Dairy Fat Intake Research Articles

Plant and Animal Fat Intake and Overall and Cardiovascular Disease Mortality

The impact of dietary fat intake on long-term human health has attracted substantial research interest, and the health effects of diverse dietary fats depend on available food sources. Yet there is a paucity of data elucidating the links between dietary fats from specific food sources and health. To study associations of dietary plant and animal fat intake with overall mortality and cardiovascular disease (CVD) mortality. This large prospective cohort study took place in the US from 1995 to 2019. The analysis of men and women was conducted in the National Institutes of Health-AARP Diet and Health Study. Data were analyzed from February 2021 to May 2024. Specific food sources of dietary fats and other dietary information were collected at baseline, using a validated food frequency questionnaire. Hazard ratios (HRs) and 24-year adjusted absolute risk differences (ARDs) were estimated using multivariable-adjusted Cox proportional hazards regression. The analysis included 407 531 men and women (231 881 [56.9%] male; the mean [SD] age of the cohort was 61.2 [5.4] years). During 8 107 711 person-years of follow-up, 185 111 deaths were ascertained, including 58 526 CVD deaths. After multivariable adjustment (including adjustment for the relevant food sources), a greater intake of plant fat (HRs, 0.91 and 0.86; adjusted ARDs, -1.10% and -0.73%; P for trend < .001), particularly fat from grains (HRs, 0.92 and 0.86; adjusted ARDs, -0.98% and -0.71%; P for trend < .001) and vegetable oils (HRs, 0.88 and 0.85; adjusted ARDs, -1.40% and -0.71%; P for trend < .001), was associated with a lower risk for overall and CVD mortality, respectively, comparing the highest to the lowest quintile. In contrast, a higher intake of total animal fat (HRs, 1.16 and 1.14; adjusted ARDs, 0.78% and 0.32%; P for trend < .001), dairy fat (HRs, 1.09 and 1.07; adjusted ARDs, 0.86% and 0.24%; P for trend < .001), or egg fat (HRs, 1.13 and 1.16; adjusted ARDs, 1.40% and 0.82%; P for trend < .001) was associated with an increased risk for mortality for overall and CVD mortality, respectively, comparing the highest to the lowest quintile. Replacement of 5% energy from animal fat with 5% energy from plant fat, particularly fat from grains or vegetable oils, was associated with a lower risk for mortality: 4% to 24% reduction in overall mortality, and 5% to 30% reduction in CVD mortality. The findings from this prospective cohort study demonstrated consistent but small inverse associations between a higher intake of plant fat, particularly fat from grains and vegetable oils, and a lower risk for both overall and CVD mortality. A diet with a high intake of animal-based fat, including fat from dairy foods and eggs, was also shown to be associated with an elevated risk for both overall and CVD mortality.

A vegetable fat-based diet delays psychomotor and cognitive development compared with maternal dairy fat intake in infant gray mouse lemurs

Dairy fat has a unique lipid profile; it is rich in short- and medium-chain saturated fatty acids that induce ketone production and has a balanced ω6/ω3 ratio that promotes cognitive development in early life. Moreover, the high consumption of vegetable oils in pregnant and lactating women raises concerns regarding the quality of lipids provided to offspring. Here, we investigate maternal dairy fat intake during gestation and lactation in a highly valuable primate model for infant nutritional studies, the gray mouse lemur (Microcebus murinus). Two experimental diets are provided to gestant mouse lemurs: a dairy fat-based (DF) or vegetable fat-based diet (VF). The psychomotor performance of neonates is tested during their first 30 days. Across all tasks, we observe more successful neonates born to mothers fed a DF diet. A greater rate of falls is observed in 8-day-old VF neonates, which is associated with delayed psychomotor development. Our findings suggest the potential benefits of lipids originating from a lactovegetarian diet compared with those originating from a vegan diet for the psychomotor development of neonates.

Full-fat dairy products and cardiometabolic health outcomes: Does the dairy-fat matrix matter?

