Can yogurt and kefir help prevent osteoporosis? Scientists examine the facts

By Priyanjana Pramanik, MSc.Reviewed by Susha Cheriyedath, M.Sc.Mar 18 2025

Scientists investigate whether fermented dairy and probiotics can help prevent osteoporosis—do they hold the key to stronger bones or is the science still uncertain?

Review: The Impact of Fermented Dairy Products and Probiotics on Bone Health Improvement. Image Credit: Crevis / Shutterstock

A recent review in the Food Science of Animal Resources journal highlights the importance of fermented dairy products in promoting bone health.

They supply essential nutrients and contain probiotics that may help reduce inflammation, support bone remodeling, and protect against osteoporosis and other bone-related disorders. However, human studies on probiotic effectiveness in bone health have shown mixed results, indicating the need for further research.

The Consequences of Poor Bone Health

Bones continuously undergo remodeling, a process regulated by genetic, hormonal, and environmental factors. When this balance is disrupted, it leads to weakened bones and increased susceptibility to fractures.

Osteoporosis, a common bone disease, occurs when bone resorption outpaces bone formation, increasing fracture risk due to reduced bone mass. Estrogen deficiency, especially after menopause, plays a significant role in osteoporosis by accelerating bone breakdown through increased osteoclast activity and reduced osteoblast function.

Estrogen helps regulate bone metabolism by inhibiting the RANKL/OPG system and lowering levels of pro-inflammatory markers like TNF-α and IL-6. When estrogen levels drop, immune cells, particularly Th17 cells, stimulate osteoclast production, increasing bone loss. Other contributors include oxidative stress and epigenetic modifications, such as deoxyribonucleic acid (DNA) methylation of bone-related genes. Research in mice suggests that probiotic effects on bone density may vary by gender, with Lactobacillus reuteri improving bone density in males but showing limited effects in females.

In addition to osteoporosis, other bone disorders include rickets and osteomalacia, which result from inadequate bone mineralization due to deficiencies in vitamin D, calcium, or phosphate.

Vitamin D, derived from sunlight and dietary sources, is converted into calcitriol, a hormone essential for phosphate and calcium absorption. Deficiency leads to weak bones, increased parathyroid hormone secretion, and excessive phosphate loss, which impair bone strength and development.

Key Determinants of Bone Health

Genetics significantly influence bone mineral density (BMD), accounting for 60%-90% of variations in bone mass. Certain genes, such as LRP5 and SOST, play a critical role in bone remodeling, while mutations in CLCN7 and TCIRG1 can contribute to osteopetrosis. Identifying genetic markers can improve early diagnosis and treatment of bone disorders.

Aging reduces BMD, making bones brittle. Physical activity, particularly resistance and weight-bearing exercises, stimulates osteocytes to promote bone formation and maintain bone strength. Chronic inflammation disrupts the bone remodeling process by elevating levels of pro-osteoclastogenic cytokines such as TNF-α. Additionally, environmental pollutants like heavy metals can interfere with calcium metabolism, further weakening bones.

The Role of Dairy in Bone Health

Dairy products, particularly fermented dairy, are crucial in combating osteoporosis and other bone disorders. These products enhance calcium absorption, modulate immune responses, and help regulate bone resorption. Fermented dairy is especially beneficial due to its probiotic content, which may improve gut health and enhance nutrient uptake, but its direct benefits on bone health remain under investigation.

Dairy products are among the richest sources of calcium, providing approximately 50%-60% of daily requirements. Calcium is vital for bone mineralization and maintaining structural integrity. Additionally, dairy products fortified with vitamin D further enhance calcium absorption and reduce the risk of bone diseases. Fermented dairy also helps break down phytates, compounds that inhibit mineral absorption, making nutrients more bioavailable.

Protein is a key component of bone formation, as it stimulates the production of insulin-like growth factor-1 (IGF-1), which promotes bone growth. Low protein intake is linked to weaker bones, shorter stature, and increased fracture risk. Dairy products also provide essential minerals such as magnesium, potassium, and phosphorus, which support bone density. A single 170g serving of yogurt contains approximately 231mg of calcium, helping individuals meet their daily calcium needs with just 3-4 servings.

Fermented dairy products, such as yogurt and kefir, contain beneficial probiotics like Lactobacillus and Bifidobacterium. These probiotics have been suggested to improve bone health by potentially increasing calcium and vitamin D absorption, helping reduce inflammation, and supporting gut microbiota balance. However, some studies, such as a 2020 human trial by Sergeev et al., found no significant improvements in bone health from probiotics, highlighting the need for more research. Additionally, probiotics produce short-chain fatty acids (SCFAs), which have been associated with inhibiting bone resorption and may protect against osteoporosis.

Conclusions

Incorporating fermented dairy products into the diet is an effective strategy for maintaining strong bones throughout life. These products provide essential nutrients such as proteins, calcium, and probiotics, which support bone metabolism and reduce bone loss. Their bioavailable nutrients make them particularly beneficial in preventing bone diseases like osteoporosis, rickets, and osteomalacia.

Probiotics in fermented dairy have been linked to improved calcium absorption, reduced bone loss markers, and enhanced gut health, all contributing to stronger bones with improved density. However, human studies show mixed results, and further research is needed to clarify their role in bone health. Regular consumption of fermented dairy may lower the risk of fractures and age-related bone deterioration.

As part of a balanced diet, fermented dairy may offer a natural and effective way to support lifelong bone health, making it a valuable addition to daily nutrition, particularly for aging populations.