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The nutritional properties and health benefits of eggs

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Purpose – Advice about the role of eggs in the diet has changed several times over the decades. The purpose of this paper is to evaluate published evidence reporting associations between egg consumption, egg nutrients and health. Design/methodology/approach – The scientific literature was searched using Medline and key words relevant to eggs and egg nutrients. In addition, a new secondary analysis of the UK National Diet and Nutrition Survey (NDNS) was undertaken to examine nutritional and health differences between consumers and non-consumers of eggs. Findings – Eggs are a rich source of protein and several essential nutrients, particularly vitamin D, vitamin B12, selenium and choline. Emerging evidence suggests that eating eggs is associated with satiety, weight management and better diet quality. In addition, antioxidants found in egg yolk may help prevent age-related macular degeneration. The secondary analysis showed that regular egg consumers with a low red and processed meat (RPM) intake ate healthier diets and had a better micronutrient status than those who did not eat eggs but who had a high RPM intake. It was concluded that egg consumption, at a range of intakes, was associated with nutrition and health benefits. Research limitations/implications – More research on eggs, and egg nutrients, is needed to confirm the health benefits. Future studies should control for other dietary and lifestyle factors. Originality/value – This paper develops knowledge about egg consumption beyond cholesterol content and provides new evidence from a secondary analysis of a large national dietary database.
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... Eggs are a rich sources of protein,fats and micro nutrient play an important role in basic nutrition,eggs also containts various trace nutrients that are important for health, eggs are rich in several nutrients that promote hearth such a betanine and choline. More than half the protein of an eggs is found in the egg white along with vitamin B2 and lower amounts of fat and cholesterol than yolk.The whites are rich source of selenium,vitamin D,B6,B12, A, D, E and K,and minerals such as zinc,iron and copper.Egg yolk contain more 77 calories, protein : 69 gram and healthy of fat :59 gram (Miranda et al., 2015;Ruxton et al., 2010). ...
... Besides, it can also relieve the symptoms of anemia. Despite its low cost, egg is rich in nutrients and considered as a kind of food with complete nutrient content (Miranda et al., 2015;Ruxton et al., 2010). ...
... Previous study also reported that eggs are a nutrientdense food , rich in essential vitamins and minerals, as well as antioxidants. Eggs may be used as a potential natural source of antioxidant,the antioxidant function of eggs could prevent humans from a large number of degenerative processes (Ruxton et al., 2010). Some nutrients in egg are zinc, selenium, retinol and tocopherols which can protect people from numerous degenerative processes. ...
... Eggs are consumed as a popular diet throughout the world and it is a highly important and available food source to meet the nutritional requirements providing 151 kilocalories of Energy, 12.5 grams (g) of protein, 391 mg of cholesterol, 200 mg of phosphorus, and adequate amounts of other vitamins and minerals, including Vitamin B 12 , Vitamin A, Iodine, and Selenium [1]. Eggs of various bird species are consumed in different countries and their nutritional composition also varies significantly. ...
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Background: Despite playing an essential role as micronutrients, when exposed to an excess level, heavy metals can augment the risk of potential health diseases among humans and animals. Due to environmental degradation and food adulteration, many people are becoming the victims of those diseases by ingesting heavy metals from those food sources. Eggs are one of the principal sources of proteinaceous food and eggshells are also a good source of calcium, therefore, it is necessary to estimate the frequency of heavy metals as the poultry feeds, nowadays, are contaminated with heavy metals. Materials and Methods: Five types of egg samples were collected from the Jahangirnagar University area including indigenous, white and brown layer chicken eggs, duck eggs, and quail eggs. The concentration of Pb, Cd, Cr, Cu, Fe, and Zn was estimated both for egg contents and eggshells (10 samples) by atomic absorption spectrophotometry compared with the standard curve. Estimated daily intake (EDI), Target hazard quotient (THQ), and Hazard Index (HI) were also calculated to observe whether egg intake possesses any health hazards or not. Results: Among all the trace elements estimated, the highest concentration was 35.36±0.4 (Zn) in white layer chicken eggs, and for eggshells, the highest concentration was 0.69875±0.082 mg/kg (Fe) in Quail eggshell. Except for Fe, Pb was relatively higher compared to other elements in eggs, the amount of Pb was the highest in Quail eggs (0.486±0.09 mg/kg). All the six elements were also within the acceptable range in eggshells where the amount of Pb was the highest in Brown layer eggshells, and Cu and Zn were the highest in indigenous eggshells. Cd and Cr were below the detection limit for all types of eggshells. Estimated daily intake (EDI), Target hazard quotient (THQ) and Hazard Index (HI) values indicated that intake of eggs does not possess any health risk. Conclusion: Interestingly, the heavy metal concentration of our samples belongs within the PTDI and USEPA limit. Therefore, based on our study, all egg samples were safe considering the average egg ingestion in our country. If the average egg consumption rises, people might be at risk for higher Pb consumption through egg intake.
