Background

The goal of this systematic review was to determine whether dietary patterns are associated with bone health. Dietary patterns were defined as the quantities, proportions, variety or combination of different foods, drinks and nutrients in diets and the frequency with which they are habitually consumed.

Conclusion statement

Limited evidence suggests that a dietary pattern higher in vegetables, fruits, grains, nuts and dairy products, and lower in meats and saturated fat, is associated with more favorable bone health outcomes in adults, including decreased risk of fracture and osteoporosis, as well as improved bone mineral density. Although a growing number of studies are examining the relationship between dietary patterns and bone health in adults, the number of high-quality studies is modest and those available employ a wide range of methodologies in study design, dietary assessment techniques and varying bone health outcomes.

Definitive conclusions regarding the relationship between dietary patterns and bone health outcomes (bone mineral density and bone mineral content) in children and adolescents cannot be drawn due to the limited evidence from a small number of studies with wide variation in study design, dietary assessment methodology and bone health outcomes.

2015 DGAC Grade:

• Adults: Limited
• Children and Adolescents: Not assignable

Methods

Literature searches were conducted using PubMed, Embase, Navigator (BIOSIS, CAB Abstracts and Food Science and Technology Abstracts) and Cochrane databases to identify studies that evaluated the association between dietary patterns and bone health studies that met the following criteria were included in the review: Randomized controlled trials (RCTs), non-randomized controlled trials, prospective cohort studies or nested case-control studies; human subjects aged two years and older who were healthy or at elevated chronic disease risk; subjects from countries with high or very high human development (2012 Human Development Index); and published in English in peer-reviewed journals. The date range was January 2000 to April 2014. The intervention or exposure was adherence to a dietary pattern (e.g., a priori patterns, data-driven patterns, reduced rank regression or patterns derived from other methods, and a description of the dietary pattern(s) (i.e., foods and beverages) consumed by subjects was provided. The outcomes were bone mass (bone mineral density and content), osteoporosis, rickets and risk of fracture.

Data from each included article was extracted, and risk of bias was assessed. The evidence was qualitatively synthesized, a conclusion statement was developed and the strength of the evidence (grade) was assessed using pre-established criteria including evaluation of the Systematic Reviews of the Dietary Patterns, Food and Nutrients Subcommittee, 2015 DGAC 170 Archived from www.NEL.gov on March 21, 2017 quality and risk of bias, quantity, consistency, magnitude of effect and generalizability of available evidence.

Findings

• This systematic review included two articles that used data from RCTs and 11 articles from prospective cohort studies published since 2000 that examined the relationship between dietary patterns and bone health
• The articles employ diverse methodologies to assess dietary patterns. Four articles used an index or score, six articles used factor analysis and principal components analysis, two articles used reduced rank regression and two articles tested dietary patterns in an intervention study where bone health or fractures were either secondary or tertiary trial outcomes. Seven studies assessed risk of fracture, six studies assessed bone mineral density, bone mineral content or bone mass and one study examined risk of osteoporosis.
• The dietary patterns examined in this systematic review were defined in various ways, making comparisons between articles difficult. However, despite heterogeneity in this body of evidence, some common characteristics of dietary patterns associated with better or adverse bone health outcomes emerged, particularly in articles where patterns were defined by index or score. Articles using data-driven methods were less consistent. The following overall conclusions can be drawn:
  • Patterns emphasizing vegetables; fruits; legumes; nuts; dairy; and cereals, grains, pasta, rice; and unsaturated fats were generally associated with more favorable bone health outcomes
  • Patterns higher in meats and saturated fats were generally associated with increased risk of adverse bone health outcomes
  • Results were far less consistent for added sugars, alcohol and sodium in relation to bone health.
• Although many cohort studies make extensive efforts to include participants across a wide range of race/ethnic groups and across the socio-economic continuum, there still may be some groups for which the association between dietary patterns and bone health cannot yet be determined (i.e., children, adolescents).

Limitations

The ability to draw strong conclusions was limited by the following issues:

• There were relatively few studies available to address this question, and those available used a wide range of methodologies in study design and dietary assessment techniques and had varying bone health outcomes.