Substitution of Milk with Whole-Fat Yogurt Products or Cheese Is Associated with a Lower Risk of Myocardial Infarction: The Danish Diet, Cancer and Health cohort

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.

Comparison of the impact of saturated fat from full-fat yogurt or low-fat yogurt and butter on cardiometabolic factors: a randomized cross-over trial

PURPOSE

Dairy foods are often a major contributor to dietary saturated fatty acids (SFA) intake. However, different SFA-rich foods may not have the same effects on cardiovascular risk factors. We compared full-fat yogurt with low-fat yogurt and butter for their effects on cardiometabolic risk factors in healthy individuals.

METHODS

Randomized, two-period crossover trial conducted from October 2022 to April 2023 among 30 healthy men and women (15 to receive full-fat yogurt first, and 15 to receive low-fat yogurt and butter first). Participants consumed a diet with 1.5-2 servings of full-fat (4%) yogurt or low-fat (< 1.5) yogurt and 10-15 g of butter per day for 4 weeks, with 4 weeks wash-out when they consumed 1.5-2 servings of low-fat milk. At baseline, and the end of each 4 weeks, fasting blood samples were drawn and plasma lipids, glycemic and inflammatory markers as well as expression of some genes in the blood buffy coats fraction were determined.

RESULTS

All 30 participants completed the two periods of the study. Apolipoprotein B was higher for the low-fat yogurt and butter [changes from baseline, + 10.06 (95%CI 4.64 to 15.47)] compared with the full-fat yogurt [-4.27 (95%CI, -11.78 to 3.23)] and the difference between two treatment periods was statistically significant (p = 0.004). Non-high-density lipoprotein increased for the low-fat yogurt and butter [change, + 5.06 (95%CI (-1.56 to 11.69) compared with the full-fat yogurt [change, - 4.90 (95%CI, -11.61 to 1.81), with no significant difference between two periods (p = 0.056). There were no between-period differences in other plasma lipid, insulin, and inflammatory biomarkers or leukocyte gene expression of ATP-binding cassette transporter 1 and CD36.

CONCLUSION

This study suggests that short-term intake of SFAs from full-fat yogurt compared to intake from butter and low-fat yogurt has fewer adverse effects on plasma lipid profile.

CLINICALTRIALS

GOV: NCT05589350, 10/15/2022.

Substitution of Dairy Products and Risk of Death and Cardiometabolic Diseases: A Systematic Review and Meta-Analysis of Prospective Studies

Substitution models in epidemiologic studies specifying both substitute and substituted food in relation to disease risk may be useful to inform dietary guidelines. A systematic review of prospective observational studies was performed to quantify the risks of all-cause mortality, cardiovascular disease, and type 2 diabetes (T2D) associated with the substitution of dairy products with other foods and between different dairy products. We systematically searched MEDLINE, Embase, and Web of Science until 28th June, 2023. We calculated summary relative risks (SRRs) and 95% confidence intervals (95% CI) in random-effects meta-analyses. We assessed the risk of bias with the Risk Of Bias In Non-randomized Studies - of Exposure (ROBINS-E) tool and certainty of evidence (CoE) using the Grading of Recommendations Assessment, Development, and Evaluations (GRADE) approach. Fifteen studies (with 34 publications) were included. There was moderate CoE that the substitution of low-fat dairy with red meat was associated with a higher risk of mortality, coronary artery disease, and T2D [SRR (95% CI): 1.11 (1.06, 1.16), 1.13 (1.08, 1.18), and 1.20 (1.16, 1.25)]. A higher risk of mortality and T2D was also observed when substituting low-fat dairy with processed meat [SRR (95% CI): 1.19 (1.11, 1.28) and 1.41 (1.33, 1.49); moderate CoE]. A lower mortality risk was associated with the substitution of dairy and yogurt with whole grains [SRR (95% CI): 0.89 (0.84, 0.93) and 0.91 (0.85, 0.97)], and butter with olive oil [SRR (95% CI): 0.94 (0.92, 0.97); all moderate CoE]. Mainly no associations were observed when substituting dairy products against each other on disease and mortality risk. Our findings indicate associations between substituting dairy with red or processed meat and higher disease risk, whereas its substitution with whole grains was associated with a lower risk. However, there is little robust evidence that substituting whole-fat with low-fat dairy is associated with disease risk. (CRD42022303198).

Role of fermented dairy products in the health benefits of a mediterranean diet

Mediterranean diet includes fermented dairy products like yogurt and cheese. These foods provide calcium, phosphorus, fat, carbohydrates and protein, all nutrients influencing various systems including bone, cardiovascular system, intermediary metabolism, cancer, central nervous system, and inflammation. In addition, they contain prebiotics and provide probiotics which are capable of modifiying microbiota composition and metabolism, potentially acting also indirectly on the various systems. A large body of evidence indicates that fermented dairy products consumption significantly contributes to the beneficial effects of a Mediterranean diet on various systems' health.

Dairy Foods: Beneficial Effects of Fermented Products on Cardiometabolic Health

PURPOSE OF REVIEW

This review of recent observational studies and understanding of the complex nature of dairy foods is intended to reappraise the effects of different types of dairy foods on cardiovascular disease (CVD).

RECENT FINDINGS

Recent guidelines from major cardiovascular societies suggest that apart from the adverse effect of butter, consumption of more complex dairy products notably fermented varieties and yogurt in particular, appear to be inversely associated with outcomes of CVD and type 2 diabetes (T2D). Reduced fat in dairy food remains preferred for people at increased CVD risk. Changed evidence has led to new advice regarding consumption of some dairy foods. The apparent beneficial effects of fermented milk products, particularly yogurt, allow for increased consumption of nutritious staple foods. Recent national guidelines reflect this view.

