Scientific Opinion on the substantiation of health claims related to
L-cysteine and L-methionine alone or in combination and maintenance of
normal hair (ID 597, 4224, 4297, 4685, 4686), maintenance of normal nails
(ID 597, 4224, 4685), maintenance of normal skin (ID 665, 666, 1916),
contribution to normal collagen formation (ID 4685) and contribution to
normal glutathione formation (ID 1745) pursuant to Article 13(1) of
Regulation (EC) No 1924/2006[sup]1[/sup]
EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA)2, 3
European Food Safety Authority (EFSA), Parma, Italy
Słowa kluczowe:
Cysteine
collagen
glutathione
hair
health claims
methionine
nails
skin
1. Charakterystyka żywności / składnika
The food constituents that are the subject of the health claims are L-cysteine and L-methionine. L-methionine is an indispensable amino acid. L-cysteine can be synthesised from L-methionine and L-serine.
L-methionine and L-cysteine can be measured in foods by established methods.
The Panel assumes that the food constituents under evaluation are L-cysteine and L-methionine consumed in addition to adequate protein intakes.
The Panel considers that the food constituents, L-cysteine and L-methionine alone or in combination, which are the subject of the health claims, are sufficiently characterised.
2. Znaczenie oświadczenia dla zdrowia człowieka
2.1. Utrzymanie prawidłowego stanu włosów (ID 597, 4224, 4297, 4685, 4686)
The claimed effects are “hair and nails health”, “hair and nail resistance and growth”, “hair growth”, “healthy hair and nails by stabilising protein structure and aids in the formation of collagen”, and “hair health as supplier of sulphur”. The Panel assumes that the target population is the general population.
The Panel considers that maintenance of normal hair is a beneficial physiological effect.
2.2. Utrzymanie prawidłowego stanu paznokci (ID 597, 4224, 4685)
The claimed effects are “hair and nails health”, “hair and nail resistance and growth”, and “healthy hair and nails by stabilising protein structure and aids in the formation of collagen”. The Panel assumes that the target population is the general population.
The Panel considers that maintenance of normal nails is a beneficial physiological effect.
2.3. Utrzymanie prawidłowego stanu skóry (ID 665, 666, 1916)
The claimed effect is “epidermic tissue”. The Panel assumes that the target population is the general population.
The Panel considers that maintenance of normal skin is a beneficial physiological effect.
2.4. Udział w prawidłowym tworzeniu kolagenu (ID 4685)
The claimed effect is “healthy hair and nails by stabilising protein structure and aids in the formation of collagen”. The Panel assumes that the target population is the general population.
The Panel considers that contribution to normal collagen formation is a beneficial physiological effect.
2.5. Udział w prawidłowym tworzeniu glutationu (ID 1745)
The claimed effect is “glutathione metabolism”. The Panel assumes that the target population is the general population.
The Panel considers that contribution to normal glutathione formation is a beneficial physiological effect.
3. Naukowe uzasadnienia wpływu na zdrowie człowieka
3.1. Utrzymanie prawidłowego stanu włosów (ID 597, 4224, 4297, 4685, 4686)
The references cited for the substantiation of the claimed effect included several reviews which did not contain any original data that could be used to substantiate the claimed effect. The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claimed effect. Four human intervention studies investigated the effect of L-cystine supplementation in combination with other food constituents on hair loss. The Panel considers that no conclusions can be drawn from studies on fixed combinations for the substantiation of the claim on L-cysteine or L- methionine alone.
Some references dealt with a case report of an 8-year old L-methionine-deficient child with a hair disorder, the structural composition of human hair or outcomes unrelated to the claimed effect. The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claimed effect.
Several animal studies dealt with the effects of L-cysteine or L-methionine intake alone or in combination with other constituents or of insufficient intake of L-cysteine or L-methionine on hair growth, hair structure or hair loss. One in vitro study looked at the reduction mechanism of L-cysteine on keratin fibres. The Panel considers that the evidence provided in animal and in vitro studies is not sufficient to predict the occurrence of an effect of the consumption of L-cysteine and L-methionine alone or in combination on the maintenance of normal hair in humans.
The Panel concludes that a cause and effect relationship has not been established between the consumption of L-cysteine and L-methionine alone or in combination and maintenance of normal hair.
3.2. Utrzymanie prawidłowego stanu paznokci (ID 597, 4224, 4685)
Among the references cited for the substantiation of the claimed effect two dealt with the structural composition of the human nail. The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claimed effect.
