Milk and dairy products: dietary partners for life?

The importance of milk in the human diet as a supplier of energy, high quality protein and other key nutrients, including calcium, is broadly accepted yet in the mind of many there remains uncertainty about whether or not these foods contribute to increased risk of cardiovascular and other chronic diseases. The evidence from long term prospective cohort studies that high milk consumption does not increase cardiovascular disease risk and indeed may provide benefit is now pretty unequivocal, although the effects of butter and cheese and benefits of fat reduced milk and saturated fat reduced milk are less certain. Milk is a crucial supplier of calcium, phosphorus and magnesium for bone growth and development in children and it is concerning that due to reduced milk consumption intake of these nutrients is often sub-optimal, particularly for female children. In addition, specific health issues in pregnant women and the elderly can be alleviated by milk or components of milk and these effects are not all explained by traditional nutrition

Comment on S´ rednicka-Tober et al.: Higher PUFA and n-3 PUFA, conjugated linoleic acid, α-tocopherol and iron, but lower iodine and selenium concentrations in organic milk: a systematic literature review and meta- and redundancy analyses

Comment on S´ rednicka-Tober et al.: Higher PUFA and n-3 PUFA, conjugated linoleic acid, α-tocopherol and iron, but lower iodine and selenium concentrations in organic milk: a systematic literature review and meta- and redundancy analyses Couvreur et al.(6) who showed that increasing grazing from 30 to 100% of the diet led to an increase in milk ALA from 4·0 to 6·1 mg/g total fatty acids (P< 0·001), similar to those reported by S´ rednicka-Tober et al.(1) shown in Table 1 for conventional and organic milk, respectively. Overall, differences in milk fatty acids in organic v. conventional systems are extremely small when examined in the context of total diets and would have very limited contribution to nutrition or health – and the differences are because of the diet of the cow and not specifically because of organic production

Comparison of different dietary sources of n-3 polyunsaturated fatty acids on immune response in broiler chickens

The study aims to research the effects of varied dietary sources of n-3 polyunsaturated fatty acids (PUFA) on the immune response in broiler chickens with stress on natural killer (NK) cell activity. Diets supplemented with one of the four sources of n-3 PUFA: linseed oil-, echium oil-, fish oil (FO) or algal biomass-enriched diets at levels of 18, 18, 50 and 15 g/kg fresh weight, were provided for one-d-old male Ross 308 broilers, totaling 340 in number, until they were slaughtered. The analyses included total lipid profile using gas chromatography (GC) for plasma, spleen, thymus, and blood. Additionally, NK cell activity and cell proliferation were investigated for thymocytes and splenocytes. The results indicated that the source of n-3 PUFA had a strong influence on fatty acid composition across all tissues. NK activity was highest in splenocytes and PBMCs from broilers fed linseed oil, followed by those fed algal biomass or echium oil, and lowest for those from broilers fed FO. The proliferative response of lymphocytes from algal biomass-fed chickens tended to be the highest, followed by those fed linseed oil in most cases. Lymphocytes from chickens fed fish oil showed the lowest proliferative response. These results could mean that a docosahexaenoic acid (DHA)-rich algal product might enrich chicken meat with n-3 PUFA without significant damaging effects on chicken immunity

Yogurt consumption is associated with higher nutrient intake, diet quality and favourable metabolic profile in children: a cross-sectional analysis using data from years 1–4 of the National diet and Nutrition Survey, UK