Dairy products and bone health

Bone mineral mass, geometry and microstructure, hence determinants of fracture risk, result bone accrual during growth and bone loss later in life. Peak bone mass, which is reached by the end of the second decade of life, is mainly determined by genetic factors. Among other factors influencing bone capital, dietary intakes, particularly calcium and protein, play a significant role in peak bone mass attainment. Both nutrients are provided in dairy products, which accounts for 50-60% and 20-30% of the daily calcium and protein intakes, respectively. Children avoiding dairy products are at higher risk of fracture, as are adults or older individuals following a diet devoid of dairy products, like vegans. Various intervention trials have shown some beneficial effects of dairy products on bone capital accumulation during growth and on bone turnover in adults. In observational studies, dairy products intake, particularly the fermented ones, which also provide probiotics in addition to calcium, phosphorus and protein, appear to be associated with a lower risk of hip fracture.

A food-level substitution analysis assessing the impact of replacing regular-fat dairy with lower fat dairy on saturated fat intake at a population level in Canada

BACKGROUND

The 2019 Canada's Food Guide recommends the consumption of lower fat dairy products to reduce saturated fat (SFA) intakes.

OBJECTIVES

The objective of this study was to assess the impact of such recommendation on SFA intake at a population level in Canada.

METHODS

Analyses were conducted based on dietary intakes from the nationally representative 2015 Canadian Community Health Survey-Nutrition (unweighted n = 20,103). Dietary intake was assessed using 24-h dietary recalls. Food-based substitution modeling analyses were conducted by replacing all regular-fat dairy products reported by an equal amount of a corresponding lower fat dairy product. Regular-fat dairy products included milks ≥2% fat, cheeses >25% fat, and yogurts ≥2% fat. Corresponding lower fat replacement products were 1% fat milks, 10-25% fat cheeses, and <2% fat yogurts. The National Cancer Institute method was used to account for within-person variation in dietary intakes.

RESULTS

Replacing all regular-fat dairy products consumed by Canadians (ages ≥2 y) by a corresponding lower fat product reduced the population's SFA intake from 10.8% of total energy intake (%E; 95% CI: 10.7%, 11.0%) to 10.0%E (95% CI: 9.8%, 10.2%). This reduction was mostly attributable to the milk and cheese substitutions (mean SFA reductions of -0.3%E each). The proportion of the population with an SFA intake <10%E was 34.7% (95% CI: 31.2%, 38.2%) before substitution and 51.5% (95% CI: 47.5%, 55.5%) after substitution.

CONCLUSIONS

This food-based substitution modeling analysis suggests that SFA intakes at a population level are slightly reduced if all regular-fat dairy products consumed by Canadians were replaced by a lower fat dairy product. Approximately half of the population would still consume SFAs in excess of 10%E even if all regular-fat dairy consumed were replaced by lower fat dairy.

Theoretical substitutions between dairy products and all-cause and cause-specific mortality. Results from the Danish diet, cancer and health cohort

A daily intake of dairy products is recommended in many countries in order to maintain optimal health throughout life. However, evidence regarding the association between intake of individual dairy products and mortality is limited. We therfore, explored associations between intake of different dairy products and all-cause and cause-specific mortality using specified theoretical substitution analyses. We analysed data from 55 775 Danish men and women aged 50-64 years between 1993 and 1997. Information about dairy product intake at baseline was collected using a validated food frequency questionnaire. Information about vital status and causes of death was obtained through national registers. Measures of associations were calculated using Cox proportional hazards regression. During a median follow-up of 19·0 years, 11 586 participants died. For all-cause mortality, we observed that the intake of low-fat milk, whole-fat milk or low-fat yogurt products in place of cheese was associated with a higher rate of death (hazard ratios between 1·03 and 1·12 per serving/d substituted). The same pattern was present for CVD mortality. For cancer mortality, whole-fat milk and low-fat yogurt products in place of cheese were also associated with a higher rate of death for men while for women, whole-fat milk in place of buttermilk was associated with a higher cancer mortality rate. The results appeared robust in several sensitivity analyses. Our results suggest that intake of low-fat milk, whole-fat milk or low-fat yogurt products in place of cheese is associated with a higher rate of all-cause and cause-specific mortality.

Intake of dairy products and associations with major atherosclerotic cardiovascular diseases: a systematic review and meta-analysis of cohort studies

Specific types of dairy products may be differentially associated with atherosclerotic cardiovascular disease (CVD). We conducted a systematic review and meta-analysis of cohort studies to summarize findings on the associations between total dairy product intake and intake of dairy product subgroups and the risk of major atherosclerotic CVDs in the general adult population. Our protocol was registered in PROSPERO (CRD42019125455). PubMed and Embase were systematically searched through 15 August 2019. For high versus low intake and dose-response meta-analysis, random-effects modelling was used to calculate summary risk ratios (RR). There were 13 cohort studies included for coronary heart disease (CHD), 7 for ischemic stroke and none for peripheral artery disease. High-fat milk was positively associated with CHD (RR 1.08 (95% confidence interval 1.00-1.16) per 200 g higher intake/day) and cheese was inversely associated with CHD (RR 0.96 (95% confidence interval 0.93-0.98) per 20 g higher intake/day). Heterogeneity, however, was observed in high versus low meta-analyses. Milk was inversely associated with ischemic stroke in high versus low meta-analysis only. In conclusion, this systematic review indicates a positive association of high-fat milk and an inverse association of cheese with CHD risk. The findings should be interpreted in the context of the observed heterogeneity.