Increasing Dairy Consumption Reduces Fracture Risk Without Compromising Cardiovascular Health in Older Adults

Older adults living in aged care facilities have increased risks of fractures and falls and widespread malnutrition, often including inadequate intakes of calcium and protein, two key nutrients for optimal bone health. A study evaluated whether increasing dairy intake could effectively reduce the risk of fractures and falls while addressing nutritional gaps (notably calcium and protein) without compromising cardiovascular health in this population.¹

Design and Methodology

A sub-study of an important 2-year cluster randomized controlled trial involving 60 Australian aged care homes was conducted. This sub-study included 245 residents at baseline (159 in the intervention group and 86 in the control group), with a median age of 88 years. Cardiovascular disease and hypertension were prevalent among participants: on average, participants had 10 medical conditions and were taking 12 medications, including lipid lowering (37%) and blood pressure (64%) medications.

Intervention

The main objective of the sub-analysis was to determine the efficacy and safety of supplemental dairy to the residents' diets. The intervention focused on nutritious, regular fat dairy products: milk (250 ml), yogurt (200 g), and cheese (40 g). Butter, cream, and ice cream were not included.

Efficacy was assessed by evaluating improvements in calcium and protein intake, and reductions in fracture and fall risk. Safety was evaluated through the impact of increased dairy consumption on cardiovascular health markers, particularly serum lipid profiles.

The study recorded dietary intakes with plate-waste analysis, providing a more accurate measure of consumption compared to self-reported methods, which are often subject to recall bias. 

Results

Daily dairy intake increased from 1.9 servings at baseline to 3.5 servings at 12 months in the intervention group while that of the control group remained relatively stable, increasing marginally from 1.7 to 2.0 daily servings.

Fasting serum lipids, which were measured at baseline and at 12 months, included total cholesterol (TC)/ high-density lipoprotein cholesterol (HDL-C) ratio, Apolipoprotein B (ApoB), low-density cholesterol (LDL-C) and non-HDL cholesterol.

Key Findings

1. No negative impact on cardiovascular health:
   • There were no changes in serum lipid profiles between the intervention and the control groups. 
2. Positive effects on nutritional intake:
   • Calcium: In the original study, at baseline, both groups had calcium intakes of 689 mg/day, which increased to 1142 mg/day in the intervention group and 700 mg/day in the control group after 24 months.²
   • Protein: The intervention significantly increased daily protein consumption from an average of 57 ± 13 g at baseline to 70 ± 18 g after 12 months.¹ The original study assessing fracture risk continued to assess protein intake until the 24-month mark and found that the intervention group sustained their increased daily protein consumption.²
   • Fat, Carbohydrates, and Energy: There were no changes in total fat, saturated fat, energy, or carbohydrate intake between the groups. Thus, increasing dairy intake did not lead to excess calorie or fat consumption. Notably, energy intake was not actively controlled in the study design.

Clinical Implications

These results build upon previous findings from the same intervention, which reported significant reductions in overall fractures (33%), hip fractures (46%), and falls (11%).² The current study demonstrates that these benefits can be achieved with increased dairy intakes (milk, yogurt and cheese) without compromising cardiovascular health, even in a population with high cardiovascular risk.¹

Mechanisms

The authors suggest several mechanisms to explain why increased dairy consumption did not adversely affect cardiovascular health markers. 

Food substitution: The intervention replaced high-fat, low-nutrient foods like cakes and biscuits, with nutritious dairy-based options. This change likely altered the fatty acid composition of the diet without increasing total fat intake.

Dairy matrix:  Dairy foods contain a complex structure of bioactive peptides and minerals, known as the dairy matrix, which helps balance the effects of saturated fats on cholesterol.

Probiotic effects: Fermented dairy products, such as many yogurts and cheeses, also offer the added benefits of probiotics. These beneficial bacteria can alter the gut microbiota, potentially improving cholesterol metabolism.

Calcium-mediated fat excretion: Research shows that consuming more than 1,100 mg of calcium daily can bind to fatty acids in the gut, preventing their absorption and increasing fat excretion. This mechanism can support the management of overall body fat levels in the body.