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.
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.
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.
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.
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.
(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.
Are you the type of person that jumps out of bed every morning with a smile on your face as soon as your alarm goes off, ready and waiting to face the day? Do you remain full of energy and on full pelt for the rest of the day before having a great night’s sleep every night? Or are you more likely to hit snooze on your alarm as much as possible before you absolutely have to get up? Then day-dream about your bed as your energy levels drop through the floor throughout the day?! If you are more likely to be the latter, you are most certainly not alone.
A persistent lack of energy is one of the most common complaints in both men and women across the nation. Daylight, and more importantly sunlight, has a great effect on our overall energy levels. Historically we are used to being outside all day benefiting from the effects of sunlight. Modern living, however, results in the majority of us spending large amounts of time indoors, deprived of sunlight and this causes problems with our body’s natural rhythm and well being.
Officially summer comes to an end this weekend with clocks going back an hour. This signals the start of dull days with very limited and less intense sunlight and even less opportunity to benefit from the sun. This can bring about a reduction in energy levels for much of the population and reduced daylight can, in some cases, cause Season Affective Disorder (SAD) – sometimes known as Winter Depression. As a result many people begin to dread the winter months. There are, however, many natural ways to combat low energy and SAD. Balancing your circadian rhythm is a great way to do this.
Below we have drawn up a brief guide on how you can boost your energy levels and prevent the frequent desire for those 3pm snoozes!
Early Morning (approx 6.30am – 9am)
Your Internal Bodyclock is in its “awakening” mode at this stage. Your metabolism is slow and rising. Your body temperature, blood pressure and cortisol levels are all also increasing, signalling to your body to wake up. You may feel ‘groggy’ first thing and crave that morning cup of coffee or a bowl of sweet, sugary breakfast cereal. This may give you a rapid increase in energy, but it will also leave you with an energy slump once the initial effects have worn off. This is where people can fall into the habit of regular caffeine or sugary snacks in an attempt to maintain this feeling.
There are better ways to boost your energy and replenish the low blood glucose levels that have developed during sleep. Try adding a slice of lemon to hot water – this has natural sugars and also helps cleanse the digestive system (having the effect of a bit of a mini detox) ready for the day ahead. Also opt for high fibre breakfasts such as 100% pure rolled porridge oats with a handful of fruit and seeds or a boiled egg with wholemeal toast. These kinds of foods will provide you with a slow and sustained release of energy throughout the morning, keeping you full for longer and reducing those energy slumps.
Try to get out in the daylight as much as possible in the morning as this will wake your body up for the day. The winter days will prevent many people from being able to do this, therefore you may wish to try using a sunrise alarm clock, like the Lumie Bodyclock Starter in the mornings. This will stimulate your brain into waking gradually, balancing your circadian rhythm and your cortisol levels, which has the added bonus of being able to also support your immune system and stress levels.
Morning until Lunch (approx 9am – 2pm)
As your cortisol levels are still increasing you are more alert and efficient and your mental capability has reached its peak of the day. This means your concentration, memory and focus are all waiting to be utilised. So use this time to get all your lingering tasks done!
You could also try using a SAD light for 30 minutes every day for energy stimulation. The effectiveness of SAD Lights is measured in lux, which is the level of light intensity that you would normally get from the sun. A SAD light with 10,000 lux is recommended for those who want to see the most benefits.
Also avoid drinking coffee at this time as this can cause the swift rises and falls in energy levels. Instead you could try green tea, which is packed with antioxidants and contains much less caffeine per cup. Other teas are also great options such as ginger tea, which is good for digestion. Peppermint, fennel and camomile are also good options.
Females should take extra care too. A lack of energy can be due to low iron levels and coffee has been shown to reduce iron stores in the body. Make sure your levels are topped up by eating foods rich in iron such as meats, some fish and leafy greens such as spinach. Consider taking an iron supplement and remember to take this with vitamin C to help its absorption. B vitamins are also great for energy – You could try adding a multivitamin with extra B Complex, such as Viridian High 5 Multi Vitamin to your daily routine.
Another helpful tip is to try to get outside during your lunch break – the fresh air and daylight can do wonders to prevent that mid-afternoon slump. When choosing your lunch, choose slow-release carbohydrates such as brown rice or wholemeal bread rather than refined carbs such as white bread or crisps. Also ensure you have some protein in your meal too – such as lean chicken, fish, beans or pulses.
Afternoon (approx 2pm – 5pm)
Your cortisol levels start to drop which can often lead to drowsiness or that mid-afternoon slump. It’s best to avoid the temptation for biscuits or chocolate for a sugar boost at this time. If you must have a snack, try a small piece of minimum 70% quality dark chocolate or some dried fruit, nuts or seeds. Make sure you prioritise your tasks for the afternoon so you know exactly what you need to achieve before home time. That way you can go home happy and content with the day. ‘A well spent day brings happy sleep’ after all. Also taking in deep breaths is great for energy levels and can help reduce stress and aid concentration.
