Energy intake and energy expenditure in the elderly

Interactions Between Diet, Physical Activity, and the Sociocultural Environment for Older Adult Health in the Urban Subarctic

This study sought to examine the relationship between the sociocultural factors that shape diet, physical activity, and nutritional status outcomes among seniors in Anchorage, Alaska. Alaskan seniors are an ideal study population because the state has the fastest growing senior population in the United States. Since much health research in the circumpolar north focuses on the influence of the economic or rural environment on nutrition, there is a need to investigate the ways social relationships shape diet, physical activity patterns, and nutritional status in urban spaces. This cross-sectional study included 82 community-living men and women (mean age = 74 years) in Anchorage. Participants underwent anthropometric measurements and completed questionnaires on their dietary intake, physical activity, and the sociocultural influences on their diet and exercise practices. T-tests indicate that diet and physical activity practices in this sample do not meet national recommendations and that diet differs adversely from national reference samples. Mann-Whitney U tests indicate the media and friends are associated with increases in energy expenditure. Family influences increased fruit consumption, while participation in cultural and social events increased intake of fats and sweets. Reaching older adults through a variety of channels, including the media, social networks, and culturally responsive programs can alleviate some of the barriers to healthy diet and exercise patterns.

The thermic effect of food is reduced in older adults

The thermic effect of food accounts for ~10% of daily energy expenditure. A reduction in the thermic effect of food, which has been variably observed in the older adults, could predispose to fat gain. We tested whether the thermic effect of food is reduced in older adults compared with young adults by analyzing our database of standardized studies conducted at the Mayo Clinic between 1999 and 2009. Data were available from 136 older adult volunteers aged 60-88 (56 females) and 141 young adults aged 18-35 years (67 females). Basal energy expenditure was measured by indirect calorimetry to assess basal metabolic rate. Body fat, fat free mass, and visceral fat were measured using a combination of dual energy X-ray absorptiometry and an abdominal CT scan. The thermic effect of food and postprandial insulinemia were measured in 123 older adults (52 females) and 86 young adults (38 females) of these volunteers. Basal metabolic rate adjusted for fat-free mass was less in older adults (p=0.01) and the thermic effect of food was ~1% (p=0.02) less in the older adults. After controlling for meal size and fat-free mass, body fat and fat distribution did not predict the thermic effect of food. Both basal metabolic rate and the thermic effect of food are less in older adults than young adults, even when they have similar amounts of lean tissue and consume a similar size meal. These factors contribute to lower daily energy expenditure in the older adults.

Resting energy expenditure, activity energy expenditure and total energy expenditure at age 91–96 years

There is a limited knowledge concerning energy requirements of the elderly, especially the oldest old (> 80 years). Energy requirements should be estimated from measurements of energy expenditure. For this purpose twenty-one free-living individuals (eight males, thirteen females) aged 91–96 years living in Göteborg, Sweden were studied. Total body water (TBW) measured by the doubly-labelled-water (DLW) technique was 29·5 (SD 5·4) KG IN FEMALES AND 35·6 (sd 4·3) kg in males. TBW measured using bioelectric impedance (BIA) was 31·6 (sd 6·4) kg in females and 42·0 (sd 7·4) kg in males. The mean difference between TBW measured by BIA and that measured by DLW was 3·54 (sd 3·6) kg (P = 0·0002). Resting metabolic rate (RMR) was measured using a ventilated-hood system and averaged 5·36 (sd 0·71) MJ/d in females (n 12) and 6·09 (sd 0·91) MJ/d in males (n 8). Difference between measured RMR and predicted BMR (n 20) was 0·015 (sd 0·86) MJ/d (NS). Total energy expenditure (TEE) measured by DLW averaged 6·3 (sd 0·81) MJ/d in females and 8·1 (sd 0·73) MJ/d in males. Activity energy expenditure (TEE - RMR), thus including diet-induced thermogenesis (DIT), averaged 0·95 (sd 0·95) MJ/d in females (n 12) and 2·02 (sd 1·13) MJ/d in males. Physical activity level (TEE/BMR) averaged 1·19 (sd 0·19) in females and 1·36 (sd 0·21) (P = 0·08) in males. If DIT is assumed to be 10 % of the TEE, energy spent on physical activity will be very low in this population.

Nutritional status and energy expenditure in elderly patients with recent hip fracture during a 2-month follow-up

A 2-month follow-up of nutritional status was performed in forty elderly patients with recent hip fracture. Patients were nutritionally assessed on admission to our rehabilitation unit (day 0), then monthly (day 30, day 60) by measurement of resting energy expenditure (REE), anthropometric, impedance and biological variables. Patients were defined as undernourished (n 13) or normally nourished (n 27) on the basis of mid-arm circumference (MAC) and triceps skinfold thickness (TST) measurements. Seven patients recovered a walking autonomy and were discharged from the hospital before day 30 (group I) whereas thirteen patients were discharged after day 30 (group II); twenty patients remained in the study at day 60 (group III). MAC and TST decreased in normally nourished patients from group III throughout the study whereas they did not change in group II or in undernourished patients from group III. REE values in relation to fat-free mass were increased compared with normal values and were similar in the three groups on day 0; they did not change during the study. Daily energy intake in relation to body weight was higher in group I and increased in group II and in undernourished patients from group III throughout the study. In contrast, it was below the recommended value at day 0 and it did not significantly improve in normally nourished patients from group III. Serum albumin, transthyretin and transferrin levels on day 0 were below reference intervals in the three groups. Albumin levels increased in group III throughout the study. Inflammatory proteins decreased in groups II and III, with C-reactive protein levels returning to normal values in group II by day 30 and in group III at day 60, while orosomucoid levels did not become completely normal over this period. Our findings indicate no improvement in nutritional status in undernourished patients after surgery for recent hip fracture, despite an adequate energy intake. An insufficient spontaneous energy intake for normally nourished patients was associated with a delayed favourable outcome resulting in a prolonged duration of hospitalization. A hypermetabolic state persisted during the 3 months after surgery.

