Best Food for MGUS to Prevent Multiple Myeloma

Best Food for MGUS to Prevent Multiple Myeloma.jpeg

Multiple myeloma is one of our most dreaded cancers. It's a cancer of our antibody-producing plasma cells, and is considered one of our most intractable blood diseases. The precursor disease is called monoclonal gammopathy of undetermined significance (MGUS). When it was named, it's significance was undetermined, but now we know that multiple myeloma is almost always preceded by MGUS. This makes MGUS one of the most common premalignant disorders, with a prevalence of about 3% in the older white general population, and about 2 to 3 times that in African-American populations.

MGUS itself is asymptomatic, you don't even know you have it until your doctor finds it incidentally doing routine bloodwork. But should it progress to multiple myeloma, you only have about four years to live. So we need to find ways to treat MGUS early, before it turns into cancer. Unfortunately, no such treatment exists. Rather, patients are just placed in a kind of holding pattern with frequent check-ups. If all we're going to do is watch and wait, researchers figured to might as well try some dietary changes.

One such dietary change is adding curcumin, the yellow pigment in the spice turmeric. Why curcumin? It's relatively safe, considering that it has been consumed as a dietary spice for centuries. And it kills multiple myeloma cells. In my video Turmeric Curcumin, MGUS, & Multiple Myeloma, you can see the unimpeded growth of four different cell lines of multiple myeloma. We start out with about 5000 cancer cells at the beginning of the week, which then that doubles, triples, and quadruples in a matter of days. If we add a little bit of curcumin, growth is stunted. If we add a lot of curcumin, growth is stopped. This was in a petri dish, but it is exciting enough to justify trying curcumin in a clinical trial. And six years later, researchers did.

We can measure the progression of the disease by the rise in blood levels of paraprotein, which is what's made by MGUS and myeloma cells. About 1 in 3 of the patients responded to the curcumin with dropping paraprotein levels, whereas there were no responses in the placebo group. These positive findings prompted researchers to commence a double-blind, randomized, controlled trial. The same kind of positive biomarker response was seen in both MGUS patients as well as those with so-called "smoldering" multiple myeloma, an early stage of the cancer. These findings suggest that curcumin might have the potential to slow the disease process in patients, delaying or preventing the progression of MGUS to multiple myeloma. However, we won't know for sure until longer larger studies are done.

The best way to deal with multiple myeloma is to not get it in the first place. In my 2010 video Meat & Multiple Myeloma, I profiled a study suggesting that vegetarians have just a quarter the risk of multiple myeloma compared to meat-eaters. Even just working with chicken meat may double one's risk of multiple myeloma, the thinking being that cancers like leukemias, lymphomas, and myelomas may be induced by so-called zoonotic (animal-to-human) cancer-causing viruses found in both cattle and chickens. Beef, however, was not associated with multiple myeloma.

There are, however, some vegetarian foods we may want to avoid. Harvard researchers reported a controversial link between diet soda and multiple myeloma, implicating aspartame. Studies suggest french fries and potato chips should not be the way we get our vegetables, nor should we probably pickle them. While the intake of shallots, garlic, soy foods, and green tea was significantly associated with a reduced risk of multiple myeloma, intake of pickled vegetables three times a week or more was associated with increased risk.

For dietary links to other blood cancers, see EPIC Findings on Lymphoma.

The turmeric story just never seems to end. I recommend a quarter teaspoon a day:

Why might garlic and tea help? See Cancer, Interrupted: Garlic & Flavonoids and Cancer Interrupted, Green Tea.

More on the effects of NutraSweet in Aspartame and the Brain and acrylamide in Cancer Risk From French Fries.

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:

Image Credit: Sally Plank / Flickr. Image has been modified.

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Best Food for MGUS to Prevent Multiple Myeloma

Best Food for MGUS to Prevent Multiple Myeloma.jpeg

Multiple myeloma is one of our most dreaded cancers. It's a cancer of our antibody-producing plasma cells, and is considered one of our most intractable blood diseases. The precursor disease is called monoclonal gammopathy of undetermined significance (MGUS). When it was named, it's significance was undetermined, but now we know that multiple myeloma is almost always preceded by MGUS. This makes MGUS one of the most common premalignant disorders, with a prevalence of about 3% in the older white general population, and about 2 to 3 times that in African-American populations.

