Does Green Tea Help Prevent Prostate Cancer?

“Prostate cancer is a leading cause of illness and death among men in the United States and Western Europe,” but rates in Asia can be as much as ten times lower. Perhaps Asians are genetically less likely to get prostate cancer? No. Japanese Americans and Chinese Americans have high prostate cancer rates as well, as you can see at 0:22 in my video Preventing Prostate Cancer with Green Tea. In the United States, up to nearly one in three men in their 30s already has small prostate cancers brewing and that grows to nearly two thirds of American men by their 60s. On autopsy, most older men were found to have unknown cancerous tumors in their prostates. What’s remarkable is that Asian men seem to have the same prevalence of these hidden, latent prostate cancers on autopsy, but they don’t tend to grow enough to cause problems. In Japan, men tend to die with their tumors rather than from their tumors. Of course, that’s changing as Asian populations continue to Westernize their diets.

What is it about Western diets that fuels cancer growth? It could be carcinogens in the diet accelerating the growth of cancer. Indeed, the typical American diet is rich in animal fats and meats, but it could also be something protective in Asian diets that is slowing the cancer growth, such as fruits, vegetables, soy foods, or green tea.

How might we determine if there is a link between tea consumption and the risk and progression of prostate cancer? Dozens of studies have examined whether tea drinkers tend to get less cancer in the future and if cancer victims tend to have drank less tea in the past. Although the results have been mixed, overall, tea consumption was associated with a lower risk of prostate cancer. So, tea consumption might indeed play a protective role. However, just because tea drinkers get less cancer doesn’t mean it’s necessarily because of the tea. Perhaps drinking tea is just a sign of a more traditional lifestyle and maybe tea drinkers are less likely to be patrons of the thousand KFC fast-food restaurants now in Japan.

In vitro studies performed in a lab allow for as many factors to be controlled as possible. When everything is removed from the equation except for green tea and prostate cancer, dripping green tea compounds directly on prostate cancer cells in a petri dish can cause them to self-destruct, as you can see at 2:31 in my video. But we do not appear to absorb enough green tea compounds into our bloodstream to reach those kinds of levels. This may explain why some studies failed to find an association between tea drinking and cancer. Maybe we’re not drinking enough? In the United States, for example, the “high” tea-drinking group may be defined as more than five cups of tea a week. In Japan, however, the “high” tea-drinking group can consume five or more cups a day, which was associated with about halving the risk of aggressive prostate cancer. How? Apparently, it was not by preventing the formation of the cancer in the first place, but perhaps by slowing or stopping the cancer’s growth. If green tea can stop the growth of prostate cancer, why not try giving green tea to prostate cancer patients to see if it will help? Green tea is actually put to the test in cancer patients in my video Treating Prostate Cancer with Green Tea.


For more on men’s health, check out:

Interested in more on tea? See:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

Last Day to Register for Obesity Webinar & New Stroke Risk Webinar

I’m excited to announce my next webinar, taking place on February 19: 

Why Do Vegetarians Have Higher Stroke Risk?

Unlike the obesity webinar, which was put together mostly just to satisfy the intellectual curiosity of fellow nutrition nerds (more info below!), my February webinar is going to be of a more practical nature. Given that high blood pressure and inadequate fruit and vegetable consumption are among the most important things we can do to lower stroke risk, you would assume those eating plant-based diets would be at significantly lower risk, just as they are with heart attacks. You might be surprised to learn that there had never been any studies on the incidence of stroke in vegetarians, though…until now. And if you think that is surprising, wait until you hear the results. Yes, they had lower heart disease risk as expected, but those eating meat-free diets appeared to have more stroke risk. If that is indeed the case, what might be the cause, and what can we do about it? I hope you’ll join me for this important event. For more information and to register, go here.

Date and Time: February 19, 2-4pm ET
Last Day to Register: February 13

 

Today is the last day to register for my next webinar on January 24 at 2pm ET:

Obesity webinarWhat Triggered the Obesity Epidemic? 

The obesity epidemic exploded throughout the industrialized world in the late 1970s. What happened? Any potential driver would have had to be global in nature and coincide with the upswing of the epidemic. So how do the various theories stack up? Was it the fat, the sugar, our genes, lack of exercise? If you are as curious as I was before I dived in, I hope you’ll join me as I sift through the possibilities and answer your questions in this 2-hour live webinar, which is (*spoiler alert*) based on the first part of my new book How Not to Diet. For more information, and to register, go here.

