John Powles

Food livestock production energy climate change and health.

Food provides energy and nutrients, but its acquisition requires energy expenditure. In post-hunter-gatherer societies, extra-somatic energy has greatly expanded and intensified the catching, gathering, and production of food. Modern relations between energy, food, and health are very complex, raising serious, high-level policy challenges. Together with persistent widespread under-nutrition, over-nutrition (and sedentarism) is causing obesity and associated serious health consequences. Worldwide, agricultural activity, especially livestock production, accounts for about a fifth of total greenhouse-gas emissions, thus contributing to climate change and its adverse health consequences, including the threat to food yields in many regions. Particular policy attention should be paid to the health risks posed by the rapid worldwide growth in meat consumption, both by exacerbating climate change and by directly contributing to certain diseases. To prevent increased greenhouse-gas emissions from this production sector, both the average worldwide consumption level of animal products and the intensity of emissions from livestock production must be reduced. An international contraction and convergence strategy offers a feasible route to such a goal. The current global average meat consumption is 100 g per person per day, with about a ten-fold variation between high-consuming and low-consuming populations. 90 g per day is proposed as a working global target, shared more evenly, with not more than 50 g per day coming from red meat from ruminants (ie, cattle, sheep, goats, and other digastric grazers).

Global sodium consumption and death from cardiovascular causes

BACKGROUND High sodium intake increases blood pressure, a risk factor for cardiovascular disease, but the effects of sodium intake on global cardiovascular mortality are uncertain. METHODS 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. RESULTS 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. CONCLUSIONS 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.).

Global, regional and national sodium intakes in 1990 and 2010: a systematic analysis of 24 h urinary sodium excretion and dietary surveys worldwide.

Objectives To estimate global, regional (21 regions) and national (187 countries) sodium intakes in adults in 1990 and 2010. Design Bayesian hierarchical modelling using all identifiable primary sources. Data sources and eligibility We searched and obtained published and unpublished data from 142 surveys of 24 h urinary sodium and 103 of dietary sodium conducted between 1980 and 2010 across 66 countries. Dietary estimates were converted to urine equivalents based on 79 pairs of dual measurements. Modelling methods Bayesian hierarchical modelling used survey data and their characteristics to estimate mean sodium intake, by sex, 5 years age group and associated uncertainty for persons aged 20+ in 187 countries in 1990 and 2010. Country-level covariates were national income/person and composition of food supplies. Main outcome measures Mean sodium intake (g/day) as estimable by 24 h urine collections, without adjustment for non-urinary losses. Results In 2010, global mean sodium intake was 3.95 g/day (95% uncertainty interval: 3.89 to 4.01). This was nearly twice the WHO recommended limit of 2 g/day and equivalent to 10.06 (9.88–10.21) g/day of salt. Intake in men was ∼10% higher than in women; differences by age were small. Intakes were highest in East Asia, Central Asia and Eastern Europe (mean >4.2 g/day) and in Central Europe and Middle East/North Africa (3.9–4.2 g/day). Regional mean intakes in North America, Western Europe and Australia/New Zealand ranged from 3.4 to 3.8 g/day. Intakes were lower (<3.3 g/day), but more uncertain, in sub-Saharan Africa and Latin America. Between 1990 and 2010, modest, but uncertain, increases in sodium intakes were identified. Conclusions Sodium intakes exceed the recommended levels in almost all countries with small differences by age and sex. Virtually all populations would benefit from sodium reduction, supported by enhanced surveillance.

Ecological study of reasons for sharp decline in mortality from ischaemic heart disease in Poland since 1991

Objective: To investigate the reasons for the decline in deaths attributed to ischaemic heart disease in Poland since 1991 after two decades of rising rates. Design: Recent changes in mortality were measured as percentage deviations in 1994 from rates predicted by extrapolation of sex and age specific death rates for 1980-91 for diseases of the circulatory system and selected other categories. Available data on national and household food availability, alcohol consumption, cigarette smoking, socioeconomic indices, and medical services over time were reviewed. Main outcome measures: Age specific and age standardised rates of death attributed to ischaemic heart disease and related causes. Results: The change in trend in mortality attributed to diseases of the circulatory system was similar in men and women and most marked (>20%) in early middle age. For ages 45 to 64 the decrease was greatest for deaths attributed to ischaemic heart disease and atherosclerosis (around 25%) and less for stroke (<10%). For most of the potentially explanatory variables considered, there were no corresponding changes in trend. However, between 1986-90 and 1994 there was a marked switch from animal fats (estimated availability down 23%) to vegetable fats (up 48%) and increased imports of fruit. Conclusion: Reporting biases are unlikely to have exaggerated the true fall in ischaemic heart disease; neither is it likely to be mainly due to changes in smoking, drinking, stress, or medical care. Changes in type of dietary fat and increased supplies of fresh fruit and vegetables seem to be the best candidates. Key messages Among former socialist countries Poland has undergone unusually rapid social and economic changes since 1988-9, including aspects of diet Mortality from heart disease declined sharply during 1991-4 after long term increases; mortality from stroke declined less strongly This study investigated what has changed in Poland to reduce the risks of fatal events in people with established ischaemic heart disease Candidate dietary explanations were the substitution of unsaturated for saturated fats and increased consumption of fresh fruit and vegetables

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.

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

Summary 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.

