While the digestive process enables us to absorb and benefit from the nutrients contained in food, it can have varying effects on therapeutic plant compounds that have been shown to have specific benefits in vitro. However, research described in the journal Phytomedicine reveals that the neuroprotective properties of green tea are actually improved by digestion, meaning that its benefits could be greater than anticipated.
Research has demonstrated that polyphenols in green and black tea help protect brain cells by binding with hydrogen peroxide and amyloid beta, which are toxic compounds that are increased in the brains of Alzheimer’s disease patients.These tea phytochemicals are broken down to produce a number of compounds during digestion. “It’s one of the reasons why we have to be so careful when we make claims about the health benefits of various foods and supplements,” explained lead researcher Dr Ed Okello of England’s Newcastle University. “There are certain chemicals we know to be beneficial and we can identify foods which are rich in them but what happens during the digestion process is crucial to whether these foods are actually doing us any good.”
Dr Okello’s team collaborated with Dr Gordon McDougall of the Scottish Crop Research Institute in Dundee who developed technology that simulates human digestion. “What was really exciting about this study was that we found when green tea is digested by enzymes in the gut, the resulting chemicals are actually more effective against key triggers of Alzheimer’s development than the undigested form of the tea,” Dr Okello remarked. “In addition to this, we also found the digested compounds had anticancer properties, significantly slowing down the growth of the tumor cells which we were using in our experiments.”
In the experiments with cultured tumor cells, varying concentrations of the digested green tea compounds were administered and the effects were noted. “The digested chemicals protected the cells, preventing the toxins from destroying the cells,” Dr Okello revealed. “We also saw them affecting the cancer cells, significantly slowing down their growth.
“Green tea has been used in Traditional Chinese medicine for centuries and what we have here provides the scientific evidence why it may be effective against some of the key diseases we face today,” he stated. “There are obviously many factors which together have an influence on diseases such as cancer and dementia – a good diet, plenty of exercise and a healthy lifestyle are all important.”