There are no high-quality data on dietary behaviour of adolescents in India. This study aimed to assess the intake of energy (E), macronutrients and selected micronutrients in a sample of 11–13-year-old schoolchildren in Delhi, India. Participants from private schools (n=10) recorded dietary intake using a 3-d food diary. Information was entered into the dietary assessment tool, Intake24, to ascertain portion size and convert data into nutrient intake through integrated food tables. Of the 514 consenting participants, 393 (76·4 %) (169 girls, 224 boys) aged 11·4 (±1·8) years completed the study. The median (interquartile range (IQR) daily E intake was 2580 (2139·3–2989·8) kcal (10·8 (9·0 − 12·5) MJ) for girls and 2941·5 (2466·7–3599·3) kcal (12·3 (10·3–15·2) MJ) for boys. The median (IQR) daily nutrient intakes for girls and boys respectively were protein 64·6 (54·8–79·3) g, 74·4 (61·4; 89·4) g; carbohydrate 336·5 (285·3–393·6) g, 379·6 (317·8–461·8) g; and saturated fat 45·6 (34·8–58·3) g, 54·6 (41·9–69·5) g. There were no significant between-gender differences in percentage E from protein (10·2 (9·2–11·4)), or carbohydrate (52·4 (48·7–56·7)). Girls obtained less percentage E from saturated fat (16·1 (11·0–18·2) compared with boys 16·3 (14·2–19·1) (P < 0·05). E from saturated fat was above FAO recommendations in >74 % of participants. The estimated average requirement for iron was achieved by < 40 % of girls. In conclusion, strategies to optimise the dietary intake of adolescents in India should focus on preventing excess intakes of E and saturated fat and improving iron intake in girls.

Restriction of dietary carbohydrates, fat and/or protein is often used to reduce body weight and/or treat (metabolic) diseases. Since diet is a key modulator of the human gut microbiome, which plays an important role in health and disease, this review aims to provide an overview of current knowledge of the effects of macronutrient-restricted diets on gut microbial composition and metabolites. A structured search strategy was performed in several databases. After screening for inclusion and exclusion criteria, thirty-six articles could be included. Data are included in the results only when supported by at least three independent studies to enhance the reliability of our conclusions. Low-carbohydrate (<30 energy%) diets tended to induce a decrease in the relative abundance of several health-promoting bacteria, including Bifidobacterium, as well as a reduction in short-chain fatty acid (SCFA) levels in faeces. In contrast, low-fat diets (<30 energy%) increased alpha diversity, faecal SCFA levels and abundance of some beneficial bacteria, including Faecalibacterium prausnitzii. There were insufficient data to draw conclusions concerning the effects of low-protein (<10 energy%) diets on gut microbiota. Although the data of included studies unveil possible benefits of low-fat and potential drawbacks of low-carbohydrate diets for human gut microbiota, the diversity in study designs made it difficult to draw firm conclusions. Using a more uniform methodology in design, sample processing and sharing raw sequence data could foster our understanding of the effects of macronutrient restriction on gut microbiota composition and metabolic dynamics relevant to health. This systematic review was registered at https://www.crd.york.ac.uk/prospero as CRD42020156929.

A low-glycaemic-index (GI) breakfast has been shown to lower blood glucose levels throughout the day. A wide variety of breakfast foods are consumed, but their GI values are largely unknown, hence limiting consumers’ ability to select healthier options. This study investigated the GI values of ten common breakfast (five Asian and five Western) foods in this region using a randomised, cross-over study design. Participants arrived after an overnight fast, and fasting blood sample was taken before participants consumed test foods. Next, blood samples were taken at fixed intervals for 180 min. Glycaemic and insulinaemic responses to test foods were calculated as incremental AUC over 120 min, which were subsequently reported as glycaemic and insulinaemic indices. In all, nineteen healthy men (nine Chinese and ten Indians) aged 24·7 (sem 0·4) years with a BMI of 21·7 (sem 0·4) kg/m2 completed the study. Asian breakfast foods were of medium (white bun filled with red bean paste=58 (sem 4); Chinese steamed white bun=58 (sem 3)) to high GI (rice idli=85 (sem 4); rice dosa=76 (sem 5); upma=71 (sem 6)), whereas Western breakfast foods were all of low GI (whole-grain biscuit=54 (sem 5); whole-grain biscuit filled with peanut butter=44 (sem 3); whole-grain oat muesli=55 (sem 4); whole-grain oat protein granola=51 (sem 4); whole-grain protein cereal=49 (sem 3)). The GI of test foods negatively correlated with protein (r s −0·366), fat (r s −0·268) and dietary fibre (r s −0·422) (all P<0·001). GI values from this study contribute to the worldwide GI database, and may assist healthcare professionals in recommending low-GI breakfast to assist in lower daily glycaemia among Asians who are susceptible to type 2 diabetes mellitus.