... Eggs are consumed as a popular diet throughout the world and it is a highly important and available food source to meet the nutritional requirements providing 151 kilocalories of Energy, 12.5 grams (g) of protein, 391 mg of cholesterol, 200 mg of phosphorus, and adequate amounts of other vitamins and minerals, including Vitamin B 12 , Vitamin A, Iodine, and Selenium [1]. Eggs of various bird species are consumed in different countries and their nutritional composition also varies significantly. ...
Article
Full-text available
Background: Despite playing an essential role as micronutrients, when exposed to an excess level, heavy metals can augment the risk of potential health diseases among humans and animals. Due to environmental degradation and food adulteration, many people are becoming the victims of those diseases by ingesting heavy metals from those food sources. Eggs are one of the principal sources of proteinaceous food and eggshells are also a good source of calcium, therefore, it is necessary to estimate the frequency of heavy metals as the poultry feeds, nowadays, are contaminated with heavy metals. Materials and Methods: Five types of egg samples were collected from the Jahangirnagar University area including indigenous, white and brown layer chicken eggs, duck eggs, and quail eggs. The concentration of Pb, Cd, Cr, Cu, Fe, and Zn was estimated both for egg contents and eggshells (10 samples) by atomic absorption spectrophotometry compared with the standard curve. Estimated daily intake (EDI), Target hazard quotient (THQ), and Hazard Index (HI) were also calculated to observe whether egg intake possesses any health hazards or not. Results: Among all the trace elements estimated, the highest concentration was 35.36±0.4 (Zn) in white layer chicken eggs, and for eggshells, the highest concentration was 0.69875±0.082 mg/kg (Fe) in Quail eggshell. Except for Fe, Pb was relatively higher compared to other elements in eggs, the amount of Pb was the highest in Quail eggs (0.486±0.09 mg/kg). All the six elements were also within the acceptable range in eggshells where the amount of Pb was the highest in Brown layer eggshells, and Cu and Zn were the highest in indigenous eggshells. Cd and Cr were below the detection limit for all types of eggshells. Estimated daily intake (EDI), Target hazard quotient (THQ) and Hazard Index (HI) values indicated that intake of eggs does not possess any health risk. Conclusion: Interestingly, the heavy metal concentration of our samples belongs within the PTDI and USEPA limit. Therefore, based on our study, all egg samples were safe considering the average egg ingestion in our country. If the average egg consumption rises, people might be at risk for higher Pb consumption through egg intake.
... Amellett, hogy alapvető élelmiszer, funkcionális tulajdonságaiból fakadóan fontos egészségmegőrző szerepet tölt be, s emellett könnyen dúsítható jótékony összetevőkkel. Pozitív tulajdonságai között kell megemlíteni, hogy segíti az agyműködést, a magzati fejlődést, az immunrendszert, csökkenti a daganatos és a kardiovaszkuláris megbetegedések, valamint a korral összefüggő szembetegségek, az érszűkület, és a trombózis kialakulásának és az időskori izomerő-és izomtömeg-csökkenés előfordulásának kockázatát [27,17,52,49,33,41,32,4,19,54]. ...
