Non-inferiority RCT on Fish Waste-Derived vs. Synthetic Vitamin D Supplementation in Healthy Adults With Suboptimal Vitamin D Levels

Summary

Vitamin D is a fat-soluble vitamin with hormone-like properties, essential for numerous physiological processes in humans. It plays a central role in maintaining calcium and phosphorus homeostasis, promoting intestinal absorption of these minerals, and ensuring optimal bone mineralization. There are two main forms: vitamin D2 (ergocalciferol), primarily obtained from plant sources and supplements, and vitamin D3 (cholecalciferol), synthesized endogenously in the skin through exposure to ultraviolet B (UVB) radiation and present in animal-derived foods such as fatty fish, liver, and egg yolks. Beyond its well-known skeletal functions, vitamin D contributes to muscle contraction, immune system modulation, and regulation of cell proliferation and differentiation. Increasing evidence suggests that adequate vitamin D status may benefit cardiovascular health, glucose metabolism, and possibly reduce the risk of certain cancers, while supplementation has been associated with improved plasma lipid profiles, a relevant factor in cardiovascular risk reduction. The European Food Safety Authority has authorized various health claims for vitamin D, including its role in normal calcium and phosphorus absorption and utilization, maintenance of normal blood calcium concentrations, bone and teeth health, normal muscle function, immune defense, and reduction of the risk of falls in older adults. Despite its importance, vitamin D deficiency is recognized as a widespread public health concern across Europe, with prevalence influenced by latitude, season, skin pigmentation, and lifestyle habits. Data indicate that up to 40% of Europeans have suboptimal vitamin D levels, with deficiency rates exceeding 70% in specific high-risk groups such as elderly individuals, people with dark skin, and those with limited sun exposure. In Italy, despite abundant sunlight, vitamin D insufficiency is highly prevalent, particularly in older adults and patients with chronic illnesses. Contributing factors include urbanization, sedentary lifestyles, reduced time spent outdoors, and cultural or clothing practices limiting sun exposure. Approximately half of the Italian population is estimated to have insufficient vitamin D levels, with rates rising in the northern regions during winter months. Prolonged deficiency has severe consequences for skeletal health, including rickets in children, osteomalacia in adults, and increased risk of osteoporosis and fractures. It is also linked to a broad range of extra-skeletal effects, such as impaired immune response with greater susceptibility to infections, increased risk of chronic diseases including cardiovascular disorders, type 2 diabetes, and certain cancers, as well as muscle weakness, higher likelihood of falls, and mood disorders such as depression and seasonal affective disorder. Addressing vitamin D deficiency requires a multifaceted approach involving dietary supplementation, food fortification strategies, and public health initiatives promoting safe sunlight exposure. Severe deficiency requires pharmacological treatment with appropriately dosed medications, whereas mild deficiency can be corrected through over-the-counter supplements. In Italy, vitamin D supplements contain up to 2000 IU per day, with the recommended daily allowance for healthy adults set at 600 IU. The demand for vitamin D supplementation is reflected in market trends: the global market was valued at USD 1.69 billion in 2022 and is projected to reach USD 3.44 billion by 2031, with an estimated compound annual growth rate of 8.22% between 2023 and 2031. Against this background, the exploration of natural, sustainable sources of vitamin D, particularly from food industry by-products such as fish waste, offers an environmentally friendly alternative to synthetic forms currently dominating the market. This concept underpins the PRIN research project "Innovative and sustainable processes for the development of Vitamin D nutraceutical from fish waste: extraction, formulation and clinical study for the evaluation of its bioavailability and clinical consequence" (VITADWASTE; 2022M9JL3%; National Coordinator: Prof. Gianni Sagratini, University of Camerino), supported by the Italian Ministry of University. The project aims to develop and clinically evaluate a fish-derived vitamin D nutraceutical as a sustainable solution. Within this context, the primary objective of the present randomized, double-blind, non-inferiority clinical trial is to assess whether supplementation with fish-derived vitamin D at a dose of 600 IU per day, corresponding to 100% of the recommended daily intake for healthy adults, has an effect on plasma vitamin D levels comparable to that of an equivalent dose of standard synthetic vitamin D in healthy adults with mild vitamin D deficiency, defined by plasma concentrations between 20 and 40 ng/mL.

Conditions

• Vitamin D
• Dietary Supplement

Interventions

OTHER

Dietary Supplement - Fish-derived Vitamin D

Cholecalciferol (vitamin D3). Other components: polyunsaturated fatty acids (PUFA), arabic gum, maltodextrin, pea protein hydrolisate, hard gelatine capsules. The fish derived vitamin D extract was obtained from sardines (Sardina pilchardus) waste ( whole fish) recovered by CNR-IRBIM (Centro Nazionale delle Ricerche-Istituto per le Risorse Biologiche e le Biotecnologie Marine) and sourced from a professional fishing fleet operating in the Adriatic Sea (Central Mediterranean). Fishes have been homogenized, freeze dried and extracted by using a Supercritical Fluid Extractor (SFE-CO2) in the laboratories of ENEA (Agenzia nazionale per le nuove tecnologie, l'energia e lo sviluppo economico sostenibile), then analyzed for the content of vitamin D3 and other bioactives by HPLC-DAD technique in the laboratories of University of Camerino and finally microencapsulated in the laboratories of University of Piemonte Orientale for the preparation of final supplement.

OTHER

Dietary Supplement - Synthetic Vitamin D

Cholecalciferol (vitamin D3). Other components: medium-chain triglycerides, alfpha-tocopherol acetate, hard gelatin capsules.

Sponsors & Collaborators

• University of Bologna

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

QUADRUPLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

60 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2026-09-01

Primary Completion

2027-09-10

Completion

2027-09-10