Reducing dairy fat intake is a common dietary guideline to limit energy and saturated fatty acid intake for the promotion of cardiometabolic health. However, research utilizing a holistic, food-based approach to assess the consumption of the fat found in dairy, a broad and diverse food group, may provide new insight into these guidelines. Dairy fat is comprised of a diverse assembly of fatty acids, triacylglycerols, sterols, and phospholipids, all uniquely packaged in a milk fat globule. The physical structure of this milk fat globule and its membrane is modified through different processing methods, resulting in distinctive dairy-fat matrices across each dairy product. The objectives of this narrative review were to first define and compare the dairy-fat matrix in terms of its unique composition, physical structure, and fat content across common dairy products (cow's milk, yogurt, cheese, and butter). With this information, we examined observational studies and randomized controlled trials published within the last 10 years (2013-2023) to assess the individual effects of the dairy-fat matrix in milk, yogurt, cheese, and butter on cardiometabolic health and evaluate the implications for nutrition guidance. Searches conducted on Ovid MEDLINE and PubMed® utilizing search terms for cardiometabolic health, both broadly and regarding specific disease outcomes and risk factors, yielded 59 studies that were analyzed and included in this review. Importantly, this review stratifies by both dairy product and fat content. Though the results were heterogeneous, most studies reported no association between intake of these individual regular-fat dairy products and cardiometabolic outcome measures, thus, the current body of evidence suggests that regular-fat dairy product consumption may be incorporated within overall healthy eating patterns. Research suggests that there may be a beneficial effect of regular-fat milk and yogurt intake on outcome measures related to body weight and composition, and an effect of regular-fat cheese intake on outcome measures related to blood lipids, but more research is necessary to define the directionality of this relationship. Lastly, we identify methodological research gaps and propose future research directions to bolster the current evidence base available for ascertaining the role of dairy fat in a healthy diet.

Dairy product consumption and lung cancer risk: A prospective analysis

Current evidence on prospective associations between dairy product, dairy fat and lactose intakes and lung cancer risk is limited and inconsistent. We conducted a prospective analysis of associations of lung cancer risk with dairy product intakes in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) cohort. Pre-diagnostic dairy product intake was assessed through a validated Diet History Questionnaire. All incident lung cancer cases were pathologically verified. Multivariable Cox regression was used to calculate hazard ratios (HR) and 95% confidence intervals (CI) for associations of lung cancer risk with intakes of total, full-fat, low-fat dairy, fermented or non-fermented dairy products; milk fat content preference; and intakes of total and saturated fats and lactose from dairy products. Among 101,709 adults (mean age of 65.5 years), a total of 1583 lung cancer cases were identified during 1,167,239 person-years of follow up. Mean total dairy product intake was 156g/1000 kilocalories (kcal), including 20g/1000kcal from fermented dairy products. Total dairy intake was not associated with lung cancer risk (HR [95% CI]=1.03 [0.89-1.18]) comparing the highest quartile with the lowest. Fermented dairy intake was inversely associated with lung cancer risk (0.85 [0.72-0.99]). In contrast, there were no statistically significant associations with low-fat, full-fat or non-fermented dairy product intakes. The preference of whole milk when consuming milk as beverage was associated with a higher risk of lung cancer than the preference of <0.5% fat milk (1.24 [1.03-1.49]). Total fat, saturated fat and lactose intakes from dairy products each were not associated with lung cancer risk. Our results suggest an inverse association of lung cancer risk with fermented dairy intake and a positive association with the whole milk preference in a US population. Future studies exploring underlying molecular mechanisms are warranted.

Updating the fatty acid profiles of retail bovine milk in China based on an improved GC-MS method: implications for nutrition.

The importance of food components to potential benefits and risks to human health is gradually being consumer awareness. Milk is an important part of the lipid content of the human diet, and there are few detailed reports on the fatty acid (FA) profiles of retail milk. In the study, we developed a gas chromatography-mass spectrometry (GC-MS) method to simultaneously determine 82 FAs, including 11 even-chain saturated FAs, 10 odd-chain saturated FAs, 9 branched-chain saturated FAs, 30 monounsaturated FAs, and 22 polyunsaturated FAs; this was applied to analyze samples (186 samples) of commercially available milk from 22 provinces throughout China and to evaluate the nutritional value of these samples based on FA-related indices. The results showed that the overall composition of milk FAs among the different regions was numerically similar, and minor FAs showed few differences. When considering the retail milk FA composition and dairy fat intake in China, regional variations have a limited impact on FA consumption. Moreover, milk accounts for approximately one-third and <10% of the maximum recommended intake of saturated FAs and trans-FAs in consumer diets, respectively. This study provides an updated report on the composition of FAs and the nutritional value of retail milk across China, which can serve as a reference for producers for future research on regulating milk FAs, for consumers to select milk, and for nutrition departments to formulate relevant nutritional guidance recommendations.

Abstract MP25: Circulating Odd-Chain Fatty Acids and Mortality Risk After Myocardial Infarction in the Alpha Omega Cohort