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Ma már egyre inkább ismert az étkezési tojás pozitív hatása, az anyatejhez hasonló, teljes biológiai értékű fehérjéket tartalmazó élelmiszer. Miután relatíve olcsó, magas tápértékű komplex táplálékforrás, az emberi szervezet napi állatifehérje-szükséglete a legolcsóbban és a legkisebb környezeti terhelés mellett a tojással fedezhető. Hasonlóan más élelmiszerekhez, a tojással kapcsolatos fogyasztói igények is jelentősen változtak az elmúlt években, egyre inkább előtérbe kerül az állatjólét, valamint az egészség- és környezettudatosság, s ennek okán egyre több kérdés merül fel a különböző tartásmódokkal, különösképpen a ketreces rendszerekkel kapcsolatosan. Ennek kapcsán a tanulmány célja, hogy megvizsgálja a különböző tartásmódok fenntarthatóságbeli kérdéseit, valamint a fogyasztók egészségére és tojásfogyasztásra ható tényezőit, a releváns nemzetközi szakirodalmak és adatbázisok szintetizálása révén.
... Además, el consumo regular de frutas y verduras podría ayudar al organismo a luchar y hacer frente a los agentes causantes de los síntomas depresivos (6). Por otro lado, algunos estudios han encontrado asociación entre el consumo adecuado de legumbres, productos lácteos y huevos con un menor riesgo de depresión (12,13). También se han demostrado posibles efectos beneficiosos del consumo de pescado sobre las enfermedades mentales como depresión y ansiedad (14). ...
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Introduction. Mental illnesses represent one of the biggest public health problems. Consuming foods rich in antioxidants such as fruits and vegetables can lower risk factors. Objective. To analyze the dietary intake and the risk of mental illnesses in Peruvian adults. Materials and methods. A cross-sectional study was carried out in 393 Peruvian adults, who came from the three regions of the country (coast, mountains and jungle). Sociodemographic and anthropometric data were obtained through a registration form and the risk of mental illnesses was determined using the General Health Questionnaire-12 (GHQ-12). The data were analyzed using the statistical software IBM SPSS, version 26. The Chi-square test was used, considering a significance level of 5%. Results. Participants who reported risk and presence of mental illness reported inadequate consumption of fruits, vegetables, and healthy fats. Adequate consumption of whole grains, fruits and vegetables was significantly higher in women (p <0.05). However, more than half of the women proved to be at risk for mental illnesses compared to men (p <0.001). Conclusions. The adequate intake of healthy foods could be beneficial in reducing the risks of mental illness in this population group.
... The egg is a natural functional food containing all essential nutrients needed for adequate and balanced nutrition (Ruxton, et al, 2010). It has the best protein quality among animal products. ...
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Neurocysticercosis is the condition of the parasite in the central nervous system. Mass effect or blocking the cerebrospinal fluid circulation, causing symptoms. Most of the symptoms are the result of the inflammatory process that accompanies the cyst degeneration. Epileptic seizures and headache are the most common causes. A 63-year-old male patient, who had no known history of chronic illness, who was learned to have a history of substance addiction (cocaine, bonsai, methamphetamine, cannabis), was brought to our Emergency Service with the complaint of a behavioral disorder that has been increasing gradually for a week and losing interest in the surroundings. There was no nausea or vomiting complaint. In brain CT; Nonspecific hyperdense areas and edema were observed in the parenchymal areas. MRI: ‘Diffuse in bilateral cerebellar hemispheres and bilateral cerebral hemispheres, the largest is approximately 9 mm in size, iso-hypointense in T1-weighted images, diffuse hyperintense in T2-weighted images, isointense in flair sequence, locally hypointense, around (thick) enhancement after intravenous contrast material injection the areas seen and cortically located nonspecific relative hyperdense areas in the supratentorial areas were reported as'. he suggested that he did not admit to the hospital before neurological symptoms developed, as the transmission had occurred a long time ago and It was predicted that while our patient was using substances (snorting cocaine), the larvae contaminated to his hand directly passed to the brain via the sinus. In this article; we tried to emphasize that infectious diseases (especially parasitic infections) should be considered in addition to neurological diseases when atypical imaging results are obtained by presenting with neurological findings.
... Likewise, eggs are a rich source of protein and several essential nutrients, particularly vitamin D, vitamin B12, selenium and choline. Emerging evidence suggests that eating eggs is associated with satiety, weight management and better diet quality (Ruxton, Derbyshire, & Gibson, 2010). Pasta predominantly provides carbohydrates and cannot be seen as a substitute for meat proteins, whereas cheese has a high-fat content. ...
