Low-Carbohydrate Diets and All-Cause Mortality: A Systematic Review and Meta-Analysis of Observational Studies

Abstract

ObjectiveLow-carbohydrate diets and their combination with high-protein diets have been gaining widespread popularity to control weight. In addition to weight loss, they may have favorable short-term effects on the risk factors of cardiovascular disease (CVD). Our objective was to elucidate their long-term effects on mortality and CVD incidence.Data sourcesMEDLINE, EMBASE, ISI Web of Science, Cochrane Library, and ClinicalTrials.gov for relevant articles published as of September 2012. Cohort studies of at least one year’s follow-up period were included.Review methodsIdentified articles were systematically reviewed and those with pertinent data were selected for meta-analysis. Pooled risk ratios (RRs) with 95% confidence intervals (CIs) for all-cause mortality, CVD mortality and CVD incidence were calculated using the random-effects model with inverse-variance weighting.ResultsWe included 17 studies for a systematic review, followed by a meta-analysis using pertinent data. Of the 272,216 people in 4 cohort studies using the low-carbohydrate score, 15,981 (5.9%) cases of death from all-cause were reported. The risk of all-cause mortality among those with high low-carbohydrate score was significantly elevated: the pooled RR (95% CI) was 1.31 (1.07–1.59). A total of 3,214 (1.3%) cases of CVD death among 249,272 subjects in 3 cohort studies and 5,081 (2.3%) incident CVD cases among 220,691 people in different 4 cohort studies were reported. The risks of CVD mortality and incidence were not statistically increased: the pooled RRs (95% CIs) were 1.10 (0.98–1.24) and 0.98 (0.78–1.24), respectively. Analyses using low-carbohydrate/high-protein score yielded similar results.ConclusionLow-carbohydrate diets were associated with a significantly higher risk of all-cause mortality and they were not significantly associated with a risk of CVD mortality and incidence. However, this analysis is based on limited observational studies and large-scale trials on the complex interactions between low-carbohydrate diets and long-term outcomes are needed.

Long‐term Low‐carbohydrate Diets and Type 2 Diabetes Risk: A Systematic Review and Meta‐analysis of Observational Studies

“…Although the dietary assessment and the diagnosis of diabetes were mainly self-reported, the relative validity of carbohydrate measures using the Food Frequency Questionnaire has generally been reported to be moderate to good, and a high validation of the diagnosis of diabetes was confirmed in most of the included studies. Despite these facts, our current study and a previous meta-analysis 8 did not find a long-term health benefit when such nutritional quality was not considered. In fact, a recent meta-analysis has suggested protective effects of a low dietary glycemic index and a low glycemic load 10 and a cohort study documented a significant association between rice intake and an increased risk of type 2 diabetes.…”

“…35 Little is known about the consequences of lowcarbohydrate diets with respect to other chronic health problems, such as cancer, kidney disease, osteoporosis, and mental conditions. The biology that underlies the positive correlation between low-carbohydrate diets and all-cause death 8 has not yet been fully explained.…”

“…Given the facts that low-carbohydrate diets are potentially unsafe 8 However, most of the target populations were free of chronic disease at baseline, and it is unlikely that the dietary habits had been modulated according to their previous health status. The dietary patterns may have varied over the course of the follow-up periods, but the dietary information was not updated in many of the studies, possibly affecting the magnitude of the risk as suggested by the subgroup analysis of the follow-up periods.…”

“…Our recent analysis has suggested that low-carbohydrate diets are associated with a significantly higher mortality and potentially increased risk of CVD, although the causes of premature death, such as diabetes-related death, remain to be elucidated. 8 Since obesity is a major risk factor for diabetes, it is speculated that low-carbohydrate diets might prevent diabetes, although the results of previous limited metaanalyses have been mixed. 9,10 In light of the worldwide diabetes epidemic and the widespread popularity of low-carbohydrate diets, explorations of their long-term preventative effects on health are of clinical importance in terms of weight control.…”

Hidratos de carbono y práctica deportiva: una etnografía virtual en Twitter

“…Existen ya metaanálisis disponibles que cuestionan este clásico paradigma al observar que para la reducción de peso a largo plazo es tan efectivo emplear dietas bajas en hidratos de carbono como dietas isoenergéticas equilibradas (1). Además, recientes estudios han demostrado que las dietas bajas en hidratos de carbono están más bien asociadas con un incremento del riesgo de mortalidad de cualquier tipo y no tanto con la disminución del riesgo en enfermedad cardiovascular (28).…”