People with insulin resistance have trouble getting sugar from the blood into tissue cells after meals. But a new study suggests that a cup of black tea might help with that problem partly by finding a way to improve blood flow.
Scientists Study How to Improve Blood Flow:
The scientists compared the effects of nitrate-rich beet juice and flavonoid-rich black tea on blood flow and insulin response in 16 volunteers. All were male, obese and insulin resistant.
Previous studies have shown that beet juice (beetroot juice in British English) can make blood vessels more flexible, improve blood flow and lower blood pressure. Flavonoids similar to those in black tea also have beneficial effects on blood vessels. How do they compare?
Each participant was given 75 grams of glucose in combination with black tea, beet juice or water. After each dose (given on separate days) blood flow was studied.
Black Tea Gave the Best Results:
Black tea reduced the resistance in all the blood vessels studied, including the tiny ones (microvessels). Beet juice reduced resistance only in some of the blood vessels (not in microvessels or conduit arteries).
Black Tea to Lower Insulin Resistance as Well as Vascular Resistance:
The insulin response was almost 30 percent lower after the participants drank black tea. Diminished vascular resistance and reduced insulin response are both beneficial reactions.
The researchers suggest further studies to determine whether long-term tea consumption could affect blood sugar control as well as improve blood flow. This would be especially helpful for people with prediabetes or metabolic syndrome.
Nutrition & Metabolism, online May 13, 2016
Other Flavonoid-Rich Foods:
There are many other foods that contain flavonoids that may be beneficial. Many fruits and vegetables are rich in these plant compounds, which could help explain why the DASH diet helps lower blood pressure. If you would like more details on how to follow a DASH diet (Dietary Approaches to Stop Hypertension), you may be interested in our book, The People’s Pharmacy Quick and Handy Home Remedies