels of dietary fats and oils in 1990 and 2010: a systematic analysis including 266 country-specific nutrition surveys

Objectives: To quantify global consumption of key dietary fats and oils by country, age, and sex in 1990 and 2010. Design: Data were identified, obtained, and assessed among adults in 16 age- and sex-specific groups from dietary surveys worldwide on saturated, omega 6, seafood omega 3, plant omega 3, and trans fats, and dietary cholesterol. We included 266 surveys in adults (83% nationally representative) comprising 1 630 069 unique individuals, representing 113 of 187 countries and 82% of the global population. A multilevel hierarchical Bayesian model accounted for differences in national and regional levels of missing data, measurement incomparability, study representativeness, and sampling and modelling uncertainty. Setting and population Global adult population, by age, sex, country, and time. Results: In 2010, global saturated fat consumption was 9.4%E (95%UI=9.2 to 9.5); country-specific intakes varied dramatically from 2.3 to 27.5%E; in 75 of 187 countries representing 61.8% of the world’s adult population, the mean intake was <10%E. Country-specific omega 6 consumption ranged from 1.2 to 12.5%E (global mean=5.9%E); corresponding range was 0.2 to 6.5%E (1.4%E) for trans fat; 97 to 440 mg/day (228 mg/day) for dietary cholesterol; 5 to 3,886 mg/day (163 mg/day) for seafood omega 3; and <100 to 5,542 mg/day (1,371 mg/day) for plant omega 3. Countries representing 52.4% of the global population had national mean intakes for omega 6 fat ≥5%E; corresponding proportions meeting optimal intakes were 0.6% for trans fat (≤0.5%E); 87.6% for dietary cholesterol (<300 mg/day); 18.9% for seafood omega 3 fat (≥250 mg/day); and 43.9% for plant omega 3 fat (≥1,100 mg/day). Trans fat intakes were generally higher at younger ages; and dietary cholesterol and seafood omega 3 fats generally higher at older ages. Intakes were similar by sex. Between 1990 and 2010, global saturated fat, dietary cholesterol, and trans fat intakes remained stable, while omega 6, seafood omega 3, and plant omega 3 fat intakes each increased. Conclusions: These novel global data on dietary fats and oils identify dramatic diversity across nations and inform policies and priorities for improving global health

Effects of Saturated Fat, Polyunsaturated Fat, Monounsaturated Fat, and Carbohydrate on Glucose-Insulin Homeostasis: A Systematic Review and Meta-analysis of Randomised Controlled Feeding Trials.

BACKGROUND: Effects of major dietary macronutrients on glucose-insulin homeostasis remain controversial and may vary by the clinical measures examined. We aimed to assess how saturated fat (SFA), monounsaturated fat (MUFA), polyunsaturated fat (PUFA), and carbohydrate affect key metrics of glucose-insulin homeostasis. METHODS AND FINDINGS: We systematically searched multiple databases (PubMed, EMBASE, OVID, BIOSIS, Web-of-Knowledge, CAB, CINAHL, Cochrane Library, SIGLE, Faculty1000) for randomised controlled feeding trials published by 26 Nov 2015 that tested effects of macronutrient intake on blood glucose, insulin, HbA1c, insulin sensitivity, and insulin secretion in adults aged ≥18 years. We excluded trials with non-isocaloric comparisons and trials providing dietary advice or supplements rather than meals. Studies were reviewed and data extracted independently in duplicate. Among 6,124 abstracts, 102 trials, including 239 diet arms and 4,220 adults, met eligibility requirements. Using multiple-treatment meta-regression, we estimated dose-response effects of isocaloric replacements between SFA, MUFA, PUFA, and carbohydrate, adjusted for protein, trans fat, and dietary fibre. Replacing 5% energy from carbohydrate with SFA had no significant effect on fasting glucose (+0.02 mmol/L, 95% CI = -0.01, +0.04; n trials = 99), but lowered fasting insulin (-1.1 pmol/L; -1.7, -0.5; n = 90). Replacing carbohydrate with MUFA lowered HbA1c (-0.09%; -0.12, -0.05; n = 23), 2 h post-challenge insulin (-20.3 pmol/L; -32.2, -8.4; n = 11), and homeostasis model assessment for insulin resistance (HOMA-IR) (-2.4%; -4.6, -0.3; n = 30). Replacing carbohydrate with PUFA significantly lowered HbA1c (-0.11%; -0.17, -0.05) and fasting insulin (-1.6 pmol/L; -2.8, -0.4). Replacing SFA with PUFA significantly lowered glucose, HbA1c, C-peptide, and HOMA. Based on gold-standard acute insulin response in ten trials, PUFA significantly improved insulin secretion capacity (+0.5 pmol/L/min; 0.2, 0.8) whether replacing carbohydrate, SFA, or even MUFA. No significant effects of any macronutrient replacements were observed for 2 h post-challenge glucose or insulin sensitivity (minimal-model index). Limitations included a small number of trials for some outcomes and potential issues of blinding, compliance, generalisability, heterogeneity due to unmeasured factors, and publication bias. CONCLUSIONS: This meta-analysis of randomised controlled feeding trials provides evidence that dietary macronutrients have diverse effects on glucose-insulin homeostasis. In comparison to carbohydrate, SFA, or MUFA, most consistent favourable effects were seen with PUFA, which was linked to improved glycaemia, insulin resistance, and insulin secretion capacity.Dr Imamura received support from the Medical Research Council Epidemiology Unit Core Support (MC_UU_12015/5). Dr Mozaffarian received funding from The National Institute of Health in the United States (R01 HL085710).This is the final version of the article. It first appeared from PLOS via http://dx.doi.org/10.1371/journal.pmed.100208

