A two-page 2009 study of alkaline water in hypertensive rats, and what it can support
In 2009 a Taiwanese food-science journal printed a two-page item on alkaline reduced water given to rats bred for high blood pressure. The Molecular Hydrogen Institute lists it in its metabolic syndrome reading list as hydrogen research.
What the study did and found
The item is “Effect of alkaline reduced water on erythrocyte oxidative status and plasma lipids of spontaneously hypertensive rats” by Chao and Chiang, pages 71–72 of volume 47, issue 2, of the Taiwanese Journal of Agricultural Chemistry and Food Science (Chao & Chiang, 2009). At two pages it is probably a short communication or meeting abstract, and the record gives no dose, water pH, duration, group sizes or direction of effect.
The same names appear on a 2024 Nutrients paper testing alkaline reduced water in diabetic and non-diabetic Wistar rats, a separate study whose methods cannot be read back into the 2009 item (Huang et al., 2024).
Why it is cited
The main referring page is the Molecular Hydrogen Institute’s reading list on metabolic syndrome, which gives the full citation under “Molecular Hydrogen Research Articles” without comment. A hydrogen-water seller and an ioniser studies page repeat the entry.
That use overstates the work. The item concerns rats bred for high blood pressure, not people with metabolic syndrome, and its title does not mention molecular hydrogen, so filing it as hydrogen research is the institute’s own reading.
Spontaneously hypertensive rats are an inbred, polygenic strain derived from Wistar rats in Kyoto to study inherited high blood pressure (Doris, 2017). Whatever the result in these animals, it would not show an effect in people.
WHO proposes no health-based guideline value for the pH of drinking water (World Health Organization, 2022). For hydrogen-rich water, which the citing list promotes, a 2026 meta-analysis of 13 trials in 757 adults judged cholesterol changes too small to matter for cardiovascular risk (Ye et al., 2026).
The topic today
Alkaline and ionised waters are still sold with health claims: in 2022 the UK Advertising Standards Authority upheld a complaint about an alkaline filter advertised as helping acid reflux (Advertising Standards Authority, 2022). A 2026 review concluded that alkaline water should not be routinely recommended in primary care (Alebrahim et al., 2026).
For the current picture, see our explainer Alkaline Water and Blood Lipids: What a 2009 Rat Study Tested.