Oonagh Markey

Dairy and cardiovascular health: friend or foe?

Cardiovascular disease (CVD) prevalence at a global level is predicted to increase substantially over the next decade due to the increasing ageing population and incidence of obesity. Hence, there is an urgent requirement to focus on modifiable contributors to CVD risk, including a high dietary intake of saturated fatty acids (SFA). As an important source of SFA in the UK diet, milk and dairy products are often targeted for SFA reduction. The current paper acknowledges that milk is a complex food and that simply focusing on the link between SFA and CVD risk overlooks the other beneficial nutrients of dairy foods. The body of existing prospective evidence exploring the impact of milk and dairy consumption on risk factors for CVD is reviewed. The current paper highlights that high milk consumption may be beneficial to cardiovascular health, while illustrating that the evidence is less clear for cheese and butter intake. The option of manipulating the fatty acid profile of ruminant milk is discussed as a potential dietary strategy for lowering SFA intake at a population level. The review highlights that there is a necessity to perform more well-controlled human intervention-based research that provides a more holistic evaluation of fat-reduced and fat-modified dairy consumption on CVD risk factors including vascular function, arterial stiffness, postprandial lipaemia and markers of inflammation. Additionally, further research is required to investigate the impact of different dairy products and the effect of the specific food matrix on CVD development.

Effect of cinnamon on gastric emptying, arterial stiffness, postprandial lipemia, glycemia, and appetite responses to high-fat breakfast

BackgroundCinnamon has been shown to delay gastric emptying of a high-carbohydrate meal and reduce postprandial glycemia in healthy adults. However, it is dietary fat which is implicated in the etiology and is associated with obesity, type 2 diabetes and cardiovascular disease. We aimed to determine the effect of 3 g cinnamon (Cinnamomum zeylanicum) on GE, postprandial lipemic and glycemic responses, oxidative stress, arterial stiffness, as well as appetite sensations and subsequent food intake following a high-fat meal.MethodsA single-blind randomized crossover study assessed nine healthy, young subjects. GE rate of a high-fat meal supplemented with 3 g cinnamon or placebo was determined using the 13C octanoic acid breath test. Breath, blood samples and subjective appetite ratings were collected in the fasted and during the 360 min postprandial period, followed by an ad libitum buffet meal. Gastric emptying and 1-day fatty acid intake relationships were also examined.ResultsCinnamon did not change gastric emptying parameters, postprandial triacylglycerol or glucose concentrations, oxidative stress, arterial function or appetite (p < 0.05). Strong relationships were evident (p < 0.05) between GE Thalf and 1-day palmitoleic acid (r = -0.78), eiconsenoic acid (r = -0.84) and total omega-3 intake (r = -0.72). The ingestion of 3 g cinnamon had no effect on GE, arterial stiffness and oxidative stress following a HF meal.Conclusions3 g cinnamon did not alter the postprandial response to a high-fat test meal. We find no evidence to support the use of 3 g cinnamon supplementation for the prevention or treatment of metabolic disease. Dietary fatty acid intake requires consideration in future gastrointestinal studies.Trial registrationTrial registration number: at http://www.clinicaltrial.gov: NCT01350284

Dietary Patterns in Relation to Cardiovascular Disease Incidence and Risk Markers in a Middle-Aged British Male Population: Data from the Caerphilly Prospective Study

Dietary behaviour is an important modifiable factor in cardiovascular disease (CVD) prevention. The study aimed to identify dietary patterns (DPs) and explore their association with CVD incidence and risk markers. A follow-up of 1838 middle-aged men, aged 47–67 years recruited into the Caerphilly Prospective Cohort Study at phase 2 (1984–1988) was undertaken. Principal component analysis identified three DPs at baseline, which explained 24.8% of the total variance of food intake. DP1, characterised by higher intakes of white bread, butter, lard, chips and sugar-sweetened beverages and lower intake of wholegrain bread, was associated with higher CVD (HR 1.35: 95% CI: 1.10, 1.67) and stroke (HR 1.77; 95% CI: 1.18, 2.63) incidence. DP3, characterised by higher intakes of sweet puddings and biscuits, wholegrain breakfast cereals and dairy (excluding cheese and butter) and lower alcohol intake, was associated with lower CVD (HR 0.76; 95% CI: 0.62, 0.93), coronary heart disease (HR: 0.68; 95% CI: 0.52, 0.90) and stroke (HR: 0.68; 95% CI: 0.47, 0.99) incidence and a beneficial CVD profile at baseline, while DP1 with an unfavourable profile, showed no clear associations after 12 years follow-up. Dietary pattern 2 (DP2), characterised by higher intake of pulses, fish, poultry, processed/red meat, rice, pasta and vegetables, was not associated with the aforementioned outcomes. These data may provide insight for development of public health initiatives focussing on feasible changes in dietary habits.

Effect of feeding high-oleic sunflower oil to dairy cows on the milk fatty acid profile – RESET study

O. Markey, K. E. Kliem, D. J. Humphries, R. Morgan, D. Vasilopoulou, A. Grandison, C. Fagan, S. Todd, K. G. Jackson, J. A. Lovegrove and D. I. Givens Hugh Sinclair Unit of Human Nutrition and Institute for Cardiovascular and Metabolic Research, Department of Food and Nutritional Sciences, Food Production and Quality Division and Department of Mathematics and Statistics, University of Reading, Reading, RG6 6AP

Plasma phospholipid fatty acid profile confirms compliance to a novel saturated fat-reduced, monounsaturated fat-enriched dairy product intervention in adults at moderate cardiovascular risk: a randomized controlled trial

BackgroundDairy products are a major contributor to dietary SFA. Partial replacement of milk SFA with unsaturated fatty acids (FAs) is possible through oleic-acid rich supplementation of the dairy cow diet. To assess adherence to the intervention of SFA-reduced, MUFA-enriched dairy product consumption in the RESET (REplacement of SaturatEd fat in dairy on Total cholesterol) study using 4-d weighed dietary records, in addition to plasma phospholipid FA (PL-FA) status.MethodsIn a randomised, controlled, crossover design, free-living UK participants identified as moderate risk for CVD (n = 54) were required to replace habitually consumed dairy foods (milk, cheese and butter), with study products with a FA profile typical of retail products (control) or SFA-reduced, MUFA-enriched profile (modified), for two 12-week periods, separated by an 8-week washout period. A flexible food-exchange model was used to implement each isoenergetic high-fat, high-dairy diet (38% of total energy intake (%TE) total fat): control (dietary target: 19%TE SFA; 11%TE MUFA) and modified (16%TE SFA; 14%TE MUFA).ResultsFollowing the modified diet, there was a smaller increase in SFA (17.2%TE vs. 19.1%TE; p < 0.001) and greater increase in MUFA intake (15.4%TE vs. 11.8%TE; p < 0.0001) when compared with the control. PL-FA analysis revealed lower total SFAs (p = 0.006), higher total cis-MUFAs and trans-MUFAs (both p < 0.0001) following the modified diet.ConclusionThe food-exchange model was successfully used to achieve RESET dietary targets by partial replacement of SFAs with MUFAs in dairy products, a finding reflected in the PL-FA profile and indicative of objective dietary compliance.Trial registrationClinicalTrials.gov Identifier: NCT02089035, date 05-01-2014.

Initial findings of the impact of an 8-week intervention of sugar reformulated product exchange on cardiovascular risk factors