MGUS itself is asymptomatic, you don't even know you have it until your doctor finds it incidentally doing routine bloodwork. But should it progress to multiple myeloma, you only have about four years to live. So we need to find ways to treat MGUS early, before it turns into cancer. Unfortunately, no such treatment exists. Rather, patients are just placed in a kind of holding pattern with frequent check-ups. If all we're going to do is watch and wait, researchers figured to might as well try some dietary changes.

One such dietary change is adding curcumin, the yellow pigment in the spice turmeric. Why curcumin? It's relatively safe, considering that it has been consumed as a dietary spice for centuries. And it kills multiple myeloma cells. In my video Turmeric Curcumin, MGUS, & Multiple Myeloma, you can see the unimpeded growth of four different cell lines of multiple myeloma. We start out with about 5000 cancer cells at the beginning of the week, which then that doubles, triples, and quadruples in a matter of days. If we add a little bit of curcumin, growth is stunted. If we add a lot of curcumin, growth is stopped. This was in a petri dish, but it is exciting enough to justify trying curcumin in a clinical trial. And six years later, researchers did.

We can measure the progression of the disease by the rise in blood levels of paraprotein, which is what's made by MGUS and myeloma cells. About 1 in 3 of the patients responded to the curcumin with dropping paraprotein levels, whereas there were no responses in the placebo group. These positive findings prompted researchers to commence a double-blind, randomized, controlled trial. The same kind of positive biomarker response was seen in both MGUS patients as well as those with so-called "smoldering" multiple myeloma, an early stage of the cancer. These findings suggest that curcumin might have the potential to slow the disease process in patients, delaying or preventing the progression of MGUS to multiple myeloma. However, we won't know for sure until longer larger studies are done.

The best way to deal with multiple myeloma is to not get it in the first place. In my 2010 video Meat & Multiple Myeloma, I profiled a study suggesting that vegetarians have just a quarter the risk of multiple myeloma compared to meat-eaters. Even just working with chicken meat may double one's risk of multiple myeloma, the thinking being that cancers like leukemias, lymphomas, and myelomas may be induced by so-called zoonotic (animal-to-human) cancer-causing viruses found in both cattle and chickens. Beef, however, was not associated with multiple myeloma.

There are, however, some vegetarian foods we may want to avoid. Harvard researchers reported a controversial link between diet soda and multiple myeloma, implicating aspartame. Studies suggest french fries and potato chips should not be the way we get our vegetables, nor should we probably pickle them. While the intake of shallots, garlic, soy foods, and green tea was significantly associated with a reduced risk of multiple myeloma, intake of pickled vegetables three times a week or more was associated with increased risk.

For dietary links to other blood cancers, see EPIC Findings on Lymphoma.

The turmeric story just never seems to end. I recommend a quarter teaspoon a day:

Why might garlic and tea help? See Cancer, Interrupted: Garlic & Flavonoids and Cancer Interrupted, Green Tea.

More on the effects of NutraSweet in Aspartame and the Brain and acrylamide in Cancer Risk From French Fries.

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:

Image Credit: Sally Plank / Flickr. Image has been modified.

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Can Peppermint Improve Athletic Performance?

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Ever since smoking was prohibited in night clubs, customers have increasingly noticed other unpleasant smells present in the club--like body odors. So, researchers in Europe thought they'd try to cover them up. The researchers measured the effects of peppermint, for example, on dancing activity and asked people to rate their energy level. They found that with peppermint scent, people felt more cheerful and danced more, and so, concluded the researchers, "environmental fragrancing may be expected to have a positive effects on club revenue." Innovative nightclubs are already inviting "aroma jockeys" to smell the places up.

The business community caught whiff of this and thought maybe peppermint smell would get their secretaries to type faster. And it worked! There was improved performance on clerical tasks associated with the administration of peppermint odor.

In an age where athletic competitions are frequently won or lost by mere hundredths of a second, athletes are continually looking for new ways to excel in their sport. Researchers threw some collegiate athletes onto a treadmill and piped different smell into their nostrils, and those on peppermint reported feeling less fatigued, more vigorous, less frustrated, and felt they performed better. But did they actually perform better? See my video, Enhancing Athletic Performance with Peppermint.