Background: Circulating odd-chain fatty acids (OCFAs) 15:0 and 17:0, potential biomarkers of dairy (fat) intake, have been associated with cardiometabolic outcomes in population-based studies. Whether circulating OCFAs are related to mortality risk in patients who experienced a myocardial infarction (MI) is not yet clear. Methods: We included 4,741 Dutch patients aged 60-80 y (78% males) from the Alpha Omega Cohort, who experienced a myocardial infarction (MI) up to 10 years prior to study enrolment. At baseline (2002-2006), data were obtained on risk factors for cardiovascular disease (CVD), medication, lifestyle factors and dietary intakes (203-item FFQ). Fatty acids in serum cholesteryl esters (CE) were assessed using gas chromatography. Multivariable Cox models were used to obtain hazard ratios (HRs) and 95% confidence intervals (CI) for total and CVD mortality in relation to 15:0 and 17:0 in CE (per 10 th to 90 th percentile range, P 10-90 ). HRs were adjusted for age, sex, education, BMI, physical activity, diabetes, other CVD risk factors, medication, circulating linoleic acid, circulating EPA+DHA, and dietary factors. Missing data imputation was performed for confounders. Findings: Most patients used cardiovascular drugs (statins: 85%) and 979 patients (21%) had diabetes. During a median follow-up period of 12.4 years (total of 52,625 person-years), 2,233 patients died, of whom 984 from CVD. Circulating levels (% of total fatty acids) were low for 15:0 (median: 0.16; P 10-90 : 0.11-0.21) and 17:0 (median: 0.08; P 10-90 : 0.00-0.11). For 15:0, age and sex adjusted HRs per P 10-90 were 0.88 (95% CI: 0.81-0.95; P =0.001) for total mortality and 0.94 (0.83-1.06) for CVD mortality. In the most adjusted model, HRs for 15:0 were 0.92 (0.84-1.00; P =0.042) and 0.97 (0.85-1.11), respectively. For 17:0, HRs were 0.94 (0.85-1.05) for total mortality and 0.97 (0.83-1.13) for CVD mortality. Stratified analyses by sex showed inverse associations for 15:0 mainly in men (total mortality: HR of 0.90 [0.82-1.00]; P =0.047). For 17:0, inverse but non-significant associations were mainly observed in women (total mortality: HR of 0.85 [0.68-1.05]). Associations for 17:0, but not for 15:0, were stronger in diabetic patients (total mortality: HR of 0.78 [0.64-0.96]; P =0.019). Conclusions: Higher circulating OCFA levels may be related to a lower mortality risk after MI, which needs confirmation in other cohorts of CVD patients. The role of dairy fat intake in this relationship warrants further investigation.

Abstract MP62: Fatty Acid Biomarkers of 15:0, 17:0 and Trans 16:1n-7 and Incident Coronary Heart Disease and Stroke: A Pooling Project of 15 Prospective Cohorts in the Fatty Acids and Outcomes Research Consortium

Introduction: Previous studies have reported inverse associations of circulating and tissue levels of pentadecanoic acid (15:0), heptadecanoic acid (17:0) and trans -palmitoleic acid ( trans 16:1n-7), which have been proposed as potential biomarkers of dairy fat intake, with risk of type-2 diabetes and certain cardiovascular outcomes. Hypothesis: We assessed the hypothesis that circulating and tissue levels of 15:0, 17:0, trans 16:1n-7 are inversely associated with risk of incident coronary heart disease (CHD) and stroke in a global consortium of prospective studies. Methods: We used data from 15 prospective cohorts in the Fatty Acids and Outcomes Research Consortium. We included adults (age≥18 years) who were free of cardiovascular diseases and had blood or adipose tissue measurements of 15:0, 17:0 or trans 16:1n-7. We used a harmonized analysis protocol with each exposure standardized to the interquintile range (IQR): difference between the 10 th and 90 th percentiles of each fatty acid to conduct new individual participant-level analyses. We harmonized covariate definitions across studies to include demographic, lifestyle and health variables, and levels of other fatty acids associated with CHD or stroke. We used inverse-variance meta-analysis to calculate the pooled relative risks (RR) and 95% confidence intervals (CI) for each outcome. We also calculated Spearman correlation coefficients between levels of each fatty acid exposure and potential dietary determinants of their levels (intakes of total, high-fat and low-fat dairy, meat from ruminant animals, fish and dietary fiber) among 6 studies with dietary data. Results and Conclusions: Among 34,187 participants, 5,790 incident CHD and 3,098 stroke cases were documented during a maximum follow-up of 23.3 years. We did not observe significant associations of any of the fatty acid biomarkers with risk of CHD or stroke. The pooled multivariate RR and 95% CI of CHD per IQR were 0.97 (0.92, 1.02) for 15:0, 0.97 (0.92, 1.02) for 17:0, 1.11 (0.97, 1.26) for trans 16:1n-7, and 0.98 (0.92, 1.04) for the sum of the fatty acids. The respective RR and 95% of stroke were 1.01 (0.93, 1.09) for 15:0, 0.91 (0.81, 1.03) for 17:0, 0.99 (0.83, 1.18) for trans 16:1n-7, and 0.93 (0.85, 1.04) for the summed fatty acids. Additionally, we did not observe significant heterogeneity by age, sex, race/ethnicity, world region, baseline hypertension status or lipid compartment. Circulating and tissue levels of 15:0, 17:0 and trans 16:1n-7 were weakly correlated with intakes of total or high-fat dairy (Spearman correlations [ r = 0.05 to 0.37]) but were not correlated with intakes of low-fat dairy, ruminant meat, fish or dietary fiber [ r = -0.08 to 0.09]. In conclusion, circulating and tissue levels of 15:0, 17:0, trans 16:1n-7 were not associated with risk of CHD or stroke. Our study suggests a limited role for these fatty acids in the etiology of cardiovascular disease.