And speaking of my new book, I was thrilled to be back on Live with Kelly and Ryan and Fox Business to discuss it. 

 

Speaking Tour Kicking Off

Speaking tourI’ve started my 200-city speaking tour. This will take me all over the US and other parts of the world. Here are a few of the upcoming events that are open to the public. You can also see the full list here.

1/12/2020 Loma Linda, CA
Loma Linda University School of Medicine 

1/17/2020 Sedona, AZ
L’Auberge de Sedona for Health and Nutrition Conference & Sedona Performing Arts Center for VegFest

2/7/2020 Boise, ID
Plant Based in Boise

2/16/2020 Camarillo, CA
Whole Conference

2/21-2/28/2020
Holistic Holiday at Sea

 

Seeking Chinese Translation Volunteers

Chinese volunteersWe’re currently seeking volunteers with experience in English-Chinese translation and editing as we continue to bring the latest research on nutrition to people in Chinese-speaking regions. You can find the volunteer position descriptions and applications here

 

 

Host a How Not to Die Screening

Over 30 How Not to Die Screening events have taken place around the world since last April. These events have brought communities together and have allowed this life-saving information to effectively reach wider audiences. Consider hosting a free event in your area. For more information and to apply, go here

 

 

 

 

Physicians Association for Nutrition

Physicians Assoc. for NutritionThe international medical organization Physicians Association for Nutrition (PAN International) is calling all health professionals supportive of a plant-based diet to add themselves to their latest website feature: an interactive map and list where patients around the globe can identify supportive practitioners near them. If you are a physician, physician assistant, registered dietician, or a nurse practitioner, please visit their website and consider adding your practice to the list!

 

Top 3 Videos of the Month

 

Are Pre-Cut Vegetables Just as Healthy?

Are Pre-Cut Vegetables Just as Healthy?

Endotoxins can build up on pre-chopped vegetables and undermine some of their benefits.

 

Are BCAA (Branched Chain Amino Acids) Healthy?

Are BCAA (Branched-Chain Amino Acids) Healthy?

Why we may want to strive not to exceed the recommended intake of protein.

 

Is Breakfast the Most Important Meal for Weight Loss?

Is Breakfast the Most Important Meal for Weight Loss?

Is the link between breakfast skipping and obesity cause-and-effect?

 

 

Live Q&As January 23

Live Q&A

 

Every month now I do Q&As live from my treadmill, and January 23 is the day.

  • Facebook Live: At 12:00 p.m. ET go to our Facebook page to watch live and ask questions.
  • YouTube Live Stream: At 1:00 p.m. ET go here to watch live and ask even more questions! 

You can now find links to all of my past live YouTube and Facebook Q&As right here on NutritionFacts.org. If that’s not enough, remember I have an audio podcast to keep you company at http://nutritionfacts.org/audio.

 

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Why Drinking Diet Soda Makes You Crave Sugar

Recommendations on limiting sugar consumption vary around the world, with guidelines ranging from “[l]imit sweet desserts to one every other day” to “[k]eep sugar consumption to 4 or less occasions per day.” In the United States, the American Heart Association is leading the charge, “proposing dramatic reductions in the consumption of soft drinks and other sweetened products” and recommending fewer than about 5 percent of calories a day from added sugars, which may not even allow for a single can of soda.

Why is the American Heart Association so concerned about sugar? “Overconsumption of added sugars has long been associated with an increased risk of cardiovascular disease,” meaning heart disease and strokes. We used to think added sugars were just a marker for an unhealthy diet. At fast-food restaurants, for example, people may be more likely to order a cheeseburger with their super-sized soda than a salad. However, the new thinking is that the added sugars in processed foods and drinks may be independent risk factors in and of themselves. Indeed, worse than just empty calories, they may be actively disease-promoting calories, which I discuss in my video Does Diet Soda Increase Stroke Risk as Much as Regular Soda?.

At 1:14 in my video, you can see a chart of how much added sugar the American public is consuming. The data show that only about 1 percent meet the American Heart Association recommendation to keep added sugar intake down to 5 or 6 percent of daily caloric intake. Most people are up around 15 percent, which is where cardiovascular disease risk starts to take off. There is a doubling of risk at about 25 percent of calories and a quadrupling of risk for those getting one-third of their daily caloric intake from added sugar.