Evening (approx 5pm – 10pm)
As the evening progresses your melatonin levels start to increase (the hormone that prepares your body for sleep) and your digestion slows. Try to avoid snacking in the evening and heavy meals before bed time. This will require a lot of digestion as insulin is less effective at night. Also your digestive system will struggle to cope with excess amounts of food before bed and this can lead to weight gain as well as disruptive sleep – contributing to an imbalanced circadian rhythm. It is best to avoid all stimulants such as coffee, tea and alcohol as much as possible at this time as these can also disrupt your sleep.
A bad night’s sleep can cause low energy the following day and contribute to reduced mental performance. This can cause stress and lead to a spiral of stress and disrupted sleep which is hard to get out of. If you have trouble drifting off at night, try a sunrise alarm clock with a sunset feature like the Lumie Bodyclock Active. The light gradually dims helping your brain to naturally switch off. If a sunset feature is not for you, then try spraying lavender on your pillow or rubbing some lavender sleep therapy balm on your body to help you switch off.
In addition to these helpful tips, specific nutrients that can support energy levels are:
Magnesium – found in leafy green vegetables such as spinach and kale
Vitamin B Complex – found in brown rice and wholemeal bread. If you supplement this, it is best taken as a “complex” of B Vitamins
Alpha Lipoic Acid (ALA) & Acetyl-l-Carnitine (ALC) – Found in green foods such as broccoli, spinach and some red meats
Co-Enzyme Q10 – found in fish, organ meats such as liver and whole grains
Iron – found in a multitude of food sources, such as red meat, beans and pulses, leafy green vegetables, tofu and fortified breads and cereals
Last week I wrote about a study which found that green tea may positively impact bone health. Today I wanted to look at a newly published study (1) which found that women who drink green tea regularly seem to have a reduced risk of stomach cancer. Past studies have linked green tea consumption to a reduced risk of cancer at various sites in the body and it is probable that this has to do with the antioxidant flavonoids/polyphenols that the tea contains such as catechins (which I also discussed last week). There is an added benefit of green tea in terms of prevention against stomach cancer – it is thought that the tea contains compounds that may fight certain types of bacteria which have been linked to stomach cancer.
This study (1) examined the association between green tea consumption and gastric cancer. Data for over 200,000 individuals were analysed for the research. In women, but not men, a significantly decreased risk of stomach cancer was observed for those women who consumed 5 or more cups of green tea per day compared to those who drank one cup or less per day. Interestingly the reduced risk of stomach cancer seemed to apply to cancers in certain parts of the stomach. The study took place in Japan where individuals frequently drink more than 5 cups of green tea daily.
Here in the UK green tea is becoming increasingly popular as a drink and also as a nutritional supplement, with many people switching their regular milky black tea for the green variety. This current study does not prove that green tea protects against stomach cancer – the researcher want to do further research to see whether drinking the tea actually reduces the risk of stomach cancer, or whether women with a lower risk simply happen to drink more of it.
As I have mentioned many times in the past, antioxidant nutrients and flavonoids appear to be very important in reducing the risk of various cancers and other diseases. The best way to boost antioxidant levels is to eat a large variety of vegetables and fruits daily, a minimum of 5 portions is recommended, however some experts say this is too low and that we need to be aiming for at least 9 a day in order to prevent various illnesses. If you feel that you consistently fall short of the recommended 5 per day you may want to consider taking an antioxidant supplement that contains a variety of flavonoids – the evidence for these supplements is currently scant but studies are presently being carried out. Please remember that supplements should never be viewed as a replacement for a balanced diet.
(1) Inoue M et al. 2009. Green tea consumption and gastric cancer in Japanese: a pooled analysis of six cohort studies. Gut. 58(10):1323-32. Written by Ani Kowal
Green tea is becoming increasingly popular as a drink in the UK and throughout the ‘West’. More and more people are also taking green tea supplements due to the numerous reports of the health benefits attributed to this drink. Previously I have written about green tea with respect to antioxidants, heart disease, cancer and ageing. Today I wanted to look at some new evidence (1) that certain chemical compounds within green tea may help to improve bone health.
The study(1) was a preliminary laboratory-based cell study and further work would be necessary before firm conclusions or recommendations can be drawn from the results, however it gives interesting evidence nonetheless. I have mentioned before that green tea contains bioactive plant chemicals, polyphenols, known as catechins. The common polyphenols which are often listed on green tea supplements include those that were researched in this study, namely epigallocatechin, gallocatechin, and gallocatechin gallate. These polyphenols have antioxidant properties in the body which probably account for many of their health benefits.
The laboratory study(1) found that tea catechins had positive effects on bone metabolism – they stimulated bone cell formation and helped to slow its breakdown. Epigallocatechin appeared to be particularly helpful in boosting bone growth and bone mineralisation (which helps to strengthen bones). This was the first study to pinpoint which chemicals in green tea are important in the possible improvement of bone health. Importantly the researchers also noted that the catechins did not appear to cause any toxic effects in the bone cells.
