Challenges in Achieving Adequate Vitamin D Status in the Adult Population/ Part 2
Challenges in Achieving Adequate Vitamin D Status in the Adult Population/ Part 2
The efficiency of different vitamin D formulations in treating suboptimal vitamin D status in
 adult population will be determined. It will provide insights into the influence of
 formulation on vitamin D absorption.

 A randomised controlled intervention trial will be conducted on at least 72 subjects (18-65
 years) with suboptimal Vitamin D status. Subjects will be selected from a pool of subjects in
 Part 1 of the study, after completion of winter sampling.

 Study subjects will be randomised into four study groups (at least 18 subjects per study
 group). Three different treatments will be compared with a control group, which will not
 receive any supplemental Vitamin D. The three tested Vitamin D preparations in the treatment
 groups will be (A) oil-based VALENS vitamin D; (B) water-based VALENS vitamin D; and (C)
 Vitamin D capsules with starch-adsorbed vitamin D (powder). All these products are
 commercially available. Prior to study, actual level of vitamin D will be determined using
 appropriate analytical method. The treatment will be with 1000 IU Vitamin D per day, for two
 months, in all three groups. Second serum vitamin D level will be determined on last day of
 the treatment, and compared with pre-treatment vitamin D level.
Inclusion Criteria:

 -  vitamin D suboptimal status

 -  Signed Informed consent form (ICF),

 -  Caucasian race

 -  Age between 18 and 65 years at the time of the signature of Informed consent form
 (ICF),

 -  Willingness to avoid a consumption of any food supplements containing Vitamin D during
 the study, except the ones prescribed by the study researchers, and to avoid use of
 solarium or other artificial UVB sources

 -  Willingness to follow all study procedures

 Exclusion Criteria:

 -  Pregnancy or breastfeeding,

 -  Known or suspected allergy to any ingredient of the tested products in Part 2,

 -  Pronounced avoidance of sunshine (eg reporting of allergy to the sun)

 -  Use of food supplements containing Vitamin D or fish oil or omega 3 fatty acids in
 last three months prior to inclusion,

 -  Special dietary habits used by a small part of the population (veganism, low-carb
 high-fat (LCHF) diet, caloric restriction diet, note: vegetarians are not excluded)

 -  Diets prescribed by the medical profession

 -  Disorders of the kidneys, thyroid, digestive tract, osteoporosis and other bone
 diseases, skin diseases

 -  Other diseases and conditions that affect the absorption and synthesis of vitamin D

 -  Exposure to stronger sunlight in the last three months prior to engaging in a survey
 (travel to countries with stronger sunshine, use of solarium),

 -  The consumption of margarine or plant substitutes for milk / milk products several
 times a day, as these foods are most often enriched with vitamin D,

 -  Visiting the solarium in the last three months before joining the survey,

 -  Mental incapacity that precludes adequate understanding or cooperation.