Two hundred years ago, we ate an estimated 7 pounds of sugar annually. Today, we may consume dozens of pounds of sugar a year. We’re hardwired to like sweet foods because we evolved surrounded by fruit, not Froot Loops, but this adaptation is “terribly misused and abused” today, “hijacked” by the food industry for our pleasure and their profits. “Why are we consuming so much sugar despite knowing too much can harm us?” Yes, it may have an addictive quality and there’s the hardwiring, but the processed food industry isn’t helping. Seventy five percent of packaged foods and beverages in the United States contain added sweeteners, mostly coming from sugar-sweetened beverages like soda, which are thought responsible for more than a 100,000 deaths worldwide and millions of years of healthy life lost. Given this, can we just switch to diet sodas? By choosing diet drinks, can’t we get that sweet taste we crave without any of the downsides? Unfortunately, studies indicate that “[r]outine consumption of diet soft drinks is linked to increases in the same risks that many seek to avoid by using artificial sweeteners—namely type 2 diabetes, metabolic syndrome heart disease, and stroke.” At 3:15 in my video, you can see data showing the increased risks of cardiovascular disease associated with regular soft drinks and also diet soda. They aren’t that dissimilar.

“In other words, the belief that artificially sweetened diet beverages reduce long-term health risks is not supported by scientific evidence, and instead, scientific data indicate that diet soft drink consumption may contribute to the very health risks people have been seeking to avoid.” But, why? It makes sense that drinking all that sugar in a regular soft drink might increase stroke risk, due to the extra inflammation and triglycerides, but why does a can of diet soda appear to increase stroke risk the same amount? It’s possible that the caramel coloring in brown sodas like colas plays a role, but another possibility is that “artificial sweeteners may increase the desire for sugar-sweetened, energy-dense beverages/foods.”

The problem with artificial sweeteners “is that a disconnect ultimately develops between the amount of sweetness the brain tastes and how much glucose [blood sugar] ends up coming to the brain.” The brain feels cheated and “figures you have to eat more and more and more sweetness in order to get any calories out of it.” So, “[a]s a consequence, at the end of the day, your brain says, ‘OK, at some point I need some glucose [blood sugar] here.’ And then you eat an entire cake, because nobody can hold out in the end.”

If people are given Sprite, Sprite Zero (a zero-calorie soda), or unsweetened, carbonated, lemon-lime water, but aren’t told which drink they’re getting or what the study is about, when they’re later offered a choice of M&M’s, spring water, or sugar-free gum, who do you think picks the M&M’s? Those who drank the artificially sweetened soda were nearly three times more likely to take the candy than those who consumed either the sugar-sweetened or unsweetened drinks. So, it wasn’t a matter of sweet versus non-sweet or calories versus no-calories. There’s something about non-caloric sweeteners that somehow tricks the brain.

The researchers did another study in which everyone was given Oreos and were then asked how satisfied the cookies made them feel. Once again, those who drank the artificially sweetened Sprite Zero reported feeling less satisfied than those who drank the regular Sprite or the sparkling water. “These results are consistent with recent [brain imaging] studies demonstrating that regular consumption of [artificial sweeteners] can alter the neural pathways responsible for the hedonic [or pleasure] response to food.”

Indeed, “[t]he only way really to prevent this problem—to break the addiction—is to go completely cold turkey and go off all sweeteners—artificial as well as fructose [table sugar and high fructose corn syrup]. Eventually, the brain resets itself and you don’t crave it as much.”

We’ve always assumed the “[c]onsumption of both sugar and artificial sweeteners may be changing our palates or taste preferences over time, increasing our desire for sweet foods. Unfortunately, the data on this [were] lacking”…until now. Twenty people agreed to cut out all added sugars and artificial sweeteners for two weeks. Afterwards, 95 percent “found that sweet foods and drinks tasted sweeter or too sweet” and “said moving forward they would use less or even no sugar.” What’s more, most stopped craving sugar within the first week—after only six days. This suggests a two-week sugar challenge, or even a one-week challenge, may “help to reset taste preferences and make consuming less or no sugar easier.” Perhaps we should be recommending it to our patients. “Eating fewer processed foods and choosing more real, whole, and plant-based foods make it easy to consume less sugar.”


Speaking of stroke, did you see my Chocolate and Stroke Risk video?

For more on added sugars, see:

You may also be interested in my videos on artificial and low-calorie sweeteners:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations: