Immune response to influenza vaccine in healthy adults and the elderly: association with nutritional status

The immune response and serum nutritional status of 153 elderly residents of nursing homes (mean age 84.4 years) and 95 health care workers (mean age 36.8 years) were assessed before and after immunization with trivalent split-virus influenza vaccine. Postvaccination titers of hemagglutination inhibition (HAI) antibody to A/H1N1 and B among the elderly were lower than those among workers, but the seroconversion rates (greater than or equal to a four-fold rise) for A/H1N1 and A/H3N2 were unexpectedly higher among the elderly than among workers. However, the difference in the seroconversion rate for either strain between workers and the elderly disappeared after adjusting for the prevaccination HAI titer. Among all subjects, lower age and higher serum concentrations of total protein, albumin, Vitamin E and folate were associated with an intact immune response (postvaccination HAI titers >/=40 for at least one strain). In an age-adjusted analysis limited to the elderly, however, only Vitamin E showed a significant association with the immune response. These results suggested that Vitamin E may play an important role in maintaining the immune response, especially among the elderly.     

Effect of adiposity on vitamin D status and the 25-hydroxycholecalciferol response to supplementation in healthy young and older Irish adults

There is increasing epidemiological evidence linking sub-optimal vitamin D status with overweight and obesity. Although increasing BMI and adiposity have also been negatively associated with the change in vitamin D status following supplementation, results have been equivocal. The aim of this randomised, placebo-controlled study was to investigate the associations between anthropometric measures of adiposity and the wintertime serum 25-hydroxycholecalciferol (25(OH)D) response to 15?μg cholecalciferol per d in healthy young and older Irish adults. A total of 110 young adults (20-40 years) and 102 older adults (?≥?64 years) completed the 22-week intervention with >85?% compliance. The change in 25(OH)D from baseline was calculated. Anthropometric measures of adiposity taken at baseline included height, weight and waist circumference (WC), along with skinfold thickness measurements to estimate fat mass (FM). FM was subsequently expressed as FM (kg), FM (%), FM index (FMI (FM kg/height m2)) and as a percentage ratio to fat-free mass (FFM). In older adults, vitamin D status was inversely associated with BMI (kg/m2), WC (cm), FM (kg and %), FMI (kg/m2) and FM:FFM (%) at baseline (r -?0·33, -?0·36, -?0·33, -?0·30, -?0·33 and -?0·27, respectively, all P values 相似文献   

补充维生素A对健康成人铁营养状况的影响

目的观察健康成人补充维生素A(VA)后铁营养状况的变化。方法选择115名健康成人志愿者,按血清视黄醇浓度用区组设计方法将男女志愿者随机分入4组(男、女各半),在日常膳食的基础上,分别补充不同剂量的VA,干预剂量(以视黄醇计)分别为600μg/d(A组)、400μg/d(B组)、200μg/d(C组)和0μg/d(D组),干预期4个月。补充剂为微胶囊化的视黄酰乙酸酯,将5日剂量装入1粒胶囊,每5日口服1粒。胶囊外包装只标注剂量类型,现场实验人员和受试者均不知道每一种胶囊的补充类型。干预期内,受试者接受常规膳食,每月进行1次24h回顾性膳食调查。干预试验前后,采集空腹上臂静脉血,取血清测定血液血红蛋白(Hb)浓度,血清视黄醇、血清铁(SI)、铁蛋白(SF)和转铁蛋白受体(TfR)浓度。结果共有108名受试者完成干预试验,A、B、C和D组各为27、28、27和26名。干预期内,4组受试者膳食能量营养素、视黄醇当量(RE)和铁摄入量无显著性差异(P>0.05)。干预结束后,A组受试者血清视黄醇浓度从干预前的(1.63±0.55)μmol/L升高到了(1.93±0.52)μmol/L(P<0.05);B和C组血清视黄醇浓度分别平均升高了0.29μmol/L和0.14μmol/L(均为P<0.05);而对照组D组变化不显著(P>0.05)。干预试验前后各组Hb差异没有显著性(P>0.05);高剂量VA组受试者干预后SI浓度比干预前显著升高,而SF和TfR浓度则显著降低(均为P<0.05);中剂量组和低剂量组在干预前后SF和TfR未见显著性变化。结论铁营养状况正常的成人,在没有专门给予膳食铁干预的情况下,通过较大剂量VA补充干预,铁营养状况仍然得到进一步提高。     