Purpose: Yogurt consumption has been associated with higher nutrient intakes, better diet quality and improved metabolic profiles in adults. Few studies have investigated these associations in children. This study investigated the association of yogurt consumption with nutrient intakes, diet quality and metabolic profile in British children. Methods: Data from 1687 children aged 4–10 and 11–18 years of the National Diet and Nutrition Survey (NDNS) years 1–4 were analysed. Yogurt consumption was determined using a 4-day diet diary. Diet quality was assessed by the Healthy Eating Index 2010 (HEI-2010). Anthropometric measures, blood pressure, pulse pressure, plasma glucose, HbA1c, C-reactive protein, triacylglycerol, total cholesterol, high-and low-density cholesterol from NDNS were used. Results: The highest tertile of yogurt consumption (T3) was associated with higher nutrient intakes, particularly for calcium (children 4–10 years: P < 0.0001; children 11–18 years P = 0.001), iodine (both age groups P < 0.0001) and riboflavin (both age groups P < 0.0001), and HEI-2010 score (both age groups P < 0.0001) in children aged 4–10 years (mean ± SD:98.4 ± 35.7 g yogurt/day) and 11–18 years (mean ± SD: 105.4 ± 37.5 g yogurt/day) compared with non-consumers (0 g yogurt/d). Yogurt consumption was associated with significantly lower pulse pressure in children aged 4–10 years and lower HbA1c concentration, being shorter and having a larger hip circumference in children aged 11–18 years, compared with non-yogurt consumers. Conclusion: This study suggests that British children who are yogurt consumers (> 60 g/day) have higher overall diet quality, nutrient intakes and adequacy, lower pulse pressure (children aged 4–10 years) and HbA1c concentrations (children aged 11–18 years), were shorter and had a smaller hip circumference (children aged 11–18 years)

Review: dairy foods, red meat and processed meat in the diet: implications for health at key life stages

Social and health care provision have led to substantial increases in life expectancy. In the UK this has become higher than 80 years with an even greater proportional increase in those aged 85 years and over. The different life stages give rise to important nutritional challenges and recent reductions in milk consumption have led to sub-optimal intakes of calcium by teenage females in particular when bone growth is at its maximum and of iodine during pregnancy needed to ensure that supply/production of thyroid hormones to the foetus is adequate. Many young and pre-menopausal women have considerably sub-optimal intakes of iron which are likely to be associated with reduced consumption of red meat. A clear concern is the low intakes of calcium especially as a high proportion of the population is of sub-optimal vitamin D status. This may already have had serious consequences in terms of bone development which may not be apparent until later life, particularly in post-menopausal women. This review aims to examine the role of dairy foods and red meat at key life stages in terms of their ability to reduce or increase chronic disease risk. It is clear that milk and dairy foods are key sources of important nutrients such as calcium and iodine and the concentration of some key nutrients, notably iodine can be influenced by the method of primary milk production, in particular, the iodine intake of the dairy cow. Recent meta-analyses show no evidence of increased risk of cardiovascular diseases from high consumption of milk and dairy foods but increasing evidence of a reduction in the risk of type 2 diabetes associated with fermented dairy foods, yoghurt in particular. The recently updated reports from the World Cancer Research Fund International/American Institute for Cancer Research on the associations between dairy foods, red meat and processed meat and various cancers provide further confidence that total dairy products and milk, are associated with a reduced risk of colorectal cancer and high intakes of milk/dairy are not associated with increased risk of breast cancer. Earlier evidence of a significant increase in the risk of colorectal cancer from consumption of red and particularly processed meat has been reinforced by the inclusion of more recent studies. It is essential that nutrition and health-related functionality of foods are included in evaluations of sustainable food production

Effect of oilseed type on milk fatty acid composition of individual cows, and also bulk tank milk fatty acid composition from commercial farms

