PubMed · 3578103
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A R Feinstein. 1987. Scientific standards and epidemiologic methods.. https://doi.org/10.1093/ajcn%2F45.5.1080
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Phenols present in olive oil may contribute to the health effects of the Mediterranean lifestyle. Olive oil antioxidants increase the resistance of low-density lipoproteins (LDL) against oxidation in vitro, but human intervention studies have failed to demonstrate similar consistent effects. To better mimic the in vivo situation, plasma was incubated with either individual olive oil phenols or olive oil extracts with different phenolic compositions, and LDL was subsequently isolated and challenged for its resistance to oxidation. The results show that the ortho-dihydroxy phenols (hydroxytyrosol and oleuropein-aglycone) are more efficient than their mono-hydroxy counterparts (tyrosol and ligstroside-aglycone) in increasing the resistance of LDL to oxidation. However, the concentration of antioxidants required to inhibit LDL oxidation when added to whole plasma was substantially higher as compared to previous data where antioxidants are directly added to isolated LDL. In conclusion, this study supports the hypothesis that extra virgin olive oil phenols protect LDL in plasma against oxidation. The explanation that in vitro studies show protective effects in contrast to the lack of effect in the majority of human studies may be that the dose of the phenols and thus their plasma concentration in humans was too low to influence ex vivo LDL oxidizability. Further studies are required to gain a better understanding of the potential health benefits that extra virgin olive oil may provide.
Estimates of exposure to intentionally added flavouring substances based on two indirect methods, namely the theoretical added maximum daily intake (TAMDI) and maximized survey-derived daily intake (MSDI), were compared with exposure estimates based on a flavourings stochastic model (FSM). Twelve flavouring substances were chosen to reflect broadly the large number of flavouring substances currently used in Europe. Over 40,000 flavour formulae used at known levels of incorporation in 31 different categories of food and beverages were examined to provide maximum concentrations, distributions of concentrations and an indication of the probability of encountering each substance in a flavoured food or beverage in any category. Food consumption data were based on the intakes of males, aged 16-24 years, according to the Dietary and Nutritional Survey of British Adults (1988). The percentage of flavoured brands within food groups was estimated using the Irish National Food Ingredient Database. For all 12 flavouring substances, the estimates of TAMDI were > 97.5th percentile of the FSM, sometimes by > 3 orders of magnitude. With the exception of 2,6-dimethyl pyrazine, the 97.5th percentile of the FSM was less than the MSDI estimate. The probability of the FSM estimates exceeding the TAMDI ranged from < 0.0001 to 0.0037 for the 12 substances, while the probability of exceeding the MSDI estimates ranged from 0.0004 to 0.0753. The study supports the findings of a recent publication using detailed dietary analysis of US data that also indicated that the MSDI appeared, within the limits of the studies, to be a practical and conservative method for assessing exposure to intentionally added flavouring substances.
Despite the documented evidence of the benefits of cardiac rehabilitation (CR) in enhancing recovery and reducing mortality following a myocardial infarction, only about one third of patients participate in such programs. Adherence to these programs is an even bigger problem, with only about one third maintaining attendance in these programs after 6 months. This review summarizes research that has investigated barriers to participation and adherence to CR programs. Some consistent factors found to be associated with participation in CR programs include lack of referral by physicians, associated illness, specific cardiac diagnoses, reimbursement, self-efficacy, perceived benefits of CR, distance and transportation, self-concept, self-motivation, family composition, social support, self-esteem, and occupation. Factors associated with non-adherence include being older, female gender, having fewer years of formal education, perceiving the benefits of CR, having angina, and being less physically active during leisure time. However, many of the studies have methodologic flaws, with very few controlled, randomized studies, making the findings tentative. Problems in objectively measuring adherence to unstructured, non-hospital-based programs, which are an increasingly popular alternative to traditional programs, are discussed. Suggestions for reducing barriers to participation and adherence to CR programs, as well as for future research aimed at clearly identifying these barriers, are discussed.