营养素补充对健康人群机体营养状况及抗氧化能力影响的研究

目的采用3日24h食物回顾法调查研究人群营养素摄入情况,观察补充复合营养素对研究对象抗氧化能力的影响。方法选择广州市20～50岁的健康人群151名,随机双盲分为对照组和干预组,采用24h膳食回忆法进行3日膳食调查,干预组服用复合营养素片(成分包括VA、VC、VE、胡萝卜素、钙、镁、锌、铁、铜等各种维生素与矿物质),对照组服用颜色、形状、大小与复合营养素片完全相同的糊精片,每天随餐服用2次,为期8周。补充前后收集血样,分析血浆各种抗氧化营养素水平及机体抗氧化能力。结果膳食调查结果显示,研究对象存在营养素摄入不足;干预组血浆中的VC、α-生育酚(α-tocopherol)、β-胡萝卜素(β-carotene)、锌(Zn)、铁(Fe)、硒(Se)的浓度与对照组相比分别提高46%、28%、116%、7%、30%和28%(P<0.05),而血浆γ-生育酚(γ-tocopherol)含量干预后较干预前低25%(P<0.05);干预组血浆谷胱甘肽过氧化物酶(GPX)、过氧化氢酶(CAT)、总抗氧化能力(T-AOC)活性较干预前及对照组增高(P<0.05),血浆过氧化物歧化酶(SOD)活性及血浆8-异前列腺素(8-isoprostanes)含量未见明显改变。结论补充复合营养素能有效改善血浆抗氧化营养素水平,提高血浆GPX、CAT、T-AOC活性,增强机体抗氧化能力。     

Plasma ubiquinone status and response to six-month supplementation combined with multivitamins in healthy elderly women--results of a randomized,double-blind,placebo-controlled study

The aim of this study was to evaluate the serum coenzyme Q10 concentrations of healthy elderly women before and after supplementation with coenzyme Q10 combined with multivitamins, selenium, and magnesium. In a randomized double-blind design, 220 free-living women aged 60 years and older were included. Median serum coenzyme Q10 concentration at baseline was 0.99 mumol/L (5-95 percentiles: 0.54-1.68) and cholesterol adjusted concentration was 0.16 (5-95 percentiles: 0.09-0.26) mmol/mol cholesterol. No significant correlations were found between Q10 levels and body mass index (BMI) or age. Q10 concentrations were not significantly different between smoking and nonsmoking women, nor between women with statin therapy and without. Furthermore no differences were seen between hyperlipidemic and normolipidemic subjects. Cholesterol-adjusted Q10 levels were positively correlated to lipid-adjusted serum tocopherol levels and negatively associated to serum beta-carotene. No significant correlation existed between adjusted Q10 levels and plasma selenium. Results of the food diaries showed a significant but weak correlation to meat and meat products and to alcohol intake. At baseline, Q10 levels did not differ between supplemented and control group. After six months, adjusted serum concentrations of the supplemented and the control group were significantly increased by 106% and 31%, respectively. In the supplemented group the change was inversely associated with the baseline concentration. A six-month supplementation with coenzyme Q10, vitamins, and selenium raises the blood concentration of coenzyme Q10 even in relatively well-nourished elderly women.     