Supplementing dairy cow diets with oilseed preparations has been shown to replace milk saturated fatty acids (SFA) with mono- and/or polyunsaturated fatty acids (MUFA, PUFA), which may reduce risk factors associated with cardio-metabolic diseases in humans consuming milk and dairy products. Previous studies demonstrating this are largely detailed, highly controlled experiments involving small numbers of animals, but in order to transfer this feeding strategy to commercial situations further studies are required involving whole herds varying in management practices. In experiment 1, three oilseed supplements (extruded linseed (EL), calcium salts of palm and linseed oil (CPLO) and milled rapeseed (MR)) were included in grass silage-based diets formulated to provide cows with ~350 g oil/day, and compared with a negative control (Control) diet containing no supplemental fat, and a positive control diet containing 350 g/cow per day oil as calcium salt of palm oil distillate (CPO). Diets were fed for 28-day periods in a 5×4 Latin Square design, and milk production, composition and fatty acid (FA) profile were analysed at the end of each period. Compared with Control, all lipid supplemented diets decreased milk fat SFA concentration by an average of 3.5 g/100 g FA, by replacement with both cis- and trans-MUFA/PUFA. Compared with CPO, only CPLO and MR resulted in lower milk SFA concentrations. In experiment 2, 24 commercial dairy farms (average herd size±SEM 191±19.3) from the south west of the United Kingdom were recruited and for a 1 month period asked to supplement their herd diets with either CPO, EL, CPLO or MR at the same inclusion level as the first study. Bulk tank milk was analysed weekly to determine FA concentration by Fourier Transform mid-IR spectroscopy prediction. After 4 weeks, EL, CPLO and MR all decreased herd milk SFA and increased MUFA to a similar extent (average −3.4 and +2.4 g/100 g FA, respectively) when compared with CPO. Differing responses observed between experiments 1 and 2 may be due in part to variations in farm management conditions (including basal diet) in experiment 2. This study demonstrates the importance of applying experimental research into commercial practice where variations in background conditions can augment different effects to those obtained under controlled conditions

Animal-derived foods: consumption, composition and effects on health and the environment: an overview

Consumption of animal-derived foods (ADFs), particularly red meat, is declining in high-income countries because of concerns over health and the effects on climate change but is increasing in low- and middle-income countries. As a group of foods, ADFs are high in good-quality protein and several key vitamins and minerals (notably vitamin B12, iron and zinc). There is evidence, though, that processed red meat poses risks of cardiovascular disease (CVD) and colorectal cancer and the same risks, although not so strong, are apparent for unprocessed red meat. Milk and milk products generally have a neutral disease risk and there is evidence of reduced risks of CVD and colorectal cancer. Similarly, white meat (chicken and fish) is not associated with disease risk whilst eggs have been linked with increased CVD risk because of their cholesterol content. The risks of chronic disease seem higher in high-income than in low- and middle-income countries, possibly due to different levels of consumption. Production of ADFs results in high greenhouse gas emissions per unit of output compared with plant proteins. Ruminant meat production has particularly high costs but wide variation between farms in different regions of the world suggests costs can be significantly lowered by changes to production systems. Reducing ADF consumption to benefit health and the environment has been proposed but in low-income countries, current levels of consumption of ADFs may be compatible with health and climate targets

Effects of forage type and extruded linseed supplementation on methane production and milk fatty acid composition of lactating dairy cows

