AIMS/HYPOTHESIS:Most studies of diet in glucose intolerance and type 2 diabetes have focused on intakes of fat, carbohydrate, fibre, fruits and vegetables. Instead, we aimed to compare diets that were available during human evolution with more recently introduced ones.

METHODS:Twenty-nine patients with ischaemic heart disease plus either glucose intolerance or type 2 diabetes were randomised to receive (1) a Palaeolithic ('Old Stone Age') diet (n = 14), based on lean meat, fish, fruits, vegetables, root vegetables, eggs and nuts; or (2) a Consensus (Mediterranean-like) diet (n = 15), based on whole grains, low-fat dairy products, vegetables, fruits, fish, oils and margarines. Primary outcome variables were changes in weight, waist circumference and plasma glucose AUC (AUC Glucose(0-120)) and plasma insulin AUC (AUC Insulin(0-120)) in OGTTs.

RESULTS:Over 12 weeks, there was a 26% decrease of AUC Glucose(0-120) (p = 0.0001) in the Palaeolithic group and a 7% decrease (p = 0.08) in the Consensus group. The larger (p = 0.001) improvement in the Palaeolithic group was independent (p = 0.0008) of change in waist circumference (-5.6 cm in the Palaeolithic group, -2.9 cm in the Consensus group; p = 0.03). In the study population as a whole, there was no relationship between change in AUC Glucose(0-120) and changes in weight (r = -0.06, p = 0.9) or waist circumference (r = 0.01, p = 1.0). There was a tendency for a larger decrease of AUC Insulin(0-120) in the Palaeolithic group, but because of the strong association between change in AUC Insulin(0-120) and change in waist circumference (r = 0.64, p = 0.0003), this did not remain after multivariate analysis.

CONCLUSIONS/INTERPRETATION:A Palaeolithic diet may improve glucose tolerance independently of decreased waist circumference.

BACKGROUND:We found marked improvement of glucose tolerance and lower dietary energy intake in ischemic heart disease (IHD) patients after advice to follow a Paleolithic diet, as compared to a Mediterranean-like diet. We now report findings on subjective ratings of satiety at meals and data on the satiety hormone leptin and the soluble leptin receptor from the same study.

METHODS:Twenty-nine male IHD patients with impaired glucose tolerance or diabetes type 2, and waist circumference>94 cm, were randomized to ad libitum consumption of a Paleolithic diet (n = 14) based on lean meat, fish, fruit, vegetables, root vegetables, eggs, and nuts, or a Mediterranean-like diet (n = 15) based on whole grains, low-fat dairy products, vegetables, fruit, fish, and oils and margarines during 12 weeks. In parallel with a four day weighed food record the participants recorded their subjective rating of satiety. Satiety Quotients were calculated, as the intra-meal quotient of change in satiety during meal and consumed energy or weight of food and drink for that specific meal. Leptin and leptin receptor was measured at baseline and after 6 and 12 weeks. Free leptin index was calculated as the ratio leptin/leptin receptor.

RESULTS:The Paleolithic group were as satiated as the Mediterranean group but consumed less energy per day (5.8 MJ/day vs. 7.6 MJ/day, Paleolithic vs. Mediterranean, p = 0.04). Consequently, the quotients of mean change in satiety during meal and mean consumed energy from food and drink were higher in the Paleolithic group (p = 0.03). Also, there was a strong trend for greater Satiety Quotient for energy in the Paleolithic group (p = 0.057). Leptin decreased by 31% in the Paleolithic group and by 18% in the Mediterranean group with a trend for greater relative decrease of leptin in the Paleolithic group. Relative changes in leptin and changes in weight and waist circumference correlated significantly in the Paleolithic group (p<0.001) but not in the Mediterranean group. Changes in leptin receptor and free leptin index were not significant.

CONCLUSIONS:A Paleolithic diet is more satiating per calorie than a Mediterranean-like diet.

TRIAL REGISTRATION:ClinicalTrials.gov NCT00419497.

Background Active commuting is related to a higher level of physical activity but more exposure to ambient air pollutants. With the rather serious air pollution in urban China, we aimed to examine the association between active commuting and risk of incident cardiovascular disease in the Chinese population.

Methods and Results A total of 104 170 urban commuters without major chronic diseases at baseline were included from China Kadoorie Biobank. Self-reported commuting mode was defined as nonactive commuting, work at home or near home, walking, and cycling. Multivariable Cox regression was used to examine associations between commuting mode and cardiovascular disease. Overall, 47.2% of the participants reported nonactive commuting, 13.4% reported work at home or work near home, 20.1% reported walking, and 19.4% reported cycling. During a median follow-up of 10 years, we identified 5374 incidents of ischemic heart disease, 664 events of hemorrhagic stroke, and 4834 events of ischemic stroke. After adjusting for sex, socioeconomic status, lifestyle factors, sedentary time, body mass index, comorbidities, household air pollution, passive smoking, and other domain physical activity, walking (hazard ratio, 0.90; 95% CI, 0.84-0.96) and cycling (hazard ratio, 0.81; 95% CI, 0.74-0.88) were associated with a lower risk of ischemic heart disease than nonactive commuting. Cycling was associated with a lower risk of ischemic stroke (hazard ratio, 0.92; 95% CI, 0.84-1.00). No significant association was found of walking or cycling with hemorrhagic stroke. The associations of commuting mode with major cardiovascular disease were consistent among men and women and across different levels of other domain physical activity.