Time in Bed, Sleeping Difficulties, and Nutrition in Pregnant New Zealand Women.

We consider the relationship between time in bed (TIB) and sleeping difficulties with demographic variables and nutrient intakes in the second (T2) and third (T3) trimester of pregnancy. Data were acquired from a volunteer sample of New Zealand pregnant women. In T2 and T3, questionnaires were administered, diets were obtained from one 24 h recall and three weighed food records, and physical activity was measured with the use of three 24 h diaries. In total, 370 women had complete information in T2 and 310 in T3. In both trimesters, TIB was associated with welfare or disability status, marital status and age. In T2, TIB was associated with work, childcare, education and pre-pregnancy alcohol consumption. There were fewer significant lifestyle covariates in T3. In both trimesters, TIB declined with increasing dietary intake, especially water, protein, biotin, potassium, magnesium, calcium, phosphorus and manganese. Adjusted for weight of dietary intake and welfare/disability, TIB declined with increasing nutrient density of B vitamins, saturated fats, potassium, fructose and lactose; and TIB increased with carbohydrate, sucrose and vitamin E. Subjective sleeping difficulties increased with the week of gestation, morning sickness severity, anxiety, dairy and saturated fat intake, and they decreased with fruit, vegetable and monounsaturated fat intake. The study highlights the changing influence of covariates throughout the pregnancy and corroborates several published findings on the relationship of diet and sleep.

Deep phenotyping and biomarkers of various dairy fat intakes in an 8-week randomized clinical trial and 2-year swine study

Health effects of dairy fats (DF) are difficult to evaluate, as DF intakes are hard to assess epidemiologically and DF have heterogeneous compositions that influence biological responses. We set out to find biomarkers of DF intake and assess biological response to a summer DF diet (R2), a winter DF diet (R3), and a R3 supplemented with calcium (R4) compared to a plant-fat-based diet (R1) in a randomized clinical trial (n=173) and a 2-year study in mildly metabolically disturbed downsized pigs (n=32). Conventional clinical measures were completed by LC/MS plasma metabolomics/lipidomics. The measured effects were modeled as biological functions to facilitate interpretation.DF intakes in pigs specifically induced a U-shaped metabolic trajectory, reprogramming metabolism to close to its initial status after a one-year turnaround. Twelve lipid species repeatably predicted DF intakes in both pigs and humans (6.6% errors). More broadly, in pigs, quality of DF modulated the time-related biological response (R2: 30 regulated functions, primarily at 6 months; R3: 26 regulated functions, mostly at 6–12 months; R4: 43 regulated functions, mostly at 18 months). Despite this heterogeneity, 9 functions overlapped under all 3 DF diets in both studies, related to a restricted area of amino acids metabolism, cofactors, nucleotides and xenobiotic pathways and the microbiota. In conclusion, over the long-term, DF reprograms metabolism to close to its initial biological status in metabolically-disrupted pigs. Quality of the DF modulates its metabolic influence, although some effects were common to all DF. A resilient signature of DF consumption found in pigs was validated in humans.

Associations between dairy fat intake, milk-derived free fatty acids, and cardiometabolic risk in Dutch adults

PurposeMilk-derived free fatty acids (FFAs) may act as both biomarkers of intake and metabolic effect. In this study we explored associations between different types of dairy consumption, a selection of milk-derived free fatty acids, and cardiometabolic disease (CMD) risk factors.MethodsSixty-seven FFAs were quantified in the plasma of 131 free-living Dutch adults (median 60 years) using gas chromatography-flame ionization detector. Intakes of different dairy foods and groups were assessed using a food frequency questionnaire. Twelve different CMD risk factors were analyzed. Multiple linear regressions were used to evaluate the associations under study.ResultsBased on the fully adjusted models, 5 long-chain unsaturated FFAs (C18:1 t13 + c6 + c7 + u, C18:2 c9t11 + u, C20:1 c11, C20:3 c8c11c14, and C20:4 c5c8c11c14), 2 medium-chain saturated FFAs (C15, C15 iso), and a trans FFA (C16:1 t9) were positively associated with at least one variable of dairy intake, as well as plasma total and LDL cholesterol, blood pressure, and SCORE (p ≤ 0.05). A long-chain PUFA associated with high-fat fermented dairy intake (C18:2 t9t12), was negatively associated with serum triglyceride levels, and a long-chain saturated FFA associated with cheese intake (C18:1 u1) was negatively associated with plasma LDL cholesterol and serum triglyceride levels. No clear associations were observed between dairy intake and CMD risk factors.ConclusionMilk-derived FFAs could act as sensitive biomarkers for dairy intake and metabolism, allowing the association between dairy and CMD risk to be more precisely evaluated.

