Table 2.

Comparison between the no-observed-adverse-effect level (NOAEL) and lowest-observed-adverse effect level (LOAEL), over requirement (RQ) ratios for indispensable amino acids in rats and humans

Indispensable amino acid	Rat study						Human study
	RQ	Sex	NOAEL	LOAEL	NOAEL/RQ	LOAEL/RQ	RQ	Sex	NOAEL	LOAEL	NOAEL/RQ	LOAEL/RQ
	mg/kg BW/day						mg/kg BW/day
L-Histidine	133.3	M	1631	3481	12.2	26.1	11.0	F	91.2	134.1	8.3	12.2
		F	1757	3592	13.2	26.9
L-Isoleucine	295.2	M	1565	3008	5.3	10.2	15.0	NI	ND	ND	ND	ND
		F	1646	3702	5.6	12.5
L-Leucine	509.5	M	3333	ND	6.5	ND	34.0	M	500.0	ND	14.7	ND
		F	3835	ND	7.5	ND
L-Lysine	438.1	M	3357	ND	7.7	ND	31.0	M	85.7	107.1	2.8	3.5
		F	3986	ND	9.1	ND
L-Methionine	309.5	M	630	1100	2.0	3.6	10.1	F/M (9/6)	46.3	91.0	4.6	9.0
		F	ND	ND	ND	ND
L-Phenylalanine	323.8	M	1548	4903	4.8	15.1	27.0*	M	169.3	ND	6.3	ND
		F	1555	4701	4.8	14.5
L-Threonine	295.2	M	3267	ND	11.1	ND	16.0	NI	ND	ND	ND	ND
		F	3673	ND	12.4	ND
L-Tryptophan	95.2	M	948	1735	10.0	18.2	4.0	F	98.4	ND	24.6	ND
		F	1956	3705	20.5	38.9
L-Valine	352.4	M	3225	ND	9.2	ND	19.0	NI	ND	ND	ND	ND
		F	1853	3721	5.3	10.6

RQ is the value of requirement. In rats, RQ is amino acid requirements for growing rats (Benevenga et al. 1994). NOAEL is the No Observed Adverse Effect Level. LOAEL is the Lowest Observed Adverse Effect Level. F and M indicate experiments performed with female and male rats, and women and men, respectively. ND means not determined. NI means not indicated. The data indicated in bold allow rapid comparison of the ratio calculated in rats and humans when available

*RQ of phenylalanine/tyrosine