Influence of low-dose polyunsaturated fatty acids supplementation on the inflammatory response of healthy adults

OBJECTIVE: The aim of the present study was to examine the immune-modulating effect of two different fat blends enriched with a low dose of anti- or proinflammatory polyunsaturated fatty acids on the fatty acid status and subsequently on the immune response of healthy volunteers. METHODS: Thirty healthy volunteers were randomly assigned to group A (anti-inflammatory blend rich in polyunsaturated fatty acids: alpha-linolenic acid, 240 mg/d; eicosapentaenoic acid, 120 mg/d; stearidonic acid, 49 mg/d; and gamma-linolenic acid, 73 mg/d) or group B (arachidonic acid, 40 mg/d; containing an inflammatory fat blend) for a 2-wk dietary supplementation period. Concentrations of interleukin-8, interleukin-10, tumor necrosis factor-alpha, prostaglandins E(1) and E(2), and leukotriene B(4) were investigated before, after 2 wk of supplementation, and 2 wk after stopping supplementation using a whole blood ex vivo lipopolysaccharide-stimulation assay. RESULTS: Plasma concentrations of alpha-linolenic acid and eicosapentaenoic acid were significantly increased in group A. In addition, dietary fat blends influenced eicosapentaenoic acid concentration in erythrocyte membranes. Supplementation of the fat blends resulted in contrasting effects on the expression of lipid mediators and cytokines after ex vivo lipopolysaccharide stimulation. Release of prostaglandin E(1) and leukotriene B(4) were significantly decreased in group A, whereas prostaglandin E(2) and interleukin-10 concentrations were significantly increased in group B. No effect on interleukin-8 or tumor necrosis factor-alpha release was found after supplementation with either fat blend. CONCLUSIONS: These results show an immune-modulating effect of a low-dose dietary polyunsaturated fatty acid supplementation. However, further studies regarding fat-blend composition and period of supplementation in patients with inflammatory conditions are required.     

Vitamin K supplementation reduces serum concentrations of under-gamma-carboxylated osteocalcin in healthy young and elderly adults

BACKGROUND: Subclinical vitamin K insufficiency, manifested by under-gamma-carboxylation of the bone matrix protein osteocalcin, may be common. OBJECTIVE: Our objective was to delineate the prevalence of submaximal gamma-carboxylation as assessed by response to phylloquinone supplementation and to evaluate the effect of this intervention on skeletal turnover in healthy North American adults. DESIGN: Healthy subjects (n = 219), approximately equally distributed by sex and age (18-30 y and >/=65 y), received daily phylloquinone (1000 microg) or placebo for 2 wk. Serum undercarboxylated osteocalcin (ucOC) and total osteocalcin, N:-telopeptides of type I collagen (NTx), bone-specific alkaline phosphatase (BSAP), and phylloquinone concentrations were measured at baseline and after weeks 1 and 2. RESULTS: At baseline, the mean serum phylloquinone concentration was lower in the young than in the old group; there was no effect of sex. Concomitantly, baseline %ucOC was highest in the young and lowest in the old men (P: < 0.0001) but did not differ significantly by age in women. After supplementation, serum phylloquinone concentration increased approximately 10-fold (P: < 0.0001) at week 1 (from 0.93 +/- 0.08 to 8.86 +/- 0.70 nmol/L, x+/- SEM); this was sustained through week 2. Among all supplemented groups, mean %ucOC decreased from 7.6% to 3. 4% without significant differences by age or sex; 102 of 112 subjects had a >1% decrease. Phylloquinone supplementation reduced serum osteocalcin but did not alter NTx or BSAP concentration. CONCLUSIONS: Usual dietary practices in this population did not provide adequate vitamin K for maximal osteocalcin carboxylation. Phylloquinone supplementation reduced serum osteocalcin concentration but did not alter other markers of serum bone turnover.     