Assessing the validity of plasma phospholipid fatty acids as biomarkers of dairy fat intake using data from a randomized controlled intervention trial

Plasma phospholipid pentadecanoic acid (C15:0), heptadecanoic acid (C17:0), and trans-palmitoleic acid (trans-C16:1n-7) are correlates of dairy fat intake. However, their relative concentrations may be influenced by other endogenous factors, such as liver fat content, and their validity as biomarkers of dairy fat intake has yet to be established. We investigated whether liver fat content modifies relations between concentrations of C15:0, C17:0, and trans-C16:1n-7 (alone and in combination with iso-C17:0) and known dairy fat intake in the context of a randomized controlled intervention study. We further examined the proportion of dairy fat intake explained by these fatty acids on their own and when considering liver fat content. We used data from a 12-wk intervention trial in which participants (n=62) consumed diets limited in dairy (0.3g/d of dairy fat), rich in low-fat dairy (8.7g/d of dairy fat), or rich in full-fat dairy (28.5g/d of dairy fat). We used linear regression models to examine relations between relative fatty acid concentrations and grams per day of dairy fat intake, liver fat percentage, and their interaction. Only trans-C16:1n-7 in isolation (β: 0.0004±0.0002, P=0.03) and combined with iso-C17:0 (β: 0.002±0.0005, P<0.0001) were consistently positively associated with dairy fat intake regardless of liver fat content. Trans-C16:1n-7 combined with iso-C17:0 also explained the greatest proportion of variation (35.4%) in dairy fat intake. C15:0 and C17:0 were not associated with dairy fat intake after adjusting for liver fat and were predicted to be higher in relation to increased dairy fat intake only among individuals with elevated liver fat. The potential for liver fat to affect relative plasma phospholipid concentrations of C15:0 and C17:0 raises questions about their validity as biomarkers of dairy fat intake. Of the fatty acid measures tested, trans-C16:1n-7 combined with iso-C17:0, especially with adjustment of liver fat, age, and sex, may provide the most robust estimate of dairy fat consumption.

Performance and milk quality parameters of Jersey crossbreds in low-input dairy systems

Previous work has demonstrated some benefit from alternative breeds in low-input dairying, although there has been no systematic analysis of the simultaneous effect of Jersey crossbreeding on productivity, health, fertility parameters or milk nutritional quality. This work aimed to understand the effects of, and interactions/interrelations between, dairy cow genotypes (Holstein-Friesian (HF), Holstein-Friesian × Jersey crossbreds (HF × J)) and season (spring, summer, autumn) on milk yield; basic composition; feed efficiency, health, and fertility parameters; and milk fatty acid (FA) profiles. Milk samples (n = 219) and breed/diet data were collected from 74 cows in four UK low-input dairy farms between March and October 2012. HF × J cows produced milk with more fat (+ 3.2 g/kg milk), protein (+ 2.9 g/kg milk) and casein (+ 2.7 g/kg milk); and showed higher feed, fat, and protein efficiency (expressed as milk, fat and protein outputs per kg DMI) than HF cows. Milk from HF × J cows contained more C4:0 (+ 2.6 g/kg FA), C6:0 (+ 1.9 g/kg FA), C8:0 (+ 1.3 g/kg FA), C10:0 (+ 3.0 g/kg FA), C12:0 (+ 3.7 g/kg FA), C14:0 (+ 4.6 g/kg FA) and saturated FA (SFA; + 27.3 g/kg milk) and less monounsaturated FA (MUFA; -23.7 g/kg milk) and polyunsaturated FA (− 22.3 g/kg milk). There was no significant difference for most health and fertility parameters, but HF × J cows had shorter calving interval (by 39 days). The superior feed, fat and protein efficiency of HF × J cows, as well as shorter calving interval can be considered beneficial for the financial sustainability of low-input dairy farms; and using such alternative breeds in crossbreeding schemes may be recommended. Although statistically significant, it is difficult to determine if differences observed between HF and HF × J cows in fat composition are likely to impact human health, considering average population dairy fat intakes and the relatively small difference. Thus, the HF × J cow could be used in low-input dairying to improve efficiency and productivity without impacting milk nutritional properties.

Dairy Product Consumption and Oligo-Astheno-Teratozoospermia Risk: A Hospital-Based Case-Control Study in China.

