Table 2.

Relationship between amino acids and hypertension.

Risk Factor	Experimental Model	Amino Acids	Findings	Reference
Hypertension	4288 participants aged 20–70 years without hypertension (3-year follow-up)	Dietary intakes of BCAAs (valine, leucine, and isoleucine)	Higher BCAA intake, particularly valine, is associated with a higher risk of incident hypertension.	[129]
	8589 Japanese subjects	Plasma AAs	Higher intake of aromatic AAs is associated with s significantly higher risk of developing hypertension.	[130]
	4287 adults (41.9% men), aged 20–70 years.	Dietary intake of AAs	High dietary intake of Leu.Ser/Thr.Trp ratio is associated with a higher risk of incident hypertension.	[131]
	172 South African adolescents (105 girls, ages 13 to <18 years)	Circulating HCY concentrations	Of these adolescents, 40% had elevated BP, of whom 37% fell in the lowest and 38% in the highest HCY tertiles.	[132]
	Normotensive or spontaneously hypertensive rats	L-Tyrosine, Tryptophan, Leucine, Isoleucine, Valine, Alanine, Arginine, and Aspartate	In spontaneously hypertensive rats, tyrosine (50 mg/kg) reduced BP by about 12 mmHg, while 200 mg/kg reduced BP by about 40 mmHg. Tryptophan injection (225 mg/kg) reduced BP in spontaneously hypertensive rats, but only by about half as much as an equivalent dose of tyrosine. Other AAs have no effect on BP.	[133]
	Spontaneously hypertensive rat	L-tyrosine	Intraventricular injection of 15 micrograms of l-tyrosine results in a significantly lower BP in the spontaneously hypertensive rat.	[134]
	4680 persons aged 40–59 years from China, Japan, the United Kingdom, and the United States	Dietary AA (glutamic, proline, phenylalanine, serine, and cystine)	Dietary glutamic acid (percentage of total protein intake) was inversely related to BP.	[135]

Legend: BCAA: Branched-chain amino acid; AA: Amino acids; Leu: Leucine; Ser: Serine; Thr: Threonine; Trp: Tryptophan; BP: Blood pressure.