Climatic influences on basal metabolic rates among circumpolar populations

This article examines evidence for elevations in basal metabolic rate (BMR) among indigenous Northern (circumpolar) populations and considers potential mechanisms and the adaptive basis for such elevations. Data on BMR among indigenous (n = 109 males; 122 females) and nonindigenous (n = 15 males; 22 females) circumpolar groups of North America and Siberia are compiled and compared to predicted BMRs based on three different references: body surface area (Consolazio et al., 1963), body mass (Schofield, 1985), and fat-free mass (Poehlman and Toth, 1995). Regardless of which reference is used, indigenous circumpolar groups show systematic and statistically significant elevations in BMR ranging from +7% to +19% above predicted values for indigenous men and from +3 to +17% for indigenous women. Nonindigenous males also show elevations in BMR, although not to the same extent as in indigenous men (deviations = +3 to +14%), whereas nonindigenous females show no clear evidence of elevated BMRs (deviations = -7 to +5%). This pattern of variation between indigenous and nonindigenous groups suggests that both functional and genetic factors play a role in metabolic adaptation to northern climes. Recent studies on the ecology and genetics of thyroid function offer insights into the mechanisms through which indigenous circumpolar populations may regulate metabolic rates. Studies of seasonal variation in thyroid hormone levels suggest that indigenous circumpolar populations may have a greater capacity to elevate BMR during severe cold than nonindigenous groups. Recent twin studies indicate a significant genetic component of thyroid responses to environmental stressors. Further research exploring the genetics of seasonal variation in thyroid function and BMR among circumpolar groups would advance understanding of the role that selection may have played in shaping metabolic variation.

Basal metabolic adaptation of the Evenki reindeer herders of Central Siberia

Previous research has suggested that basal metabolic rates (BMRs of indigenous circumpolar populations are elevated, perhaps as an adaptation to chronic, severe cold stress. This study examines variation in BMR among indigenous (Evenki) and nonindigenous (Russian immigrant) populations living in Central Siberia to determine: 1) whether the Evenki show evidence of increased metabolic rates, and 2) whether the metabolic responses of the Evenki are different from those of the recent Russian migrants ("controls"). BMRs were measured among 58 Evenki (19 men, 39 women) and 24 Russian (8 men, 16 women) adults (18-56 years of age) from three Siberian villages. Measured BMRs were compared to those predicted based on body weight and body SA (Consolazio et al., 1963; Schofield, 1985a,b). BMRs per unit weight and FFM were similar in Evenki and Russian men, whereas Evenki women had higher BMRs than their Russian peers. Relative to the Schofield (body weight) norms, Evenki men and women and Russian men all showed modest elevations in BMR, whereas Russian women had lower than expected BMRs. Compared to the Consolazio (surface area) estimates, both Evenki men and women showed significant elevations in BMR. Russian men also showed higher than expected BMRs, while those of Russian women were slightly below predicted levels. Age-related declines in BMR were evident among the women of both ethnic groups, but not among the men. Additionally, residence location was an important predictor of metabolic variation in the Evenki, with those of the more traditional village showing greater elevations in BMR. These results suggest that the Evenki display elevated metabolic needs, and this long-term adaptation reflects the interaction of genetics and level of acculturation. Am. J. Hum. Biol. 12:75-87, 2000. Copyright 2000 Wiley-Liss, Inc.

Limb blood flow and vascular conductance are reduced with age in healthy humans: relation to elevations in sympathetic nerve activity and declines in oxygen demand

BACKGROUND

We tested the hypothesis that basal (resting) limb blood flow and vascular conductance are reduced with age in adult humans and that these changes are related to elevations in sympathetic vasoconstrictor nerve activity and reductions in limb oxygen demand.

METHODS AND RESULTS

Sixteen young (28+/-1 years; mean+/-SEM) and 15 older (63+/-1 years) healthy normotensive adult men were studied. Diastolic blood pressure and body fat were higher (P<0.005) in the older men, but there were no other age-related differences in subject characteristics. Femoral artery blood flow (Doppler ultrasound) was 26% lower in the older men (P<0.005), despite similar levels of cardiac output (systemic arterial blood flow) in the 2 groups. Femoral artery vascular conductance was 32% lower and femoral vascular resistance was 45% higher in the older men (P<0. 005). Muscle sympathetic nerve activity (peroneal microneurography) was 74% higher in the older men (P<0.001) and correlated with femoral artery blood flow (r=-0.55, P<0.005), vascular conductance (r=-0.65, P<0.001), and vascular resistance (r=0.61, P<0.001). The age-related differences in femoral hemodynamics were no longer significant after correction for the influence of muscle sympathetic nerve activity. There were no significant age-group differences in leg tissue mass (by dual-energy x-ray absorptiometry), but estimated leg oxygen consumption was 15% lower in the older men (P<0.001). Femoral artery blood flow was directly related to estimated leg oxygen consumption (r=0.78, P<0.001). The age-group differences in femoral artery blood flow were no longer significant after correction for estimated leg oxygen consumption by ANCOVA.

CONCLUSIONS

(1) Basal whole-leg arterial blood flow and vascular conductance are reduced with age in healthy adult men; (2) these changes are associated with elevations in sympathetic vasoconstrictor nerve activity; and (3) the lower whole-limb blood flow is related to a lower oxygen demand that is independent of tissue mass.