Olive oil before carbs reduces blood sugar spikes in mice study

Researchers have found new evidence that eating olive oil before carbohydrates can reduce blood sugar spikes. In a study published in Diabetes, mice fed olive oil before consuming glucose saw a reduced increase in blood sugar afterward. This suggests that meal sequencing is an emerging dietary approach to help manage diabetes and obesity.

The findings were reported by endocrinologist Daisuke Yabe from Kyoto University. The team conducted experiments to evaluate three separate conditions after an overnight fast on the mice. They found that the order in which nutrients reach the gut can engage a coordinated hormone-nerve response.

In the experiment, one group received olive oil 15 minutes before being given glucose while another group received it afterward. Blood tests showed that mice fed olive oil first had significantly lower blood glucose immediately after the meal at the 15- and 30-minute marks. The effects appeared to diminish by 60 minutes compared to control groups consuming water.

The study suggests certain nutrients slow the process of gastric emptying, which means food moves more slowly into the small intestine. This delays the absorption of glucose into the bloodstream and triggers the secretion of hormones like glucagon-like peptide-1. These hormones are known for being appetite-suppressing and insulin-boosting.

Further tests showed that olive oil's ability to mitigate blood sugar increases involves both hormones and neural pathways. Researchers blocked the animals' glucagon and GLP-1 signaling individually, finding that if one pathway was disrupted the effect remained but weakened if both were blocked. Surgically disrupting vagus nerve signaling also weakened or erased the benefits even though hormonal responses stayed intact.

The researchers tested other fats including flaxseed oil, lard, coconut oil, and fish oil alongside olive oil. Olive oil generally performed the best in terms of controlling blood sugar although flaxseed oil and lard produced similar results in some measures. In mouse models of diabetes, pre-loaded olive oil offered similar benefits to blood sugar and gastric emptying.

While the findings offer a clearer biological explanation for meal order, they have so far only been shown in mice with no guarantee we would see the same benefits in human patients. Additional clinical studies will be needed to determine whether these mechanisms can be used to improve blood sugar regulation in people. The researchers note this is appealing because it changes how a meal is eaten rather than requiring avoidance of food groups.