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High levels of meat consumption are increasingly being criticised for ethical, environmental, and social reasons. Plant-based meat substitutes have been identified as healthy sources of protein in comparison to meat. This alternative offers several social, environmental, and health benefits and may reduce meat consumption. However, there has been a lack of research on how specific meat substitute attributes can influence consumers to replace or partially replace meat in their diets. Research demonstrates that in many countries, consumers are highly attached to meat. They consider it as an essential and integral element of their daily diet. For these consumers, who are not interested in vegan or vegetarian alternatives to meat, meat blended with plant-based-proteins could be a low-threshold option for a more sustainable food consumption behaviour. In these products only a fraction of the meat product (e.g., 20% to 50%) is replaced with plant-based proteins. In this paper, the results of an online survey with 501 Belgium consumers are presented with a focus on preferences and attitudes relating to meat blended with plant-based proteins. The results show that more than fifty per cent of consumers substitute meat at least occasionally. Thus, about half of the respondents reveal an eligible consumption behaviour regarding sustainability and healthiness to a certain degree. Concerning the determinants of choosing either meat blended with plant-based proteins or the corresponding meat product, it becomes evident that a substantial effect is exerted by the health perception. The healthier meathybrids are perceived, the higher is the choice probability. Thus, this motive seems to outperform altruistic motives like animal welfare or environmental concerns when choosing this new product category.
... The egg is a natural functional food containing all essential nutrients needed for adequate and balanced nutrition (Ruxton, et al, 2010). It has the best protein quality among animal products. ...
Chapter
LIMBIC SYSTEM SUBCORTICAL STRUCTURES AND ALZHEIMER'S DISEASE.
... Hens' egg is considered a nutritionally complete food. Consumed all over the world in numerous dishes and reviewed as a cheap source of protein (Ruxton et al., 2010). Because the majority of consumers believe that organic food is safer for the health due to its production which is based on special standards they pay more for the price premiums demanded in the marketplace. ...
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Key words: Microbial quality, Antibiotic residues, Conventional table eggs, Organic table eggs. Chicken eggs are important as food to humans. The present study was conducted in Kafrelsheikh governorate, Egypt. A total of 250 samples (each sample contains 3 eggs) were purchased from different retail stores (conventional and organic, 125samples for each). These samples were subjected to microbiological examination for assessment of the sanitary quality and detection of incidence, serological and molecular characterization of salmonella, and subjected to chemical examination to detect the incidence of 2 antibiotic residues (oxytetracycline and tylosin) in both types of egg. Aerobic plate count showed mean values of 8.0×10 2 ± 4.6×10 cfu/ml for conventional eggs and 6.2×10 2 ± 3.2×10 cfu/ml for organic eggs, the coliform count showed a mean value of 4.6×10 2 ± 3.2×10 cfu /ml and 3.7×10 2 ± 2.6 ×10 cfu/ml for conventional and organic eggs respectively. Staphylococcus aureus count showed a mean value of 3.1×10 2 ±3.1 ×10 cfu/ml for conventional eggs and 2.3×10 2 ± 2.7 ×10 cfu/ml for organic egg. Mold and yeast count showed a mean value of 7.3×10 ± 3.8×10 cfu/ml and 4.2×10 ± 1.8 ×10 cfu/ml for conventional and organic eggs respectively. Salmonella was detected in 4 samples (1.6 % from total samples). All of them were only isolated from conventional eggs with a percentage of 3.2%. Serotype identification of four isolates was S. Kentucky. Salmonella Species were not isolated from organic egg contents. Multiplex PCR detected 3 virulence genes (hila, spvC, and stn) (100% of Salmonella isolates). No positive samples for microbial inhibitor test and no antibiotic residues in organic eggs and 4 conventional egg samples were detected positive for microbial inhibitor test with bacillus subtilis, which confirmed by HPLC for detection of 2 antibiotic residues (oxytetracycline and tylosin) and results revealed that 2 out of 4 positive inhibitor test samples were positive for oxytetracycline residues (317 µg /gm and 382 µg /gm) respectively, and 3 out of the same 4 samples were positive for tylosin residues (8.6 µg /gm, 48 µg /gm, and 18.5 µg /gm) respectively, and all positive samples exceeded the maximal residues limit (MRL 0.2 µg /gm) for both oxytetracycline and tylosin residues. The rate of detection of oxytetracycline and tylosin residues was (1.60%) and (2.4%) respectively from the conventional egg. Public health and economic importance for the isolated microorganisms and antibiotic residues were investigated. Results revealed that organic egg is safer than the conventional one.
