On 2015 Oct 09, Simon Young commented:

The authors of this study conclude “there was a statistically significant decrease on depression, stress, and mood disturbances scores among the intervention group”. They attribute this to the nutritional content of the Talbinah. However another explanation is more plausible. During the intervention period the participants received a single serving of Talbinah once a day, and during the control phase they received no nutritional supplement. Even if the participants were not aware of the belief that Talbinah improves mood before the study they would have been informed of this in description of the study in the consent form. Thus participants were fully aware of the fact that they were receiving a nutritional supplement thought to improve mood during one period and nothing in the other period. Given the lack of an active control group the expectations of the participants could have explained the changes seen when ingesting Talbinah. In this type of study a plausible placebo treatment is essential if the effect of an intervention is to be established. The authors discuss three potential mechanisms for the effect of Talbinah. The first is the effect of the carbohydrate in the Talbinah. The supplement contained 21.6g of carbohydrate per dose, which would obviously be a small percentage of the participants’ total daily carbohydrate intake and highly unlikely to alter mood significantly over the period of a day. While the paper includes information, on page 283, on nutrient intakes during intervention and control periods, results are given only for total calories (increased by 9.2% during the intervention period, although the Talbinah alone would have increased it by only 6.5%), zinc and magnesium. Although the authors must have had information on the increase in carbohydrate intake during the intervention, that information, surprisingly, is not included in the paper. The second potential mechanism is an increase in brain tryptophan and serotonin due to the tryptophan content of the Talbinah. The paper documents the fact that the ratio of trp:BCAA in Talbinah is much higher than in either milk or barley. However, the authors are not correct in stating on p.284 that “The amino acid composition of food is associated with brain serotonin levels, especially trp:BCAA and trp:LNCAA” and that “The ratio of trp:BCAA may have increased the tryptophan available to the brain”. As stated in the reference they cite in support of these statements (number 9 in the reference list) Wurtman RJ, 2003 “Brain tryptophan concentrations and the flux of tryptophan from blood to brain, depend, in turn, partly on plasma tryptophan and partly on plasma concentrations of ≥ 6 other large neutral amino acids (LNAAs): tyrosine, phenylalanine, leucine, isoleucine, valine, and methionine, which compete with tryptophan for blood-brain barrier transport”. The ratio of trp:BCAA is irrelevant as the brached chain amino acids are only some of the amino acids that compete with tryptophan for transport from blood to brain. The authors docment on page 284 of the manuscript that Talbinah has a low trp:LNAA ratio of 1:21. Given the low protein content of the Talbinah (1.2 g per dose, Table 1) and the low trp:LNAA ratio the Tablinah could not have increased brain tryptophan and serotonin to any appreciable extent. The third potential mechanism is an increase in zinc levels. Several studies have shown that zinc levels are often low in depressed patients. A recent review includes four studies on the effect of zinc on depressed mood Lai J, 2012. Two studies with a daily dose of 25 mg zinc showed an antidepressant effect in patients with major depression, while two other studies, one with a dose of 7 mg per day and the other with doses of 10.1 mg per day and 20.2 mg per day in different groups, did not reliably show an effect on mood in healthy people. In this paper the Tablinah increased mean zinc intake from 3.7 mg per day to 8.7 mg per day. There is no evidence that a supplemental dose of 5 mg per day of zinc can influence mood. In conclusion there is no plausible bioligcal mechanism for an effect of Talbinah, at the dose given, on mood. Given the way the study was designed the most plausible explanation for the effects on mood was a psychological mechanism, the expections of the participants.

On 2015 Oct 09, Simon Young commented:

The authors of this study conclude “there was a statistically significant decrease on depression, stress, and mood disturbances scores among the intervention group”. They attribute this to the nutritional content of the Talbinah. However another explanation is more plausible. During the intervention period the participants received a single serving of Talbinah once a day, and during the control phase they received no nutritional supplement. Even if the participants were not aware of the belief that Talbinah improves mood before the study they would have been informed of this in description of the study in the consent form. Thus participants were fully aware of the fact that they were receiving a nutritional supplement thought to improve mood during one period and nothing in the other period. Given the lack of an active control group the expectations of the participants could have explained the changes seen when ingesting Talbinah. In this type of study a plausible placebo treatment is essential if the effect of an intervention is to be established. The authors discuss three potential mechanisms for the effect of Talbinah. The first is the effect of the carbohydrate in the Talbinah. The supplement contained 21.6g of carbohydrate per dose, which would obviously be a small percentage of the participants’ total daily carbohydrate intake and highly unlikely to alter mood significantly over the period of a day. While the paper includes information, on page 283, on nutrient intakes during intervention and control periods, results are given only for total calories (increased by 9.2% during the intervention period, although the Talbinah alone would have increased it by only 6.5%), zinc and magnesium. Although the authors must have had information on the increase in carbohydrate intake during the intervention, that information, surprisingly, is not included in the paper. The second potential mechanism is an increase in brain tryptophan and serotonin due to the tryptophan content of the Talbinah. The paper documents the fact that the ratio of trp:BCAA in Talbinah is much higher than in either milk or barley. However, the authors are not correct in stating on p.284 that “The amino acid composition of food is associated with brain serotonin levels, especially trp:BCAA and trp:LNCAA” and that “The ratio of trp:BCAA may have increased the tryptophan available to the brain”. As stated in the reference they cite in support of these statements (number 9 in the reference list) Wurtman RJ, 2003 “Brain tryptophan concentrations and the flux of tryptophan from blood to brain, depend, in turn, partly on plasma tryptophan and partly on plasma concentrations of ≥ 6 other large neutral amino acids (LNAAs): tyrosine, phenylalanine, leucine, isoleucine, valine, and methionine, which compete with tryptophan for blood-brain barrier transport”. The ratio of trp:BCAA is irrelevant as the brached chain amino acids are only some of the amino acids that compete with tryptophan for transport from blood to brain. The authors docment on page 284 of the manuscript that Talbinah has a low trp:LNAA ratio of 1:21. Given the low protein content of the Talbinah (1.2 g per dose, Table 1) and the low trp:LNAA ratio the Tablinah could not have increased brain tryptophan and serotonin to any appreciable extent. The third potential mechanism is an increase in zinc levels. Several studies have shown that zinc levels are often low in depressed patients. A recent review includes four studies on the effect of zinc on depressed mood Lai J, 2012. Two studies with a daily dose of 25 mg zinc showed an antidepressant effect in patients with major depression, while two other studies, one with a dose of 7 mg per day and the other with doses of 10.1 mg per day and 20.2 mg per day in different groups, did not reliably show an effect on mood in healthy people. In this paper the Tablinah increased mean zinc intake from 3.7 mg per day to 8.7 mg per day. There is no evidence that a supplemental dose of 5 mg per day of zinc can influence mood. In conclusion there is no plausible bioligcal mechanism for an effect of Talbinah, at the dose given, on mood. Given the way the study was designed the most plausible explanation for the effects on mood was a psychological mechanism, the expections of the participants.