Cognitive performance in relation to vitamin status in healthy elderly German women-the effect of 6-month multivitamin supplementation

BACKGROUND: Prior investigations have reported a link between poor status of antioxidants, folate, and cobalamin resulting in elevated total plasma homocysteine (tHcy) and methylmalonic acid (MMA) concentrations with an increased risk for reduced cognitive performance. The aim of the study was to evaluate the effect of a 6-month multivitamin supplementation on the cognitive performance of female seniors and to assess cognitive functioning in relation to vitamin status, tHcy, and MMA values at baseline. METHODS: The study was performed as a randomized placebo-controlled double-blind trial. 220 healthy, free-living women (aged 60-91 years) were included. Blood drawings and cognitive tests were performed at the Institute of Food Science of the University of Hanover, Germany. Vitamin and cognitive status have been evaluated prior to and 6 months after supplementation. Plasma ascorbic acid, serum concentrations of alpha-tocopherol, beta-carotene, and coenzyme Q10, serum and erythrocyte folate as well as serum cobalamin, serum MMA, and plasma tHcy concentrations were measured. Activity coefficient of erythrocyte alpha aspartic aminotransferase was used as functional index for vitamin B(6) status. The cognitive performance was assessed by the Symbol Search test, a subtest of the Wechsler Adult Intelligence Scale (WAIS-III) and the pattern-recognition test. Intelligence as assessed by the 'Kurztest für Allgemeine Intelligenz' (KAI) was a further variable. RESULTS: No significant differences in pattern-recognition and intelligence score were observed between vitamin and placebo group prior to and after multivitamin supplementation. In the Symbol Search test, the vitamin group exhibited better test results than the placebo group at both measure points. One-way ANOVA showed a marginally significant linear trend between the baseline tHcy concentration and the pattern-recognition score (P = 0.051) in the total sample. Multiple backward regression revealed only a significant influence of the school graduation on baseline cognitive function test results. A general linear model showed that the changes in cognitive function scores could not be explained by the type of treatment or blood parameters. CONCLUSIONS: Our data indicate that 6 months supplementation of physiological dosages of antioxidants and B vitamins have no effect on cognitive performance in presumedly healthy and well-nourished female seniors. An intervention period of only 6 months may be too short for improving cognitive performance in well-educated elderly women without dementia.     

Selenium supplementation in healthy Belgian adults: response in platelet glutathione peroxidase activity and other blood indices

Selenium status was explored by investigating effects of a 60-d Se supplementation with DL-selenomethionine (100 micrograms Se/d) in a group of 10 adults (plasma Se levels, 0.76-1.33 mumol/L). Plasma, erythrocyte, and urinary Se and activities of glutathione peroxidase (GSH Px) in plasma, erythrocytes, and platelets were measured before intervention and after 5, 15, 30, 45, and 60 d. A placebo was given to six adults. Plasma and urinary Se were the most sensitive indices to Se exposure. Se in plasma increased steadily during the course of the study whereas urinary Se reached a plateau between 30 and 60 d. By contrast erythrocyte Se did only change after 45 d. Enzyme in plasma and erythrocytes did not respond whereas platelet GSH Px did. The plateau of activity that was observed after 15 d for plasma Se in the range 1.40-1.50 mumol/L could mean that the Se status is insufficient for an optimal function of GSH Px and implies that dietary intake in Belgium (less than 50-60 micrograms Se/d) is not adequate.     

Vitamin B6 status of Finnish elderly. Comparison with Dutch younger adults and elderly. The effect of supplementation

About 25% of Finnish and Dutch elderly appeared to be more or less deficient in vitamin B6 as compared to younger adults. Deficiency was observed at the cellular (PLP, EGOT and alpha-EGOT) as well as at the plasma level (PLP). The benefit of a one-year daily supplementation with 2 mg of pyridoxine-HCl was investigated at the biochemical and psychological level as compared to a placebo group. After one year, none of the supplemented elderly was deficient in biochemical terms. At the psychological level and at the level of general well-being, the elderly supplemented with vitamin B6 showed slight improvements. However, for the psychological variables significant correlations with the vitamin B6 parameters were not observed. Plasma fatty acids (e.g. gamma-linolenic acid) showed no correlation with the vitamin B6 status.     