Accumulating evidence indicates that saturated fat intake is related to mortality risk increase, whereas unsaturated fat intake is associated with reduced mortality risk. The aim of the present study was to estimate the mortality risk reduction related to a dietary change from saturated fat to mono- or polyunsaturated fat intake. The American National Health and Nutrition Examination Surveys conducted between 1999 and 2010 were linked to the 2011 national US death registry resulting in an observational prospective mortality study. Proportional hazards Cox models were used to evaluate the association between saturated, monounsaturated and polyunsaturated fat with all-cause and cause-specific mortality. Substitution analysis was conducted to estimate an iso-energetic substitution of 10 % of the energy from dietary fat intake applied to the substitution of saturated fat with an equal amount of energy from monounsaturated or polyunsaturated fat. The highest tertile intakes of saturated fat resulted in an increased risk (12 %) of all-cause and specific-cause mortality, whereas the highest tertile intakes of polyunsaturated fat resulted in a reduced risk (7 %) of all-cause and specific-cause mortality when compared with the corresponding lowest tertile. Iso-energetic substitution revealed that a substitution of 10 % of energy (from total fat) from saturated fat to an equal amount of energy from monounsaturated or polyunsaturated fat resulted in a significant reduction of the mortality risk ranging from 4 to 8 %. Iso-energetic substitution of saturated fat with monounsaturated and polyunsaturated fat reduced all-cause and specific-cause mortality in US adults.

The formation of amylose–lipid complexes (ALC) had been associated with reduced starch digestibility. A few studies have directly characterised the extent of ALC formation with glycaemic response. The objectives of this study were to investigate the effect of using fats with varying degree of saturation and chain length on ALC formation as well as glycaemic and insulinaemic responses after consumption of bread. Healthy men consumed five test breads in a random order: control bread without any added fats (CTR) and breads baked with butter (BTR), coconut oil (COC), grapeseed oil (GRP) or olive oil (OLV). There was a significant difference in glycaemic response between the different test breads (P=0·002), primarily due to COC having a lower response than CTR (P=0·016), but no significant differences between fat types were observed. Insulinaemic response was not altered by the addition of fats/oils. Although BTR was more insulinotropic than GRP (P<0·05), postprandial β-cell function did not differ significantly. The complexing index (CI), a measure of ALC formation, was significantly higher for COC and OLV compared with BTR and GRP (P<0·05). CI was significantly negatively correlated with incremental AUC (IAUC) of change in blood glucose concentrations over time (IAUCglucose) (r –0·365, P=0·001). Linear regression analysis showed that CI explained 13·3 % of the variance and was a significant predictor of IAUCglucose (β=–1·265, P=0·001), but IAUCinsulin did not predict IAUCglucose. Our study indicated that a simple way to modulate glycaemic response in bread could lie in the choice of fats/oils, with coconut oil showing the greatest attenuation of glycaemic response.

