Nutrition refers to the process by which a living organism ingests and digests food and uses the nutrients therein for growth, tissue maintenance and all other functions essential to life. Food components interact with our body at molecular, cellular, organ and system level. Nutrients come in complex mixtures, in which the presence and concentration of single compounds as well as their interactions with other compounds and the food matrix influence their bioavailability and bioefficacy. Traditionally, nutrition research mainly concentrated on supplying nutrients of quality to nourish populations and on preventing specific nutrient deficiencies. More recently, it investigates health-related aspects of individual ingredients or of complete diets, in view of health promotion, performance optimisation, disease prevention and risk assessment. This review focuses on proteins and peptides, their role as nutrients and biomarkers and on the technologies developed for their analysis. In the first part of this review, we provide insights into the way proteins are currently characterised and analysed using classical and emerging proteomic approaches. The scope of the second part is to review major applications of proteomics to nutrition, from characterisation of food proteins and peptides, via investigation of health-related food benefits to understanding disease-related mechanisms.

An understanding of how infant eating behaviour relates to later obesity is required if interventions in infancy are to be attempted. The aim of this paper is to review findings from the Gateshead Millennium Study to describe (i) what we have already established about the relationship between infant feeding transitions, infancy weight gain and eating behaviour and (ii) describe new analyses that examine how infant eating behaviour and temperament relate to infancy weight gain and childhood adiposity. The Gateshead Millennium Study recruited 1029 infants at birth and parents completed questionnaires five times in the first year. We have already described how starting solids and ceasing breast-feeding seems to be a response to rapid early weight gain, rather than a cause, and that parents identify and respond to the individual appetite characteristics of their child. A number of questions about eating behaviour at 12 months were used to construct an infancy eating avidity score that was positively associated with height at age 7–8 years, but not with an adiposity index constructed using bioelectrical impedance, waist and skinfolds. Infancy eating avidity score was associated with greater fussiness and lower satiety responsivity on the Child Eating Behaviour Questionnaire at age 6–8 years. Temperament measured at age 6 weeks and 8 months showed no consistent associations with either infancy weight gain or adiposity at 6–8 years. While infancy may seem a logical time to intervene with children at risk of future obesity, the collective findings from this substantial population-based study largely suggest otherwise.

The AMP-activated protein kinase (AMPK) is a sensor of cellular energy status, and a regulator of energy balance at both the cellular and whole body levels. Although ubiquitously expressed, its function is best understood in skeletal muscle. AMPK contains sites that reversibly bind AMP or ATP, with an increase in cellular AMP:ATP ratio (signalling a fall in cellular energy status) switching on the kinase. In muscle, AMPK activation is therefore triggered by sustained contraction, and appears to be particularly important in the metabolic changes that occur in the transition from resistance to endurance exercise. Once activated, AMPK switches on catabolic processes that generate ATP, while switching off energy-requiring processes not essential in the short term. Thus, it acutely activates glucose uptake (by promoting translocation of the transporter GLUT4 to the membrane) and fatty acid oxidation, while switching off glycogen synthesis and protein synthesis (the later via inactivation of the mammalian target-of-rapamycin pathway). Prolonged AMPK activation also causes some of the chronic adaptations to endurance exercise, such as increased GLUT4 expression and mitochondrial biogenesis. AMPK contains a glycogen-binding domain that causes a sub-fraction to bind to the surface of the glycogen particle, and it can inhibit glycogen synthesis by phosphorylating glycogen synthase. We have shown that AMPK is inhibited by exposed non-reducing ends in glycogen. We are working on the hypothesis that this ensures that glycogen synthesis is rapidly activated when glycogen becomes depleted after exercise, but is switched off again as soon as glycogen stores are replenished.

The role of nutrition is especially important in certain ‘lifestyle’ diseases that impact disproportionately on ethnic minority populations. The aim of this paper is to review the evidence of risk, health outcomes and interventions for certain diseases that affect the UK's largest ethnic minority group (South Asians) in order to help professionals better address the needs of this diverse population. Research evidence is presented on factors influencing access to services by ethnic minority populations and the changing UK policy background for public health and preventive care. The available research base on obesity, diabetes and CVD is discussed. Conditions such as type 2 diabetes, which are more prevalent among the South Asian population, are associated with poorer health outcomes and appear to exhibit links to diet and nutrition that start in childhood or even before birth; all making preventive care important. Obesity is a major risk factor and it appears that BMI thresholds may need to be lower for South Asians. Targeted interventions to improve diet and outcomes in the South Asian population also appear promising. Recent moves to promote access to evidence of ethnicity and health and to improve the cultural competence of organisations are discussed. Health professionals will increasingly need to promote lifestyle changes in a manner that meets the needs of a diverse population in order to address future public health challenges. Nutritionists and other professionals will need to ensure that interventions are culturally appropriate and involve engagement with extended family members and communities.

