Why you should eat grapefruit after drinking tea, according to a scientist

An American scientist who caused a storm in a teacup last month when she suggested adding salt in tea has more advice for tea-lovers - consider grapefruit.

But while her previous recommendation became a major controversy, Professor Michelle Francl’s most recent advice is less fraught and might even be useful to help you stay more awake after a cuppa.

In order to extend the caffeine buzz from a brew, the chemistry professor from Bryn Mawr College in Pennsylvania said that eating plenty of grapefruit can help extend the amount of time the caffeine from tea stays in your system, keeping you alert for longer.

She added that some vegetables have an adverse effect, "clearing" the caffeine from your system more quickly.

Speaking at an online webinar for Chemistry World magazine, Prof Francl said: "If you eat a lot of grapefruit, you can increase the time the caffeine remains in the system.

"And if you add cabbage, broccoli and Brussel sprouts to your diet, you can clear caffeine more quickly."

Prof Francl found herself in the middle of a US-UK row about tea after she suggested adding a pinch of salt and a squeeze of lemon juice to a cuppa for the perfect brew.

She told the Guardian last month that sodium ion in salt can help tea taste less bitter, while a small amount of lemon juice can remove "scum" that sometimes forms on the surface of the tea.

Her advice became a controversial subject on social media as horrified Brits condemned her methods, prompting statements from the US embassy and the Cabinet Office.

In a post on X, formerly Twitter, the US embassy wrote: "We cannot stand idly by as such an outrageous proposal threatens the very foundation of our Special Relationship.

"Tea is the elixir of camaraderie, a sacred bond that unites our nations. Therefore, we want to ensure the good people of the UK that the unthinkable notion of adding salt to Britain’s national drink is not official United States policy. And never will be.

"Let us unite in our steeped solidarity and show the world that when it comes to tea, we stand as one."

However, the embassy’s social media team couldn’t resist one last opportunity to wind Brits up, adding: "The US embassy will continue to make tea in the proper way - by microwaving tea."

The Cabinet Office’s social media team then felt the need to wade into the row and wrote in a responding post on X: "We appreciate our Special Relationship, however, we must disagree wholeheartedly… Tea can only be made using a kettle."

The response to Prof Francl’s advice left her "bowled over", she said during the webinar.

However, something that may get Britons on her side is her dissatisfaction with Americans’ use of the microwave to make a cup of tea. She said that using a microwave encouraged the formation of scum on the surface of the brew, made of calcium and magnesium carbonates.

"It happens when you microwave tea because you bring things to the boiling point so quickly, you do not remove the oxygen and carbon dioxide," she was quoted as saying in the Guardian.

"So you have more carbonates in the water and oxygen also promotes the development of the organics that lead to this raft of floating stuff."

Prof Francl also recommended a cup of earl grey tea to reduce anxiety and said that the "characteristic scent" of this particular brew - headed up by bergamot fruit - can help us feel calmer.

Bergamot is a citrus fruit, and its oil in earl grey means the tea contains high amounts of linalool. Prof Francl said: "It turns out that linalool activates the same pain relief pathways as opioids.

"Earl grey tea with that characteristic scent is something that can reduce anxiety in humans. So when my husband has that cup of tea before his departmental meeting, he’s on to something."

Watch: What Happens to Your Body When You Drink Tea Everyday

Read more about tea:

• Health benefits of tea as one cup a day could cut risk of diabetes by a quarter (Yahoo Life UK, 3-min read)

• Gut health benefits of tea as Brits found to prefer a cuppa over coffee (Yahoo Life UK, 5-min read)

• Scientists say that these teas can actually help you to lose weight (Yahoo Life UK, 4-min read)