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In the present study, we investigated the prevalence of Salmonella in various parts of table eggs collected from various union councils of Peshawar, Khyber Pakhtunkhwa Pakistan. For this purpose, 200 egg samples were collected. The culturing of Salmonella from egg shell and their contents was carried out according to ISO guidelines for Salmonella isolation. A total of twenty-two (22) eggs were positive for Salmonella species. The antibiotic susceptibility testing revealed that Salmonella isolates were resistant to ampicillin, amoxicillin/clavulanic acid, cefotaxime, and kanamycin while isolates were susceptible to chloramphenicol, gentamicin, kanamycin and streptomycin. These positive samples were further investigated and confirmed through PCR by targeting serovars specific genes i.e rfbJ, fliC, fljB for S. Typhimurium and ST11, SPV, SefA for S. Enteritidis. The prevalence of Salmonella was found to be 22 (11%), out of which 17 (77.27%) isolates were S. Enteritidis and 5 (22.73%) isolates were found to be S. Typhimurium as confirmed through PCR. The presence of infectious Salmonella in table eggs in Peshawar presents a serious public health threat and should be monitored on routine basis for the presence of Salmonella.
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High-quality proteins make a valuable contribution to the synthesis and maintenance of muscle and indirectly to the regulation of blood glucose levels, thus contributing to power, strength, and energy. Eggs have traditionally been used as the standard of comparison for measuring protein quality because of their essential amino acid (EAA) profile and high digestibility. They provide a nutrient-dense source of energy from protein and fat, approximately 75 kcal per large egg, as well as several B vitamins, including thiamin, riboflavin, folate, B12, and B6, which are required for the production of energy by the body. Given the unique complementary relationship between the EAA leucine and glucose utilization by muscle, it would follow that a diet rich in the amino acid leucine would be advantageous to men and women undergoing endurance training. Leucine is also a critical element in regulating muscle protein synthesis and may be the key amino acid defining the increased needs for EAA to optimize skeletal muscle mass. Increased tissue levels of leucine combine with circulating insulin to allow skeletal muscles to manage protein metabolism and fuel selection in relation to diet composition. Moreover, muscle recovery from exercise, both resistance and endurance, seems to be dependent on dietary leucine. Because eggs are an excellent, nutrient-rich source of leucine, as well as other EAAs, these protein-related benefits may be important to active individuals who routinely consume eggs as part of a varied, balanced diet
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Background: The food matrix in which carotenoids are found affects their bioavailability. Lutein and zeaxanthin are abundant in egg yolks and accumulate in the macular region of the retina, where they may affect visual function. Objective: We sought to determine whether plasma lutein and zeaxanthin concentrations are elevated after dietary supplementation with egg yolk. Design: Eleven moderately hypercholesterolemic men and women consumed 2 separate baseline diets, which contained 29–33% of energy as total fat, with 20% of energy as either beef tallow or corn oil. These diets were supplemented with cooked chicken egg yolks (1.3 egg yolks/d for an intake of 10.4 MJ). Each subject consumed all 4 diets. Each diet was consumed for 4.5 wk, with a washout period of ≥2 wk between diet phases. At the end of each diet phase, fasting morning plasma samples were collected and stored for carotenoid analysis by HPLC. Commercial chicken egg yolks were analyzed for carotenoids and cholesterol. Results: Egg yolk supplementation of the beef tallow diet increased plasma lutein by 28% (P < 0.05) and zeaxanthin by 142% (P < 0.001); supplementation of the corn oil diet increased plasma lutein by 50% (P < 0.05) and zeaxanthin by 114% (P < 0.001). Changes in plasma lycopene and β-carotene were variable, with no consistent trend. Egg yolk supplementation increased plasma LDL-cholesterol concentrations by 8–11% (P < 0.05). Conclusions: Egg yolk is a highly bioavailable source of lutein and zeaxanthin. The benefit of introducing these carotenoids into the diet with egg yolk is counterbalanced by potential LDL-cholesterol elevation from the added dietary cholesterol.
