Citrus and grapes may protect against type 2 diabetes
A daily blend of citrus and grape extracts with chromium normalised blood sugar in people with prediabetes within six months during a recent study, outperforming diet alone.
The six-month clinical trial found that a supplement containing citrus and red grape extracts, chromium and hesperidin helped people with impaired fasting glucose – a prediabetic condition – achieve normal blood sugar levels faster than diet alone.
The randomised, double-blind, placebo-controlled study involved 62 Italian adults aged 18 to 75 with impaired fasting glucose (fasting blood sugar levels between 100 and 125 mg/dL).
All participants followed an isocaloric DASH diet (Dietary Approaches to Stop Hypertension), designed to support cardiovascular and metabolic health.
Half also received two tablets of the supplement daily, taken after lunch and dinner.
Each dose provided 250 micrograms of chromium and 560 milligrams of flavonoids from lemon, red grape and orange extracts.
After three months, fasting blood glucose in the supplement group fell from 114 to 94 mg/dL, reaching normal levels and remaining stable through six months.
The placebo group showed only a modest reduction, from 113 to 107 mg/dL, remaining within the prediabetes range.
The supplement also improved lipid profiles. LDL, or “bad”, cholesterol dropped from 114 to 73 mg/dL, while HDL, or “good”, cholesterol rose from 38 to 56 mg/dL.
Triglycerides – fats found in the blood – decreased significantly in the supplement group but increased among those on the placebo.
HbA1c, which reflects average blood sugar over three months, decreased only in the supplement group. Insulin levels and insulin resistance, measured by HOMA-IR, showed no treatment effect in either group.
Prediabetes is a major metabolic health challenge linked to increased cardiovascular disease risk.
While diet and exercise can reverse it, adherence is often low, prompting interest in nutritional strategies that complement lifestyle changes.
The supplement’s formulation provided chromium, known to support glucose metabolism, alongside flavonoids – plant compounds with antioxidant properties – derived from citrus and red grapes. It also included hesperidin, a citrus flavonoid associated with improved vascular health.
Blood samples were collected at baseline, three months and six months to assess glucose, cholesterol, insulin and liver and kidney function.
Measures of aspartate transaminase (AST), alanine transaminase (ALT) and creatinine confirmed the supplement was well tolerated with no adverse effects.
Researchers acknowledged the study’s limitations, including its single-centre design, the exclusion of participants with a body mass index over 30, and the absence of post-trial follow-up to assess long-term effects.
The findings suggest that this combination of plant-derived flavonoids and chromium may offer a useful approach for managing prediabetes and improving cardiovascular health markers.
Larger, multicentre studies are recommended to confirm these results in broader populations.