Dietary quality among men and women in 187 countries in 1990 and 2010: a systematic assessment.

BACKGROUND: Healthy dietary patterns are a global priority to reduce non-communicable diseases. Yet neither worldwide patterns of diets nor their trends with time are well established. We aimed to characterise global changes (or trends) in dietary patterns nationally and regionally and to assess heterogeneity by age, sex, national income, and type of dietary pattern. METHODS: In this systematic assessment, we evaluated global consumption of key dietary items (foods and nutrients) by region, nation, age, and sex in 1990 and 2010. Consumption data were evaluated from 325 surveys (71·7% nationally representative) covering 88·7% of the global adult population. Two types of dietary pattern were assessed: one reflecting greater consumption of ten healthy dietary items and the other based on lesser consumption of seven unhealthy dietary items. The mean intakes of each dietary factor were divided into quintiles, and each quintile was assigned an ordinal score, with higher scores being equivalent to healthier diets (range 0-100). The dietary patterns were assessed by hierarchical linear regression including country, age, sex, national income, and time as exploratory variables. FINDINGS: From 1990 to 2010, diets based on healthy items improved globally (by 2·2 points, 95% uncertainty interval (UI) 0·9 to 3·5), whereas diets based on unhealthy items worsened (-2·5, -3·3 to -1·7). In 2010, the global mean scores were 44·0 (SD 10·5) for the healthy pattern and 52·1 (18·6) for the unhealthy pattern, with weak intercorrelation (r=-0·08) between countries. On average, better diets were seen in older adults compared with younger adults, and in women compared with men (p<0·0001 each). Compared with low-income nations, high-income nations had better diets based on healthy items (+2·5 points, 95% UI 0·3 to 4·1), but substantially poorer diets based on unhealthy items (-33·0, -37·8 to -28·3). Diets and their trends were very heterogeneous across the world regions. For example, both types of dietary patterns improved in high-income countries, but worsened in some low-income countries in Africa and Asia. Middle-income countries showed the largest improvement in dietary patterns based on healthy items, but the largest deterioration in dietary patterns based on unhealthy items. INTERPRETATION: Consumption of healthy items improved, while consumption of unhealthy items worsened across the world, with heterogeneity across regions and countries. These global data provide the best estimates to date of nutrition transitions across the world and inform policies and priorities for reducing the health and economic burdens of poor diet quality. FUNDING: The Bill & Melinda Gates Foundation and Medical Research Council.The study was sponsored by The Bill & Melinda Gates Foundation, and and FI was supported by Medical Research Council Unit Programme number MC_UU_125015/5.This paper was originally published in Lancet Global Health (Imamura F, Micha R, Khatibzadeh S, Fahimi S, Shi P, Powles J, Mozaffarian D, Lancet Global Health 2015, 3 e132–142, doi:10.1016/S2214-109X(14)70381-X)

Global sodium consumption and death from cardiovascular causes.

