Tim Bond: Exploring the Science of Tea

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One of the driving forces behind the increasing consumption of tea around the world is the beverage’s powerful health message. But who is responsible for carrying out the research and for verifying all the positive information? Tim Bond, technical director AVT Tea Services is one of the scientists behind this important work.

By Jane Pettigrew

Whenever news about the health benefits of tea make headlines in British or European newspapers and magazines, these articles almost always contain quotes and comments from Dr. Tim Bond.

Bond is technical director at AVT Tea Services, manufacturer and supplier of decaffeinated tea and tea extracts, with facilities in Kochi, Southern India and in London. As well as supplying decaffeinated teas, soluble base tea powders, green tea and specialty tea powdered extracts, tea aromas, and spices, the company also runs a center for research and development with a state-of-the-art analytical laboratory. One of the most interesting aspects of AVT’s work is the development of its range of green tea powders and complex extracts in which the manufacture focuses on a particular compound, such as catechins, EGCG or caffeine, within the tea. The percentage of an individual constituent can be increased or decreased to suit customer requirements.

In London, Bond works on all aspects of this side of the business, including health claims and sustainability issues, and he sits on a number of important bodies and committees. His first role in the tea industry was with Unilever Research where he was head of global flavonoid research and development in the UK and India. Today, he is a member of the US Tea Association, the UK and European Tea Committees, and is a project leader on the International Standards Organization (ISO) Tea Committee, helping to ensure that tea can be produced, traded and consumed safely and to agreed standards. And for a number of years, he has been a member of the Tea Advisory Panel (TAP), an expert panel of public health experts (funded by the UK Tea and Infusions Council) which provides independent and objective information about the latest health benefits, particularly of black tea; answers questions about nutrition, hydration, and diet; and commissions study reviews and market research initiatives to investigate further the ‘natural’ well-being benefits associated with black tea.

Bond’s work over the years has focused on the flavonoids in tea and the part they play in lowering the risk of heart disease, stroke, cognitive decline, and cancer; and he has also been involved in  research into hydration, caffeine, fluoride and bone health, pesticide mrls (maximum residue levels), and L-theanine.

Setting standards

Although certain countries have always driven research into tea’s health benefits (in particular the UK and Germany), several other countries (China, India, Sri Lanka, etc.) have always collaborated and are now becoming more involved in running new research projects. Bond has the support of his colleagues at AVT to work with the ISO to collaborate with researchers in other countries to gather data and set standards for pesticide mrls and for any other substances found in tea. AVT Tea carries out due diligence and flags any problems, working with the lobbying companies and organizations to decide the mrl level that tea producers must work to, and to then publish the ‘gold standard’ to the rest of the tea producing world. Indeed, AVT has created a data base that now publishes information about which pesticides are being used in which regions of which countries, and about any other unusual substances detected in tea.

Other companies and agencies in Europe and beyond also carry out tests and share their results with AVT and, if they contribute data to AVT’s central information resource, they then have open access to the entire data base. As food production around the world has become more controlled and more technical over the years, more bodies have been created to deliver certification to prove good practice. As well as the EFSA (European Food Safety Authority) and the ISO, there is now also HACCP (Hazard Analysis Critical Control Point) system, the FSSC (Food Safety System Certification), the FSA (Food Standards Agency), Intertek Auditing and Certification - Food Services, etc., and, as is happening in the field of ethical and environmental certification bodies, these different control organizations are now beginning to share information to make the system more efficient and effective.

Tea flavonoids

The regular newsletter, published by Bond with his TAP colleague Dr. Carrie Ruxton as part of their role to provide the public with independent information about tea, wrote a few weeks ago, “A recent article in the American Journal of Nutrition found that drinking just two cups of tea daily was associated with a 40% reduced risk of mortality.” Ruxton responded, “This is not particularly surprising given that tea is a major source of flavonoid compounds  ….. of particular note, a higher flavonoid intake of around 350 mg, equivalent to approximately two cups of tea, was associated with a 40-50% reduced risk of cardiovascular disease and cancer mortality compared with those with the lowest intake.” And Bond’s overall message is that “Data pooled from one recent large study, consisting of 22 studies, found that regular tea consumption reduces the risk of coronary heart disease by 27% and that drinking three cups of black tea a day produces significant reduction in unhealthy low-density lipoprotein (LDL) cholesterol, both systolic and diastolic blood pressure, and reduces the risk of suffering a stroke, or dying from stroke, by 21%.” 

Bond also explained that the benefits of tea drinking are further extended to women, as shown in a ten-year Australian study involving 1,188 women. The consumption of three or more cups of tea a day was associated with a statistically significant 30% decrease in the risk of osteoporotic fractures and, says Bond, “It is thought that the flavonoids found in tea may have contributed to these benefits. And data from 14 studies and 9,958 cases of hip fracture also found that the risk of hip fracture was 16% lower among the highest versus the lowest consumers of tea. Compared with no tea consumption, drinking one to four cups of tea per day reduced the risk of hip fracture by 28%.

