Updated perspectives on vitamin D deficiency, screening, supplementation and clinical guidance

Published on Monday, 14 September 2026

Abstract

Vitamin D functions like a hormone and plays a crucial role in regulating calcium levels and maintaining normal bone metabolism.

A deficiency of vitamin D can lead to an increased risk of fractures, osteoporosis and osteomalacia that’s why research has linked vitamin D deficiency to various chronic diseases and certain types of cancer, thereby enhancing interest in its overall health implications. vitamin D deficiency is still prevalent among many populations.

It is often found in older adults, individuals with chronic health conditions, those residing in care facilities and women who are either pregnant or nursing. There exists significant variability in clinical practices. Experts have differing opinions on who should undergo screening, what serum levels indicate sufficiency and the appropriate timing for initiating supplementation.

This narrative review explores the key reservations that influence the diagnosis and management of vitamin D deficiency and current perspectives on screening, identifies high-risk populations that may benefit from testing and delineates circumstances in which empirical supplementation is a sensible and effective approach. Monitoring is beneficial and discusses how target levels correlate with bone health outcomes.

A specific focus is directed towards the frequently cited 25(OH)D threshold of 30 ng/mL which is broadly linked to optimal bone health and underscores the synergistic significance of vitamin D and calcium in the management of osteoporosis and elucidates the reasons that why cholecalciferol is the favored formulation of vitamin D due to its advantageous pharmacological characteristics.

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About this publication.

- The Di Bella Method (A Fixed Part - Dihydrotachysterol, Alfacalcidol, synthetic Vitamin D3 - Preferably the blood concentration value should be around the middle between 75ng/ml and 100ng/ml);

- Vitamin D (analogues and/or derivatives) and cancer - In vitro, review and in vivo publications;

- The Di Bella Method (A Fixed Part - Vitamin C/Ascorbic Acid, 2–4 grams, twice a day orally);

- The Di Bella Method (A Fixed Part - Calcium, 2 grams per day, orally);

- The Di Bella Method (A Variable Part - Omega 3 Essential/Unsaturated Fatty Acids. From 1.5 grams up to 3.0 grams per day orally);

- The Di Bella Method (A Fixed Part - Somatostatin, Octreotide, Sandostatin LAR, analogues and/or derivatives since 1977);

- Somatostatin in oncology, the overlooked evidences - In vitro, review and in vivo publications;

- Publication, 2018 Jul: Over-Expression of GH/GHR in Breast Cancer and Oncosuppressor Role of Somatostatin as a Physiological Inhibitor (from Di Bella's Foundation);

- Publication, 2018 Sep: The over-expression of GH/GHR in tumour tissues with respect to healthy ones confirms its oncogenic role and the consequent oncosuppressor role of its physiological inhibitor, somatostatin: a review of the literature (from Di Bella's Foundation);

- Publication, 2019 Aug: The Entrapment of Somatostatin in a Lipid Formulation: Retarded Release and Free Radical Reactivity (from Di Bella's Foundation);

- Publication, 2019 Sep: Effects of Somatostatin and Vitamin C on the Fatty Acid Profile of Breast Cancer Cell Membranes (from Di Bella's Foundation);

- Publication, 2019 Sep: Effects of somatostatin, curcumin, and quercetin on the fatty acid profile of breast cancer cell membranes (from Di Bella's Foundation);

- Publication, 2020 Sep: Two neuroendocrine G protein-coupled receptor molecules, somatostatin and melatonin: Physiology of signal transduction and therapeutic perspectives (from Di Bella's Foundation);

- The Di Bella Method (A Fixed Part - Bromocriptine and/or Cabergoline);

- Prolactin inhibitors in oncology - In vitro, review and in vivo publications;

- The Di Bella Method (A Fixed Part - Cyclophosphamide 50mg tablets and/or Hydroxyurea 500mg tablets, one or two per day);

The Di Bella's Method: Use of Vitamin D analogues and/or derivatives - together with others chemical compounds: the dosage and administration schedule must be individualised for each patient - in several Oncological Pathologies:

- A retrospective observational clinical study of triple negative breast cancer cases treated with Di Bella Method: A preliminary data;

- The Synergism of Somatostatin, Melatonin, Vitamins Prolactin and Estrogen Inhibitors Increased Survival, Objective Response and Performance Status In 297 Cases of Breast Cancer;

- Complete objective response, stable for 5 years, with the Di Bella Method, of multiple-metastatic carcinoma of the breast;

- Evaluation of the safety and efficacy of the first-line treatment with somatostatin combined with melatonin, retinoids, vitamin D3, and low doses of cyclophosphamide in 20 cases of breast cancer: a preliminary report;

- The Di Bella Method (DBM) improved survival, objective response and performance status in a retrospective observational clinical study on 122 cases of breast cancer;

- Complete objective response to biological therapy of plurifocal breast carcinoma;

- A retrospective observational study on cases of anaplastic brain tumors treated with the Di Bella Method: A rationale and effectiveness;

- Recurrent Glioblastoma Multiforme (grade IV – WHO 2007): a case of complete objective response achieved by means of the concomitant administration of Somatostatin and Octreotide – Retinoids – Vitamin E – Vitamin D3 – Vitamin C – Melatonin – D2 R agonists (Di Bella Method – DBM) associated with Temozolomide;

- The Di Bella Method DBM improved survival objective response and performance status in a retrospective observational clinical study on 23 tumours of the head and neck;

- Chronic Lymphocytic Leukemia: Long-Lasting Remission with Combination of Cyclophosphamide, Somatostatin, Bromocriptine, Retinoids, Melatonin, and ACTH;

- Somatostatin, retinoids, melatonin, vitamin D, bromocriptine, and cyclophosphamide in advanced non-small-cell lung cancer patients with low performance status;

- Somatostatin, retinoids, melatonin, vitamin D, bromocriptine, and cyclophosphamide in chemotherapy-pretreated patients with advanced lung adenocarcinoma and low performance status;