Growing evidence supports the conclusion that consumption of protein in close temporal proximity to the performance of resistance exercise promotes greater muscular hypertrophy. We can also state with good certainty that merely consuming energy, as carbohydrate for example, is also not sufficient to maximise muscle protein synthesis leading to anabolism and net new muscle protein accretion. Recent work also indicates that certain types of proteins, particular those that are rapidly digested and high in leucine content (i.e. whey protein), appear to be more efficient at stimulating muscle protein synthesis. Continued practice of consumption of these types or proteins after exercise should lead to greater hypertrophy. Reviews of numerous training studies indicate that studies in which milk proteins and principally whey protein show an advantage of these proteins over and above isoenergetic carbohydrate and soya protein in promoting hypertrophy. Thus, the combined evidence suggests a strategic advantage of practising early post-exercise consumption of whey protein or dairy-based protein to promote muscle protein synthesis, net muscle protein accretion and ultimately hypertrophy.

As a population subgroup, older people are more vulnerable to malnutrition especially those who are institutionalised. Recognition of deteriorating or poor nutritional status is key in reversing the effects of undernutrition and reinforces the value of regular weight checks and/or the use of screening tools. Commercially produced supplements are often the first option used to address undernutrition in both acute and community settings. They can be expensive and, although regularly prescribed, have undergone only limited evaluation of their effectiveness in community settings. An alternative but less researched approach to improve the nutritional status of undernourished people is food fortification. This approach may be particularly useful for older people, given their often small appetites. The ability to eat independently has been significantly related to decreased risk of undernutrition. Assisting people who have difficulty feeding themselves independently should become a designated duty and may be crucial in optimising nutritional status. Lack of nutrition knowledge has been identified as the greatest barrier to the provision of good nutritional care. Education and training of care staff are pivotal for the success of any intervention to address undernutrition. The development of undernutrition is a multi-factorial process and a package of approaches may be required to prevent or treat undernutrition. Nutrition must be at the forefront of care if national care standards are to be met.

Micronutrients are essential for optimal human health. However, in some cases, raising intake by supplementation has not proven to be beneficial and there is even some evidence that supplementation may increase disease risk, highlighting the importance of assessing the functional status of micronutrients. Techniques such as gene microarrays and single-nucleotide polymorphism analysis have the potential to examine effects of micronutrient intake on patterns of gene expression and inter-individual variation in micronutrient metabolism. Recent genomic research related to selenium (Se) provides examples illustrating how studies of functional single-nucleotide polymorphism and gene expression patterns can reveal novel biomarkers of micronutrient function. Both in vitro and in vivo experiments show that there are functionally relevant polymorphisms in genes encoding glutathione peroxidases 1, 3 and 4, selenoprotein P, selenoprotein S and the 15 kDa selenoprotein. Disease association studies investigating these gene variants have so far been relatively small but an association of a polymorphism in the selenoprotein S gene with colorectal cancer risk has been replicated in two distinct populations. Future disease association studies should examine effects of multiple variants in combination with nutritional status. Gene microarray studies indicate that changes in Se intake alter expression of components of inflammatory, stress response and translation pathways. Our hypothesis is that Se intake and genetic factors have linked effects on stress response, inflammation and apoptotic pathways. Combining such data in a systems biology approach has the potential to identify both biomarkers of micronutrients status and sub-group populations at particular risk.

Therapy of choice in obese children and adolescents is lifestyle intervention based on nutrition education, behavioural treatment and exercise treatment. Its efficacy even after the end of intervention has been proven by several randomised-controlled trials and meta-analyses including a recent Cochrane review. However, randomised-controlled trials are likely to overestimate the effectiveness. Studies under normal day-to-day circumstances demonstrated only a very moderate effect on weight loss (<10% success rate 2 years after the onset of intervention). A reduction of >0·5 SDS-BMI (which means a stable weight over 1 year in growing children) is associated with an improvement of cardiovascular risk factors, while improvements of quality of life seem independent of the degree of weight loss. Younger children and less overweight children particularly profit from lifestyle interventions in contrast to extremely obese adolescents. Recent studies demonstrated that involving parents is crucial for success, suggesting that parents and children and not children alone should be the primary target of interventions. Failures in weight reduction are attributed not only to a lack of motivation but also to other aspects particular to the genetic background. The techniques, more than the contents, of an intervention influence the treatment outcome. Besides behavioural therapy, systemic and solution-focused treatments are important. Future longitudinal research should focus on the identification of which children and adolescents profit from which kind of intervention, in order to be able to tailor specific treatment approaches. Studies under normal day-to-day circumstances are necessary to prove the benefit of this kind of intervention.