Last month I wrote about the link between onions and bone health and have also written about carotenoids and bone strength as well as the importance of fruits and vegetables for bones. The link between all these factors, including green tea, seems to be antioxidants. As I said on Monday the best way to get dietary antioxidants is through eating a variety of fruits and vegetables daily. Supplements cannot be seen as an alternative to a good diet but can be used as a support if you feel that you regularly struggle to include a minimum of five portions of vegetables and fruits into your daily diet. More evidence is continually being published regarding the importance of flavonoids and antioxidants for health.
I would like to end this post by pointing out that antioxidant flavonoids/polyphenols are also found in cocoa as I have previously discussed! This is why good quality dark chocolate (70% cocoa solids or above) can be enjoyed in small quantities guilt-free! There are many studies which now extol the benefits of cocoa for health. As I finish writing this piece I am allowing a square of my favourite 85% cocoa solids dark chocolate to melt on my tongue!
(1)Ko, CH et al. 2009. Effects of Tea Catechins, Epigallocatechin, Gallocatechin, and Gallocatechin Gallate, on Bone Metabolism. J. Agric. Food Chem. 57 (16): 7293–7297
A recently published small study (1) has found that men with prostate cancer who consumed an active green tea supplement had significant reductions in biological-markers predictive of prostate cancer progression.
Green tea has become an incredibly popular drink and supplement and an increasing number of studies are being published with regards its health benefits. The number of current human studies investigating the relationship between green tea and prostate cancer is small. This study (1) was preliminary but informative. It involved just 26 men aged 41-72 years old who were diagnosed with prostate cancer and due to undergo radical prostatectomy. The trial looked to determine the effects of short-term supplementation with the active compounds found in green tea on biological-markers in patients diagnosed with prostate cancer. These biomarkers [technically looking at hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF) and prostate specific antigen (PSA)] are good prognostic indicators of prostate cancer progression.
The men involved in the study were given 4 green tea capsules for an average of 34 days prior to surgery. The 4 capsules provided the equivalent of around 12 cups of normally brewed green tea. Results showed that there was a significant reduction in blood serum levels of the biological-markers of prostate cancer after treatment with the green tea capsules. Some of the patients had reductions in the biomarker levels of more than 30%. The supplements had no effect on liver function, which was used as a measure of toxicity.
The supplement used contained 1.3g tea polyphenols, bioactive plant nutrients, that are found naturally in green tea: 800 mg of epigallocatechin-3-gallate (EGCG) and lesser amounts of epicatechin, epigallocatechin, and epicatechin-3-gallate. Green tea supplements often have these polyphenols listed as active ‘ingredients’.
In a press release(2) one of the authors commented: “These studies are just the beginning and a lot of work remains to be done, however, we think that the use of tea polyphenols alone or in combination with other compounds currently used for cancer therapy should be explored as an approach to prevent cancer progression and recurrence“.
In the same press release(2) William G. Nelson, V., M.D., Ph.D., professor of oncology, urology and pharmacology at the Johns Hopkins Kimmel Cancer Center, said that he believed the reduced blood serum biomarkers of prostate cancer may be attributable to some sort of benefit relating to green tea components “Unfortunately, this trial was not a randomized trial, which would have been needed to be more sure that the observed changes were truly attributable to the green tea components and not to some other lifestyle change (better diet, taking vitamins, etc.) men undertook in preparation for surgery,”. However, “this trial is provocative enough to consider a more substantial randomized trial.”
The researchers of this study are currently conducting a comparable trial among patients with breast cancer.
For general information about nutrition and prostate health please read my previous blog posts on the subject (Prostate health Part I and II). For more information on prostate cancer please visit the Prostate Cancer Care website.
The World Cancer Research Fund (WCRF) estimate that lifestyle factors such as being overweight, eating an unhealthy diet and being inactive are responsible for about a third of all cancers in developed countries (3). Please visit the WCRF website for information related to diet and cancer prevention.
1. McLarty J et al. 2009. Tea Polyphenols Decrease Serum Levels of Prostate-Specific Antigen, Hepatocyte Growth Factor, and Vascular Endothelial Growth Factor in Prostate Cancer Patients and Inhibit Production of Hepatocyte Growth Factor and Vascular Endothelial Growth Factor In vitro. Cancer Prevention Research, 10.1158/1940-6207.CAPR-08-0167. Published online June 19 2.Sciencedaily.com press release. American Association for Cancer Research (2009, June 22). Green Tea May Slow Prostate Cancer Progression. ScienceDaily. Retrieved June 23, 2009, from http://www.sciencedaily.com¬ /releases/2009/06/090619112329.htm (3) WCRF/AICR. 2009. Policy and action for cancer prevention. Food, nutrition and physical activity: a global perspective. Washington DC: AICR, 2009.
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.