The effect of flavourings on black tea

Surprisingly despite most people knowing a few benefits tea can have, very few understand that what you add on top can completely change the benefits. So bring on the science as I try to explain what happens to your precious tea once you add a bit of milk or sugar.

clear condiment shaker with brown sugar cubes near gray teacup

Sugar – this additive has the unusual effect not only of masking the bitter taste of both tea and coffee but also of actually changing the chemistry of the caffeine within these drinks. A research paper, led by Dr. Seishi Shimizu, published in Food and Function shows the original theory that the suppression of the bitter flavour was attributed to the addition of sugar was incorrect. Researchers discovered that when caffeine was placed in hot water the molecules would stick together. However, the addition of sugar enhanced this effect by binding the sugar to the caffeine.

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Milk – unfortunately, the results of some research conducted on 16 healthy women to compare the effects of tea, tea with milk and water on their vascular systems suggest that having milk in tea negates the tea’s property of relaxing the body’s blood vessels. The scientists believe that this effect is most likely caused by the caseins (a protein found in milk) forming complexes with the catechins present in tea (flavonoids) that prohibit the catechins from being absorbed by the body. Interestingly, the researchers also found that the proteins found in soy milk have the same effect.  

lemonade juice filled white ceramic cup with saucer

Lemon – rich in vitamin C, lemons act as an antioxidant that fights free radicals, which can cause heart disease and diabetes. The majority of benefits associated with tea come from the theaflavin antioxidants and adding lemon does not inhibit the nutritional effect. As well as providing an additional source of antioxidants, lemons can also increase the staying power of the antioxidants found in black tea. Researchers of a comparative study published in a 2000 issue of Indian Journal of Physiology and Pharmacology confirmed that tea with lemon increases the antioxidant potential more than tea without lemon.

spoon honey jar glass

Honey – when adding honey to tea, the major health benefits are only present if the honey is raw because when honey is processed it is heated, meaning the active ingredients (such as phytonutrients, antioxidants, and other nutrients that give honey both its anti-fungal and anti-bacterial properties) are denatured upon heating. Local honey also has a sample of local pollen and therefore may help relieve hay fever symptoms. However, honey should not be added to tea when the water is boiling (above 42°C), because honey contains volatile aromatic compounds found in the nectar. This leaves simply sweetness with no health benefits.

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Vanilla Extract – there is no clear research about the effect of the vanilla extract on tea; however, adding vanilla extract to black tea may provide certain health benefits. A traditional use of vanilla extract is adding it to boiling water as a remedy for nausea, vomiting and upset stomachs, and the aroma may also help ease queasiness. 



red apple fruit beside clear glass jarApple Juice – adding apple juice to tea has no proven benefits, as no research has been done in this field, but there are possible claims that can be made. Much like tea, apples are a great source of antioxidants such as polyphenols and flavonoids, which are beneficial towards heart health. Potassium is also crucial for the heart and can be found in rather high quantities (107mg every 100g). There is also a large amount of vitamin C that helps improve the immune system and assists the body in combating germs and bacteria; added to the vitamin C already present in tea, it could prove incredibly effective. The health benefits associated with apples and therefore apple juice, are only effective when the juice is fresh, as the benefits of Vitamin C are lost due to oxidation.

There are various health benefits of tea that have been studied by scientists all over the world. Some contradict each other, as each time the tea is processed and then brewed, the health benefits will be different. However, I will always suggest that you go with your instincts. If a nice cup of black tea with a splash of milk and too much sugar to be healthy is the most soothing and relaxing thing ever, then it will offer you more health benefits than what the milk or sugar will take away.

Don’t forget to have some tea on me.

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2 Comments Add yours

  1. shennongblog says:

    My guilty tea pleasure at the moment is Scottish Breakfast with a slice of lemon 😛

  2. Thanks for providing information

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