It has been reported from supply data that at a population level, every 628kJ/d (150kcal/d) increase in sugar availability, (equivalent to approximately one can of sugar-sweetened beverage daily), is independently associated with a 1.1% increase in diabetes mellitus prevalence (1) . The WHO has recommended restricting non-milk extrinsic sugars (NMES) to £ 10% of E (2) . Reformulation of sugarcontaining processed foods is considered by some as a key option for achieving this target and for improving population health (3) . The impact of a sugar reformulated product exchange on cardiovascular risk factors was assessed using a randomised controlled, double-blind, crossover dietary intervention study. Fifty healthy volunteers (16 male, 34 female; age 31.3 (SD 9.6) years; BMI 24.0 (SD 3.3) kg/m 2 ) were randomly assigned to consume either unmodified or sugar reformulated foods and drinks, including juice, soft drinks, pasta sauces, baked beans, muesli, chocolate, ketchup and jam, for an 8-week period. This was followed by a 4-week washout period before volunteers crossed to the alternate intervention. The minimum target difference in dietary NMES intake between the unmodified and reformulated product exchange was 38g/d. Fasting serum was collected pre-and post-intervention and used to determine glucose, lipid and inflammatory markers. Logarithmically transformed data were statistically analysed using ANCOVA. There was no significant effect of the intervention on BMI. When adjusted for BMI, dietary restraint, age and gender there were no differences in fasting serum glucose, total cholesterol, TAG, NEFA or C-reactive protein (CRP) concentrations between interventions.

Consumer acceptance of dairy products with a saturated fatty acid–reduced, monounsaturated fatty acid–enriched content

Agriculture-based reformulation initiatives, including oleic acid-rich lipid supplementation of the dairy cow diet, provide a novel means for reducing intake of saturated fatty acids (SFA) at a population level. In a blinded manner, this study evaluated the consumer acceptance of SFA-reduced, monounsaturated fatty acid-enriched (modified) milk, Cheddar cheese, and butter when compared with control and commercially available comparative samples. The effect of providing nutritional information about the modified cheese was also evaluated. Consumers (n = 115) rated samples for overall liking (appearance, flavor, and texture) using 9-point hedonic scales. Although no significant differences were found between the milk samples, the modified cheese was liked significantly less than a regular-fat commercial alternative for overall liking and liking of specific modalities and had a lower liking of texture score compared with the control cheese. The provision of health information significantly increased the overall liking of the modified cheese compared with tasting the same sample in a blinded manner. Significant differences were evident between the butter samples for overall liking and modalities of liking; all of the samples were significantly more liked than the commercial butter and sunflower oil spread. In conclusion, this study illustrated that consumer acceptance of SFA-reduced, monounsaturated fatty acid-enriched dairy products was dependent on product type. Future research should consider how optimization of the textural properties of fatty acid-modified (and fat-reduced) cheese might enhance consumer acceptance of this product.

Chronic consumption of conventional and saturated-fat reduced dairy products have differential effects on low-density lipoprotein cholesterol levels in adults at moderate cardiovascular disease risk

Reducing the intake of dietary saturated fatty acids (SFA) to ⩽10 % of total energy intake is a key public health strategy aimed at lowering current cardiovascular disease (CVD) incidence. Consumption of dairy products (including butter) represents approximately 35 % of total dietary SFA intake(1). Supplementation of the bovine diet with oleic acid-rich plant oil has been reported to depress SFA and increase cis-monounsaturated fatty acids levels in milk, providing a strategy to lower total dietary SFA intake (2). This human intervention study aimed to investigate whether consumption of SFA-reduced, compared with conventional dairy products, would impact on the fasting lipid profile, glucose and insulin concentrations of adults at moderate CVD risk. Fifty-four adults (mean age 53 (SD 13) years, BMI 26 (SD 3) kg/m2), completed a double blind, randomised, controlled 12-week cross-over study with an 8-week washout period between treatment arms. Participants replaced habitual dairy foods/snacks with SFA-reduced or conventional UHT milk, Cheddar cheese and butter (fatty acid (FA) composition of SFA-reduced vs. conventional dairy products: total SFA: -7·0 g/d, C18:1cis: 3·0 g/d, C18:1trans: 2·4 g/d), achieving an isoenergetic daily dietary exchange (41 g/d total fat). At the beginning and end of each treatment period, fasting blood samples were collected for biochemical analysis. LDL-C was estimated using the Friedewald formula. The homeostatic model assessment of insulin resistance (HOMA-IR) was calculated using the glucose and insulin data.