Background: Researches on the association of dairy products consumption with Oligo-astheno-teratozoospermia (OAT) risk has been limited and controversial. Therefore, we aim to explore the aforementioned association among Chinese men.Methods: A hospital-based case-control study was conducted in men consisting of 106 cases of OAT and 581 controls. Intakes of dairy products and their related nutrients were collected using a semi-quantitative food frequency questionnaire and semen quality was analyzed according to the World Health Organization guidelines. The daily intake of dairy products and their related nutrients was categorized into three groups with the lowest tertile serving as the reference category. Odds ratios (ORs) and 95% confidence intervals (CIs) of association between dairy intake and OTA risk were calculated by the multivariable logistic regression models.Results: No significant association was found between total dairy (OR T3vs.T1 =1.53, 95% CI: 0.85–2.78), protein (OR T3vs.T1 =1.51, 95% CI: 0.84–2.75), or calcium (OR T3vs.T1 = 1.46, 95% CI: 0.81–2.66) and the OAT risk in the main findings. However, we observed a statistically significant positive association of dairy fat intake with OAT risk (OR T3vs.T1 =1.93, 95% CI: 1.06–3.58). The findings were consistent with the main results when we carried out subgroup analysis stratified by body mass index.Conclusion: A significant positive association was found between dairy fat intake and the risk of OAT. Further large-scale prospective studies are required to confirm this finding.

Whole-fat dairy products do not adversely affect adiposity or cardiometabolic risk factors in children in the Milky Way Study: a double-blind randomized controlled pilot study

ABSTRACTBackgroundLimited evidence supports the common public health guideline that children >2 y of age should consume dairy with reduced fat content.ObjectivesWe aimed to investigate the effects of whole-fat compared with reduced-fat dairy intake on measures of adiposity and biomarkers of cardiometabolic risk in healthy 4- to 6-y-old children.MethodsThe Milky Way Study enrolled 49 children (mean ± SD age: 5.2 ± 0.9 y; 47% girls) who were habitual consumers of whole-fat dairy, then randomly assigned them in a double-blind fashion to remain on whole-fat dairy or switch their dairy consumption to reduced-fat products for 3 mo. Primary endpoints included measures of adiposity, body composition, blood pressure, fasting serum lipids, blood glucose, glycated hemoglobin (HbA1c), and C-reactive protein (CRP) and were assessed at baseline and study end. Pre- and postintervention results were compared using linear mixed models, adjusted for growth, age, and sex.ResultsDairy fat intake was reduced by an adjusted (mean ± SEM) 12.9 ± 4.1 g/d in the reduced-fat compared with the whole-fat dairy group (95% CI: –21.2, –4.6 g/d; P = 0.003), whereas dietary energy intakes remained similar (P = 0.936). We found no significant differential changes between dairy groups in any measure of adiposity, body composition, blood pressure, or fasting serum lipids, glucose, HbA1c, and CRP.ConclusionsOur results suggest that although changing from whole-fat to reduced-fat dairy products does reduce dairy fat intake, it does not result in changes to markers of adiposity or cardiometabolic disease risk in healthy children.This trial was registered at www.anzctr.org.au as ACTRN12616001642471.

Humans possess the ability to discriminate food fat content solely based on retronasal olfaction

Dietary fat overconsumption contributes to the development of obesity and related comorbidities; however, its sensory perception is poorly understood. Although humans can discriminate between vapor-phase fatty acids, both ortho- and retronasally, evidence of orthonasal fat discrimination in real foods is limited, and non-existent for retronasal olfaction.In two experiments, we investigated the human ability of olfactory food fat content discrimination in dairy milk and assessed whether this ability is affected by habitual dairy intake. Participants undertook a series of DR A-not A discrimination tests (analysed with R-index analyses) coupled with perceptual ratings and a questionnaire on dairy consumption habits.In the first experiment (n = 66), ortho- and retronasal discrimination was evaluated using dairy milk samples manipulated to contain 0%, 1.5% and 3.5% fat. Subjects could discriminate between all three fat levels orthonasally (p < .001), whereas retronasally they were able to do so between 0 and 1.5% (p < .001) and 0–3.5% (p < .001). The second experiment (n = 44) focused only on retronasal discrimination, using (manipulated) dairy milk samples of 3.5%, 7%, 10.5% and 14% fat. Here, discrimination was possible between 3.5 and 14% (p < .001) and 7–14% (p < .05) samples. No effects of total dairy fat intake, total dairy product intake or dairy exposure frequency were observed on discrimination ability in both experiments.This is the first study demonstrating that humans are capable of discriminating food fat content solely based on retronasal olfaction. Results also suggest that this ability is unaffected by habitual intake.