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Context Reduction in egg consumption has been widely recommended to lower blood cholesterol levels and prevent coronary heart disease (CHD). Epidemiologic studies on egg consumption and risk of CHD are sparse. Objective To examine the association between egg consumption and risk of CHD and stroke in men and women. Design and Setting Two prospective cohort studies, the Health Professionals Follow-up Study (1986-1994) and the Nurses' Health Study (1980-1994). Participants A total of 37,851 men aged 40 to 75 years at study outset and 80,082 women aged 34 to 59 years at study outset, free of cardiovascular disease, diabetes, hypercholesterolemia, or cancer. Main Outcome Measures Incident nonfatal myocardial infarction, fatal CHD, and stroke corresponding to daily egg consumption as determined by a food-frequency questionnaire. Results We documented 866 incident cases of CHD and 258 incident cases of stroke in men during 8 years of follow-up and 939 incident cases of CHD and 563 incident cases of stroke in women during 14 years of follow-up. After adjustment for age, smoking, and other potential CHD risk factors, we found no evidence of an overall significant association between egg consumption and risk of CHD or stroke in either men or women. The relative risks (RRs) of CHD across categories of intake were less than 1 per week (1.0), 1 per week (1.06), 2 to 4 per week (1.12), 5 to 6 per week (0.90), and ≥1 per day (1.08) (P for trend=.75) for men; and less than 1 per week (1.0), 1 per week (0.82), 2 to 4 per week (0.99), 5 to 6 per week (0.95), and ≥1 per day (0.82) (P for trend=.95) for women. In subgroup analyses, higher egg consumption appeared to be associated with increased risk of CHD only among diabetic subjects (RR of CHD comparing more than 1 egg per day with less than 1 egg per week among diabetic men, 2.02 [95% confidence interval, 1.05-3.87; P for trend=.04], and among diabetic women, 1.49 [0.88-2.52; P for trend=.008]). Conclusions These findings suggest that consumption of up to 1 egg per day is unlikely to have substantial overall impact on the risk of CHD or stroke among healthy men and women. The apparent increased risk of CHD associated with higher egg consumption among diabetic participants warrants further research.
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The Report of the Reorganisation Commission for Eggs, published in June 1968, was a condemnation of the British Egg Marketing Scheme which had at that time operated for ten years. The Commission criticised not only the detailed operations of the Board but also questioned the validity of the Board's major activities. Its condemnation contained the charges: firstly, that those who set up and operated the Scheme had been misguided and had worked in a way that was contrary to the well-being of the egg industry and, secondly, that there is little value in the producer marketing board type of organisation. Both of these charges are serious and neither of them has been substantiated. This paper is devoted to showing that the major charges of the Commission were not supported by fact: the market support operations of the Board did not cause over-production: market support operations improved price stability: the Board's marketing costs were not excessive; seen in the correct historical perspective, the Board from 1957 made a positive and helpful contribution to the development of egg marketing.
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Summary  The idea that dietary cholesterol increases risk of coronary heart disease (CHD) by turning into blood cholesterol is compelling in much the same way that fish oil improves arthritis by lubricating our joints! Dietary cholesterol, chiefly in the form of eggs, has long been outlawed as a causative agent in CHD through its association with serum cholesterol. However, the scientific evidence to support a role for dietary cholesterol in CHD is relatively insubstantial in comparison with the incontrovertible link between its circulating blood relative in low density lipoprotein (LDL) cholesterol and CHD. Interpretation of the relationship between dietary cholesterol and CHD has been repeatedly confounded by an often inseparable relationship between dietary cholesterol and saturated fat. It has also been exaggerated by the feeding of unphysiologically high intakes of eggs. Nonetheless, numerous studies have shown that dietary cholesterol can increase serum LDL-cholesterol, but the size of this effect is highly variable between individuals and, according to over 30 years of prospective epidemiology, has no clinically significant impact on CHD risk. Variation in response to dietary cholesterol is a real phenomenon and we can now identify nutrient–gene interactions that give rise to this variation through differences in cholesterol homeostasis. More importantly, to view eggs solely in terms of the effects of their dietary cholesterol on serum cholesterol is to ignore the potential benefits of egg consumption on coronary risk factors, including obesity, diabetes and metabolic syndrome. Cardiovascular risk in these conditions is largely independent of LDL-cholesterol. These conditions are also relatively unresponsive to any LDL-cholesterol raising effects of dietary cholesterol. Treatment is focused primarily on weight loss, and it is in this respect that eggs may have a new and emerging role in facilitating weight loss through increased satiety.