Selenium status in healthy Italian adults

The purpose of this study was to determine the amount of selenium in serum of an Italian population of 143 subjects. Data suggest that an adequate amount of selenium is consumed in the diet, since the level of selenium concentration in the blood is normal (70.7 μ g/ 1), A correlation coefficient of 0.82 (p<0.001) between selenium concentration in blood and selenium content of the diet was found in a group of subjects in whom both variables were measured.     

Watercress supplementation in diet reduces lymphocyte DNA damage and alters blood antioxidant status in healthy adults

BACKGROUND: Cruciferous vegetable (CV) consumption is associated with a reduced risk of several cancers in epidemiologic studies. OBJECTIVE: The aim of this study was to determine the effects of watercress (a CV) supplementation on biomarkers related to cancer risk in healthy adults. DESIGN: A single-blind, randomized, crossover study was conducted in 30 men and 30 women (30 smokers and 30 nonsmokers) with a mean age of 33 y (range: 19-55 y). The subjects were fed 85 g raw watercress daily for 8 wk in addition to their habitual diet. The effect of supplementation was measured on a range of endpoints, including DNA damage in lymphocytes (with the comet assay), activity of detoxifying enzymes (glutathione peroxidase and superoxide dismutase) in erythrocytes, plasma antioxidants (retinol, ascorbic acid, alpha-tocopherol, lutein, and beta-carotene), plasma total antioxidant status with the use of the ferric reducing ability of plasma assay, and plasma lipid profile. RESULTS: Watercress supplementation (active compared with control phase) was associated with reductions in basal DNA damage (by 17%; P = 0.03), in basal plus oxidative purine DNA damage (by 23.9%; P = 0.002), and in basal DNA damage in response to ex vivo hydrogen peroxide challenge (by 9.4%; P = 0.07). Beneficial changes seen after watercress intervention were greater and more significant in smokers than in nonsmokers. Plasma lutein and beta-carotene increased significantly by 100% and 33% (P < 0.001), respectively, after watercress supplementation. CONCLUSION: The results support the theory that consumption of watercress can be linked to a reduced risk of cancer via decreased damage to DNA and possible modulation of antioxidant status by increasing carotenoid concentrations.     

Differential responses to selenomethionine supplementation by sex and genotype in healthy adults

A year-long intervention trial was conducted to characterise the responses of multiple biomarkers of Se status in healthy American adults to supplemental selenomethionine (SeMet) and to identify factors affecting those responses. A total of 261 men and women were randomised to four doses of Se (0, 50, 100 or 200 μg/d as L-SeMet) for 12 months. Responses of several biomarkers of Se status (plasma Se, serum selenoprotein P (SEPP1), plasma glutathione peroxidase activity (GPX3), buccal cell Se, urinary Se) were determined relative to genotype of four selenoproteins (GPX1, GPX3, SEPP1, selenoprotein 15), dietary Se intake and parameters of single-carbon metabolism. Results showed that supplemental SeMet did not affect GPX3 activity or SEPP1 concentration, but produced significant, dose-dependent increases in the Se contents of plasma, urine and buccal cells, each of which plateaued by 9-12 months and was linearly related to effective Se dose (μg/d per kg0·75). The increase in urinary Se excretion was greater for women than men, and for individuals of the GPX1 679 T/T genotype than for those of the GPX1 679 C/C genotype. It is concluded that the most responsive Se-biomarkers in this non-deficient cohort were those related to body Se pools: plasma, buccal cell and urinary Se concentrations. Changes in plasma Se resulted from increases in its non-specific component and were affected by both sex and GPX1 genotype. In a cohort of relatively high Se status, the Se intake (as SeMet) required to support plasma Se concentration at a target level (Se(pl-target)) is: Se(in) = [(Se(pl - target) - Se(pl))/(18.2ng d kg?.??/ml per mu g)] .     

