Associations of fats and carbohydrates with cardiovascular disease and mortality—PURE and simple?
Authors: Xi-Peng Cao, Chen-Chen Tan, Jin-Tai Yu
Journal: The Lancet (2018)

The Prospective Urban Rural Epidemiological (PURE) study1Dehghan M Mente A Zhang X et al.Associations of fats and carbohydrate intake with cardiovascular disease and mortality in 18 countries from five continents (PURE): a prospective cohort study.Lancet. 2017; 390: 2050-2062Summary Full Text Full Text PDF PubMed Scopus (643) Google Scholar has attracted considerable attention in both academia and the public domain. The conclusions of the study challenge the dietary advice and guidelines people have adhered to for decades. Scholars have questioned the accuracy of macronutrient distribution data reported in the PURE study for the Chinese population. The study reported that about 77% of the population in China consume at least 60% of energy from carbohydrate and 43% of individuals consume at least 70% of energy from carbohydrate, with a mean of 67·0% energy derived from carbohydrate and 17·7% from fat. However, these percentages differ from national data collected using the China Health and Nutrition Survey (CHNS). The CHNS was the first reliable, large-scale survey dataset collected in China. Between 1991 and 20012Zhai FY Du SF Wang ZH Zhang JG Du WW Popkin BM Dynamics of the Chinese diet and the role of urbanicity, 1991–2011.Obes Rev. 2014; 15: 16-26Crossref PubMed Scopus (341) Google Scholar a rapid decline in energy intake from carbohydrate and an increase in energy intake from fat were observed. The basement survey3Corsi DJ Subramanian SV Chow CK et al.Prospective Urban Rural Epidemiology (PURE) study: baseline characteristics of the household sample and comparative analyses with national data in 17 countries.Am Heart J. 2013; 166 (46.e4): 636Summary Full Text Full Text PDF PubMed Scopus (101) Google Scholar of the PURE study was done in September, 2005. In view of the CHNS dataset from 2000 to 2011,2Zhai FY Du SF Wang ZH Zhang JG Du WW Popkin BM Dynamics of the Chinese diet and the role of urbanicity, 1991–2011.Obes Rev. 2014; 15: 16-26Crossref PubMed Scopus (341) Google Scholar it is reasonable to infer that Chinese participants in the PURE study during the basement survey period obtained 54·3–59·8% energy from carbohydrate and 27·8–32·0% energy from fat, which differs from the percentages reported in the PURE study. Several factors could account for these discrepancies. The PURE study and the CHNS used different methods to collect dietary survey data. In the PURE study, food intake was recorded using Food Frequency Questionnaires at baseline with multiple 24 h dietary recalls as the reference method for validation, whereas the 2002 CHNS used 3 day, 24 h dietary recalls, combined with food weighing and Food Frequency Questionnaires. Furthermore, the measurement of edible oils (eg, cooking oils) is important. The five main sources of total fat for the Chinese population in the PURE study are highly controversial because edible oils were not listed, which are the main source of fat among the Chinese population,4Ng SW Zhai F Popkin BM Impacts of China's edible oil pricing policy on nutrition.Soc Sci Med. 2008; 66: 414-426Crossref PubMed Scopus (41) Google Scholar accounting for more than 40% of fat intake.2Zhai FY Du SF Wang ZH Zhang JG Du WW Popkin BM Dynamics of the Chinese diet and the role of urbanicity, 1991–2011.Obes Rev. 2014; 15: 16-26Crossref PubMed Scopus (341) Google Scholar Using Food Frequency Questionnaires to record the use of edible oils can also be inaccurate. Frying and broiling are the main cooking methods used in China, thus the measurement of cooking oil used in food preparation is important for the accuracy of data collected from the Chinese population. In 2010, the CHNS was updated to include the measurement of cooking oils and condiments before cooking. We declare no competing interests. Associations of fats and carbohydrate intake with cardiovascular disease and mortality in 18 countries from five continents (PURE): a prospective cohort studyHigh carbohydrate intake was associated with higher risk of total mortality, whereas total fat and individual types of fat were related to lower total mortality. Total fat and types of fat were not associated with cardiovascular disease, myocardial infarction, or cardiovascular disease mortality, whereas saturated fat had an inverse association with stroke. Global dietary guidelines should be reconsidered in light of these findings. Full-Text PDF Associations of fats and carbohydrates with cardiovascular disease and mortality—PURE and simple?The authors of the Prospective Urban Rural Epidemiological (PURE) study (Nov 4, 2017, p 2050)1 suggest that "removing current restrictions on fat intake, but limiting carbohydrate (when high) might improve health" and that