A different study published in the Journal of Sport and Exercise Psychology measured actual performance, and participants were actually able to squeeze out one extra pushup before collapsing and cut almost two seconds off a quarter mile dash with an odorized adhesive strip stuck to their upper lip. Interestingly there was no significant difference in basketball free throws. The researchers think the reason is that free throws actually require some skill, and all the peppermint can do is really improve athlete's motivation.

Unfortunately follow-up studies were not able to replicate these results, showing no beneficial effect of smelling peppermint on athletic performance, so how about eating peppermint? Researchers measured the effects of peppermint on exercise performance before and after ten days of having subjects drink bottles of water with a single drop of peppermint essential oil in them. And all the subjects' performance parameters shot up, churning out 50 percent more work, 20 percent more power, and a 25 percent greater time to exhaustion. Improvements were found across the board in all those physiological parameters, indicating increased respiratory efficiency. They attribute these remarkable results to the peppermint opening up their airways, increasing ventilation and oxygen delivery.

Now, you can overdose on the stuff, but a few drops shouldn't be toxic. Why not get the best of both worls by blending fresh mint leaves in water rather than use the oil?

Sometimes aromatherapy alone may actually help, though:

Beet juice can also enhance athletic performance. See the dozen or so videos in the series starting with Doping With Beet Juice. Other ways healthy food can synergize with exercise:

I use peppermint in my Pink Juice with Green Foam recipe and talk about using the dried in Antioxidants in a Pinch. It can also help reduce IBS symptoms, as seen in Peppermint Oil for Irritable Bowel Syndrome.

Some other tea caveats, though:

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--2013: Uprooting the Leading Causes of Death, More Than an Apple a Day, 2014: From Table to Able: Combating Disabling Diseases with Food, 2015: Food as Medicine: Preventing and Treating the Most Dreaded Diseases with Diet, and my latest, 2016: How Not To Die: The Role of Diet in Preventing, Arresting, and Reversing Our Top 15 Killers.

Image Credit: Cory Denton / Flickr

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Side-Effects of Aspartame on the Brain

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The National Institutes of Health AARP study of hundreds of thousands of Americans followed for years found that frequent consumption of sweetened beverages, especially diet drinks, may increase depression risk among older adults. Whether soda, fruit-flavored drinks, or iced tea, those artificially sweetened drinks appeared to carry higher risk. There was a benefit in coffee drinkers compared to non-drinkers, but if they added sugar, much of the benefits appeared to disappear, and if they added Equal or Sweet-and-Low, the risk appeared to go up.

Various effects of artificial sweeteners, including neurological effects, have been suspected. For example, aspartame--the chemical in Equal and Nutrasweet--may modulate brain neurotransmitters such as dopamine and serotonin, although data have been controversial and inconsistent. Scientific opinions range from "safe under all conditions" to "unsafe at any dose." The controversy started in the 80's soon after aspartame was approved. Researchers at the Mass College of Pharmacy and MIT noted:

"given the very large number of Americans routinely exposed, if only 1% of the 100,000,000 Americans thought to consume aspartame ever exceed the sweetener's acceptable daily intake, and if only 1% of this group happen coincidentally to have an underlying disease that makes their brains vulnerable to the effects, then the number of people who might manifest adverse brain reactions attributable to aspartame could still be about 10,000, a number on the same order as the number of brain and nerve-related consumer complaints already registered with the FDA before they stopped accepting further reports on adverse reactions to the sweetener."

Those with a history of depression might be especially vulnerable. Researchers at Case Western designed a study I highlighted in my video Aspartame and the Brain to ascertain whether individuals with mood disorders are particularly vulnerable to adverse effects of aspartame. Although they had planned on recruiting 40 patients with depression and 40 controls, the project was halted early by the Institutional Review Board for safety reasons because of the severity of reactions to aspartame within the group of patients with a history of depression.

It was decided that it was unethical to continue to expose people to the stuff.

