1,721,142 research outputs found
Dieting
No full textDieting, defined as intentional caloric restriction to reduce body weight, is part of a multi-factorial approach and not the only strategy for weight loss. A correct diet requires a caloric deficit of 500 to 1000 kcal/day, usually inducing a weight loss at the rate of 1 to 2 lb/ week. It has to be prescribed by a clinical nutritionist or registered dietitian in order to ensure an adequate nutrient composition. The short-term efficacy of low-calorie diets has been consistently demonstrated independent of the macronutrient composition of the diets, but has to be integrated with other approaches (exercise, psychological support ) as needed by each patient, to improve long-term treatment outcome
NUTRITION AND FERTILITY
No full textThe first studies about fertility and nutrition
date back to the 70ies and already showed a
strict relation among female fertility, weight
and body composition. However, the mechanisms
of this connection started to be explained
only after leptin’s discovery. According
to some authors’ opinion, leptin could interact
with reproductive axis at multiple sites
with stimulatory effects at the hypothalamus
and pituitary and stimulatory or inhibitory
actions at the gonads. Leptin could play a
role in other physiologic processes such as
menstruation and pregnancy, and could initiate
the complex process of puberty. It has
been showed that conditions in which nutritional
status is suboptimal, such as eating
disorders, exercise induced amenhorrea,
functional hypothalamic amenhorrea and
polycystic ovarian syndrome, are associated
with abnormal leptin levels. These conditions,
are characterized by severe changes
in body composition and dietary habits. Since
leptin is regulated by body composition and
dietary factors, (such as energy intake and
macronutrient composition), a strict connection
between nutritional intake and fertility
regulated by leptin is confirmed. This
review focuses on the current knowledge
about nutritional factors that influence leptin
levels. Since clinical and subclinical nutritional
imbalance can determine the development
and the maintenance of neuroendocrine
and metabolic aberrations, studies
on fertility need a deeper attention about dietary
habits and nutritional status
The role of gut microbiota in human obesity: Recent findings and future perspectives
No full textAims: In recent years, gut microbiota have gained a growing interest as an environmental factor that may affect the predisposition toward adiposity. In this review, we describe
and discuss the research that has focused on the involvement of gut microbiota in human obesity. We also summarize the current knowledge concerning the health effects of the
composition of gut microbiota, acquired using the most recent methodological approaches, and the potential influence of gut microbiota on adiposity, as revealed by animal studies.
Data synthesis: Original research studies that were published in English or French until December 2011 were selected through a computer-assisted literature search. The studies conducted to date show that there are differences in the gut microbiota between obese and normal-weight experimental animals. There is also evidence that a high-fat diet may induce
changes in gut microbiota in animal models regardless of the presence of obesity. In humans, obesity has been associated with reduced bacterial diversity and an altered representation of bacterial species, but the identified differences are not homogeneous among the studies.
Conclusions: The question remains as to whether changes in the intestinal microbial community are one of the environmental causes of overweight and obesity or if they are a consequence of obesity, specifically of the unbalanced diet that often accompanies the development of excess weight gain. In the future, larger studies on the potential role of intestinal microbiota in human obesity should be conducted at the species level using standardized analytical techniques and taking all of the possible confounding variables into account
Alimentazione equilibrata
No full textPer alimentazione equilibrata si intende un’alimentazione che assicuri, da un lato la copertura dei fabbisogni di energia e nutrienti di un individuo o gruppo di popolazione tenendo conto delle ca atteristiche personali e dello stile di vita
e, dall’altro, integri le raccomandazioni nutrizionali per la prevenzione delle malattie. Si tratta cioè di evitare sia carenze che eccessi nutrizionali attraverso un apporto proporzionato di alimenti. Alla definizione e implementazione di
un’alimentazione equilibrata concorrono le raccomandazioni sull’assunzione dei nutrienti, le linee guida alimentari e gli obiettivi nutrizionali. Le raccomandazioni o standard nutrizionali sono livelli quantitativi stabiliti per la maggior parte dei nutrienti al fine di coprire i fabbisogni ed evitare livelli tossici.
Le linee guida alimentari sono la traduzione qualitativa delle raccomandazioni espresse sotto forma di consigli pratici e mirate ad affrontare le criticità dell’alimentazione; non esistono quindi per tutti i nutrienti ma solo per quelli per cui esiste nella popolazione un’assunzione squilibrata. Gli obiettivi
nutrizionali, infine, identificano traguardi da raggiungere stabiliti da organizzazioni scientifiche e sanitarie nazionali e internazionali per migliorare la salute della popolazione attraverso l’alimentazione. L’importanza di stabilire standard nutrizionali, linee guida e obiettivi nasce dalla consapevolezza della relazione esistente tra alimentazione e salute e poggia su evidenze scientifiche consolidate
Composizione corporea
No full textLa composizione corporea è una delle variabili che definiscono lo stato di nutrizione.
Lo studio della composizione corporea, iniziato oltre 100 anni fa, costituisce oggi un’area attiva della scienza di base e della ricerca clinica mirata alla quantificazione in vivo dei componenti corporei, allo studio delle relazioni quantitative tra i componenti, all’analisi delle alterazioni dei componenti in relazione a fattori fisiopatologici.
Nell’atleta agonista la valutazione della composizione corporea è rilevante in quanto la sola misurazione del peso corporeo non fornisce indicazioni sul rapporto tra massa magra e grassa che può condizionare la prestazione. La composizione corporea dello sportivo è diversa rispetto al soggetto sedentario
e può cambiare nelle varie fasi dell’allenamento, competizione e periodi di riposo
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