On Monday I was discussing the benefits of traditional Mediterranean diets. Today I wanted to take a look at a study that took place a little further afield. In China and Japan green tea has long been believed to have important health benefits. These benefits are now being increasingly researched and studies are showing that green tea may be useful for the prevention of many conditions from heart disease to cancer. The health benefits probably come from the many bioactive plant chemicals (flavonoids) that green tea contains, these may work through various mechanisms including via antioxidant means.
A recent study (1) investigated diet and breast cancer risk in Chinese women. The rate of breast cancer in China is lower, around four times lower, than in the UK. However, this rate is now increasing, especially in the more affluent parts of China. Part of this increase in cancer cases is thought to be linked to a move away from a traditional Chinese diet toward a more Western style diet.
The study (1) involved 1009 women from Southeast China aged 20-87 who had been diagnosed with breast cancer between the years 2004 and 2005. In addition to this, 1009 age-matched healthy women, with no breast cancer, were recruited to act as ‘controls’. Dietary interviews and questionnaires were conducted amongst the women. The researchers found that a higher dietary intake of mushrooms, both fresh and dried, was associated with a decreased breast cancer risk in premenopausal and postmenopausal Chinese women and an additional decreased risk of breast cancer was found from the additive or joint effect of mushrooms and green tea.
Traditionally mushrooms and green tea form a large part of the Chinese diet. The study specifically found that women who ate 10g or more fresh mushrooms daily were about 60% less likely to develop breast cancer compared to those who did not eat mushrooms. Women eating 4g or more of dried mushrooms daily were about half as likely to suffer with breast cancer compared to those not consuming dried mushrooms. In addition, the risk of breast cancer was lowered further in women who drank green tea daily as well as consuming fresh and dried mushrooms.
The study is a preliminary study and does not prove that mushrooms and green tea protect against breast cancer. However, investigating associations between diet and disease is always interesting and informative. More research is certainly warranted in this area.
Mushrooms, green tea, vegetables and fruits in general are high in a variety of vitamins, minerals and phytochemicals or flavonoids (biologically active plant chemicals). These ‘nutrients’ could be having a positive effect via a variety of complex mechanisms in our bodily cells e.g. through acting as powerful antioxidants. Eating a healthy diet rich in these foods and low in refined and processed foods will help to provide all kinds of essential nutrients, as well as fibre, and may help to protect us from a variety of diseases. The messages coming out of studies such as this one and the Mediterranean diet studies discussed on Monday is that eating ‘real food’ or what might be termed a more ‘traditional’ diet and minimising processed and refined food (fast foods and junk foods) in the diet is good for our health (which is not so surprising)! Our bodies are complex machines which need the right fuel in order to function well. Processed and refined foods contain calories but very little in the way of nutrients. Traditional diets rich in a variety of fruits, vegetables, pulses, nuts and seeds, healthy fats, unprocessed meats and fish will provide us with the nutrients necessary for optimal health and wellbeing. Sometimes we may fall short with our diets, taking a good quality ‘food-state’ multivitamin and mineral supplement together with an essential omega 3 fatty acid supplement is something that can be considered in order to make up for any lack during times of dietary deficiency. Supplements, however, cannot be viewed as a substitute for long-term healthy eating!
(1)Zhang M, Huang J, Xie X, Holman CD. 2009. Dietary intakes of mushrooms and green tea combine to reduce the risk of breast cancer in Chinese women. Int J Cancer. 124(6):1404-8.
Written by Ani Kowal