Healthful plant-based diets reduce the risk of osteoporosis

Introduction

Globally, osteoporosis affects 1 in 3 women and 1 in 5 men aged 50 years and older.(1) Lifestyle factors, including diet, play a significant role in its development.

Aim

The aim of this study was to explore the association between plant-based diets and osteoporosis in older Chinese adults.(2)

Method

Adults over 60 years of age were recruited from nine communities in China. In a face to face interview, participants completed a range of questionnaires and underwent assessments covering sociodemographics, smoking and alcohol consumption habits, physical activity patterns, fracture history, and anthropometric data.

Dietary assessment using the plant-based index

Using data collected from food frequency questionnaires (FFQ), dietary patterns were scored using a previously validated system to produce three plant-based diet indices:

• Plant-based diet index (PDI): a high score reflecting a diet high in healthy and unhealthy plant foods and low in animal foods

• Healthy PDI (HPDI): a high score reflecting high intakes of healthy plant foods (whole grains, fruits, fresh vegetables, legumes, seaweed, nuts, and tea) and low intakes of refined plant foods and animal foods

• Unhealthy PDI (UPDI): a high score indicative of a diet high in unhealthy plant foods (refined grains, potatoes, desserts, sugary drinks, and other) but low in meat and healthy plant foods.

Osteoporosis

Participants’ heel bone mineral density (BMD) was measured using an ultrasonic bone densitometer. Osteoporosis was defined as t-scores at or below -2.5 standard deviations.

Results

9,613 participants (62% female) with a mean age of 69 years were recruited into the study with 19% diagnosed with osteoporosis based on heel BMD.

The odds ratio (OR) was estimated for the three PDI and osteoporosis, after fully adjusting for other sociodemographic and lifestyle confounding factors.

Comparing highest and lowest quartiles for PDI

• The highest quartile of PDI and HPDI had higher heel BMD and associated with a 20% lower risk of osteoporosis (OR = 0.80, 95% CI 0.69–0.93 and OR HPDI= 0.64, 95%CI 0.56–0.74, p<0.05).

• Diets in the highest quartile for UPDI were associated with lower BMD and an estimated 42% higher risk of osteoporosis (OR = 1.42, 95% CI 1.23–1.65, p<0.05).

Individual foods and association with osteoporosis

In terms of single foods, whole grains, fresh fruits, fresh vegetables, nuts, legumes, and tea were identified as the most protective against osteoporosis, whilst refined grains, sugary drinks and desserts were associated with a higher risk of osteoporosis.

Conclusion

This study demonstrates that in older adults, diets low in animal foods and high in healthful plant foods support bone health and can help protect against the risk of osteoporosis. The findings also emphasise the importance of analysing results separately for healthy and unhealthy plant dietary patterns in clinical studies.

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