Calcium, Protein and Vitamin D: The Bone Health Trio for Adults Introduction

Introduction

Bone health is a cornerstone of an individual’s lifelong mobility, strength and independence. From childhood through old age, our bones undergo remodeling, a process by which old bone is broken down and new bone is formed. With peak bone mass achieved in early adulthood to gradual bone loss with aging, a steady supply of nutrients plays an important role in helping them stay strong.

Bone health has been an emerging concern in India, with bone diseases being one of the major health issues in older adults. There are various factors impacting bone characteristics, such as hormonal changes, smoking, physical inactivity, low body mass index and inadequate body musculature.¹ But dietary deficits in nutrients such as calcium, protein, and vitamin D, along with an absence of active vitamin D from sun exposure, are amongst the most significant risk factors contributing to bone health degradation. Lifestyle factors like tobacco use, sunlight exposure, age and height influence bone health in both genders.²

Importance of Bone Health in Adults

Bones provide structure; protect organs, anchor muscles and store essential minerals like calcium, phosphorus and protein (primarily as collagen).³ Most people will reach their peak bone mass between the ages of 25-30. Around age 40, bone resorption gradually exceeds bone formation, and there is a likelihood of developing weakened bones later in life.⁴

If the body does not receive adequate nutrients, bone strength and bone density can abruptly decline. This can lead to risk of fractures, postural and balance issues and conditions like osteoporosis (progressive loss of bone mass), especially in women and older adults.

Calcium: Key Element of Bone Structure

Calcium, the most abundant mineral in the human body, is important for building and maintaining strong bones. It accounts for about 30-50% of peak bone mass.⁵ Besides bone health, dietary calcium intake is involved with various physiological functions, including cardiac function, muscle contraction and relaxation, enzymatic signaling and transmission of nerve impulses.⁶

The absorption efficiency of calcium plays an important role in maintaining calcium balance. Calcium absorption can be enhanced by vitamin D intake. However, with age, the calcium absorption tends to decline due to various factors such as a decline in intestinal vitamin D receptors, deficiency of 25-hydroxyvitamin D and decreased active calcium transport. Low calcium intake influences bone metabolism, bone markers and is also associated with a higher risk of fractures. Studies have shown that a higher intake of calcium through dairy foods, which is also rich in protein, leads to a significant reduction in falls and hip fractures in elderly individuals.^{7 8}Hence, include dietary sources of calcium such as low fat milk and milk products (curd and paneer), ragi, soybean, tofu and sesame seeds.

Vitamin D: Regulator of Calcium Absorption

It is a fat soluble vitamin essential for the metabolism of calcium and phosphorus that are needed for normal mineralization of bone, muscle contraction, nerve conduction and general cellular function in all the cells of the body.⁹ Vitamin D promotes calcium absorption from the small intestine and enables mineralization of newly formed osteoid tissue in bone.

Dietary sources of Vitamin D include dairy products, fatty fish (salmon, sardines, mackerel), egg yolk and fortified foods like breakfast cereals. But it can also be synthesized in the skin through adequate sunlight exposure.

The level of 25-hydroxy vitamin D 25(OH) D is considered the best determinant of vitamin D status in an individual. Both calcium and vitamin D deficiency are important risk factors for the development of osteoporosis. Vitamin D deficiency, with 25(OH) D <20ng/ml, manifests as osteomalacia (softening of bones due to poor mineralization) in adults. Less severe Vitamin D deficiency, also known as vitamin D insufficiency, with 25(OH) D ≥20-29 ng/ml may lead to bone loss, muscle weakness, falls and fragility in older people.^ix

Protein: Building block for Bone formation

Protein makes up approximately 50% of bone volume and one-third of its mass. It provides the structural matrix of bone and is required for the growth of muscles and other tissues.¹⁰ Protein intake may influence bone mineral density (BMD) through various pathways. The anabolic effects of protein on bone can be observed via stimulation of insulin-like growth factor 1(IGF-1) production and better intestinal calcium absorption.

Since collagen fragments released during remodeling cannot be reutilized to build new bone matrix, a continuous supply of amino acids and minerals is necessary.¹¹ Protein-rich foods are low-fat dairy, pulses, legumes, eggs, chicken, fish and lean meat. Studies have shown a positive correlation between high protein intake and improved BMD, particularly in the lumbar spine and hips.^12.

Bone Health Trio

In much of  Asia-Pacific, including India, where calcium intake is low, serum 25(OH) D levels are also low.¹³ Alongside, deficiencies of protein and vitamin D are also common.^{14 15} Thus, adequate intake of these nutrients and, moreover, their combined action is considered more significant for adult bone health. According to the Recommended Dietary Allowances (RDA) of Nutrients for Indians, the average daily requirements for these nutrients for adult men and women >18 years of age:¹⁶

The protein requirements may also vary according to activity levels.

Vitamin D aids calcium absorption. Calcium mineralizes the protein matrix of the bone, while high quality protein intake also has been shown to improve calcium absorption. The synergistic relation between this trio has been recognized in European Food Safety Authority (EFSA) scientific opinion as well.

