Scientific Opinion on the substantiation of health claims related to
vitamin B6 and protein and glycogen metabolism (ID 65, 70, 71), function
of the nervous system (ID 66), red blood cell formation (ID 67, 72, 186),
function of the immune system (ID 68), regulation of hormonal activity
(ID 69) and mental performance (ID 185) pursuant to Article 13(1) of
Regulation (EC) No 1924/2006[sup]1[/sup]
EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA)2
European Food Safety Authority (EFSA), Parma, Italy
Słowa kluczowe:
Vitamin B6
glycogen
health claims
hormones
immune system
iron
metabolism
nervous system
protein
red blood cells
1. Charakterystyka żywności / składnika
The food constituent that is the subject of the health claims is vitamin B6, which is a group of compounds comprising three free forms, pyridoxine, pyridoxal, pyridoxamine, and their 5'-phosphates derivatives (PNP, PLP and PMP). Vitamin B6 occurs naturally in foods, mainly as pyridoxal phosphate (animals), pyridoxine beta-glucoside (plants), and some pyridoxyl peptides (processed foods), with varied bioavailability as vitamin B6. Vitamin B6 is a well recognised nutrient and is measurable in foods by established methods.
Vitamin B6 it is authorised for addition to foods (Annex I of the Regulation (EC) No 1925/20064 and Annex I of Directive 2002/46/EC5). This evaluation applies to vitamin B6 naturally present in foods and those forms authorised for addition to foods (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 B6, which is the subject of the health claims, is sufficiently characterised.
2. Znaczenie oświadczenia dla zdrowia człowieka
2.1. Metabolizm białek i glikogenu (ID 65, 70, 71)
The claimed effect is “protein, glucose, glycogen/stored carbohydrate, macronutrient metabolism”. The Panel assumes that the target population is the general population.
The Panel considers that a normal protein and glycogen metabolism is beneficial to human health.
2.2. Funkcjonowanie układu nerwowego (ID 66)
The claimed effect is “nervous system function”. The Panel assumes that the target population is the general population.
The Panel considers that normal function of the nervous system is beneficial to human health.
2.3. Tworzenie erytrocytów (czerwonych krwinek) (ID 67, 72, 186)
The claimed effects are “transport and metabolism of iron”, “blood health”, “vitamin B6 helps the body effective use iron”. The Panel assumes that the target population is the general population.
In the context of the proposed wordings, the Panel notes that the claimed effect relates to the formation of normal red blood cells.
The Panel considers that normal red blood cell formation is beneficial to human health.
2.4. Funkcjonowanie układu odpornościowego (ID 68)
The claimed effect is “immune system function”. The Panel assumes that the target population is the general population.
The Panel considers that normal function of the immune system is beneficial to human health.
2.5. Regulacja aktywności hormonalnej (ID 69)
The claimed effect is “essential co-factor in fatty acid metabolism that impacts upon hormonal health”. The Panel assumes that the target population is the general population.
The Panel notes that the claimed effect has not been sufficiently defined in the evidence provided. The Panel assumes that the claimed effect relates to the regulation of hormonal activity.
The Panel considers that regulation of hormonal activity is beneficial to human health.
2.6. Zdolności umysłowe (ID 185)
The claimed effect is “mental state and performance”. The Panel assumes that the target population is the general population.
The Panel considers that normal mental performance is beneficial to human health.
3. Naukowe uzasadnienia wpływu na zdrowie człowieka
Vitamin B6 functions as a coenzyme in a variety of enzymatic reactions in the metabolism of amino acids, one-carbon units, lipids, the pathways of gluconeogenesis, haem, and neurotransmitter biosynthesis (McCormick, 2006; Mackey, 2006).
3.1. Metabolizm białek i glikogenu (ID 65, 70, 71)
Nearly all amino acids require at least one pyridoxal phosphate (PLP)-dependent enzyme in their metabolism. PLP is a coenzyme for aminotransaminases that catalyse reversible conversions of amino acids to their corresponding alpha-keto acids with the simultaneous transfer of the amino group to yield PMP. Amino acids can also be modified by PLP-dependent decarboxylation, dehydration, and desulfuration reactions. PLP-dependent decarboxylation reactions are particularly important in the biosynthesis of neurotransmitters (Mackey et al., 2006; IoM, 2000).
Vitamin B6, as PLP, plays a dual role in the synthesis of glucose. Glycogen phosphorylase relies on PLP as a coenzyme in the enzymatic cleavage of glycogen that sequentially releases glucose-1- phosphate units. PLP-dependent transaminases convert gluconeogenic amino acids to alpha-keto acids to create substrates for the production of glucose (Mackey et al., 2006).
