The review confirms that tea, particularly green tea, plays a crucial role in preventing cardiovascular diseases (CVDs), obesity, diabetes, and certain types of cancer. Tea’s neuroprotective effects, ability to reduce muscle loss in seniors, and its anti-inflammatory and antimicrobial activities further highlight its potential health-promoting properties. However, the study also identifies potential health concerns, particularly with bottled and bubble teas, which may contain harmful additives like artificial sweeteners and preservatives.

Tea, made from the leaves of Camellia sinensis, has been consumed globally for centuries, initially for its medicinal properties and later as a popular beverage. It has long been recognized for its rich polyphenolic content, particularly catechins, which contribute to its health benefits. This review aims to provide a detailed analysis of tea's impact on various health conditions, supported by both experimental and human studies. Despite extensive studies on green tea, there is limited information on the effects of other tea types, such as black, oolong, and white tea, especially concerning their comparative health benefits. Furthermore, the health concerns raised by the presence of additives and contaminants in some commercial tea beverages are addressed.

A study published in Beverage Plant Research by Mingchuan Yang & Li Zhou’s team, Tea Research Institute, Chinese Academy of Agricultural Sciences, underlines the need for further research to better understand tea’s health benefits and risks.

The review delves into various health conditions linked to tea consumption. Green tea is highlighted for its cardiovascular protective effects, reducing blood pressure and improving cholesterol levels. Multiple cohort studies also show that regular tea consumption can lower the risk of all-cause mortality, CVDs, and certain cancers. Furthermore, tea's role in weight management and its potential in controlling diabetes are discussed, with evidence suggesting that green tea catechins can aid in weight reduction and improve metabolic parameters in obese individuals. Notably, tea also shows promise in neuroprotection and muscle mass preservation. Studies indicate that regular tea drinkers experience a reduced prevalence of cognitive decline and Alzheimer’s disease biomarkers, particularly in older adults. Similarly, tea catechins may prevent muscle loss in seniors, contributing to better physical performance and muscle strength. However, while tea has numerous benefits, commercial tea products such as bottled or bubble tea, often contain sugar, artificial sweeteners, and preservatives, which may reduce or negate the health benefits. Additionally, concerns regarding pesticide residues, heavy metals, and microplastics in tea have been raised. These contaminants, though not posing significant health risks in typical consumption, remain a concern for long-term heavy tea drinkers. Moreover, the review addresses the issue of nutrient absorption interference, specifically with non-heme iron and calcium, potentially affecting people on vegetarian diets or those with specific nutritional needs.

The health benefits of tea are clear, but its consumption in processed forms like bottled tea and bubble tea should be moderated due to added sugars and preservatives. The findings from this review suggest that moderate consumption of traditional, freshly brewed tea can be beneficial, especially for preventing cardiovascular diseases, diabetes, and cancer. Future studies focusing on the long-term health effects of different tea types and the impact of contaminants will help refine our understanding of tea's health benefits and risks.