Replacing dairy products with grains and olive oil reduces the risk of disease

A recent review and meta-analysis published in Current Developments in Nutrition examines long-term associations between various foods (mainly dairy) and noncommunicable diseases (NCDs)., including overall mortality, type 2 diabetes (T2D) and cardiovascular disease (CVD). The study conducted a literature search in three online scientific repositories, resulting in 2544 publications identified, of which 34 met the inclusion criteria and were included in the meta-analysis.

After accounting for within-study bias and specificity, and adjusting for demographic and medical factors, the study results showed that different dairy products did not statistically change the risk of ND in study participants. However, replacing dairy products with red meat and processed meats was associated with an increased risk of ND, while replacing these foods with whole grains and olive oil improved long-term risk of ND. This study debunks the “healthy dairy” hypothesis while clarifying the role of dietary patterns in modulating the risk of ND.

Non-communicable chronic diseases represent the leading cause of death in the world today, with about 73% of all deaths in 2017 falling into this category. Despite significant advances in medicine, the prevalence of ND continues to rise, with recent research implicating the role of healthy lifestyle habits (sleep patterns, physical activity levels and diet) in the risk and progression of ND. Diet, in particular, has been identified as a potentially modifiable health risk factor.

In this review and meta-analysis, researchers collected and synthesized data from more than 30 publications from three online scientific repositories to identify changes in the risk of ND and overall health outcomes when replacing dairy products with 1. Other dairy products, 2. Plant-based foods, or 3. Other products of animal origin. The review methodology followed the recommendations outlined in the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) checklist and was registered in the international register of systematic reviews PROSPERO.

Publication data was obtained through sequential repository searches, title and abstract screening, and full text analysis of three scientific publication databases: MEDLINE, Embase, and Web of Science. Data was collected until June 28, 2023.

Of the 2544 publications identified by the keyword search of the database, 34 publications (representing 15 unique cohorts of participants) met the inclusion criteria for the review. Of these, 25 were included in the meta-analysis after assessing the risk of bias.

The study results highlighted the lack of significant changes in the risk of ND between “healthy” (eg, low-fat milk) and “unhealthy” (eg, high-fat butter) dairy products. In contrast, replacing butter with olive oil significantly improved risk scores for ND, suggesting long-term health benefits of replacing dairy products with healthier plant-based foods. In contrast, replacing dairy products with red meat or processed meats significantly increased the risk of ND.

This study is the largest meta-analysis to date in which researchers have identified the effect of replacing dairy products with other dairy products or other plant or animal products on the risk of ND. The results show that all dairy products carry the same risk of ND, and substitutions within the group (dairy products) do not have significant long-term public health benefits. However, replacing dairy products with plant- or animal-based alternatives was associated with changes in the risk of ND: plant-based foods improved risk scores, while red and processed meats worsened them.