The Panel concludes that a cause and effect relationship has been established between the dietary intake of vitamin B6 and normal protein and glycogen metabolism. However, the evidence provided does not establish that inadequate intake of vitamin B6 leading to impaired protein and glycogen metabolism occurs in the general EU population.
3.2. Funkcjonowanie układu nerwowego (ID 66)
The references provided included 11 textbooks and two reports. One of the reports was on pantothenic acid and the other was an opinion on upper levels of vitamin B6.
Vitamin B6 is taken up into the brain via a transport carrier that has not been well described. In humans, vitamin B6 deficiency is rare. However, when identified, it has been associated with increased seizure activity, an effect which can be ameliorated by vitamin B6 (Fernstrom and Fernstrom, 2005).
The Panel concludes that a cause and effect relationship has been established between the dietary intake of vitamin B6 and normal function of the nervous system. However, the evidence provided does not establish that inadequate intake of vitamin B6 leading to an impaired function of the nervous system occurs in the general EU population.
3.3. Tworzenie erytrocytów (czerwonych krwinek) (ID 67, 72, 186)
Vitamin B6 plays an important role in haem biosynthesis in the form of PLP. The first enzyme and committed step in haem biosynthesis, aminolevulinate synthase (ALAS), uses PLP as a coenzyme. ALAS catalyses the condensation of succinyl coenzyme A and glycine to form δ-aminolevulinate, which is the precursor for the porphyrin ring. Chronic vitamin B6 deficiency can cause microcytic, hypochromic anaemia in which the haemoglobin concentration of erythrocytes is reduced. Sideroblastic anaemia is an inherited form of ALAS deficiency which can often be successfully treated with pyridoxine supplementation (Mackey et al., 2006; IoM, 2000). Pyridoxal and pyridoxal phosphate also bind to haemoglobin increasing the oxygen-binding capacity, and preventing sickling in sickle-cell haemoglobin (EVM, 2002).
The Panel concludes that a cause and effect relationship has been established between the dietary intake of vitamin B6 and normal red blood cell formation. However, the evidence provided does not establish that inadequate intake of vitamin B6 leading to impaired red blood cell formation occurs in the general EU population.
3.4. Funkcjonowanie układu odpornościowego (ID 68)
The importance of adequate vitamin B6 status for proper immune function in animals, particularly cell-mediated and to a lesser degree humoral immunity, has been shown since the 1950s (Chandra and Sudhakaran, 1990). Vitamin B6 is required as a coenzyme in the metabolism of antibodies and cytokines. Lymphocytes isolated from vitamin B6-deficient persons display reduced proliferation, reduced interleukin-2 production in response to mitogens, and reduced antibody production in response to immunisation (Mackey et al., 2006; Wintergerst et al., 2007).
The Panel concludes that a cause and effect relationship has been established between the dietary intake of vitamin B6 and normal function of the immune system. However, the evidence provided does not establish that inadequate intake of vitamin B6 leading to an impaired function of the immune system occurs in the general EU population.
3.5. Regulacja aktywności hormonalnej (ID 69)
Vitamin B6 in the form of pyridoxal phosphate (PLP) has a role in controlling the action of hormones that act by binding to a nuclear receptor protein and modulating gene expression. Such hormones include androgens, oestrogens, progesterone, glucocorticoids, and thyroid hormone. PLP reacts with a lysine residue in the receptor protein and displaces the hormone-receptor complex from DNA binding, so terminating the hormone action (Bender, 2005).
The Panel concludes that a cause and effect relationship has been established between the dietary intake of vitamin B6 and regulation of hormonal activity. However, the evidence provided does not establish that inadequate intake of vitamin B6 leading to impaired regulation of hormonal activity occurs in the general EU population.
3.6. Zdolności umysłowe (ID 185)
A total of eight references were provided in the consolidated list to support this claim. These included three reviews, one textbook and four human studies where the effect of vitamin B6 on symptoms of depression, cognition, ageing, premenstrual syndrome and memory performance was assessed. The daily doses of vitamin B6 supplementation ranged from 40 - 600 mg.
The Panel notes that the evidence provided for substantiation of the claim relates to studies with vitamin B6 at intakes above the Tolerable Upper Intake Level (UL) (25 mg; SCF, 2000) and that the proposed conditions of use refer to intakes up to three times the UL. The Panel considers that this claim (the proposed wording of this claim) encourages excess consumption of vitamin B6 and therefore does not comply with the criteria laid down in Regulation (EC) No 1924/2006 (Article 3c).