Exploring the Links between Diet and Inflammation: Dairy Foods as Case Studies

ABSTRACTSystemic chronic inflammation may be a contributing factor to many noncommunicable diseases, including diabetes, cardiovascular disease, and obesity. With the rapid rise of these conditions, identifying the causes of and treatment for chronic inflammation is an important research priority, especially with regard to modifiable lifestyle factors such as diet. An emerging body of evidence indicates that consuming certain foods, including dairy foods like milk, cheese, and yogurt, may be linked to a decreased risk for inflammation. To discuss both broader research on diet and inflammation as well as research on links between individual foods and inflammation, the National Dairy Council sponsored a satellite session entitled “Exploring the Links between Diet and Inflammation: Dairy Foods as Case Studies” at the American Society for Nutrition's 2020 LIVE ONLINE Conference. This article, a review based on the topics discussed during that session, explores the links between diet and inflammation, focusing most closely on the relations between intake of dairy fat and dairy foods like milk, cheese, and yogurt, and biomarkers of inflammation from clinical trials. While there is currently insufficient evidence to prove an “anti-inflammatory” effect of dairy foods, the substantial body of clinical research discussed in this review indicates that dairy foods do not increase concentrations of biomarkers of chronic systemic inflammation.

Biomarkers of dairy fat intake, incident cardiovascular disease, and all-cause mortality: A cohort study, systematic review, and meta-analysis.

We aimed to investigate the association of serum pentadecanoic acid (15:0), a biomarker of dairy fat intake, with incident cardiovascular disease (CVD) and all-cause mortality in a Swedish cohort study. We also systematically reviewed studies of the association of dairy fat biomarkers (circulating or adipose tissue levels of 15:0, heptadecanoic acid [17:0], and trans-palmitoleic acid [t16:1n-7]) with CVD outcomes or all-cause mortality. We measured 15:0 in serum cholesterol esters at baseline in 4,150 Swedish adults (51% female, median age 60.5 years). During a median follow-up of 16.6 years, 578 incident CVD events and 676 deaths were identified using Swedish registers. In multivariable-adjusted models, higher 15:0 was associated with lower incident CVD risk in a linear dose-response manner (hazard ratio 0.75 per interquintile range; 95% confidence interval 0.61, 0.93, P = 0.009) and nonlinearly with all-cause mortality (P for nonlinearity = 0.03), with a nadir of mortality risk around median 15:0. In meta-analyses including our Swedish cohort and 17 cohort, case-cohort, or nested case-control studies, higher 15:0 and 17:0 but not t16:1n-7 were inversely associated with total CVD, with the relative risk of highest versus lowest tertile being 0.88 (0.78, 0.99), 0.86 (0.79, 0.93), and 1.01 (0.91, 1.12), respectively. Dairy fat biomarkers were not associated with all-cause mortality in meta-analyses, although there were ≤3 studies for each biomarker. Study limitations include the inability of the biomarkers to distinguish different types of dairy foods and that most studies in the meta-analyses (including our novel cohort study) only assessed biomarkers at baseline, which may increase the risk of misclassification of exposure levels. In a meta-analysis of 18 observational studies including our new cohort study, higher levels of 15:0 and 17:0 were associated with lower CVD risk. Our findings support the need for clinical and experimental studies to elucidate the causality of these relationships and relevant biological mechanisms.

Association of the odd-chain fatty acid content in lipid groups with type 2 diabetes risk: A targeted analysis of lipidomics data in the EPIC-Potsdam cohort

Plasma odd-chain saturated fatty acids (OCFA) are inversely associated with type 2 diabetes (T2D) risk and may serve as biomarkers for dairy fat intake. Their distribution across different lipid classes and consequences for diabetes risk remain unknown. To investigate the prospective associations of OCFA-containing lipid species with T2D risk and their dietary determinants. Within the European Prospective Investigation into Cancer and Nutrition-Potsdam study (n=27,548), we applied a nested case-cohort design (subcohort: n=1,248; T2D cases: n=820; median follow-up 6.5 years). OCFA-containing lipids included triacylglycerols, free fatty acids (FFA), cholesteryl esters (CE), phosphatidylcholines, phosphatidylethanolamines, lysophosphatidylcholines, lysophosphatidylethanolamines, monoacylglycerols, and diacylglycerols. We estimated lipid class-specific associations between OCFA-containing lipids and T2D in sex-stratified Cox proportional-hazards models. We investigated correlations between lipids and dietary intakes derived from food-frequency questionnaires. We observed heterogeneous integration of OCFA in different lipid classes: triacylglycerols, FFA, CE, and phosphatidylcholines contributed most to the total OCFA-plasma abundance. The relative concentration of OCFA was particularly high in monoacylglycerols, and the contribution of C15:0 versus C17:0 to the total OCFA-abundance differed across lipid classes. In women, several OCFA-containing phospholipids were inversely associated with T2D risk [phosphatidylcholine(C15:0), HR Q5 vs Q1: 0.56, 95% CI 0.32-0.97; phosphatidylcholine(C17:0), HR per SD: 0.59, 95% CI 0.48-0.71; lysophosphatidylcholine(C17:0), HR Q5 vs Q1: 0.42, 95% CI 0.23-0.76]. In men, we did not detect statistically significant inverse associations in phospholipids, and lysophosphatidylcholine(C15:0) was associated with higher T2D risk (HR Q5 vs. Q1: 1.96, 95% CI 1.06-3.63). Besides, CE(C17:0), monoacylglycerols(C15:0), and diacylglycerols(C15:0) were inversely associated with T2D risk; FFA(C17:0) was positively associated with T2D risk in women. Consumption of fat-rich dairy and fiber-rich foods were positively and red meat inversely correlated to OCFA-containing lipid plasma levels. OCFA-containing lipids are linked to T2D risk in a lipid class and sex-specific manner, and they are correlated with several foods.