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Summary1Introduction2Physiological mechanisms of satiation and satiety2.1 Physiological mechanisms of satiation2.1.1 Gastric mechanisms of satiation2.1.2 Intestinal mechanisms of satiation2.2 Physiological mechanisms of satiety2.2.1 Gut hormones – episodic signals of satiety2.2.2 Tonic satiety signals2.3 The integration of satiety signals in the brain2.3.1 Anorexigenic pathways in the hypothalamus2.3.2 Orexigenic pathways in the hypothalamus2.3.3 Other areas of the brain involved in satiation and satiety2.3.4 Reward pathways3Measuring satiation and satiety3.1 Measuring satiation3.2 Measuring satiety3.2.1 Free living vs. laboratory studies3.2.2 Preload studies3.2.3 Self-reported measures of satiety3.2.4 Measuring food intake3.2.5 Quantifying satiety3.3 Confounders in satiety research3.3.1 Physiological confounders3.3.2 Behavioural confounders4The effects of foods and drinks on satiety4.1 Protein and satiety4.2 Carbohydrates and satiety4.3 Fibre and satiety4.4 Intense sweeteners and satiety4.5 Fat and satiety4.6 Liquids and satiety4.7 Alcohol and satiety4.8 Energy density and satiety5The effect of external factors on satiation and satiety5.1 Palatability5.2 Variety5.3 Portion size5.4 Sleep5.5 Physical activity5.6 Television viewing and other distractions5.7 Social situations6Satiation, satiety and weight control6.1 Obesity genes and satiety6.2 Physiological differences in satiation and satiety responses in obese people6.3 Behavioural differences in the response to satiation and satiety in obesity7Conclusions SummaryIn the context of the rising prevalence of obesity around the world, it is vital to understand how energy balance and bodyweight are controlled. The ability to balance energy intake and expenditure is critical to survival, and sophisticated physiological mechanisms have developed in order to do this, including the control of appetite. Satiation and satiety are part of the body's appetite control system and are involved in limiting energy intake. Satiation is the process that causes one to stop eating; satiety is the feeling of fullness that persists after eating, suppressing further consumption, and both are important in determining total energy intake.Satiation and satiety are controlled by a cascade of factors that begin when a food or drink is consumed and continues as it enters the gastrointestinal tract and is digested and absorbed. Signals about the ingestion of energy feed into specific areas of the brain that are involved in the regulation of energy intake, in response to the sensory and cognitive perceptions of the food or drink consumed, and distension of the stomach. These signals are integrated by the brain, and satiation is stimulated. When nutrients reach the intestine and are absorbed, a number of hormonal signals that are again integrated in the brain to induce satiety are released. In addition to these episodic signals, satiety is also affected by fluctuations in hormones, such as leptin and insulin, which indicate the level of fat storage in the body.Satiation and satiety can be measured directly via food intake or indirectly via ratings of subjective sensations of appetite. The most common study design when measuring satiation or satiety over a short period is using a test preload in which the variables of interest are carefully controlled. This is followed by subjects rating aspects of their appetite sensations, such as fullness or hunger, at intervals and then, after a predetermined time interval, a test meal at which energy intake is measured. Longer-term studies may provide foods or drinks of known composition to be consumed ad libitum and use measures of energy intake and/or appetite ratings as indicators of satiety. The measurement of satiation and satiety is complicated by the fact that many factors besides these internal signals may influence appetite and energy intake, for example, physical factors such as bodyweight, age or gender, or behavioural factors such as diet or the influence of other people present. For this reason, the majority of studies on satiation and satiety take place in a laboratory, where confounders can be controlled as much as possible, and are, therefore, of short duration.It is possible for any food or drink to affect appetite, and so it is important to determine whether, for a given amount of energy, particular variables have the potential to enhance or reduce satiation or satiety. A great deal of research has been conducted to investigate the effect of different foods, drinks, food components and nutrients on satiety. Overall, the characteristic of a food or drink that appears to have the most impact on satiety is its energy density. That is the amount of energy it contains per unit weight (kJ/g, kcal/g). When