Research
A multicenter randomized controlled trial of a plant-based nutrition program to reduce body weight and cardiovascular risk in the corporate setting: the GEICO study
S Mishra, J Xu, [...], and N D Barnard
Abstract
BACKGROUND/OBJECTIVES: To determine the effects of a low-fat plant-based diet program on anthropometric and biochemical measures in a multicenter corporate setting.
SUBJECTS/METHODS: Employees from 10 sites of a major US company with body mass index ⩾25 kg/m2and/or previous diagnosis of type 2 diabetes were randomized to either follow a low-fat vegan diet, with weekly group support and work cafeteria options available, or make no diet changes for 18 weeks. Dietary intake, body weight, plasma lipid concentrations, blood pressure and glycated hemoglobin (HbA1C) were determined at baseline and 18 weeks.
RESULTS: Mean body weight fell 2.9 kg and 0.06 kg in the intervention and control groups, respectively (P<0.001). Total and low-density lipoprotein (LDL) cholesterol fell 8.0 and 8.1 mg/dl in the intervention group and 0.01 and 0.9 mg/dl in the control group (P<0.01). HbA1C fell 0.6 percentage point and 0.08 percentage point in the intervention and control group, respectively (P<0.01).
Among study completers, mean changes in body weight were −4.3 kg and −0.08 kg in the intervention and control groups, respectively (P<0.001). Total and LDL cholesterol fell 13.7 and 13.0 mg/dl in the intervention group and 1.3 and 1.7 mg/dl in the control group (P<0.001). HbA1C levels decreased 0.7 percentage point and 0.1 percentage point in the intervention and control group, respectively (P<0.01).
CONCLUSIONS: An 18-week dietary intervention using a low-fat plant-based diet in a corporate setting improves body weight, plasma lipids, and, in individuals with diabetes, glycemic control.
Can lifestyle changes reverse coronary heart disease? The Lifestyle Heart Trial.
Ornish D1, Brown SE, Scherwitz LW, Billings JH, Armstrong WT, Ports TA, McLanahan SM, Kirkeeide RL, Brand RJ, Gould KL.
Abstract
In a prospective, randomised, controlled trial to determine whether comprehensive lifestyle changes affect coronary atherosclerosis after 1 year, 28 patients were assigned to an experimental group (low-fat vegetarian diet, stopping smoking, stress management training, and moderate exercise) and 20 to a usual-care control group. 195 coronary artery lesions were analysed by quantitative coronary angiography. The average percentage diameter stenosis regressed from 40.0 (SD 16.9)% to 37.8 (16.5)% in the experimental group yet progressed from 42.7 (15.5)% to 46.1 (18.5)% in the control group. When only lesions greater than 50% stenosed were analysed, the average percentage diameter stenosis regressed from 61.1 (8.8)% to 55.8 (11.0)% in the experimental group and progressed from 61.7 (9.5)% to 64.4 (16.3)% in the control group. Overall, 82% of experimental-group patients had an average change towards regression. Comprehensive lifestyle changes may be able to bring about regression of even severe coronary atherosclerosis after only 1 year, without use of lipid-lowering drugs.
Veganism, aging and longevity: new insight into old concepts.
Abstract
PURPOSE OF REVIEW: Plant-based diets are associated with better health and longevity. Veganism is a strict form of vegetarianism, which has gained increasing attention in recent years. This review will focus on studies addressing mortality and health-span in vegans and vegetarians and discuss possible longevity-enhancing mechanisms.
RECENT FINDINGS: Studies in vegans are still limited. Epidemiologic studies consistently show lower disease rates, such as lower incidence of cancer and cardiovascular disease, but mortality rates are comparable with rates in vegetarians and occasional meat eaters. Reasons for following strict vegan diets differ, which may affect diet quality, and thus health and life-span. New insights into some characteristics of veganism, such as protein restriction or restriction in certain amino acids (leucine or methionine) show potentially life-span-enhancing potential. Veganism improves insulin resistance and dyslipidemia and associated abnormalities. Gut microbiota as mediator of dietary impact on host metabolism is more diverse in vegans and has been suggested to be a health-promoting factor. Vegan diets do not fulfill the requirements of children, pregnant women or old individuals who should receive adequate supplements.
SUMMARY:There is substantial evidence that plant-based diets are associated with better health but not necessarily lower mortality rates. The exact mechanisms of health promotion by vegan diets are still not entirely clear but most likely multifactorial. Reasons for and quality of the vegan diet should be assessed in longevity studies.