People with Type 2 diabetes are not able to produce sufficient insulin from their pancreas to regulate blood sugar, which means that their blood sugar can reach dangerously high levels.
However, findings presented at The Endocrine Society’s 97th annual meeting in San Diego on Thursday (25 August) revealed that the extract of an onion bulb can “strongly lower” high blood sugar and total cholesterol levels when given alongside antidiabetic drug metformin.
Lead study author Anthony Ojieh of Delta State University in Abraka, Nigeria, said: “Onion is cheap and available and has been used as a nutritional supplement. It has the potential for use in treating patients with diabetes.”
The researchers tested the theory on rats. In total, three groups of rats with medically induced diabetes were given various doses of the onion extract to see if it would enhance the drug’s effect.
The doses were 200mg, 400mg, and 600mg per kilogram of body weight. The researchers also gave the drug and onion to three groups of nondiabetic rats with normal blood sugar.
The study found that, of the diabetic rats, those given 400mg and 600mg per kilogram of body weight “strongly reduced” their blood sugar levels by 50 per cent and 35 per cent respectively compared with a baseline level.
The onion extract also lowered the total cholesterol level in diabetic rats, with the 400mg and 600mg having the greatest effects.
The study also found that the onion extract led to weight gain among the nondiabetic rats, but not the diabetic rats.
“Onion is not high in calories,” Ojieh explained. “However, it seems to increase the metabolic rate and, with that, to increase the appetite, leading to an increase in feeding.
“We need to investigate the mechanism by which onion brought about the blood glucose reduction. We do not yet have an explanation.”