Impact of a reduced red and processed meat dietary pattern on disease risks and greenhouse gas emissions in the UK: a modelling study

Objectives Consumption of red and processed meat (RPM) is a leading contributor to greenhouse gas (GHG) emissions, and high intakes of these foods increase the risks of several leading chronic diseases. The aim of this study was to use newly derived estimates of habitual meat intakes in UK adults to assess potential co-benefits to health and the environment from reduced RPM consumption. Design Modelling study using dietary intake data from the National Diet and Nutrition Survey of British Adults. Setting British general population. Methods Respondents were divided into fifths by energy-adjusted RPM intakes, with vegetarians constituting a sixth stratum. GHG emitted in supplying the diets of each stratum was estimated using data from life-cycle analyses. A feasible counterfactual UK population was specified, in which the proportion of vegetarians measured in the survey population doubled, and the remainder adopted the dietary pattern of the lowest fifth of RPM consumers. Outcome measures Reductions in risks of coronary heart disease, diabetes and colorectal cancer, and GHG emissions, under the counterfactual. Results Habitual RPM intakes were 2.5 times higher in the top compared with the bottom fifth of consumers. Under the counterfactual, statistically significant reductions in population aggregate risks ranged from 3.2% (95% CI 1.9 to 4.7) for diabetes in women to 12.2% (6.4 to 18.0) for colorectal cancer in men, with those moving from the highest to lowest consumption levels gaining about twice these averages. The expected reduction in GHG emissions was 0.45 tonnes CO2 equivalent/person/year, about 3% of the current total, giving a reduction across the UK population of 27.8 million tonnes/year. Conclusions Reduced consumption of RPM would bring multiple benefits to health and environment.

Estimating the global and regional burden of suboptimal nutrition on chronic disease: methods and inputs to the analysis.

Background/Objectives:Global burdens of cardiovascular disease (CVD), diabetes and cancer are on the rise. Little quantitative data are available on the global impact of diet on these conditions. The objective of this study was to develop systematic and comparable methods to quantitatively assess the impact of suboptimal dietary habits on CVD, diabetes and cancer burdens globally and in 21 world regions.Subjects/Methods:Using a comparative risk assessment framework, we developed methods to establish for selected dietary risk factors the effect sizes of probable or convincing causal diet–disease relationships, the alternative minimum-risk exposure distributions and the exposure distributions. These inputs, together with disease-specific mortality rates, allow computation of the numbers of events attributable to each dietary factor.Results:Using World Health Organization and similar evidence criteria for convincing/probable causal effects, we identified 14 potential diet–disease relationships. Effect sizes and ranges of uncertainty will be derived from systematic reviews and meta-analyses of trials or high-quality observational studies. Alternative minimum-risk distributions were identified based on amounts corresponding to the lowest disease rates in populations. Optimal and alternative definitions for each exposure were established based on the data used to quantify harmful or protective effects. We developed methods for identifying and obtaining data from nationally representative surveys. A ranking scale was developed to assess survey quality and validity of dietary assessment methods. Multi-level hierarchical models will be developed to impute missing data.Conclusions:These new methods will allow, for the first time, assessment of the global impact of specific dietary factors on chronic disease mortality. Such global assessment is not only possible but is also imperative for priority setting and policy making.

Vitamin C and Cardiovascular Disease: A Systematic Review:

Background Laboratory studies suggest that antioxidants, such as vitamin C, are important inhibitors of atherosclerotic lesions. Most epidemiological reviews have considered all antioxidants together. This review seeks to clarify the current state of knowledge specifically concerned with vitamin C. Methods All ecological studies, case-control studies, prospective studies and trials in humans that examined the association between vitamin C intake or blood levels of vitamin C and cardiovascular disease were included. Relevant references were located by a MEDLINE search for articles published from 1966 to 1996, by an EMBASE search for articles published from 1980 to 1996, by searching personal bibliographies, books and reviews and from citations in located articles. Results For coronary heart disease four of seven ecological studies, one of four case-control studies and three of 12 cohort studies found a significant protective association with vitamin C intake or status. For strokes two of two ecological studies, none of one case-control study and two of seven cohort studies found a significant protective association. For total circulatory disease, two of three cohort studies reported a significant protective association. Conclusions The evidence, albeit limited, is consistent with vitamin C having protective effect against stroke whereas the evidence that vitamin C is protective against coronary heart disease is less consistent. The lack of an association for coronary heart disease could be explained in terms of there being a true lack of effect, dietary measurement error, a threshold effect, an effect of seasonal variations in intake, an interaction with other dietary constituents or a relatively short duration of follow-up.

Lung cancer mortality at ages 35-54 in the European Union: ecological study of evolving tobacco epidemics

Epidemiological analyses indicate that disease attributable to smoking is a leading contributor to the large gap in premature mortality between the 15 countries that formerly made up the European Union and the new member states from central and eastern Europe.1 However, the prevalence of smoking in most countries has not been measured in a sufficiently consistent way, or over a long enough period, to be used to predict trends in diseases caused by smoking. Lung cancer mortality can provide a useful measure of a populations exposure to smoking,2 3 especially the population segment aged 35-54, when around 80-90% of cases are caused by smoking. We used trends, for each sex, in age standardised mortality due to lung cancer for ages 35-54 to map the lagged effects of the smoking epidemic in the 15 original EU member states and new members from central and eastern Europe, and to …