ID 4223 - 5-hydroksytryptofan

PL: 5-hydroksytryptofan
EN: 5-HTP
Pdf: 5-hydroxytryptophan

1. Charakterystyka żywności / składnika

The food constituent that is the subject of the claim is 5-hydroxytryptophan (5-HTP), which is an intermediate metabolite of the essential amino acid tryptophan in the biosynthesis of serotonin.
5-HTP has a molecular weight of 220.23 Da and can be measured using High Performance Liquid Chromatography (HPLC) methods (Lemaire and Adosraku, 2002). Dietary sources of 5-HTP are limited. Whilst it naturally occurs in some foods (including bananas, tomatoes, plums and avocados), the amounts are extremely small. Also, consumption of tryptophan-containing foods does not significantly increase 5-HTP concentrations. 5-HTP is usually consumed in the form of food supplements obtained via solvent extraction from seeds of the African tree Griffonia simplicifolia (Vahl ex DC) Baill.
The Panel considers that the food constituent, 5-HTP, which is the subject of the claim, is sufficiently characterised.

2. Znaczenie oświadczenia dla zdrowia człowieka

The claimed effect is “satiety”. The Panel assumes that the target population is the general population.
Satiety is the decrease in motivation to eat after consumption of food. The effect may persist up to several hours, may reduce energy intake either at the next meal or across the day and, if sustained, may lead to a reduction in body weight.
The Panel considers that an increase in satiety leading to a reduction in energy intake, if sustained, might be a beneficial physiological effect.

3. Naukowe uzasadnienia wpływu na zdrowie człowieka - Stałe zwiększenie sytości prowadzące do redukcji przyjmowanej energii

Among the references provided in relation to the claim was a confidential report with insufficient data for a full scientific evaluation and one publication that investigated the effects of 5-HTP on outcomes
other than measures of satiety (reduction of hot flushes). The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claim.
In a double-blind, placebo-controlled intervention study (Cangiano et al., 1998), 25 (11 females) overweight non-insulin dependent diabetic outpatients (age range 35-70 years, BMI 25-30 kg/m2), some of whom were taking oral hypoglycaemic medications, were randomised to consume 5-HTP (750 mg/day; n=12) or placebo (corn starch, mannitol and magnesium stearate; n=13) for two consecutive weeks. On days 7 and 14, food intake (assessed by daily weighed dietary records), eating behaviour and body weight were evaluated. The effect of 5-HTP and placebo on appetite ratings was not assessed. The Panel considers that no conclusions can be drawn from this study for the scientific substantiation of the claim.
In a double-blind, placebo-controlled intervention study by Cangiano et al. (1992), 28 obese female subjects (mean age 43.2 years, BMI 30–40 kg/m2) were randomly assigned to receive either 5-HTP (900 mg/day) or a placebo (corn starch, mannitol and magnesium stearate). Interventions were administered in capsule form three times per day 30 minutes before meals for 12 weeks. The study duration was subdivided into two consecutive six-week periods. During the first period no dietary restrictions were imposed, whereas during the second period a 5,040 kJ/day diet containing 53 % carbohydrates, 29 % lipids and 18 % proteins (as % energy) was recommended. During both study periods the participants were asked to report, in a questionnaire, on the presence of a series of symptoms which included early satiety. The Panel notes that this questionnaire was not validated to assess satiety. Subjects were also examined every two weeks to evaluate eating behaviour and body weight. Total daily energy intake and single macronutrient selection were assessed at each time point using a three-day food diary. Subjects were instructed to weigh the food before and after consumption with reports being checked by a next of kin’s signatures. The Panel notes that as a result of the placebo group failing to adhere to the dietary restriction in the second study period, the impact of 5-HTP on satiety, food intake and body weight independently of dietary restriction cannot be determined during this phase. Twenty participants, 10 in each study group, completed the study. The Panel notes the high drop-out rate, and that direct statistical comparisons between the intervention and placebo groups with respect to changes in energy intake and body weight were not reported. The Panel considers that no conclusions can be drawn from this study for the scientific substantiation of the claim.
In a double-blind, placebo-controlled cross-over study (Ceci et al., 1989), 19 obese female subjects (mean age 41 years, BMI 30–40 kg/m2) consumed 5-HTP (8 mg/kg/day) and placebo (not specified) in capsules 30 minutes before each meal for five weeks each, with a wash-out period of one week in between. The order of the intervention was randomised. No dietary restrictions were prescribed during the study periods. Subjective self-evaluations of appetite and satiety at lunchtime were obtained twice weekly by the Silverstone test. Food intake and eating behaviour were assessed at the beginning and at the end of the two treatment periods using a three-day weighed dietary record. Dietary records were checked by next of kin’s signatures. Body weight was also assessed on a weekly basis. Power calculations were not performed, the primary outcome of the study was not reported, carry-over effects were not addressed, and no adjustments for multiple testing were made. The Panel notes the major limitations of this study and considers that no conclusions can be drawn from it for the scientific substantiation of the claim.
The Panel concludes that a cause and effect relationship has not been established between the consumption of 5-HTP and a sustained increase in satiety leading to a reduction in energy intake.

Warunki i możliwe ograniczenia stosowania oświadczenia

2 tablets per day before each meal (300 mg of 5-HTP per day)