Pistachios and diabetic rats in Istanbul: what a 2009 study measured
In 2009 three Istanbul biochemists fed pistachio-enriched chow to diabetic rats and measured blood glucose and oxidative stress. The health site Organic Facts cites the paper on pistachios helping control diabetes.
What the study did and found
The paper, “Pistachio Consumption has Beneficial Effects in Diabetic Rat Model”, appeared in 2009 in the Firat University Medical Journal of Health Sciences (Alturfan et al., 2009). In the study, 32 Wistar rats were split into four groups of eight; two groups were made diabetic with streptozotocin, and one healthy and one diabetic group ate chow with 1.26% pistachio for eight weeks.
In the diabetic rats, pistachio lowered TBARS, a marker of lipid oxidation, from 5.86 to 3.99 nmol/mL and raised total antioxidant activity from 1.12 to 1.42 mmol/L, both reported as significant (Alturfan et al., 2009). Blood glucose fell from 21.94 to 19.87 mmol/L, a fall the authors call insignificant.
Why it is cited
The main referring page is the Spanish version of Organic Facts’ article on pistachio benefits, which says pistachio antioxidants reduce glycation and so help control diabetes, linking this record on the word “controlar”. The German and Italian versions carry the same link.
That use overstates the work. The study measured no glycation marker, such as HbA1c or fructosamine, and involved no people. Its glucose fall was not significant, so control of diabetes is the site’s reading, not the paper’s result.
The study tested a single dose in eight rats per group, and streptozotocin mainly models type 1-like diabetes (Furman, 2021). Its positive findings rest on TBARS and total antioxidant activity, assays a 2022 expert consensus advises against in clinical studies (Murphy et al., 2022).
Pooled human trials give a more modest picture: small falls in fasting glucose, of about 3.6 to 5.3 mg/dL, and inconsistent effects on HbA1c (Hadi et al., 2023; Baghery et al., 2022).
The topic today
Diabetes guidelines treat nuts as part of an overall eating pattern, not as a treatment: the American Diabetes Association’s 2026 Standards advise more plant protein, such as nuts, mainly to cut cardiovascular risk (American Diabetes Association, 2026). Diabetes UK counts 30 g of unsalted nuts as one portion (Diabetes UK, n.d.).
For the current picture, see our explainer Can Pistachios Help With Diabetes? What a 2009 Rat Study Found.