Dietary energy compensation in response to reduced sugar diet in non-obese men and women

Consumption of reformulated sugar-containing processed products has been recommended as a strategy for reducing non-milk extrinsic sugars (NMES) to no more than 10% of total energy intake (EI) and as a weight reducing strategy in today’s obesity epidemic. It is therefore important to determine the impact of sugar reformulated food consumption on energy balance dynamics. The REFORM study (ClinicalTrials.gov NCT01645995) examined the impact of an 8-week sugar reformulated product exchange on EI, energy expenditure (EE) and energy balance (EB), in a double-blind, randomised, controlled, crossover design. Forty five healthy, non-dieting, non-obese volunteers (14 male, 31 female; age: 32·0 (SD 9·8) years; BMI: 23·5 (SD 3·0) kg/m) were randomly assigned to consume either regular sugar or sugar-reformulated food and drink products including confectionary, pasta sauces, baked beans, muesli, condiments and sugar-sweetened beverages for a 56 d period, with a 28 d washout period. The minimum target difference in dietary NMES intake between the regular and reformulated product exchange was 38 g/d (152 kcal). Weighed food diaries (4 d) and accelerometer data (7 d) were used to assess EI, EE and EB at baseline and following each dietary exchange period. There was no significant effect of the intervention on body weight, EI, EE or EB. Significant time x treatment interactions were evident for carbohydrate (CHO; g and % EI; P< 0·000), total sugar intake (g and % EI; P< 0·000) and fat (% EI; P < 0·001). Significantly higher CHO, total sugar and lower fat as a percentage of EI were consumed following the regular sugar treatment. Body weight at the end of the reformulated dietary exchange period was predicted to be 2·5 (SE 0·001) kg lower using the National Institute of Diabetes and Digestive and Kidney (NIDDK) body weight simulator, compared to the observed body weight. The predicted body weight accounted for 98·8% of the variance in the observed body weight, suggesting that the volunteers’ energy compensated. Long-term sugar reformulated product exchange resulted in energy compensation, when consumed as part of an habitual diet, partly through increased voluntary fat intake. Furthermore, body weight was predicted to be lower (using the NIDDK model) than observed, following the reformulated dietary exchange period, supporting the hypothesis of dietary energy compensation. In conclusion consumption of reformulated-sugar products as part of a blinded dietary exchange, resulted in a significant reduction in sugar intake, but had no effect on energy balance or body weight due to dietary energy compensation in non-obese men and women. Future work is required to determine if these findings have relevance to energy compensation in obesity and if consumed without blinding.

Resistance exercise stimulates mixed muscle protein synthesis in lean and obese young adults

Obese individuals exhibit a diminished muscle protein synthesis response to nutrient stimulation when compared with their lean counterparts. However, the effect of obesity on exercise‐stimulated muscle protein synthesis remains unknown. Nine lean (23.5 ± 0.6 kg/m2) and 8 obese (33.6 ± 1.2 kg/m2) physically active young adults participated in a study that determined muscle protein synthesis and intracellular signaling at rest and following an acute bout of resistance exercise. Mixed muscle protein synthesis was determined by combining stable isotope tracer ([13C6]phenylalanine) infusion with serial biopsies of the vastus lateralis. A unilateral leg resistance exercise model was adopted so that resting and postexercise measurements of muscle protein synthesis could be obtained simultaneously. Obesity was associated with higher basal levels of serum insulin (P < 0.05), plasma triacylglycerol (P < 0.01), plasma cholesterol (P < 0.01), and plasma CRP (P < 0.01), as well as increased insulin resistance determined by HOMA‐IR (P < 0.05). However, resting and postexercise rates of muscle protein synthesis were not significantly different between lean and obese participants (P = 0.644). Furthermore, resistance exercise stimulated muscle protein synthesis (~50% increase) in both groups (P < 0.001), with no difference between lean and obese (P = 0.809). Temporal increases in the phosphorylation of intracellular signaling proteins (AKT/4EBP1/p70S6K) were observed within the exercised leg (P < 0.05), with no differences between lean and obese. These findings suggest a normal anabolic response to muscle loading in obese young adults.