global guidelines should be reconsidered in light of their findings. Full-Text PDF Associations of fats and carbohydrates with cardiovascular disease and mortality—PURE and simple?The Prospective Urban Rural Epidemiological (PURE) investigators previously published ecological analyses showing that total and cardiovascular mortality was substantially higher in low-income countries than in high-income countries (total mortality hazard ratio [HR] 3·66 and cardiovascular mortality HR 6·05).1 Full-Text PDF Associations of fats and carbohydrates with cardiovascular disease and mortality—PURE and simple?In The Lancet, Mahshid Dehghan and colleagues1 reported a positive association between carbohydrate intake and non-cardiovascular mortality, and an unexpected inverse association between non-cardiovascular mortality and saturated fat intake. The authors recommended changes in dietary guidelines on the basis of assumed causality. Full-Text PDF Associations of fats and carbohydrates with cardiovascular disease and mortality—PURE and simple?We congratulate Mahshid Dehghan and colleagues on the Prospective Urban Rural Epidemiological (PURE) study.1 Their results are consistent with evidence suggesting that a diet high in fat might reduce mortality2 and incidence of cardiovascular disease.3 Full-Text PDF Associations of fats and carbohydrates with cardiovascular disease and mortality—PURE and simple?Much has been said on the results from the Prospective Urban Rural Epidemiological (PURE) study by Mahshid Dehghan and colleagues.1 Data from 18 countries are represented, providing a valuable contribution to the body of prospective observational evidence. PURE is not the largest, most comprehensive, or longest running cohort study; however, the diverse sampling method is a valuable addition to nutrition epidemiology, should the PURE data be found usable. Full-Text PDF Associations of fats and carbohydrates with cardiovascular disease and mortality—PURE and simple?The Prospective Urban Rural Epidemiological (PURE) study1 investigators did outstanding work, but we have concerns regarding data presentation and interpretation. Full-Text PDF Associations of fats and carbohydrates with cardiovascular disease and mortality—PURE and simple? – Authors' replyWe concur with Jim Mann and colleagues that dietary recommendations should be informed with all available evidence, and that ideally large randomised trials on clinical outcomes should be used. In the absence of randomised trials, large, well designed observational studies on clinical outcomes provide the next best type of evidence. Our results are consistent with previous observational studies1 that showed no harm with high fat intake—even when mean fat intake was higher than in the Prospective Urban Rural Epidemiological (PURE) study. Full-Text PDF Associations of fats and carbohydrates with cardiovascular disease and mortality—PURE and simple?It is better to be rich and healthy than poor and sick: this is the main conclusion from a study1 by Mahshid Dehghan and colleagues published in The Lancet. In the Prospective Urban Rural Epidemiological (PURE) study, investigators examined nutrition and disease in 18 countries, focusing on understudied regions. More than 135 000 participants were enrolled between 2003 and 2013, with a median follow-up of 7·4 years. Full-Text PDF Associations of fats and carbohydrates with cardiovascular disease and mortality—PURE and simple?As intake of dietary fat remains a topic of intense debate,1,2 both in the scientific field and the media, epidemics of type 2 diabetes and coronary heart disease in some low-income countries threaten to become pandemic.3 Scholars, including the authors of the Prospective Urban Rural Epidemiological (PURE) study,4 warn that guidelines on dietary fat have been made on the basis of observational data, which should not be relied on. In India, clinical and public health professionals trying to prevent and control type 2 diabetes and coronary heart disease have developed guidelines and interventions using risk factors, including diet and fats (especially from cheap, reheated oils). Full-Text PDF Associations of fats and carbohydrates with cardiovascular disease and mortality—PURE and simple?The Prospective Urban Rural Epidemiological (PURE) study,1 which included 18 cohorts from low-income, middle-income, and high-income countries worldwide, reported that high carbohydrate intake was associated with an increased risk of total mortality, whereas high intake of total fat and individual types of fat were associated with reduced total mortality. These results contribute valuable evidence to the field of nutrition, but using questionnaires to infer the amount, quality, and composition of intake of fats is error prone because of the complexity of foods and the possibility of implausible questionnaire entries. Full-Text PDF