Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Role of Skin in Vitamin D Synthesis01:23

Role of Skin in Vitamin D Synthesis

The skin plays a crucial role in the synthesis of vitamin D, a vital nutrient for various physiological processes in the body. Vitamin D is unique because it can be synthesized in the skin through a series of chemical reactions triggered by exposure to ultraviolet B (UVB) radiation from sunlight.
The solar UV B rays (290-315 nm) are absorbed by the skin, and 7-dehydrocholesterol (provitamin D3) photolyzes it to previtamin D3, which undergoes a rapid transformation to vitamin D3(cholecalciferol).
Role of Vitamins in Maintaining Bone Health01:25

Role of Vitamins in Maintaining Bone Health

The growth and maintenance of bone are regulated by a combination of nutritional factors, including vitamins, such as vitamin A, B12, C, D, and K.
Vitamin A
Vitamin A is involved in the process of bone remodeling. Retinoic acid, the active metabolite of Vitamin A, has nuclear receptors in osteoblasts and osteoclasts, which are involved in bone remodeling.
Vitamin B12
Vitamin B12 acts as a cofactor during the formation of osteoblast-related proteins, such as osteocalcin. Vitamin B12 plays a role...
Connective Tissue Cell Types01:22

Connective Tissue Cell Types

Connective tissue develops from the mesoderm of a developing embryo and consists of cells, fibers, and ground substance: a gel-like material containing large complexes of carbohydrates and proteins. Connective tissue was first identified as a separate tissue family in the 18th century, and Johannes Peter Muller coined the term connective tissue.
Fat cells (adipocytes), smooth muscle cells (myoblasts), and bone cells (osteoblasts) are some connective tissue cell types. Some immune system cells...
Vitamins01:30

Vitamins

Vitamins, derived from the Latin word for life, are essential organic substances required in small quantities for optimal growth and overall well-being. Unlike other organic nutrients, vitamins don't act as sources of energy or building materials but rather facilitate these nutrients' utilization by the body. Vitamins are predominantly coenzymes, assisting enzymes in specific chemical actions, like the oxidation of glucose for energy involving B vitamins. Most vitamins are not produced in our...
Skeleton and Calcium Homeostasis01:21

Skeleton and Calcium Homeostasis

Calcium is not only the most abundant mineral in bone but also the most abundant mineral in the human body. Calcium ions are needed for bone mineralization, tooth health, heart rate regulation and strength of contraction, blood coagulation, the contraction of smooth and skeletal muscle cells, and the regulation of nerve impulse conduction. The average calcium level in the blood is about 10 mg/dL. When the body cannot maintain this level, a person will experience hypo or hypercalcemia.
Essential Minerals for Bone Health01:31

Essential Minerals for Bone Health

The minerals contained in all of the food we consume are essential for our organ systems. However, certain essential minerals, such as calcium, phosphorus, magnesium, manganese, and fluoride, largely affect bone health.
Calcium and Phosphorus
Calcium is a critical component of bones, especially in the form of calcium phosphate and calcium carbonate. Since the body cannot make calcium, it must be obtained from the diet. However, calcium cannot be absorbed from the small intestine without...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Health-related quality of life instruments for older persons with osteoporosis: a WHO-BOHEG systematic review of measurement properties for use in clinical trials and routine practice.

Age and ageing·2026
Same author

Orthogeriatric Fracture Syndrome: A Large-Scale Bibliometric Analysis of a Proposed Concept for Cross-Disciplinary Awareness and Coordinated Care.

Journal of clinical medicine·2026
Same author

Vitamin D Receptor Polymorphisms and the Effect of Vitamin D Supplementation on Diabetes Risk Among Adults With Prediabetes.

JAMA network open·2026
Same author

Correction: Predictive value of BMD for hip and other fractures: a meta-analysis to update FRAX.

Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA·2026
Same author

Trajectories of physical function and biological aging in generally healthy older adults with and without incident invasive cancer over a three-year follow-up: findings from the DO-HEALTH study.

npj aging·2026
Same author

Correction: A meta-analysis of previous falls and subsequent fracture risk in cohort studies.

Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA·2026

Related Experiment Videos

Where do we stand on vitamin D?

Heike Annette Bischoff-Ferrari1, Bess Dawson-Hughes

  • 1Department of Rheumatology and Institute for Physical Medicine, University Hospital Zurich, Gloriastrasse 25, 8091 Zurich, Switzerland. hbischof@hsph.Harvard.edu

Bone
|May 1, 2007
PubMed
Summary

Adequate vitamin D3 supplementation (700-800 IU daily) significantly reduces fracture risk in older adults. Recent trials questioning vitamin D benefits may be confounded by low adherence, insufficient doses, or the use of vitamin D2.

Related Experiment Videos

Area of Science:

  • Gerontology
  • Nutritional Science
  • Bone Health

Background:

  • A 2005 meta-analysis indicated oral cholecalciferol (D3) at 700-800 IU daily or 100,000 IU intermittently reduced hip and non-vertebral fractures.
  • Higher achieved 25-hydroxyvitamin D (25(OH)D) levels (≥74 nmol/l) correlated with fracture efficacy, and higher doses suggested fall risk reduction.
  • Recent trials have yielded conflicting results regarding vitamin D's efficacy in fracture and fall prevention.

Purpose of the Study:

  • To re-evaluate the efficacy of vitamin D supplementation for fracture and fall prevention in older adults.
  • To identify factors that may explain discrepancies in recent trial outcomes.
  • To provide evidence-based recommendations for optimal vitamin D dosing and adherence.

Main Methods:

  • Review and meta-analysis of primary prevention high-quality trials on vitamin D supplementation.
  • Analysis of factors including vitamin D dosage (D3 vs. D2), adherence rates, and patient risk profiles.
  • Comparison of achieved 25-hydroxyvitamin D (25(OH)D) levels with observed fracture efficacy.

Main Results:

  • Doses of 400 IU vitamin D were insufficient for fracture efficacy.
  • Low adherence (<60%) in recent trials likely negated the benefits of 800 IU D3 plus calcium.
  • Vitamin D2 (ergocalciferol) showed no fracture reduction efficacy in institutionalized or community-dwelling older individuals.

Conclusions:

  • Achieving a 25(OH)D level of at least 75 nmol/l is crucial for fracture efficacy.
  • Sufficient adherence to vitamin D3 supplementation is essential for achieving desired bone health outcomes.
  • Vitamin D3, at adequate doses (700-800 IU daily), remains a viable strategy for primary fracture prevention.