To access publisher's full text version of this article click on the hyperlink at the bottom of the pageHigh sodium intake increases blood pressure, a risk factor for cardiovascular disease, but the effects of sodium intake on global cardiovascular mortality are uncertain.We collected data from surveys on sodium intake as determined by urinary excretion and diet in persons from 66 countries (accounting for 74.1% of adults throughout the world), and we used these data to quantify the global consumption of sodium according to age, sex, and country. The effects of sodium on blood pressure, according to age, race, and the presence or absence of hypertension, were calculated from data in a new meta-analysis of 107 randomized interventions, and the effects of blood pressure on cardiovascular mortality, according to age, were calculated from a meta-analysis of cohorts. Cause-specific mortality was derived from the Global Burden of Disease Study 2010. Using comparative risk assessment, we estimated the cardiovascular effects of current sodium intake, as compared with a reference intake of 2.0 g of sodium per day, according to age, sex, and country.In 2010, the estimated mean level of global sodium consumption was 3.95 g per day, and regional mean levels ranged from 2.18 to 5.51 g per day. Globally, 1.65 million annual deaths from cardiovascular causes (95% uncertainty interval [confidence interval], 1.10 million to 2.22 million) were attributed to sodium intake above the reference level; 61.9% of these deaths occurred in men and 38.1% occurred in women. These deaths accounted for nearly 1 of every 10 deaths from cardiovascular causes (9.5%). Four of every 5 deaths (84.3%) occurred in low- and middle-income countries, and 2 of every 5 deaths (40.4%) were premature (before 70 years of age). The rate of death from cardiovascular causes associated with sodium intake above the reference level was highest in the country of Georgia and lowest in Kenya.In this modeling study, 1.65 million deaths from cardiovascular causes that occurred in 2010 were attributed to sodium consumption above a reference level of 2.0 g per day. (Funded by the Bill and Melinda Gates Foundation.).Bill and Melinda Gates Foundatio

Global, regional and national consumption of major food groups in 1990 and 2010 : a systematic analysis including 266 country-specific nutrition surveys worldwide

Objective: To quantify global intakes of key foods related to non-communicable diseases in adults by region (n=21), country (n=187), age and sex, in 1990 and 2010. Design: We searched and obtained individual-level intake data in 16 age/sex groups worldwide from 266 surveys across 113 countries. We combined these data with food balance sheets available in all nations and years. A hierarchical Bayesian model estimated mean food intake and associated uncertainty for each age-sex-country-year stratum, accounting for differences in intakes versus availability, survey methods and representativeness, and sampling and modelling uncertainty. Setting/population: Global adult population, by age, sex, country and time. Results: In 2010, global fruit intake was 81.3 g/day (95% uncertainty interval 78.9–83.7), with country-specific intakes ranging from 19.2–325.1 g/day; in only 2 countries (representing 0.4% of the world's population), mean intakes met recommended targets of ≥300 g/day. Country-specific vegetable intake ranged from 34.6–493.1 g/day (global mean=208.8 g/day); corresponding values for nuts/seeds were 0.2–152.7 g/day (8.9 g/day); for whole grains, 1.3–334.3 g/day (38.4 g/day); for seafood, 6.0–87.6 g/day (27.9 g/day); for red meats, 3.0–124.2 g/day (41.8 g/day); and for processed meats, 2.5–66.1 g/day (13.7 g/day). Mean national intakes met recommended targets in countries representing 0.4% of the global population for vegetables (≥400 g/day); 9.6% for nuts/seeds (≥4 (28.35 g) servings/week); 7.6% for whole grains (≥2.5 (50 g) servings/day); 4.4% for seafood (≥3.5 (100 g) servings/week); 20.3% for red meats (≤1 (100 g) serving/week); and 38.5% for processed meats (≤1 (50 g) serving/week). Intakes of healthful foods were generally higher and of less healthful foods generally lower at older ages. Intakes were generally similar by sex. Vegetable, seafood and processed meat intakes were stable over time; fruits, nuts/seeds and red meat, increased; and whole grains, decreased. Conclusions: These global dietary data by nation, age and sex identify key challenges and opportunities for optimising diets, informing policies and priorities for improving global health.peer-reviewe

WHO draft guidelines on dietary saturated and trans fatty acids: time for a new approach?

The 2018 WHO draft guidelines on dietary saturated fatty acids and trans fatty acids recommend reducing total intake of saturated fat and replacing it with polyunsaturated and monounsaturated fatty acids. The recommendations fail to take into account considerable evidence that the health effects of saturated fat varies depending on the specific fatty acid and on the specific food source. Maintaining general advice to reduce total saturated fatty acids will work against the intentions of the guidelines and weaken their effect on chronic disease incidence and mortality. A food based translation of the recommendations for saturated fat intake would avoid unnecessary reduction or exclusion of foods that are key sources of important nutrients