4. Uwagi do zaproponowanego brzmienia oświadczenia
4.1. Metabolizm białek i glikogenu (ID 65, 70, 71)
The Panel considers that the following wording reflects the scientific evidence: “Vitamin B6 contributes to normal protein and glycogen metabolism”.
4.2. Funkcjonowanie układu nerwowego (ID 66)
The Panel considers that the following wording reflects the scientific evidence: “Vitamin B6 contributes to the normal function of the nervous system”.
4.3. Tworzenie erytrocytów (czerwonych krwinek) (ID 67, 72, 186)
The Panel considers that the following wording reflects the scientific evidence: “Vitamin B6 contributes to normal red blood cell formation”.
4.4. Funkcjonowanie układu odpornościowego (ID 68)
The Panel considers that the following wording reflects the scientific evidence: “Vitamin B6 contributes to normal function of the immune system”.
4.5. Regulacja aktywności hormonalnej (ID 69)
The Panel considers that the following wording reflects the scientific evidence: “Vitamin B6 contributes to the regulation of hormonal activity”.
5. Warunki i możliwe ograniczenia stosowania oświadczenia
The Panel considers that in order to bear the claims a food should be at least a source of vitamin B6 as per Annex to Regulation (EC) No 1924/2006. Such amounts can be easily consumed as part of a balanced diet. The target population is the general population. Tolerable Upper Intake Levels (UL) have been established for vitamin B6 in children, adolescents and adults (SCF, 2000).
Wnioski
On the basis of the data presented, the Panel concludes that:
The food constituent, vitamin B6, which is the subject of the health claims is sufficiently characterised.
Protein and glycogen metabolism (ID 65, 70, 71)
The claimed effect is “protein, glucose, glycogen/stored carbohydrate, macronutrient metabolism”. The target population is assumed to be the general population. Normal protein and glycogen metabolism is beneficial to human health.
A cause and effect relationship has been established between the dietary intake of vitamin B6 and normal protein and glycogen metabolism.
The evidence provided does not establish that inadequate intake of vitamin B6 leading to impaired protein and glycogen metabolism occurs in the general EU population.
The following wording reflects the scientific evidence: “Vitamin B6 contributes to normal protein and glycogen metabolism”.
Function of the nervous system (ID 66)
The claimed effect is “nervous system function”. The target population is assumed to be the general population, especially women. Normal function of the nervous system is beneficial to human health.
A cause and effect relationship has been established between the dietary intake of vitamin B6 and normal function of the nervous system.
The evidence provided does not establish that inadequate intake of vitamin B6 leading to an impaired function of the nervous system occurs in the general EU population.
The following wording reflects the scientific evidence: “Vitamin B6 contributes to the normal function of the nervous system”.
Red blood cell formation (ID 67, 72, 186)
The claimed effects are “transport and metabolism of iron”, “blood health”, “vitamin B6 helps the body effective use iron”. The target population is assumed to be the general population. Normal red blood cell formation is beneficial to human health.
A cause and effect relationship has been established between the dietary intake of vitamin B6 and normal red blood cell formation.
The evidence provided does not establish that inadequate intake of vitamin B6 leading to impaired red blood cell formation occurs in the general EU population.
The following wording reflects the scientific evidence: “Vitamin B6 contributes to normal red blood cell formation”.
Function of the immune system (ID 68)
The claimed effect is “immune system function”. The target population is assumed to be the general population. Normal function of the immune system is beneficial to human health.
A cause and effect relationship has been established between the dietary intake of vitamin B6 and normal function of the immune system.
The evidence provided does not establish that inadequate intake of vitamin B6 leading to an impaired function of the immune system occurs in the general EU population.
The following wording reflects the scientific evidence: “Vitamin B6 contributes to normal function of the immune system”.
Regulation of hormonal activity (ID 69)
The claimed effect is “essential co-factor in fatty acid metabolism that impacts upon hormonal health”. The target population is assumed to be the general population. Regulation of hormonal activity is beneficial to human health.
A cause and effect relationship has been established between the dietary intake of vitamin B6 and regulation of hormonal activity.
The evidence provided does not establish that inadequate intake of vitamin B6 leading to impaired regulation of hormonal activity occurs in the general EU population.
The following wording reflects the scientific evidence: “Vitamin B6 contributes to the regulation of hormonal activity”.
Mental performance (ID 185)
The claimed effect is “mental state and performance”. The target population is assumed to be the general population. Normal mental performance is beneficial to human health.
The claim should not be evaluated in the context of health claims made on foods.
Conditions and possible restrictions of use
In order to bear the claim a food should be at least a source of vitamin B6 as per Annex to Regulation (EC) No 1924/2006. Such amounts can be easily consumed as part of a balanced diet. The target population is the general population.
