Mediterranean Diet and High Dietary Acid Load Associated with Mixed Nuts: Effect on Bone Metabolism in Elderly Subjects

OBJECTIVES: To analyze the effect of differing diet on the acid load content on bone metabolism.
DESIGN: Multicentric, randomized, single-blind, parallel-group clinical trial.
SETTING: Outpatient clinics.
PARTICIPANTS: Two hundred thirty-eight elderly men and women aged 60 to 80 at high risk for cardiovascular disease were randomly assigned to three interventional groups: a recommended low-fat diet (control diet group), a Mediterranean diet supplemented with virgin olive oil, or a Mediterranean diet supplemented with mixed nuts.
MEASUREMENTS: Main outcomes were 12-month changes from baseline in bone formation and resorption markers and bone mass measured according to quantitative ultrasound scanning.
RESULTS: The baseline data on the anthropometric, bone densitometry, and biochemical variables did not differ between the three groups. Dietary potential renal acid load (PRAL) and daily net endogenous acid production (NEAP) at baseline did not differ between groups. After intervention, subjects allocated to the Mediterranean diet with mixed nuts had a significant increase of PRAL and NEAP. In comparison, subjects in the Mediterranean diet with nuts group had higher parathyroid hormone (PTH) levels (2.63, 95% confidence interval (CI)=−1.01–6.35, P =.02) and a nonsignificantly higher (0.31, 95% CI=−0.13–0.74, P =.14) urine free deoxypyridoxine:creatinine ratio, a marker of bone resorption, than the control group and the Mediterranean diet with virgin olive oil group.
CONCLUSION: A Mediterranean dietary pattern associated with a high dietary acid load derived from consumption of mixed nuts does not seem to have a much greater effect on bone metabolism biomarkers, with the exception of PTH levels, than a Mediterranean diet without mixed nuts or a control diet in elderly subjects.     

Effect of cooked and raw egg consumption on ovalbumin content of human milk: a randomized, double-blind, cross-over trial

BACKGROUND: Maternal avoidance of egg intake has been recommended to treat egg allergy in breastfed infants. OBJECTIVE: To determine if the concentration of ovalbumin (OVA) in human milk is directly related to the quantity and form of egg consumed by breastfeeding mothers. METHODS: Randomized, blinded, cross-over, intervention trial. Breastfeeding women (n = 41) attended four clinic days between 11 and 14 weeks of lactation and on each day were randomly allocated to receive a test breakfast, identical except for the egg content (no egg, one raw egg, half a cooked egg or one cooked egg). Breast milk samples were collected at two hourly intervals for 8 h and their OVA concentration measured by ELISA. RESULTS: There was a direct, dose-response between the amount of cooked egg ingested and the peak OVA concentration (no egg 0.05 ng/mL [95% confidence interval (CI), 0.01-0.11], half a cooked egg 2.24 ng/mL [95% CI, 0.57-3.91], one cooked egg 3.16 ng/mL [95% CI, 1.41-4.91], n = 41, P<0.05) as well as the total OVA excretion (no egg 0.18 ng/mL/h [95% CI, 0.04-0.39], half a cooked egg 4.93 ng/mL/h [95% CI, 1.40-8.46], one cooked egg 9.14 ng/mL/h [95% CI, 4.25-14.03], n = 41, P<0.05). The peak concentration and total OVA excretion in response to one raw egg did not differ from ingesting half a cooked egg. There was no detectable OVA in the breast milk of 24% (10/41) women up to 8 h after any egg challenge. CONCLUSION: OVA was detected in the breast milk of lactating women up to 8 h after a controlled intake of egg. A dose-response correlation was indicated. As excretion of OVA in human milk appears to be a normal phenomenon, further studies need to determine the threshold of OVA excretion that leads to symptoms in egg-allergic breastfed infants.     

女性体力活动、膳食因素与心血管疾病危险因素

目的 探讨健康成年女性人群体力活动和膳食与心血管疾病危险因素之间多因素综合相关关系。方法 通过标准化的体力活动问卷（MOSPA）和膳食调查方法评价女性日常体力活动和膳食营养素摄入状况，并测量其心血管疾病危险因素水平（包括体质指数、血压、机体氧化应激水平、胰岛素敏感性和血脂水平），采用典型相关分析的统计方法探讨女性体力活动和膳食与心血管疾病危险因素之间的关系。结果 体力活动、膳食与心血管疾病危险因素之间的相关关系主要表现为：膳食总能量和抗氧化物的摄入与机体抗氧化状态之间，以及体力活动能耗与血脂之间的关系。结论 体力活动、膳食与心血管疾病危险因素之间有较密切的相关关系。     

Dietary patterns of female nonsmokers with and without exposure to environmental tobacco smoke

The relationship of passive smoking to diet was examined in 82 female nonsmokers who provided a quantitative diet history in 1986. Exposure to environmental tobacco smoke (ETS) was assessed by urinary cotinine measurement. Mean values for each dietary variable, adjusted for age, ethnicity, education, and last week's ethanol intake, were compared among unexposed women and women with low or high ETS exposure. Linear relationships with amount of ETS exposure were also sought. Intakes of beta-carotene and cholesterol were found to be inversely related to ETS exposure. Since these nutrients have been associated with lung cancer risk, they are potential confounders of the passive-smoking/lung-cancer relationship. Although we estimate the confounding effect of these dietary factors to be modest, they should be measured carefully in future studies of this relationship.This work was supported in part by Public Health Service grant CA-33619 from the National Cancer Institute, and the International Agency for Research on Cancer.     