Imbalances in dietary fat intakes are linked to several chronic diseases. This study describes dietary intakes and food sources of fat and fatty acids in 1051 Irish adults (aged 18–90 years), using data from the 2011 national food consumption survey, the National Adult Nutrition Survey. It also compares current intakes for 18–64-year-olds with those reported in the last such survey in 2001, the North/South Ireland Food Consumption Survey. Dietary fat intakes were estimated using data from 4-d semi-weighed (2011) and 7-d estimated (2001) food diaries. In 2011, intakes for 18–64-year-olds were as follows: total fat, 34·1 (sd 6·1) % total energy (%TE); SFA, 13·3 (sd 3·3) %TE; MUFA, 12·5 (sd 2·6) %TE; PUFA, 6·1 (sd 2·2) %TE; and trans-fat, 0·511 (sd 0·282) %TE. Apart from MUFA, intakes decreased (P<0·001) compared with 2001. There was no statistically significant difference in intakes of EPA and DHA by 18–64-year-olds in 2011 (269·0 (sd 515·0) mg/d) and 2001 (279·1 (sd 497·5) mg/d). In 2011, adults aged >65 years had the highest intakes of SFA; however, intakes were typically higher than UK-recommended values for all groups. In contrast, intakes of long-chain n-3 fatty acids were lowest in younger age groups. Intakes of trans-fat were well within UK-recommended levels. Although there have been some improvements in the profile of intakes since 2001, imbalances persist in the quantity and quality of dietary fat consumed by Irish adults, most notably for total and SFA and for younger age groups for long-chain n-3 fatty acids.

Few longitudinal studies carried out in US adults have evaluated long-term dietary fat intakes and compared them with the national recommendations during the two-decade period when the prevalence of obesity and insulin resistance increased substantively. In the present study, we examined trends in the intakes of dietary fats and rich dietary sources of fats in the Framingham Heart Study Offspring Cohort over a 17-year period. The cohort was established in 1971–75 with follow-up examinations being conducted approximately every 4 years. Dietary data were collected using a semi-quantitative FFQ beginning in 1991 (exam 5). We included 2732 adults aged ≥ 25 years with complete dietary data in at least three examinations from 1991 to 2008. Descriptive statistics were generated using SAS version 9.3, and a repeated-measures model was used to examine trends in macronutrient and food intakes using R. Over the 17 years of follow-up, the percentage of energy derived from total fat and protein increased (27·3–29·8 % of energy and 16·8–18·0 % of energy, respectively) and that derived from carbohydrate decreased (51·0–46·8 % of energy; P-trend < 0·001). Increases in the percentage of energy derived from all fat subtypes were observed, except for that derived from trans-fats, which decreased over time (P-trend < 0·001). Trends were similar between the sexes, although women exhibited a greater increase in the percentage of energy derived from saturated fat and less reduction in the percentage of energy derived from trans-fats (P interaction < 0·05). Trends in fat intake were similar across the BMI categories. The number of weekly servings of cheese, eggs, ice cream desserts, nuts, butter and sausages/processed meats increased, whereas the intake of milk, margarine, poultry, confectioneries, chips and breads decreased (P-trend < 0·001). In this cohort of predominantly Caucasian older adults, the percentage of energy derived from dietary fats increased over time, but it remained within the national recommendations of less than 35 % of total energy, on average.

The objective of this review is to provide an overview of nutritional factors involved in cognitive aging and dementia with a focus on nutrients that are also important in neurocognitive development. Several dietary components were targeted, including antioxidant nutrients, dietary fats and B-vitamins. A critical review of the literature on each nutrient group is presented, beginning with laboratory and animal studies of the underlying biological mechanisms, followed by prospective epidemiological studies and randomised clinical trials. The evidence to date is fairly strong for protective associations of vitamin E from food sources, the n-3 fatty acid, DHA, found in fish, a high ratio of polyunsaturated to saturated fats, and vitamin B12 and folate. Attention to the level of nutrient intake is crucial for interpreting the literature and the inconsistencies across studies. Most of the epidemiological studies that observe associations have sufficient numbers of individuals who have both low and adequate nutrient status. Few of the randomised clinical trials are designed to target participants who have low baseline status before randomising to vitamin supplement treatments, and this may have resulted in negative findings. Post-hoc analyses by some of the trials reveal vitamin effects in individuals with low baseline intakes. The field of diet and dementia is a relatively young area of study. Much further work needs to be done to understand dietary determinants of cognitive aging and diseases. Further, these studies must be particularly focused on the levels of nutrient intake or status that confer optimum or suboptimal brain functioning.

