Summary Introduction What are unsaturated fatty acids? Unsaturated fatty acids in the UK diet Unsaturated fatty acids in health and disease Unsaturated fatty acids and public health Conclusions Acknowledgements References Summary  Fat provides energy; indeed it is the most energy dense of all the macronutrients, with 1 g providing 37 kJ (9 kcal). However, the constituent parts of fat, fatty acids, are required by the body for many other functions than simply as an energy source, and there is an increasing awareness of the potential health benefits of specific types of fatty acids. Fatty acids are long hydrocarbon chains, with a methyl group at one end (the omega or n‐end) and an acid group at the other. Unsaturated fatty acids are hydrocarbon chains containing at least one carbon–carbon double bond; monounsaturated fatty acids contain one double bond, and polyunsaturated fatty acids (PUFAs) contain many double bonds. The position of the double bond relative to the omega end determines whether a PUFA is an n‐3 (omega 3) or an n‐6 (omega 6) fatty acid. Most fatty acids can be synthesised in the body, but humans lack the enzymes required to produce two fatty acids. These are called the essential fatty acids and must be acquired from the diet. In humans, the essential fatty acids are the n‐3 PUFA α‐linolenic acid and the n‐6 PUFA linoleic acid. Although humans can elongate dietary α‐linolenic acid to the long chain n‐3 PUFAs eicosapentaenoic acid and docosahexaenoic acid, the rate of synthesis may not be sufficient to meet requirements, and it is, therefore, recommended that good sources of these fatty acids, namely, oil‐rich fish, are also included in the diet. Fat is found in most food groups, and foods containing fat generally provide a range of different fatty acids, both saturated and unsaturated. In the UK, the major dietary sources of unsaturated fatty acids include meat & meat products, cereals & cereal products and potatoes & savoury snacks; primarily as a result of the vegetable oil used in processing. Recommended intakes of both total fat and the different types of fatty acids have been set for the UK population, and it is possible to monitor fat intake from the data collected in nationwide dietary surveys. As a population, we are not currently meeting these recommendations, so there is still scope for dietary change. In Western diets, n‐6 fatty acids are the predominant PUFAs, and this is in line with current dietary advice to consume a minimum of 1% energy as n‐6 PUFAs and 0.2% energy as n‐3 PUFAs. The balance of n‐3 and n‐6 PUFAs in Western diets has changed substantially over the last 100 years or so, and as the two families of PUFAs share a common metabolic pathway, concerns have been raised that this might be detrimental to health; what is becoming increasingly clear is that both n‐3 and n‐6 PUFAs have independent health effects in the body, and as intakes of the n‐6 PUFAs are within the guidelines for a healthy diet, concerns about the n‐6 to n‐3 ratio are driven by low intakes of n‐3 rather t...

BackgroundDeficiencies of micronutrients can affect the growth and development of children. There is increasing evidence of vitamin D deficiency world-wide resulting in nutritional rickets in children and osteoporosis in adulthood. Data on the micronutrient status of children in Malaysia is limited. The aim of this study was to determine the anthropometric and micronutrient status of primary school children in the capital city of Kuala Lumpur.MethodsA cross sectional study of primary aged school children was undertaken in 2008. A total of 402 boys and girls aged 7-12 years, attending primary schools in Kuala Lumpur participated in the study. Fasting blood samples were taken to assess vitamin D [as 25(OH)D], vitamin B12, folate, zinc, iron, and ferritin and haemoglobin concentrations. Height-for-age and body mass index for age (BMI-for-age) of the children were computed.ResultsMost of the children had normal height-for-age (96.5%) while slightly over half (58.0%) had normal BMI-for-age. A total of 17.9% were overweight and 16.4% obese. Prevalence of obesity was significantly higher among the boys (25%) than in the girls (9.5%) (χ2 = 22.949; P < .001). Most children had adequate concentrations of haemoglobin, serum ferritin, zinc, folate and vitamin B12. In contrast, 35.3% of the children had serum 25(OH)D concentrations indicative of vitamin D deficiency(≤37.5 nmol/L) and a further 37.1% had insufficiency concentrations (> 37.5-≤50 nmol/L). Among the boys, a significant inverse association was found between serum vitamin D status and BMI-for-age (χ2 = 5.958; P = .016).ConclusionsThis study highlights the presence of a high prevalence of sub-optimal vitamin D status among urban primary school children in a tropical country. In light of the growing problem of obesity in Malaysian children, these findings emphasize the important need for appropriate interventions to address both problems of obesity and poor vitamin D status in children.

SUMMARY INTRODUCTION SKELETAL FUNCTIONS OF CALCIUM Bone Bone growth Body calcium changes Fetal growth Pre‐term infants Infancy Childhood and adolescence Attainment of peak bone mass Skeletal calcium changes in later life Calcium and dental health REGULATORY ROLE OF CALCIUM Introduction Intracellular calcium Role in blood clotting Role in digestion Role in neurological and muscular function CALCIUM HOMEOSTASIS AND METABOLISM Plasma calcium homeostasis Absorption Markers of calcium absorption and status Excretion Factors that influence urinary calcium excretion DIETARY REFERENCE VALUES Dietary reference values Guidance on high intakes SOURCES OF CALCIUM IN THE DIET Milk and dairy products Cereal products Plant foods Additional sources of calcium CALCIUM INTAKE IN THE UK Main dietary sources Current intakes in the UK Trends in intake BIOAVAILABILITY OF CALCIUM FROM FOODS Dietary factors affecting calcium absorption Vitamin D Fat Protein Other dietary factors Bioavailability from different dietary sources Milk and milk products Calcium from plants Other food sources BONE CALCIUM LOSS Bone calcium loss Pregnancy and lactation Factors affecting age‐related bone loss Osteoporosis Definition Public health implications Primary and secondary osteoporosis Dietary calcium, bone mass and age‐related loss of bones Bone loss and calcium supplementation in early‐post‐menopausal women Bone loss and calcium supplementation in late‐post‐menopausal women Fracture risk CALCIUM IN HEALTH AND DISEASE Calcium and cancer Calcium and cardiovascular disease Calcium and weight management Hypercalcaemia Calcium stone formation CONCLUSIONS ACKNOWLEDGEMENTS REFERENCES Summary  Calcium is an essential nutrient as all living cells require calcium to remain viable; calcium is also required for a number of specific roles in the body. The majority (∼99%) of calcium present in the body is found in bone, with a smaller amount found in teeth. The remainder (<1%) is found in soft tissues and body fluids. The average adult skeleton contains 1200 g of calcium, present in the form of hydroxyapatite, an inorganic crystalline structure made up of calcium and phosphorus [Ca10(PO4)6(OH)2], which provides rigidity. Calcium is essential for bone growth as it is required for the mineralisation (impregnation of the bone matrix with minerals) of bone; the rate of calcium deposition in bone is proportional to rate of growth. An adequate intake of calcium is one of a number of factors which are important for acquiring bone mass and attaining peak bone mass (PBM). Diets containing insufficient amounts of calcium may lead to a low bone mineral density, which may have implications for bone health, notably risk of osteoporosis, in later life. As well as having a skeletal function, calcium plays a regulatory role in a number of specialised functions in the...

A daily intake of approximately 0.7 g DHA increases LDL cholesterol by 7% in middle-aged men and women. It is suggested that DHA down-regulates the expression of the LDL receptor.