Tocotrienol rich fraction supplementation improved lipid profile and oxidative status in healthy older adults: A randomized controlled study

Background

Vitamin E supplements containing tocotrienols are now being recommended for optimum health but its effects are scarcely known. The objective was to determine the effects of Tocotrienol Rich Fraction (TRF) supplementation on lipid profile and oxidative status in healthy older individuals at a dose of 160 mg/day for 6 months.

Methods

Sixty-two subjects were recruited from two age groups: 35-49 years (n = 31) and above 50 years (n = 31), and randomly assigned to receive either TRF or placebo capsules for six months. Blood samples were obtained at 0, 3^rd and 6^th months.

Results

HDL-cholesterol in the TRF-supplemented group was elevated after 6 months (p < 0.01). Protein carbonyl contents were markedly decreased (p < 0.001), whereas AGE levels were lowered in the > 50 year-old group (p < 0.05). Plasma levels of total vitamin E particularly tocopherols were significantly increased in the TRF-supplemented group after 3 months (p < 0.01). Plasma total tocotrienols were only increased in the > 50 year-old group after receiving 6 months of TRF supplementation. Changes in enzyme activities were only observed in the > 50 year-old group. SOD activity was decreased after 3 (p < 0.05) and 6 (p < 0.05) months of TRF supplementation whereas CAT activity was decreased after 3 (p < 0.01) and 6 (p < 0.05) months in the placebo group. GPx activity was increased at 6 months for both treatment and placebo groups (p < 0.05).

Conclusion

The observed improvement of plasma cholesterol, AGE and antioxidant vitamin levels as well as the reduced protein damage may indicate a restoration of redox balance after TRF supplementation, particularly in individuals over 50 years of age.     

Taurine status and response to intravenous taurine supplementation in adults with short-bowel syndrome undergoing long-term parenteral nutrition: a pilot study

Taurine deficiency in patients on long-term parenteral nutrition may be involved in cholestasis. We aimed to assess plasma taurine and tauro-conjugated bile acids in adults with short-bowel syndrome and their response to intravenous taurine. Thirty-two adult patients, who had been on taurine-free parenteral nutrition for a mean of 59 (SE 14) months for short-bowel syndrome, were studied retrospectively. In a second study, a subgroup of ten patients with chronic cholestasis received taurine-enriched (6.0 (SE 0.6) mg/kg per d) parenteral nutrition for 55 (SE 13) months. Post-absorptive plasma taurine and bile acid concentrations were measured and liver function tests routinely sampled. At baseline, plasma taurine was lower in patients with a jejunal length of less than 35 cm (group A, n 16) than in those with a jejunal length of 35 cm or more (group B, n 16): 43 (SE 3) v. 58 (SE 4) micromol/l (P=0.01). The groups were no different in terms of chronic cholestasis (12/16 v.13/16 patients), total bile acids (26 (SE 13) v.14 (SE 5) micromol/l) or the ratio of tauro-conjugated:glyco-conjugated bile acids (5 (SE 2) v.8(SE 4)%, usual range 30-60%). After supplementation, there was an increase in plasma taurine level (63 (SE 8) v. 43 (SE 4), P=0.007) but was no change in either total bile acids or the ratio of tauro-conjugated: glyco-conjugated bile acids. There was a significant decrease in aspartate aminotransferase level. Long-term parenteral nutrition for short-bowel syndrome is associated with an impaired tauro-conjugation of bile acids (enterohepatic pool), irrespective of plasma taurine level (systemic pool) and despite long-term taurine intravenous supplementation.     

