Long-term caloric restriction

Abstract

Objectives: We determined whether caloric restriction (CR) has cardiac-specific effects that attenuate the established aging-associated impairments in diastolic function.

Background: Caloric restriction retards the aging process in small mammals; however, no information is available on the effects of long-term CR on human aging. In healthy individuals, Doppler echocardiography has established the pattern of aging-associated diastolic impairment, whereas little change is observed in systolic function.

Methods: Diastolic function was assessed in 25 subjects (age 53 +/- 12 years) practicing CR for 6.5 +/- 4.6 years and 25 age- and gender-matched control subjects consuming Western diets. Diastolic function was quantified by transmitral flow, Doppler tissue imaging, and model-based image processing (MBIP) of E waves. C-reactive protein (CRP), TNF-alpha and TGF-beta1 were also measured.

Results: No difference in systolic function was observed between groups; however, standard transmitral Doppler flow diastolic function indexes of the CR group were similar to those of younger individuals, and MBIP-based, flow-derived diastolic function indexes, reflecting chamber viscoelasticity and stiffness, were significantly lower than in control subjects.

Blood pressure, serum CRP, TNF-alpha, and TGF-beta1 levels were significantly lower in the CR group (102 +/- 10/61 +/- 7 mm Hg, 0.3 +/- 0.3 mg/l, 0.8 +/- 0.5 pg/ml, 29.4 +/- 6.9 ng/ml, respectively) compared with the Western diet group (131 +/- 11/83 +/- 6 mm Hg, 1.9 +/- 2.8 mg/l, 1.5 +/- 1.0 pg/ml, 35.4 +/- 7.1 ng/ml, respectively).

Conclusions: Caloric restriction has cardiac-specific effects that ameliorate aging-associated changes in diastolic function. These beneficial effects on cardiac function might be mediated by the effect of caloric restriction on blood pressure, systemic inflammation, and myocardial fibrosis.

SOURCE: J Am Coll Cardiol

EDITOR’S NOTE: The middle-aged adults in the calorie restriction group maintained an average blood pressure (102/61) that in Western society is normally characteristic of a pre-teen.


Caloric restriction ± exercise

Abstract

Calorie restriction (CR) delays the development of age-associated disease and increases lifespan in rodents, but the effects in humans remain uncertain.

Purpose. Determine the effect of 6 months of CR with or without exercise on cardiovascular disease (CVD) risk factors and estimated 10-year CVD risk in healthy non-obese men and women.

Methods. Thirty-six individuals were randomized to one of three groups for 6 months: Control, 100% of energy requirements; CR, 25% calorie restriction; CR+EX, 12.5% CR + 12.5% increase in energy expenditure via aerobic exercise. CVD risk factors were assessed at baseline, 3 and 6 months.

Results. After 6 months, CR and CR+EX lost approximately 10% of body weight. CR significantly reduced triacylglycerol (-31 ± 15 mg/dL) and factor VIIc (-10.7 ± 2.3%). Similarly CR+EX reduced triacylglycerol (-22 ± 8 mg/dL) and additionally reduced LDL-C (-16.0 ± 5.1 mg/dL) and DBP (-4.0 ± 2.1 mmHg). In contrast, both triacylglycerol (24 ± 14 mg/dL) and factor VIIc (7.9 ± 2.3%) were increased in the control group. HDL-cholesterol was increased in all groups while hsCRP was lower in the Controls vs. CR+EX. Estimated 10-year CVD risk significantly declined from baseline by 29% in CR (P< 0.001) and 38% in the CR+EX (P<0.001) while remaining unchanged in the Control group.

Conclusions. Based on combined favorable changes in lipid and blood pressure, caloric restriction with or without exercise that induces weight loss favorably reduces risk for CVD even in already healthy non-obese individuals.

SOURCE: Atherosclerosis


Calorie restriction or exercise …

Coronary heart disease (CHD) risk factors and the risk of CHD increase with increased adiposity. Fat loss induced by negative energy balance improves all metabolic CHD risk factors.

To determine whether fat loss induced by long-term calorie restriction (CR) or increased energy expenditure induced by exercise (EX) has different effects on CHD risk factors in nonobese subjects, we conducted a 1-yr controlled trial involving 48 nonobese subjects who were randomly assigned to one of three groups: CR, 20% CR diet (n = 18); EX, 20% increase in energy expenditure through daily exercise with no increase in energy intake (n = 18); or HL, healthy lifestyle guidelines (n = 10). Subjects were 29 women and 17 men aged 57 ± 3 yr, with BMI 27.3 ± 2.0 kg/m2.

Assessments included total body fat by DEXA, lipoproteins, blood pressure, HOMA-IR, C-reactive protein (CRP), and estimated 10-yr CHD risk score. Body fat decreased by 6.3 ± 3.8 kg in CR, 5.6 ± 4.4 kg in EX, and 0.4 ± 1.7 kg in HL, which corresponded to reductions of 24.9, 22.3, and 1.2% of baseline body fat mass, respectively.

The energy deficits [induced by either caloric restriction or exercise] were accompanied by reductions in most of the major CHD risk factors, including plasma LDL-cholesterol, total cholesterol/HDL ratio, HOMA-IR index, and CRP concentrations that were similar in the two intervention groups.

Data from the present study provide evidence that [both calorie restriction and exercise-induced] negative energy balance result in substantial and similar improvements in the major risk factors for coronary heart disease in normal-weight and overweight middle-aged adults.

SOURCE: Am J Physiology