Green tea also has a beneficial effect on teeth. As Bond explained, “a new lab study looked at the effects of green tea on tooth dentine, the second layer of the tooth that can become eroded. After dentin samples had been submersed in green tea solution for up to three days, it was found that this helped to reduce the wear and roughness caused by dentine erosion. And other work with green tea showed that green tea extracts have benefits in terms of lowering numbers of oral cariogenic bacteria.” Other studies show other benefits and found that within just 30 minutes to one hour of drinking green tea, the brain waves increased, indicating that the green tea seems to have an important effect on cognitive function.

Tea and hydration

The UK Government’s Eatwell Guide recently stated that individuals should aim to drink 6 to 8 glasses of fluid every day and said that could include water, tea, lower-fat milk, and sugar-free drinks. A study sponsored by the Tea Advisory Panel’s study aimed to ascertain whether tea is as effective a hydrator as water.

Many people believe that, because of its caffeine content, tea acts as a diuretic and therefore reduces the hydrating effects of the beverage. Bond explains that a study of this type must be carried out on a group of healthy individuals and that parameters for research are set by the European Food Safety Authority. “Today’s studies are not just about the antioxidant effects of tea on human health but on the mechanisms of absorption of those antioxidants and their effects on different functions in the body. A number of studies into green tea were carried out in the 1990s but now there are more research programs looking at black tea. Green tea is easier to study because catechins such as EGCg (epigallocatechin gallate), can be easily tracked in the blood.

“During the oxidation of black tea, EGCg is converted to thearubigins and theaflavins which are more soluble and disappear easily into the system, making them much harder to track as they pass through the body. It’s therefore much harder to assess the effects.” In order to measure tea’s effects on hydration in the body, a group of 21 healthy, resting men between the ages of 20 and 55 were given four mugs of 240ml servings of black tea over a 24-hour period, and four mugs of 240ml of water over a second 24-hour period. Samples of urine were measured for creatinine concentration, osmolality, and the concentration of certain electrolytes. Blood samples were measured for levels of electrolytes, protein concentration, urea, creatinine and osmolality, and after analysis of the measurements, tea was found to have the same hydrating properties as water.

L-theanine research

Bond and the Tea Advisory Panel’s work have also been involved in research into L-theanine but few tea companies have used information about L-theanine as a marketing tool since a 2011 report from the EFSA said that more research was needed before claims can be made about the calming benefits of this amino-acid that only exists in the Bay Bolete mushroom, Ilex Guayusa, an Amazonian tree related to the holly, and Camellia sinensis.

The EFSA report states: “Scientific substantiation of the claimed effect: The references provided included a report from an authoritative body on the effects of isolated L-theanine given at pharmacological doses, narrative reviews and monographs on the characterization of the Camellia sinensis (L.) Kuntze plant and its byproducts, and a number of narrative reviews about the health effects of L-theanine. These publications did not contain original data which could be used for the scientific substantiation of the claims. A number of the references provided reported either on the effects of food constituents (e.g. caffeine and catechins) other than L-theanine, on the effects of L-theanine in combination with other food constituents (e.g. caffeine), or on health outcomes (e.g. anxiety, mood, brain chemistry, brain ischaemia, theanine bioavailability, theanine toxicity, hydration and cardiovascular health) other than the claimed effects. The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claims.”

However, studies carried out in Japan at the University of Shiga Prefecture, Human Culture Department, found that “the properties of L-theanine can be summed up as being a relaxing agent without sedation and is also implicated in reducing the perception of stress and slightly improving attention.” And Tim Bond, commenting on a Dutch study into the effects of L-theanine, explained that the study “evaluated the effects of two key ingredients in black tea – L-theanine and caffeine - on cognitive performance. The researchers gave a combination of 97 mg L-theanine and 40 mg caffeine (i.e., moderate levels) as compared to placebo treatment and looked at the effects on cognitive performance, alertness, blood pressure, and heart rate in a sample of 44 young adults.

“Cognitive performance, self-reported mood, blood pressure, and heart rate were measured before L-theanine and caffeine administration (i.e. at baseline) and 20 minutes and 70 minutes later. This combination of moderate levels of L-theanine and caffeine significantly improved accuracy during task switching and self-reported alertness and reduced self-reported tiredness. These findings are in agreement with those of another recent study in human subjects which showed that consumption of two servings of black tea improves the ability to react to stimuli and to focus attention on the task in hand.”

There is more work to be carried out in this field before claims about the benefits of L-theanine can be made. However, the results of other research work being carried out by AVT, by the Tea Advisory Panel, and other similar bodies around the world into other aspects of tea and health are increasingly positive. And so Tim Bond’s words of advice to the consuming public are: “Drinking black, green and oolong tea all tick a lot of boxes when it comes to our health - from reducing diabetes, cardiovascular disease, stroke, arthritis, and obesity risks to possessing protective properties against cancer, as well as oral health and hydration benefits. With the strong body of positive scientific evidence around its health benefits, tea should be enjoyed on a daily basis.”