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At least 613 records · Page 34Linked to original sources
PubMed1998

Caloric restriction retards the aging associated changes in gamma-aminobutyric acidA receptor gene expression in rat cerebellum.

It is widely accepted that calorie restriction is an effective way of delaying the aging process. Also, there is an indication that the beneficial effects exerted by dietary manipulation may be due to a direct effect at the molecular level like gene expression. The studies were conducted to determine whether calorie restriction prevents any age-related changes in the structural and molecular aspects of the GABAA-BZ receptor. In aged (24-month old diet ad libitum) rats, the binding of [35S]t-butyl-bicyclophosphorothionate (TBPS) was significantly reduced in the cerebellum. In contrast, [35S]TBPS binding remained unchanged in the cerebellum of calorie restricted old rats. In order to evaluate the molecular basis of these changes, the alpha sub-unit mRNA levels were measured. The GABAA receptor alpha1 sub-unit mRNA level remained unchanged in both the old groups of rats. The alpha2 subunit mRNA level was significantly decreased in the cerebellum of aged rats (24-month old ad libitum), whereas it remained unchanged in the cerebellum of calorie restricted old animals. These findings indicate a selective age and diet related modulation in the stoichiometry of the GABAA receptor in aging.

Aging↗
PubMed1986

The effect of exercise on non-restricted caloric intake in male joggers.

This study examined the effects of both increasing and decreasing normal energy expenditure over periods of one week on the self-reported caloric intake of seven male joggers (22-27 years). The three levels of energy expenditure were: no exercise, regular exercise and double exercise. Despite significant difference in energy expenditure across conditions, self-reported caloric intake did not differ significantly, suggesting that energy intake was not affected by short-term changes in energy expenditure.

Adult↗
PubMed1997

Effect of body weight and caloric restriction on serum complement proteins, including Factor D/adipsin: studies in anorexia nervosa and obesity.

Complement plays important roles in host immune defences, and recent studies suggest that adipose tissue is an important site of production for some complement proteins. Starvation has been associated with low complement levels, but studied populations have usually had concomitant opportunistic infections or other conditions which might affect complement levels. To determine the impact of body weight and changes in body weight on serum complement, we investigated levels of complement proteins in otherwise healthy patients with a wide range of body weights, including patients with anorexia nervosa before and after treatment, obese dieters before and after weight loss, and normal weight controls. We found that complement proteins of the alternative pathway (C3, B, and D), alternative pathway haemolytic activity (AP50) and the inhibitors H and I were low in starving anorectics and normalized with weight gain. C3a levels were comparable in anorectics at low weight and after weight gain, indicating that low serum complement levels were attributable to hypoproduction and not complement cascade activation with consumption. Further, levels of C3, B, AP50, H and I, but not D, were higher than controls in obese patients and decreased toward normal after weight loss. Overall, percentage of ideal body weight, changes in body weight, and serum transferrin were each highly correlated with serum levels of complement proteins. We conclude that levels of alternative pathway complement components are determined in part by factors that influence body weight and by weight changes, possibly due to changes in production in adipose tissue or at other sites.

Adult↗
PubMed1992

The calorically restricted low-fat nutrient-dense diet in Biosphere 2 significantly lowers blood glucose, total leukocyte count, cholesterol, and blood pressure in humans.

Biosphere 2 is a 3.15-acre space containing an ecosystem that is energetically open (sunlight, electric power, and heat) but materially closed, with air, water, and organic material being recycled. Since September 1991, eight subjects (four women and four men) have been sealed inside, living on food crops grown within. Their diet, low in calories (average, 1780 kcal/day; 1 kcal = 4.184 kJ), low in fat (10% of calories), and nutrient-dense, conforms to that which in numerous animal experiments has promoted health, retarded aging, and extended maximum life span. We report here medical data on the eight subjects, comparing preclosure data with data through 6 months of closure. Significant changes included: (i) weight, 74 to 62 kg (men) and 61 to 54 kg (women); (ii) mean systolic/diastolic blood pressure (eight subjects), 109/74 to 89/58 mmHg (1 mmHg = 133 Pa); (iii) total serum cholesterol, from 191 +/- 11 to 123 +/- 9 mg/dl (mean +/- SD; 36% mean reduction), and high density lipoprotein, from 62 +/- 8 to 38 +/- 5 (risk ratio unchanged); (iv) triglyceride, 139 to 96 mg/dl (men) and 78 to 114 mg/dl (women); (v) fasting glucose, 92 to 74 mg/dl; (vi) leukocyte count, 6.7 to 4.7 x 10(9) cells per liter. We conclude that drastic reductions in cholesterol and blood pressure may be instituted in normal individuals in Western countries by application of a carefully chosen diet and that a low-calorie nutrient-dense regime shows physiologic features in humans similar to those in other animal species.

Adult↗
PubMedDate not supplied

Need for dietary control by caloric restriction in rodent toxicology and carcinogenicity studies.

The conditions under which laboratory animals are maintained can powerfully influence the results of toxicological studies utilized for risk assessment. Nutrition is of importance in toxicological bioassays and research, because diet composition and the conditions under which it is fed can affect the metabolism and activity of xenobiotic test substances and alter the results and reproducibility of long-term studies. It is known that ad libitum (AL) overfed sedentary laboratory rodents suffer from an early onset of degenerative disease and diet-related tumors that lead to poor survival in chronic bioassays. AL-fed animals are not well-controlled subjects for any experimental studies. Examination of study-to-study variability in food consumption, body weight, and survival in carcinogenicity studies for the same strain or stock of rodents shows tremendous laboratory-to-laboratory variability. However, a significant correlation between average food (calorie) consumption, adult body weight, and survival has been clearly established. The use of moderate dietary restriction (DR) results in a better controlled rodent model with a lower incidence or delayed onset of spontaneous diseases and tumors. Operationally simple, moderate DR significantly improves survival, controls adult body weight and obesity, reduces age-related renal, endocrine, and cardiac diseases, increases exposure time, and increases the statistical sensitivity of these expensive, chronic bioassays to detect a true treatment effect. A moderate DR regimen of 70-75% of the maximum unrestricted AL food intake is recommended as a nutritionally intelligent, well-established method in conducting well-controlled toxicology and carcinogenicity studies.

Animals↗