Replacing dietary grass silage (GS) with maize silage (MS) and dietary fat supplements may reduce milk concentration of specific saturated fatty acids (SFA) and can reduce methane production by dairy cows. The present study investigated the effect of feeding an extruded linseed supplement on milk fatty acid (FA) composition and methane production of lactating dairy cows, and whether basal forage type, in diets formulated for similar neutral detergent fiber and starch, altered the response to the extruded linseed supplement. Four mid-lactation Holstein-Friesian cows were fed diets as total mixed rations, containing either high proportions of MS or GS, both with or without extruded linseed supplement, in a 4 × 4 Latin square design experiment with 28-d periods. Diets contained 500 g of forage/kg of dry matter (DM) containing MS and GS in proportions (DM basis) of either 75:25 or 25:75 for high MS or high GS diets, respectively. Extruded linseed supplement (275 g/kg ether extract, DM basis) was included in treatment diets at 50 g/kg of DM. Milk yields, DM intake, milk composition, and methane production were measured at the end of each experimental period when cows were housed in respiration chambers. Whereas DM intake was higher for the MS-based diet, forage type and extruded linseed had no significant effect on milk yield, milk fat, protein, or lactose concentration, methane production, or methane per kilogram of DM intake or milk yield. Total milk fat SFA concentrations were lower with MS compared with GS-based diets (65.4 vs. 68.4 g/100 g of FA, respectively) and with extruded linseed compared with no extruded linseed (65.2 vs. 68.6 g/100 g of FA, respectively), and these effects were additive. Concentrations of total trans FA were higher with MS compared with GS-based diets (7.0 vs. 5.4 g/100 g of FA, respectively) and when extruded linseed was fed (6.8 vs. 5.6 g/100 g of FA, respectively). Total n-3 FA were higher when extruded linseed was fed compared with no extruded linseed (1.2 vs. 0.8 g/100 g of FA, respectively), whereas total n-6 polyunsaturated FA were higher when feeding MS compared with GS (2.5 vs. 2.1 g/100 g of FA, respectively). Feeding extruded linseed and MS both provided potentially beneficial decreases in SFA concentration of milk, and no significant interactions were found between extruded linseed supplementation and forage type. However, both MS and extruded linseed increased trans FA concentration in milk fat. Neither MS nor extruded linseed had significant effects on methane production or yield, but the amounts of supplemental lipid provided by extruded linseed were relatively small

Correspondence

quantification, real-time PCR, rumen, stearic acid producers

Associations between red meat, processed red meat and total red and processed red meat consumption, nutritional adequacy and markers of health and cardio‑metabolic diseases in British adults: a cross‑sectional analysis using data from UK National Diet and Nutrition Survey

Purpose To determine the association between red meat (RM), processed red meat (PRM) and total red and processed red meat (TRPRM) consumption on nutritional adequacy and markers of health and cardio-metabolic diseases in British adults. Methods In this cross-sectional study of adults (19–64 y) from the National Diet and Nutrition Survey (NDNS) (n = 1758), RM and PRM consumption were assessed from 4 day estimated food diaries. Anthropometric measures, blood pressure (BP), pulse pressure (PP), plasma glucose, HbA1c, C-reactive protein, TAG, TC, LDL-C and HDL-C from the NDNS were used. Results 43% of adults (men 57% and women 31%) consumed more than the 70 g/d TRPRM guidelines. Fewer adults in the highest tertile of TRPRM intake were below lower reference nutrient intakes (LRNIs), particularly for zinc and iron, respectively. In model 3 (controlled for age, energy intake, socioeconomic classification, number of daily cigarettes, BMI, dietary factors), higher RM consumption was associated with being significantly taller (model 3: P-ANCOVA = 0.006; P-T3/T1 = 0.0004) in men and lower diastolic BP (model 3: P-ANCOVA = 0.004; P-T3/T2 = 0.002) in women. Higher PRM in men was associated with significantly higher plasma ferritin concentration (model 3: P-ANCOVA = 0.0001; PT2/ T1 = 0.0001), being taller (P-ANCOVA = 0.019; P-T1/T2 = 0.047, T1/T3 = 0.044), increased body weight (model 3: P-ANCOVA = 0.001; P-T1/T3 = 0.0001), BMI (model 3: P-ANCOVA = 0.007; P-T1/T3 = 0.006) and smaller hip circumference (model 3: P-ANCOVA = 0.006; P-T3/T1 = 0.024; P-T2/T1 = 0.013) and in women significantly higher TC (model 3: P-ANCOVA = 0.020; P-T3/T2 = 0.016), LDL-C (P-ANCOVA = 0.030; P-T3/T2 = 0.025), HbA1c (model 3: P-ANCOVA = 0.0001; P-T2/T1 = 0.001; P-T3/T2 = 0.001) and higher PP (model 3: P-ANCOVA = 0.022; P-T3/T1 = 0.021). Higher PRM consumption was associated with significantly higher BMI and hip circumference in men, and higher TC, LDL-C, HbA1c and PP in women, which was not observed for RM consumption