ID 156 - Witamina D

PL: Witamina D
EN: Vitamin D
Pdf: vitamin D

Oświadczenie (2)

1. Charakterystyka żywności / składnika

The food constituent that is the subject of the health claim is vitamin D which is a well recognised nutrient and is measurable in foods by established methods. Vitamin D occurs naturally in foods as vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Different forms of vitamin D are authorised for addition to foods and for use in food supplements (Annex II of the Regulation (EC) No 1925/20064 and Annex II of Directive 2002/46/EC5). This evaluation applies to vitamin D naturally present in foods and those forms authorised for addition to foods and for use in food supplements (Annex II of the Regulation (EC) No 1925/2006 and Annex II of Directive 2002/46/EC).
The Panel considers that the food constituent, vitamin D, which is the subject of the health claim, is sufficiently characterised.

2.4. Funkcjonowanie tarczycy (ID 156)

The claimed effect is that vitamin D is “endcocrine / thyroid metabolism”. The Panel assumes that the target population is the general population.
The Panel considers that normal thyroid function is beneficial to human health.

3. Naukowe uzasadnienia wpływu na zdrowie człowieka

Vitamin D can be obtained from dietary sources or can be synthesised in the body by exposure to UV-radiation from the sun. Even though it is more suitable to refer to vitamin D as a hormone, vitamin D resembles true vitamins, since humans deprived of solar exposure depend on a food source. Synthesis of vitamin D in the skin by the action of sunlight is insufficient to meet requirements in European countries, especially during winter months when there is little sunlight exposure.
Vitamin D is biologically inactive and requires successive hydroxylations; first in the liver, where 25- hydroxyvitamin D (25-OHD) is formed, and the next hydroxylation in the kidneys form 1,25- dihydroxyvitamin D (1,25-(OH)2D), which is the biologically active form of vitamin D. 1,25-(OH)2D interacts with a specific nuclear receptor in its target tissues that results in a biological response. The major target tissues for 1,25-(OH)2D are the intestine and bone; however, nuclear receptors for 1,25- (OH)2D have been identified in several other tissues and in cultured tumour cells. Serum concentration of 25-OHD is accepted as a valid marker of vitamin D status.
The principal physiological function of vitamin D in all vertebrates including humans is to maintain serum calcium and phosphorus concentrations in a range that supports cellular processes, neuromuscular function, and bone ossification. Vitamin D accomplishes this goal by enhancing the efficiency of the small intestine to absorb dietary calcium and phosphorous, and by mobilising calcium and phosphorus from the bone.
Vitamin D also has other functions in tissues not primarily related to mineral metabolism. One example is the haematopoietic system, in which vitamin D affects cell differentiation and proliferation including such effects also in cancer cells. Vitamin D furthermore participates in the process of insulin secretion. The active metabolite of vitamin D, 1,25(OH)2D, regulate the transcription of a large number of genes through binding to a transcription factor, the vitamin D receptor (VDR) (SCF, 2002).

3.4. Funkcjonowanie tarczycy (ID 156)

Three references were cited to substantiate the claimed effect. These references referred to intervention studies in patients with end-stage renal disease and patients who underwent total thyroidectomy and were not related to the claimed effect. The Panel notes that the references cited did not provide any scientific data that could be used to substantiate the claimed effect.
The Panel concludes that a cause and effect relationship has not been established between the dietary intake of vitamin D and normal thyroid function.

5. Warunki i możliwe ograniczenia stosowania oświadczenia

The Panel considers that in order to bear the claim a food should be at least a source of vitamin D as per Annex to Regulation (EC) 1924/2006. Such amounts can be easily consumed as part of a balanced diet. The target population is the general population.

Warunki i możliwe ograniczenia stosowania oświadczenia

Typical adults dosages 5 – 50 mcg daily for vitamin D2, (ergocalciferol, and up to 100 mcg daily for vitamin D3 (cholecalciferol). Must meet minimum requirements for use of the claim "source of [name of vitamin/s] and/or [name of mineral/s]" as per Annex