Zinc metabolism and immune function in healthy elderly people

Changes in immune function have been described in the elderly, and zinc is known to influence immune parameters. Zinc supplementation has, however, produced contradictory results. We evaluated zinc metabolism and immunity in 15 healthy non-institutionalised elderly people on a self-selected diet and compared the results with those obtained from 10 young healthy subjects. The elderly subjects had reduced serum zinc levels and their zinc absorption values were lower than in the young subjects. Circulating immune parameters were within the normal range, while delayed immune response was altered in 8 of the 15 elderly subjects. Zinc supplementation (25 mg/day) did not result in a significant improvement in dermal hypersensitivity responses although some effect was seen in 5 cases. It is concluded that zinc supplementation is unnecessary in elderly healthy subjects even if they present zinc metabolism alterations, but may be indicated in the presence of disease.     

Zinc and immunocompetence in elderly people: effects of zinc supplementation for 3 months

One hundred and three apparently healthy elderly subjects age 60-89 y were randomly assigned to one of three treatments: placebo, 15 mg zinc/d, or 100 mg Zn/d for 3 mo. Plasma Zn was significantly increased only in the 100 mg Zn group. Zn concentrations in erythrocytes, platelets, mononuclear cells, and polymorphonuclear leukocytes were not significantly increased by any treatment. None of the treatments significantly altered delayed dermal hypersensitivity (DDH) to a panel of seven recall antigens or in vitro lymphocyte proliferative responses (LPR) to mitogens and antigens. Fifteen subjects had initially poor lymphocyte proliferative responses that improved in 14 of these individuals during the study; this was not due to Zn supplementation but might have been caused by one or more components of a vitamin-mineral supplement administered to all study subjects.     

Zinc and iron status and growth in healthy infants

OBJECTIVE: To elucidate the relationships between growth and zinc and iron status in normal infants. STUDY DESIGN: Growth of normal infants (less than 3 y old: n = 66) was prospectively assessed with a mean delay of 24+/-6 weeks between measurements; subjects were free from illness and presented with a normal growth. Growth was compared to serum zinc (s-zinc), IGF-1 and iron status. SETTING: Teaching hospital of Caen. RESULTS: No relation was found between linear or weight growth and s-zinc; when taking into account the effect of age, linear growth was significantly associated with ferritin (P<0.001); weight gain was significantly correlated with IGF-1 (P = 0.034) and ferritin (P = 0.008). No relationship was found between s-zinc and iron status. CONCLUSIONS: In normal infants iron status, more than serum zinc, seems to be correlated with growth.     

Metabolic response to a ketogenic breakfast in the healthy elderly

Objective  To determine whether the metabolism of glucose or ketones differs in the healthy elderly compared to young or middle-aged adults during mild, short-term ketosis induced by a ketogenic breakfast. Design and participants  Healthy subjects in three age groups (23±1, 50±1 and 76±2 y old) were given a ketogenic meal and plasma -hydroxybutyrate, glucose, insulin, triacylglycerols, total cholesterol, non-esterified fatty acids and breath acetone were measured over the subsequent 6 h. Each subject completed the protocol twice in order to determine the oxidation of a tracer dose of both carbon-13 (¹³C) glucose and ¹³C- -hydroxybutyrate. The tracers were given separately in random order. Apolipoprotein E genotype was also determined in all subjects. Results  Plasma glucose decreased and -hydroxybutyrate, acetone and insulin increased similarly over 6 h in all three groups after the ketogenic meal. There was no significant change in cholesterol, triacylglycerols or non-esterified fatty acids over the 6 h. ¹³C-glucose and ¹³C- -hydroxybutyrate oxidation peaked at 2–3 h post-dose for all age groups. Cumulative ¹³C-glucose oxidation over 24 h was significantly higher in the elderly but only versus the middle-aged group. There was no difference in cumulative 13C- -hydroxybutyrate oxidation between the three groups. Apolipoprotein E ( 4) was associated with elevated fasting cholesterol but was unrelated to the other plasma metabolites. Conclusion  Elderly people in relatively good health have a similar capacity to produce ketones and to oxidize ¹³C- -hydroxybutyrate as middle-aged or young adults, but oxidize ¹³C-glucose a little more rapidly than healthy middle-aged adults.