energy density is controlled, the macronutrient composition of foods does not appear to have a major impact on satiety. In practice, high-fat foods tend to have a higher energy density than high-protein or high-carbohydrate foods, and foods with the highest water content tend to have the lowest energy density. Some studies have shown that energy from protein is more satiating than energy from carbohydrate or fat. In addition, certain types of fibre have been shown to enhance satiation and satiety. It has been suggested that energy from liquids is less satiating then energy from solids. However, evidence for this is inconsistent, and it may be the mode of consumption (i.e. whether the liquid is perceived to be a food or drink) that influences its effect on satiety. Alcohol appears to stimulate energy intake in the short-term, and consuming energy from alcohol does not appear to lead to a subsequent compensatory reduction in energy intake.The consumption of food and drink to provide energy is a voluntary behaviour, and, despite the existence of sophisticated physiological mechanisms to match intake to requirements, humans often eat when sated and sometimes refrain from eating when hungry. Thus, there are numerous influences on eating behaviour beyond satiation and satiety. These include: the portion size, appeal, palatability and variety of foods and drinks available; the physiological impact on the body of physical activity and sleep; and other external influences such as television viewing and the effect of social situations.Because satiation and satiety are key to controlling energy intake, inter-individual differences in the strength of these signals and responsiveness to their effects could affect risk of obesity. Such differences have been observed at a genetic, physiological and behavioural level and may be important to consider in strategies to prevent or treat obesity.Overall, it is clear that, although the processes of satiation and satiety have the potential to control energy intake, many individuals override the signals generated. Hence, in such people, satiation and satiety alone are not sufficient to prevent weight gain in the current obesogenic environment. Knowledge about foods, ingredients and dietary patterns that can enhance satiation and satiety is potentially useful for controlling bodyweight. However, this must be coupled with an understanding of the myriad of other factors that influence eating behaviour, in order to help people to control their energy intake.
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Plain language summary No evidence of the efficacy of vitamin B12 supplementation for cognitive function Vitamin B12 is essential for maintaining normal function of the nervous system, but the relationship between vitamin B12 and cognitive function is not fully understood. From the three studies involving people with dementia or cognitive impairment and low blood levels of vitamin B12 eligible for inclusion in this review there was no statistically significant effect of vitamin B12 supplementation on cognition. The variety of measurement scales used to assess outcomes and uncertainty about diagnostic criteria for vitamin B12 deficiency create difficulties in pooling the results of trials.
Article
Increasingly, scientists are debating whether photochemical synthesis of vitamin D in Western countries is adequate, and whether dietary intakes can plug the gap between endogenous vitamin D production and requirements, particularly in young and older populations. The debate is driven by the plethora of evidence suggesting that, in addition to its important role in maintaining bone health, vitamin D may be involved in ameliorating cell ageing and preventing cardiovascular disease, diabetes, immune dysfunction and some cancers. Observational evidence from different populations suggests a significant degree of vitamin D insufficiency, often defined as plasma 25-hydroxyvitamin D [25(OH)D] <25 nmol/l. Some experts have argued that daily intakes up to 40 µg/day may be needed to ensure a desirable vitamin D status, even after accounting for sun exposure. However, there is presently no consensus on the most appropriate vitamin D status for maintaining bone health and preventing chronic disease. In addition, the UK has not set a vitamin D recommendation for most adults under 65 years. Given the plethora of information about vitamin D and bone health, this article reviews evidence for a link between vitamin D and other aspects of health. In conclusion, three actions are suggested: (1) agreement on optimal plasma 25(OH)D levels for health; (2) a debate on whether UK dietary recommendations need revision; and (3) better promotion of dietary vitamin D via food sources and, for certain groups, supplements.