Daily diet may have implications for skin ageing. However, data on the relationship between diet and the parameters of skin conditions are scarce. The present study aimed to examine the associations of biophysical properties of the skin of women with intakes of fats and antioxidant micronutrients as well as food groups as sources of these nutrients. In a cross-sectional study, we measured the hydration, surface lipids and elasticity of the skin of 716 Japanese women using non-invasive techniques. The extent of facial wrinkles in the crow's-foot area was determined by observation using the Daniell scale. Each subject's usual diet was determined with the use of a validated FFQ. After controlling for covariates including age, smoking status, BMI and lifetime sun exposure, the results showed that higher intakes of total fat, saturated fat and monounsaturated fat were significantly associated with increased skin elasticity. A higher intake of green and yellow vegetables was significantly associated with a decreased Daniell wrinkling score. Intake of saturated fat was significantly inversely associated with the Daniell wrinkling score after additional adjustment for green and yellow vegetable intake. Further studies with more accurate measurement methods are needed to investigate the role of daily diet in skin ageing.

A role of dietary nutrients in relation to insulin resistance has been suggested but conclusive evidence in human beings is lacking. Asian Indians and South Asians are prone to develop insulin resistance and the metabolic syndrome. In the present paper, data pertaining to nutrient intake, insulin resistance and cardiovascular risk factors in Asian Indians and South Asians have been reviewed. In these populations, several dietary imbalances have been reported: low intake of MUFA, n-3 PUFA and fibre, and high intake of fats, saturated fats, carbohydrates and trans-fatty acids (mostly related to the widespread use of Vanaspati, a hydrogenated oil). Some data suggest that these nutrient imbalances are associated with insulin resistance, dyslipidaemia and subclinical inflammation in South Asians. Specifically, in children and young individuals, a high intake of n-6 PUFA is correlated with fasting hyperinsulinaemia, and in adults, high-carbohydrate meal consumption was reported to cause hyperinsulinaemia, postprandial hyperglycaemia and hypertriacylglycerolaemia. Dietary supplementation with n-3 PUFA leads to an improved lipid profile but not insulin sensitivity. Inadequate maternal nutrition in pregnancy, low birth weight and childhood ‘catch-up’ obesity may be important for the development of the metabolic syndrome and diabetes. Even in rural populations, who usually consume traditional frugal diets, there is an increasing prevalence of cardiovascular risk factors and the metabolic syndrome due to changes in diets and lifestyle. Nationwide community intervention programmes aimed at creating awareness about the consequences of unhealthy food choices and replacing them by healthy food choices are urgently needed in urban and rural populations in India, other countries in South Asia and in migrant South Asians.

A positive energy balance (energy intake>energy expenditure), in which total fat intake plays an important role, is commonly regarded as a major factor contributing to obesity. Adipose tissue development, i.e. both size (hypertrophy) and number (hyperplasia), is stimulated by high dietary fat intake during early postnatal development, a susceptibility that now appears to continue well into adulthood. Recent human and animal studies suggest that by altering rates of adipocyte differentiation and proliferation, differences in the composition of dietary fat may also contribute to adipose tissue development. At least in rodent models, the relative intake of n-6 to n-3 PUFA is clearly emerging as a new factor in this development. In these models, higher linoleate intake raises tissue arachidonic acid, which increases prostacyclin production and, in turn, stimulates signalling pathways implicated in adipogenesis. Signalling pathways stimulated by arachidonic acid probably include phospholipase and/or cyclo-oxygenase activation and may be linked as much to relatively low intake of n-3 PUFA as to excessive dietary linoleate. One factor potentially contributing to oversight about the apparent role of dietary n-6 PUFA (especially excess dietary linoleate) in adipose tissue development is the historical overestimation of linoleate requirements and the enthusiasm for higher intake of ‘essential fatty acids’. More research is needed to address whether disequilibration of dietary PUFA intake contributes to the risk of obesity in humans.