One animal study looked at nail growth in rats fed diets differing in available L-cysteine and L-methionine. The Panel considers that while effects shown in animal studies may be used as supportive evidence, human studies are required for the substantiation of a claim, and that the evidence provided in animal studies alone is not sufficient to predict the occurrence of an effect of the consumption of L-cysteine and L-methionine alone or in combination on the maintenance of normal nails in humans.
The remaining references addressed outcomes unrelated to the claimed effect. The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claimed effect.
The Panel concludes that a cause and effect relationship has not been established between the consumption of L-cysteine and L-methionine alone or in combination and maintenance of normal nails.
3.3. Utrzymanie prawidłowego stanu skóry (ID 665, 666, 1916)
All but one references cited for the substantiation of the claimed effect were unrelated to the claimed effect. The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claimed effect. One reference was an in vitro study investigating the effect of cell-growth stimulating agents, including L-cysteine, on human epidermal keratinocytes. The Panel considers that while effects shown in in vitro studies may be used as supportive evidence, human studies are required for the substantiation of a claim, and that the evidence provided in in vitro studies alone is not sufficient to predict the occurrence of an effect of the consumption of L-cysteine and L- methionine alone or in combination on the maintenance of normal skin in humans.
The Panel concludes that a cause and effect relationship has not been established between the consumption of L-cysteine and L-methionine alone or in combination and maintenance of normal skin.
3.4. Udział w prawidłowym tworzeniu kolagenu (ID 4685)
Six references were provided for the substantiation of the claimed effect. Two animal studies, one human study and one in vitro study were unrelated to the claimed effect. One reference was a website in which the claimed effect was not mentioned. One was an animal study examining the effect of an intramuscular administration of cysteine on collagen fibres. The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claimed effect.
The Panel concludes that a cause and effect relationship has not been established between the consumption of L-cysteine and L-methionine alone or in combination and contribution to normal collagen formation.
3.5. Udział w prawidłowym tworzeniu glutationu (ID 1745)
The only reference provided for the scientific substantiation of the claimed effect was a reference to a natural medicines database in which the claimed effect was not mentioned. The Panel considers that no conclusions can be drawn from this reference for the scientific substantiation of the claimed effect.
The Panel concludes that a cause and effect relationship has not been established between the consumption of L-cysteine and L-methionine alone or in combination and contribution to normal glutathione formation.
Wnioski
On the basis of the data presented, the Panel concludes that:
The food constituents, L-cysteine and L-methionine alone or in combination, which are the subject of the health claims, are sufficiently characterised.
Maintenance of normal hair (ID 597, 4224, 4297, 4685, 4686)
The claimed effects are “hair and nails health”, “hair and nail resistance and growth”, “hair growth”, “healthy hair and nails by stabilising protein structure and aids in the formation of collagen”, and “hair health as supplier of sulphur”. The target population is assumed to be the general population. Maintenance of normal hair is a beneficial physiological effect.
A cause and effect relationship has not been established between the consumption of L-cysteine and L-methionine alone or in combination and maintenance of normal hair.
Maintenance of normal nails (ID 597, 4224, 4685)
The claimed effects are “hair and nails health”, “hair and nail resistance and growth”, and “healthy hair and nails by stabilising protein structure and aids in the formation of collagen”. The target population is assumed to be the general population. Maintenance of normal nails is a beneficial physiological effect.
A cause and effect relationship has not been established between the consumption of L-cysteine and L-methionine alone or in combination and maintenance of normal nails.
Maintenance of normal skin (ID 665, 666, 1916)
The claimed effect is “epidermic tissue”. The target population is assumed to be the general population. Maintenance of normal skin is a beneficial physiological effect.
A cause and effect relationship has not been established between the consumption of L-cysteine and L-methionine alone or in combination and maintenance of normal skin.
Contribution to normal collagen formation (ID 4685)
The claimed effect is “healthy hair and nails by stabilising protein structure and aids in the formation of collagen”. The target population is assumed to be the general population. Contribution to normal collagen formation is a beneficial physiological effect.
A cause and effect relationship has not been established between the consumption of L-cysteine and L-methionine alone or in combination and contribution to normal collagen formation.
Contribution to normal glutathione formation (ID 1745)
The claimed effect is “glutathione metabolism”. The target population is assumed to be the general population. Contribution to normal glutathione formation is a beneficial physiological effect.
A cause and effect relationship has not been established between the consumption of L-cysteine and L-methionine alone or in combination and contribution to normal glutathione formation.