A Ketogenic Diet Increases the Resistance to Pentylenetetrazole-Induced Seizures in the Rat

Summary: Purpose: The purpose of this study was to test the hypothesis that a ketogenic diet would increase the resistance of rats to pentylenetetrazole (PTZ)-induced seizures and to understand the relation of ketonemia to seizure resistance.
Methods: A freely consumed, high-fat (ketogenic) diet was administered to male Sprague-Dawley rats for 5–10 weeks, while control animals were fed either rodent chow or a high-carbohydrate diet. Ketonemia was measured as plasma levels of β-hydroxybutyric acid (β-OHB). Seizures were induced by tail-vein infusion of pentylenetetrazole.
Results: The ketogenic diet produced a highly significant (p <0.01) increase in β-OHB levels within 5 days. Induction of seizures by PTZ 35 days after animals were placed on their respective diets showed that ketogenic animals had a significantly (p <0.01) increased threshold for seizure induction compared with those fed an isocaloric diet of either high-carbohydrate or normal rodent chow. Ketogenic animals did not exhibit increased seizure severity relative to controls, despite receiving consistently higher doses of PTZ.
Conclusions: The ketogenic diet resulted in an increased seizure threshold, confirming the hypothesis, and seizure threshold was found to be a direct function of the level of ketonemia.     

Down-regulation of cannabinoid-1 (CB-1) receptors in specific extrahypothalamic regions of rats with dietary obesity: a role for endogenous cannabinoids in driving appetite for palatable food?

Agonists at cannabinoid-1 (CB-1) receptors stimulate feeding and particularly enhance the reward aspects of eating. To investigate whether endogenous cannabinoids might influence appetite for palatable food, we compared CB-1 receptor density in the forebrain and hypothalamus, between rats fed standard chow (n=8) and others given palatable food (n=8) for 10 weeks to induce dietary obesity. CB-1 receptor density was significantly decreased by 30–50% (P<0.05) in the hippocampus, cortex, nucleus accumbens and entopeduncular nucleus of diet-fed rats. Furthermore, CB-1 receptor density in the hippocampus, nucleus accumbens and entopeduncular nucleus was significantly inversely correlated with intake of palatable food (r²=0.25–0.35; all P<0.05). By contrast, CB-1 receptor binding in the hypothalamus was low and not altered in diet-fed rats. CB-1 receptor down-regulation is consistent with increased activation of these receptors by endogenous cannabinoids. Acting in areas such as the nucleus accumbens and hippocampus, which are involved in the hedonic aspects of eating, cannabinoids may therefore drive appetite for palatable food and thus determine total energy intake and the severity of diet-induced obesity. However, cannabinoids in the hypothalamus do not appear to influence this aspect of eating behaviour.     

Maternal experiences of peanut avoidance during pregnancy/lactation: An in-depth qualitative study

In 1998 the Department of Health Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment issued a report to British general practitioners, which advised that pregnant mothers with a family history of atopy may wish to avoid peanuts during pregnancy/lactation. To explore the lived-in experience of mothers who avoided/did not avoid peanuts during pregnancy/lactation in the light of the information issued. A qualitative approach, using unstructured in-depth interviews to explore what it was like for mothers to have a particular experience. A purposive sample frame was designed to ensure a maximum variation of participants. Forty-two interviews were conducted: 25 participants avoided peanuts; 15 with a family history of atopy and 10 with no such history. Seventeen participants did not avoid peanuts; 10 with a family history of atopy and seven with no such history. Emergent themes included: variations in information provision, a lack of clarity in relation to information and advice about peanut avoidance, the risks entailed and the introduction of peanuts to the developing child's diet; the importance of atopy in influencing participants' decisions to avoid peanuts and the importance of individual's choice in the decision making process. There was a significant difference in family size with respect to avoidance behaviour with 'avoider' families being smaller (p = 0.007). Avoidance was more likely in single child families (71% vs. 53%) although this difference was not significant. Improvements to the experience of avoidance and/or non-avoidance were primarily focused around provision of information and advice. In particular, a need for clear, consistent factual information and advice about the real risks associated with peanut consumption during pregnancy/lactation, and to whom these risks apply.     

No association between fruit,vegetables, antioxidant nutrients and risk of renal cell carcinoma

Previous epidemiologic studies that have examined the relationship between renal cell carcinoma (RCC) risk and intakes of plant foods and antioxidant nutrients have yielded inconsistent results. We therefore examined the associations between intakes of fruit, vegetables, carotenoids, flavonoids, vitamin E and vitamin C and RCC risk in the Alpha‐Tocopherol, Beta‐Carotene Cancer Prevention (ATBC) Study cohort. At baseline, 27,062 male Finnish smokers aged 50–69 years completed a 276‐item dietary questionnaire that included questions on frequency of consumption and portion size. During up to 19 years of follow‐up, 255 men developed RCC. Cox proportional hazards models were utilized to estimate relative risks (RR) and 95% confidence intervals (CI). Despite a large range in intake, no association was observed between fruit, vegetables or antioxidant nutrients and RCC risk. For example, multivariate RRs and 95% CIs for the highest versus the lowest quartile of intake were 0.79 (0.55–1.14), 1.23 (0.85–1.79), 1.09 (0.74–1.60), 0.83 (0.57–1.21), 1.09 (0.73–1.64) and 0.99 (0.67–1.46) for fruit, vegetables, total carotenoids, total flavonoids, total vitamin E and vitamin C, respectively (all p values for trend > 0.05). Our results indicate that diet may not play a large role in the etiology of RCC in male smokers, although further examination of these associations in nonsmokers, women and diverse racial populations is warranted.