Ensuring dietary intake of  the bone health trio (calcium, vitamin D and protein) as part of a balanced diet and alongside physical activity is crucial in maintaining musculoskeletal health.  Complan Viemax provides this essential triple nutrient combination of high-quality proteins, Vitamin D and calcium which helps to support bone health and overall strength when taken as part of a balanced diet.

Reference

1. Anand, A., Gurjar, H. S., & Sharma, M. (2023). Association of obesity and bone disease among older adults in India: Role of modifiable risk factors. Clinical Epidemiology and Global Health, 23, 101349. https://doi.org/10.1016/j.cegh.2023.101349

2. Bhat, G., Ireland, A., Shah, N., Gondhalekar, K., Kajale, N., & Khadilkar, A. (2025). Bone health and its association with lifestyle factors among urban and rural middle-aged Indian adults. Archives of Osteoporosis, 20(1), 148. https://doi.org/10.1007/s11657-025-01623-3

3. Bone health: Tips to keep your bones healthy. Available at https://www.mayoclinic.org/healthy-lifestyle/adult-health/in-depth/bone-health/art-20045060. Last accessed on 19th January 2026.

4. Healthy bones at every age. Available at https://orthoinfo.aaos.org/en/staying-healthy/healthy-bones-at-every-age/. Last accessed on 19th January 2026.

5. Balk, E. M., Adam, G. P., Langberg, V. N., Earley, A., Clark, P., Ebeling, P. R., Mithal, A., Rizzoli, R., Zerbini, C. a. F., Pierroz, D. D., & Dawson-Hughes, B. (2017). Global dietary calcium intake among adults: a systematic review. Osteoporosis International, 28(12), 3315–3324. https://doi.org/10.1007/s00198-017-4230-x

6. Caffarelli, C., Refaie, A. A., Mondillo, C., Cavati, G., Lora, A., Gennari, L., Nuti, R., & Gonnelli, S. (2025). Influence of dietary calcium intake on skeletal health and body composition in an Italian elderly population. Nutrients, 17(13), 2073. https://doi.org/10.3390/nu17132073

7. Iuliano, S., Poon, S., Robbins, J., Bui, M., Wang, X., De Groot, L., Van Loan, M., Zadeh, A. G., Nguyen, T., & Seeman, E. (2021). Effect of dietary sources of calcium and protein on hip fractures and falls in older adults in residential care: cluster randomized controlled trial. BMJ, 375, n2364. https://doi.org/10.1136/bmj.n2364

8. Yuan, M., Hu, F. B., Li, Y., Cabral, H. J., Das, S. K., Deeney, J. T., Zhou, X., Paik, J. M., & Moore, L. L. (2023). Types of dairy foods and risk of fragility fracture in the prospective Nurses’ Health Study cohort. American Journal of Clinical Nutrition, 118(6), 1172–1181. https://doi.org/10.1016/j.ajcnut.2023.09.015

9. Goel, S. (2020). Vitamin D status in Indian subjects: a retrospective analysis. International Journal of Research in Orthopaedics, 6(3), 603. https://doi.org/10.18203/issn.2455-4510.intjresorthop20201735

10. Tsagari, A. (2020). Dietary protein intake and bone health. Journal of Frailty Sarcopenia and Falls, 05(01), 1–5. https://doi.org/10.22540/jfsf-05-001

11. Wallace, T. C. (2019). Optimizing dietary protein for lifelong bone health. Nutrition Today, 54(3), 107–115. https://doi.org/10.1097/NT.0000000000000340

12. Chen, X., Fu, Y., & Zhu, Z. (2025). Association between dietary protein intake and bone mineral density based on NHANES 2011–2018. Scientific Reports, 15(1), 8638. https://doi.org/10.1038/s41598-025-93642-w

13. Balk, E. M., Adam, G. P., Langberg, V. N., Earley, A., Clark, P., Ebeling, P. R., Mithal, A., Rizzoli, R., Zerbini, C. a. F., Pierroz, D. D., & Dawson-Hughes, B. (2017b). Global dietary calcium intake among adults: a systematic review. Osteoporosis International, 28(12), 3315–3324. https://doi.org/10.1007/s00198-017-4230-x

14. Kumar, S., Pramanik, S., Reardon, T., & Revathi, E. (2025). Links between protein-source diversity, household behavior, and protein consumption inadequacy in the Indian rural semi-arid tropics. Frontiers in Sustainable Food Systems, 9. https://doi.org/10.3389/fsufs.2025.1490050

15. Sundarakumar, J. S., Hameed, S. K. S., Team, S. S., & Ravindranath, V. (2021). Burden of vitamin D, vitamin B12 and folic acid deficiencies in an aging, rural Indian community. Frontiers in Public Health, 9, 707036. https://doi.org/10.3389/fpubh.2021.707036

16. ICMR-NIN Expert Group on Short Summary Report of Nutrient Requirements for Indians, Recommended Dietary Allowances (RDA) and Estimated Average Requirements (EAR). Published: 2020, Updated: 2024.