Microbiota and Metabolite Modifications after Dietary Exclusion of Dairy Products and Reduced Consumption of Fermented Food in Young and Older Men.

The gut microbiota adapts to age-related changes in host physiology but is also affected by environmental stimuli, like diet. As a source of both pre- and probiotics, dairy and fermented foods modulate the gut microbiota composition, which makes them interesting food groups to use for the investigation of interactions between diet and ageing. Here we present the effects of excluding dairy products and limiting fermented food consumption for 19 days on gut microbiota composition and circulating metabolites of 28 healthy, young (YA) and older (OA) adult men. The intervention affected gut microbial composition in both groups, with significant increases in Akkermansia muciniphila and decreases in bacteria of the Clostridiales order. Lower fasting levels of glucose and insulin, as well as dairy-associated metabolites like lactose and pentadecanoic acid, were observed after the intervention, with no effect of age. The intervention also decreased HDL and LDL cholesterol levels. Dairy fat intake was positively associated with the HDL cholesterol changes but not with the LDL/HDL ratio. In conclusion, restricting the intake of dairy and fermented foods in men modified their gut microbiota and blood metabolites, while the impact of the dietary restrictions on these outcomes was more marked than the effect of age.

Abstract 026: Biomarkers Of Dairy Fat Intake Associated With Lower Cardiovascular Disease Risk: A Cohort Study And Meta-analysis

Introduction: Dietary recommendations promote low-fat rather than full fat dairy consumption. Emerging evidence, however, has raised doubts if avoidance of dairy fat will lower CVD risk. Traditionally, self-reported estimates of dairy fat intake were used to study its relationship with CVD, which are subject to recall biases and measurement error. Here, we employed circulating levels of pentadecanoic acid [15:0] as a biomarker of dairy fat intake to examine its association with CVD incidence and all-cause mortality in a Swedish population-based cohort. We also conducted a systematic review of prospective studies that assessed 15:0, and other dairy fat biomarkers (heptadecanoic acid [17:0] and trans -palmitoleic acid [ t 16n-7]) and their associations with CVD and all-cause mortality. Hypothesis: We assessed the hypothesis that higher levels of dairy fat biomarkers 15:0, 17:0 and t 16n-7 would be associated with lower risk of incident CVD events and all-cause mortality. Methods: In a cohort of 60-year old Swedish women (n=2133) and men (n=2017), we measured 15:0 in serum cholesterol esters at baseline in 1997-99. Cox proportional hazard models were used to assess the associations between serum 15:0 with CVD outcomes and all-cause mortality, after adjusting for demographics and CVD risk factors. In the meta-analysis, five databases were searched to include prospective observational studies that examined the associations between circulating or adipose tissues levels of 15:0, 17:0 and t 16n-7 and CVD and mortality risks. Pooled associations of each dairy fat biomarker with incidence of CVD and all-cause mortality were estimated using a random-effects model. Results: During a median follow-up of 16.6 years, 578 incident CVD events and 676 deaths were identified using national registers. In multivariable-adjusted models, higher serum 15:0 was associated with lower incidence of CVD in a linear dose-response manner [HR: 0.75 per interquintile range; 95% CI: 0.61, 0.93), but in a non-linear relationship with all-cause mortality (P nonlinearity = 0.03); with a nadir of mortality risk around the median level of 15:0. In the meta-analysis including our Swedish cohort and 17 other studies, the relative risk of total CVD comparing the highest versus the lowest tertile was 0.88 (0.78, 0.99) for 15:0 (n=17), 0.86 (0.79, 0.93) for 17:0 (n=12), and 1.01 (0.91, 1.12) for t16n-7 (n=6). In meta-analyses of ≤3 studies, there was little evidence that dairy fat biomarkers were associated with all-cause mortality. Conclusion: In conclusion, our de novo Swedish cohort study and an updated systematic review including 18 studies suggests that higher levels of dairy fat biomarkers (15:0 and 17:0) were associated with a lower risk of CVD incidence. These results justify further investigation in interventional and experimental studies to elucidate the potential causality of these relationships and relevant mechanisms.