Tea is on the list of the most popular drinks in the world. Everyone has opinions about making the perfect cup, which makes the tea personal for anyone. But, how to get the most of your own drink according to science?
Tea consumption is linked to a number of health benefits. It helps to improve mood and cognition, and reduce risk of heart disease and diabetes.
Tea is a rich with micronutrients, including fluoride, magnesium, and zinc. However, the health benefits we get from that perfect cup are mostly linked to three main bioactive compounds: Catechins, caffeine and L-theanine. Bioactive compounds are non-essential nutrients that may impact health.
According to laboratory and animal studies these compounds may have multiple health effects. But, the results in human studies are much less clear. Catechins are a type of polyphenol, which is a group of chemicals with antioxidant properties. Antioxidants are molecules that prevent cell damage.
Caffeine helps you feel alert and the amino acid L-theanine is considered to be responsible for tea’s relaxing properties. These compounds also contribute to your brew’s taste and mouthfeel.
Which tea is the healthiest for you?
The black, oolong, white and green tea are types of tea that come from the same plant, Camellia sinensis. The harvest timing and processing makes the differences between them, particularly the level of oxidation which is a reaction that occurs when processed leafs are exposed to high oxygen levels.
Black tea is fully oxidised, oolong is partially oxidized, green and white teas are unoxidised. White teas are made from early harvests, green from later.
The processing has little impact on L-theanine, and the levels found are similar in all teas. The varying levels are wide in caffeine. However, black tea typically has the most caffeine. Catechins are changing by oxidisation, which makes the levels to be highest in green and white teas.
The green tea is considered the healthier option because it has more antioxidants and less caffeine. This have putted the green tea in the focus of most studies of the health benefits. However, it is important to mention, all teas are a good source of L-theanine, caffeine and catechins.
But, we have to warn that having “tea” on the label doesn’t guarantee bioactive content or health benefits. Pre-packaged iced teas and instant teas may have limited bioactives and usually are high in sugar. The properties in herbal and fruit teas vary because they don’t contain any actual tea leaf.
However, the excessive consumption of tea can be harmful, and may lead to over consumption of caffeine. Tannins – another group of polyphenols in tea can also bind to iron and reduce iron absorption if it is consumed with or soon after a meal.
In order to get the maximum health benefit from your cup, the more important is the brewing than the tea you choose.
If you shake the tea bag around in the cup, for just 15-30 seconds, you are only getting a fraction of the bioactives you would by following the maker’s instructions.
Research has found that brewing for 20-30 minutes at 80°C (176°F) extracts the maximum level of bioactives. The longer you brew the more bioactives you get, but also the stronger the taste. The problem here is that it is not really practical for daily life, and not that tasty!
Brewing with freshly boiled water for two to three minutes, as per the instructions, extracts about 60 percent of the catechins, 75 percent of the caffeine and 80 percent of the L-theanine.
Another impact of your drink and its extraction process has the pH of water. Low pH (acidic) water extracts bioactives better than high pH (basic) water. The pH of tap water is about seven, which is neutral, so there might be a benefit to adding lemon with your tea, rather than after its brewed.
Tea in the microwave?
It’s argued microwaves are inferior to kettles for heating water, as there is less control over the temperature. Although the idea of making tea in the microwave is horrifying for purists, the microwave could actually be a useful tool for extracting more bioactives.
Microwaves, actually can increase the levels of bioactives in your cup. With adding freshly boiled water to the teabag, steeping for 30 seconds, with a minute in the microwave on medium power after that, extracts more bioactives than a standard three minute steep.
Many have their tea with adding some milk in it, but what science says about that?
Some studies have suggested milk alters the antioxidant activity and health benefits of tea.
But others have shown the same level of antioxidants reach the blood after consuming tea with and without milk. The question about the timing for adding the milk is not yet well studied. The Royal Society of Chemistry suggests adding it first prevents denaturation, or clumping, of milk proteins, which might give the milk a stale taste.
It is believed that loose leaf may contain more bioactives because they use higher quality leaves. But leaves in teabags are cut smaller, and this is believed to enhance the extraction process.
Lower quality teas can include more stems, which are higher in L-theanine than the leaves. So, although the fancy loose leaf might taste better, you probably get more bang for buck from a humble tea bag.
Whichever type of tea you choose, the longer you brew, the more goodness in each cup. Patience is the key.