Glutamic acid intake and blood pressure in 4680 people
What it found
People who got more of their protein from glutamic acid had slightly lower blood pressure.
This was seen across 4680 adults in four countries.
What they found
Studies in people
Lower blood pressure readings
When glutamic acid made up about 4.72% more of total protein eaten, systolic blood pressure was 1.5 to 3.0 mm Hg lower. Diastolic blood pressure was 1.0 to 1.6 mm Hg lower. These differences held up after adjusting for many other factors.
Typical daily intake
Across all participants, average glutamic acid intake was 15.7 grams per day. It made up 20.1% of total protein eaten. Only 2% of people took supplements containing it.
Other amino acids tested
Proline, phenylalanine, and serine were also linked to lower blood pressure. However, the differences were smaller than those seen for glutamic acid.
Other findings
Main food sources
Seven food groups supplied 83.6% of the glutamic acid people ate. Vegetable foods provided 41.9% and animal foods provided 41.7%.
What the authors conclude
- They suggest that glutamic acid from food may help lower blood pressure on its own.
- They say this could partly explain why diets rich in vegetable protein are linked to lower blood pressure.
- They call for these findings to be checked in other populations and in controlled trials.
How it was done
Earlier work showed that eating more vegetable protein was linked to lower blood pressure. Glutamic acid is the most common amino acid in vegetable protein, so the authors wanted to see if it played a role.
Researchers measured blood pressure and diet in 4680 men and women aged 40 to 59. Participants lived in China, Japan, the United Kingdom, or the United States. Each person attended four visits and gave detailed records of everything they ate and drank over 24 hours, along with two full days of urine samples.
What it can’t tell you
- Because everyone was measured at one point in time, this design cannot prove that glutamic acid caused the lower blood pressure.
- The study only included people aged 40 to 59, so scientists do not yet know if the same link exists in younger or older people.
- Day-to-day changes in what people eat mean the true effect size might be slightly different from what was recorded.
Who paid
- Funding
- Funded by Medical Research Council; NHLBI NIH HHS (from the PubMed record).
- Authors work at
- Northwestern University, USA
The paper
- Title
- Glutamic acid, the main dietary amino acid, and blood pressure: the INTERMAP Study (International Collaborative Study of Macronutrients, Micronutrients and Blood Pressure)
- Type
- Study
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Stamler J, Brown IJ, Daviglus ML, et al (2009). Glutamic acid, the main dietary amino acid, and blood pressure: the INTERMAP Study (International Collaborative Study of Macronutrients, Micronutrients and Blood Pressure). Circulation. doi:10.1161/CIRCULATIONAHA.108.839241Free full textPubMed 19581495DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error