Conclusions In urban China, cycling was associated with a lower risk of ischemic heart disease and ischemic stroke. Walking was associated with a lower risk of ischemic heart disease.

The cardio-protective effects of a low carbohydrate ketogenic diet following global ischaemic injury as compared to rats fed a normal and high carbohydrate diet for a period of 19 weeks, were investigated. The reperfusion recovery of coronary flow was highly significant in the low carbohydrate ketogenic diet group. Although the initial reperfusion recovery of the pressure developed in the left ventricle, Pmax was similar in all groups, after 15 minutes, the momentum for faster recovery was maintained in the low carbohydrate ketogenic diet group. Ultrastructural observations of the cardiac muscles have shown that there was a decrease in the number of mitochondria in rats fed a high carbohydrate diet and an increase in the number of mitochondria in those fed a low carbohydrate ketogenic diet as compared to the normal diet group.This study demonstrates that a low carbohydrate ketogenic diet is cardio-protective functionally.

INTRODUCTION: Ischaemia and reperfusion lead to cell death. These pathways are regulated and hence are subjected to therapeutic intervention. Previously, we have shown that a low carbohydrate ketogenic diet (LCKD) reduces the risk factors for heart disease in obese patients. This study is aimed at understanding the cardio-protective effects of LCKD following global ischaemic injury in rats.

MATERIALS AND METHODS: Rats weighing 190-250 g were divided into normal diet (ND), LCKD and high carbohydrate diet (HCD) groups consisting of six animals in each group. Specific diets were given to each group for a period of 19 weeks. Changes in body weight, ultrastructure of the cardiac muscles and the cardio-protective effects of the LCKD group as compared to the ND and HCD groups were investigated in rats following global ischaemic injury.

RESULTS: Electron microscopic studies have shown that there was a decrease in the number of mitochondria in rats fed a high carbohydrate diet and an increase in the number of mitochondria in those fed a low carbohydrate ketogenic diet as compared to the normal diet group. Rats on LCKD had a remarkable tolerance to ischaemia and a faster recovery of cardiac function following reperfusion. The initial reperfusion recovery of the pressure developed in the left ventricle, Pmax was similar in all groups. However, after 15 minutes, the momentum for faster recovery was significantly maintained in the LCKD group (P < 0.05). The reperfusion recovery of coronary flow was highly significant (P < 0.05) in the LCKD regime. The increase in left ventricle end diastolic pressure, coronary vascular resistance and the changes in body weight were not significant between the experimental groups.

DISCUSSION AND CONCLUSION: This is a unique study showing ultrastructural variation in cardiac muscle in relation to cardio-protective function in rats fed a low carbohydrate ketogenic diet. This study suggests that the LCKD is cardio-protective functionally.The underlying mechanism of the cardio-protective effect of an LCKD needs to be elucidated.

BACKGROUND:Beneficial effects of vegetarian and vegan diets on health outcomes have been supposed in previous studies.

OBJECTIVES:Aim of this study was to clarify the association between vegetarian, vegan diets, risk factors for chronic diseases, risk of all-cause mortality, incidence and mortality from cardio-cerebrovascular diseases, total cancer and specific type of cancer (colorectal, breast, prostate and lung), through meta-analysis.

METHODS:A comprehensive search of Medline, EMBASE, Scopus, The Cochrane Library and Google Scholar was conducted.

RESULTS:Eighty-six cross-sectional and 10 cohort prospective studies were included. The overall analysis among cross-sectional studies reported significant reduced levels of body mass index, total cholesterol, LDL-cholesterol, and glucose levels in vegetarians and vegans versus omnivores. With regard to prospective cohort studies, the analysis showed a significant reduced risk of incidence and/or mortality from ischemic heart disease (RR 0.75; 95% CI, 0.68 to 0.82) and incidence of total cancer (RR 0.92; 95% CI 0.87 to 0.98) but not of total cardiovascular and cerebrovascular diseases, all-cause mortality and mortality from cancer. No significant association was evidenced when specific types of cancer were analyzed. The analysis conducted among vegans reported significant association with the risk of incidence from total cancer (RR 0.85; 95% CI, 0.75 to 0.95), despite obtained only in a limited number of studies.

CONCLUSIONS:This comprehensive meta-analysis reports a significant protective effect of a vegetarian diet versus the incidence and/or mortality from ischemic heart disease (-25%) and incidence from total cancer (-8%). Vegan diet conferred a significant reduced risk (-15%) of incidence from total cancer.