Tag Archives: green tea

Green tea and male fertility

A new study has found that an extract from green tea affects sperm quality (1). The research, published last month in the journal Molecular Nutrition and Food Research, found that low doses of a chemical compound (epigallocatechin gallate or EGCG) which is present in green tea can improve sperm quality.

Sub-fertility among men is common, and numbers of men affected are increasing. Recent data suggests that 1 in 5 men between the ages of 18-25 now have fertility problems linked to semen quality (2). In around 50% of cases, the cause of male subfertility is unknown, and in such cases nutritional and lifestyle measures are often recommended as a means of boosting sperm quality.

In this recent study, researchers exposed human sperm samples to a range of concentrations of EGCG, a chemical compound present in green tea. Results showed that, at low concentrations, EGCG was associated with increased sperm motility, viability, and phosphorylation of proteins controlling cell survival.

The aim of the study was to find out whether the extract from green tea increased the sperm’s ability to fertilise an egg by improving a process called ‘capacitation’. Capacitation is simply a series of biological processes needed to ‘activate’ the sperm so that it can fertilise the waiting egg.

At low and medium doses, the results were positive. The researchers reported that “depending on the used concentration, ECGC/estrogen receptors are able to improve fertilisation potential of the human male gamete, evidencing the specific effects on motility, viability and energy expenditure in human sperm”. In short, the sperm treated with ECGG helped sperm to swim well. It also increased the number of living sperm, and supported essential signalling inside the sperm.

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At very high concentrations, ECGC had the opposite effect. Such results highlight the need for further research in this area.

There is in fact a growing amount of research surrounding the potential benefits of nutrients in boosting male fertility, with previous studies assessing the effectiveness of nutrients such as l-carnitine and coenzyme Q10.

Previous studies support the value of antioxidants in boosting male fertility (3). The high antioxidant value of green tea is well known, and this characteristic may therefore play a role in its fertility-boosting potential. Sperm damage is thought to occur when highly reactive particles called free radicals circulate in the body, causing damage to sperm cells. This damage may reduce fertility by lowering sperm counts or reducing the sperm’s ability to fertilise an egg. For this reason, antioxidants, which fight those free radicals, are thought to be helpful.

Further controlled trials are certainly needed to provide solid guidelines on the benefits of nutrients in treating male fertility. My feeling is that further research will serve to confirm the crucial role for diet and lifestyle in this area.  The European Science Foundation recently reported new figures showing a rapid increase in male reproductive disorders. This indicates that these fertility issues are caused by environmental factors or changes in our lifestyle rather than genetic factors, meaning that they may be entirely preventable with the a natural approach focussing on nutrition and lifestyle.

Written by Nadia Mason, BSc MBANT NTCC CNHC.

References

1.De Amicis et al (2012) Epigallocatechin gallate affects survival and metabolism of human sperm Mol Nutr Food Res Nov;56(11):1655-64.

2. Male Reproductive Health – Its impacts in relation to general wellbeing and low European fertility rates. ESF Science Policy Briefing 40, October 2010.

3. Showell et al (2011) Antioxidants for male subfertility. Cochrane Database Syst Rev. Jan 19;(1):CD007411.

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Green tea found to reduce levels of “bad” cholesterol

Green tea, both the beverage and the supplement form, can reduce levels of ‘bad’ cholesterol, according to a recent US study (1).

The meta-analysis, published last month in the Journal of the American Dietetic Association, analysed 20 randomised controlled trials.

Green Tea can help support healthy cholesterol levels
Green Tea can help support healthy cholesterol levels (2.)

Each of the 20 trials measured the effects of either green tea itself, or capsules containing green tea compounds called catechins. Each participant was given either a daily green tea supplement or drink, or else a placebo capsule or drink.

In total, the trails involved a total of 1,415 adults with raised cholesterol levels. Each of the trials lasted between three and six months. Green tea was found to reduce the trial participants’ total cholesterol and ‘bad’ LDL cholesterol by 5-6 more points than placebo drinks or capsules.

It is thought that the catechin compounds in green tea work to lower cholesterol levels by reducing its absorption in the gut.

Further research is needed in order to determine the optimal dose of green tea compounds. Senior researcher Olivia Phung also added that green tea is not a substitute for prescribed medication, but suggests that “adding green tea to your diet could be one way to further improve cholesterol numbers”.

It is also important to note that green tea and its extracts contain caffeine, which some people may need to avoid.

Overall, the study indicates that the use of herbal supplements such as green tea is one strategy to lower cholesterol, alongside medication and lifestyle changes.

Other strategies include reducing levels of saturated fat in your diet, such as fatty meats, and baked goods such as biscuits, pastries and cakes. Saturated fats should be replaced by healthy fats such as those present in nuts, seeds, avocado and oily fish.

Taking regular exercise can also reduce levels of LDL cholesterol, and reducing alcohol intake can lower both LDL cholesterol and triglycerides.

To learn more about the causes, treatment and prevention of high cholesterol, visit the British Heart Foundation website.

Written by Nadia Mason, BSc MBANT NTCC CNHC

References

(1.) Phung OJ, et al. Green Tea Catechins Decrease Total and Low-Density Lipoprotein Cholesterol: A Systematic Review and Meta-Analysis. Journal of the American Dietetic Association, November 2011. 111(11): 1720-1729.

(2.) Image courtesy of dem10

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