CHD is a multifactorial disease that is associated with non-modifiable risk factors, such as age, gender and genetic background, and with modifiable risk factors, including elevated total cholesterol and LDL-cholesterol levels. Lifestyle modification should be the primary treatment for lowering cholesterol values. The modifications recommended include dietary changes, regular aerobic exercise, and normalization of body weight. The recommended dietary changes include restriction in the amount of total fat, saturated fat and cholesterol together with an increase in the consumption of complex carbohydrate and dietary fibre, especially water-soluble fibre. However, nutrition scientists continue to question the value of these universal concepts and the public health benefits of low-fat diets, and an intense debate has been conducted in the literature on whether to focus on reduction of total fat or to aim efforts primarily towards reducing the consumption of saturated and trans fats. Moreover, it is well known that there is a striking variability between subjects in the response of serum cholesterol to diet. Multiple studies have examined the genediet interactions in the response of plasma lipid concentrations to changes in dietary fat and/or cholesterol. These studies have focused on candidate genes known to play key roles in lipoprotein metabolism. Among the gene loci examined, APOE has been the most studied, and the current evidence suggests that this locus might be responsible for some of the inter-individual variability in dietary response. Other loci, including APOA4, APOA1, APOB, APOC3, LPL and CETP have also been found to account for some of the variability in the fasting and fed states.

Cardiovascular diseases (CVD) are growing contributors to global disease burdens, with epidemics of CVD advancing across many regions of the world which are experiencing a rapid health transition. Diet and nutrition have been extensively investigated as risk factors for major cardiovascular diseases like coronary heart disease (CHD) and stroke and are also linked to other cardiovascular risk factors like diabetes, high blood pressure and obesity. The interpretation of evidence needs to involve a critical appraisal of methodological issues related to measurement of exposures, nature of outcome variables, types of research design and careful separation of cause, consequence and confounding as the basis for observed associations.

Adequate evidence is available, from studies conducted within and across populations, to link several nutrients, minerals, food groups and dietary patterns with an increased or decreased risk of CVD. Dietary fats associated with an increased risk of CHD include trans–fats and saturated fats, while polyunsaturated fats are known to be protective. Dietary sodium is associated with elevation of blood pressure, while dietary potassium lowers the risk of hypertension and stroke. Regular frequent intake of fruits and vegetables is protective against hypertension, CHD and stroke. Composite diets (such as DASH diets, Mediterranean diet, ‘prudent’ diet) have been demonstrated to reduce the risk of hypertension and CHD. Sufficient knowledge exists to recommend nutritional interventions, at both population and individual levels, to reduce cardiovascular risk. That knowledge should now be translated into policies which promote healthy diets and discourage unhealthy diets. This requires coordinated action at the level of governments, international organizations, civil society and responsible sections of the food industry.

The contribution of the home use of margarines, made with partially hydrogenated vegetables oils, to total trans fatty acid intake is difficult to determine using dietary assessment because food composition databases are incomplete for trans fatty acids; moreover, hidden fats in manufactured foods may be the predominant sources of trans fatty acids. The objective of our study was to determine, using plasma phospholipid trans fatty acid composition as a surrogate measure of exposure, whether the home use of margarine or butter is an important determinant of trans fatty acid status. We conducted a community-based (Dunedin, New Zealand), cross-sectional survey of people who consumed either margarine (n 65) or butter (n 64) but not both for home use. The levels of the 18:1 trans isomers commonly found in partially hydrogenated vegetable oils were all significantly higher in the plasma phospholipids of margarine compared with butter consumers, with the exception of 18:1n-7t, which did not differ. Among margarine consumers, the percentage of total fat from margarine was significantly correlated with levels of phospholipid 18:1n−6t, 18:1n-8t and 18:1n-1/t isomers (r 0·57–0·63, P<0·001) but only weakly with 18:1n-7t (r 0·30, P=0·016). The intake of fat from fast foods, bakery products or meat and meat products was not associated with plasma phospholipid trans isomeric composition. The home use of margarine, made with partially hydrogenated vegetable oils, is an important determinant of trans fatty acid exposure in New Zealand.