How Does Dairy Intake Affect Bone Mineral Density?

As part of a healthy, habitual dietary pattern, daily intake of low-fat or nonfat dairy products may be associated with improved bone mineral density (BMD) of the total body and at some specific sites, according to a new systematic review. The findings also reveal that dairy intake may be associated with fewer fractures among older adults.

The researchers conducted the review after controversy stemmed from recent research that suggested that dairy consumption is associated with an increased risk of fracture.

“Over the past 30 years, the US Dietary Guidelines for Americans have included recommendations around dairy consumption, largely based on meeting recommendations for calcium intake with the intended purpose of osteoporosis prevention,” the authors wrote. “Although dairy products provide more bone-beneficial nutrients per unit of energy than any other food group, the relevance of dairy products for long-term bone health and fracture prevention has resurged as some observational studies have suggested consumption to be associated with a greater risk of fractures.”

To explore this further, the researchers evaluated evidence on dairy consumption and bone health across the lifespan. By searching the PubMed, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials databases, the researchers identified 30 randomized controlled trials, 28 prospective cohorts, 23 cross-sectional studies, and 10 case-control studies that had reported on the effect of dairy products on BMD, bone mineral content, and/or fractures.

“Dairy products provide the raw materials for bone structure; however, other lifestyle choices also influence the growth and preservation of bone,” the researchers wrote of their review findings. “Dairy intakes that provide adequate dietary calcium may enhance the effectiveness of physical activity on bone density and strength. Dairy intake does not seem to increase the risk of fractures.”

Still, more evidence—especially among certain patient populations—is needed. Based on their review, the researchers determined that there was insufficient evidence for the effect of dairy among infants and toddlers (aged newborn to <36 months), children (aged 3 to <10 years), and young adults (aged 19 to <50 years). The effect of dairy in adolescents (aged 10 to <19 years) had limited evidence. Meanwhile, the researchers found moderate evidence for the effect of dairy in middle-aged to older adults (aged ≥50 years). 

More research is especially needed in regard to bone mass among adults aged 20 to 50 years and individuals who are not Chinese or White, according to the researchers.

Reference:

Wallace TC, Bailey RL, Lappe J, et al. Dairy intake and bone health across the lifespan: a systematic review and expert narrative. Crit Rev Food Sci Nutr. Published online September 14, 2020. doi:10.1080/10408398.2020.1810624