Normally when we study a drug or a food, the company donates the product to the researchers because they're proud of the benefits or safety of their product. But the Nutrasweet company refused to even sell it to these researchers. The researchers managed to get their hands on some, and within a week there were significantly more adverse effects reported in the aspartame group than in the placebo group. They concluded that individuals with mood disorders may be particularly sensitive to aspartame, and therefore its use in this population should be discouraged.

In a review of the direct and indirect cellular effects of aspartame on the brain, it was noted that there are reports of aspartame causing neurological and behavioral disturbances in sensitive individuals, such as headaches, insomnia and seizures. The researchers go even further and propose that excessive aspartame ingestion might be involved in the development of certain mental disorders and also in compromised learning and emotional functioning. They conclude that "due to all the adverse effects caused by aspartame, it is suggested that serious further testing and research be undertaken to eliminate any and all controversies," to which someone responded in the journal that "there really is no controversy," arguing that aspartame was conclusively toxic.

But what do they mean by excessive ingestion? The latest study on the neuro-behavioral effects of aspartame consumption put people on a high aspartame diet compared to a low aspartame diet. But even the high dose at 25 mg/kg was only half the adequate daily intake set by the FDA. The FDA says one can safely consume 50mg a day, but after just eight days on half of that, participants had more irritable mood, exhibited more depression, and performed worse on certain brain function tests. And these weren't people with a pre-existing history of mental illness; these were just regular people. The researchers concluded that "given that the higher intake level tested here was well below the maximum acceptable daily intake level [40mg in Europe, 50mg here] careful consideration is warranted when consuming food products that may affect neurobehavioral health."

Easier said than done, since it's found in more than 6,000 foods, apparently making artificial sweeteners "impossible to completely eradicate from daily exposure." While that may be true for the great majority of Americans, it's only because they elect to eat processed foods. If we stick to whole foods, we don't even have to read the ingredients lists, because the healthiest foods in the supermarket are label-free, they don't even have ingredients lists--produce!

I've previously touched on artificial sweeteners before:

The healthiest caloric sweeteners are blackstrap molasses and date sugar (whole dried powdered dates). The least toxic low-calorie sweetener is probably erythritol (Erythritol May Be a Sweet Antioxidant).

Coffee may decrease suicide and cancer risk (Preventing Liver Cancer with Coffee? and Coffee and Cancer) but may impair blood flow to the heart (Coffee and Artery Function).

Other ways to improve mood include:

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--2013: Uprooting the Leading Causes of Death, More Than an Apple a Day, 2014: From Table to Able: Combating Disabling Diseases with Food, 2015: Food as Medicine: Preventing and Treating the Most Dreaded Diseases with Diet, and my latest, 2016: How Not To Die: The Role of Diet in Preventing, Arresting, and Reversing Our Top 15 Killers.

Image Credit: Mike Mozart / Flickr

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The Role of Caffeine in Artery Function

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There are dietary guidelines for food, but what about for beverages? A Beverage Guidance Panel was "assembled to provide guidance on the relative health and nutritional benefits and risks of various beverage categories." They ranked them from one to six, and water was ranked number one.

Soda ranked last at number six. Whole milk was grouped with beer, with a recommendation for zero ounces a day, in part out of concern for links between milk and prostate cancer, as well as aggressive ovarian cancer due to IGF-1. Number two on the list, though, after water, was tea and coffee, preferably without creamer or sweetener.

Even without creamer, though, lots of unfiltered coffee can raise cholesterol, but the cholesterol-raising compounds are trapped by the paper filter in brewed coffee, so filtered coffee is probably better.

But about ten years ago, a study was published on the effects of coffee on endothelial function, the function of our arteries. I profile this study in my video Coffee and Artery Function, showing that within 30 minutes of drinking a cup of coffee there was a significant drop in the ability of our arteries to dilate, whereas decaf did not seem to have a significant effect. This was the first study to demonstrate an acute unfavorable effect on arterial function of caffeinated coffee, but one cup of decaf didn't seem to affect performance. And two cups of decaf appeared to have a beneficial effect. So maybe it's a "battle between caffeine and antioxidants." Something in caffeinated coffee appears to be hurting arterial function, whereas something in decaf appears to be helping.

It's similar to red wine. De-alcoholized red wine significantly improves arterial function, as there are grape components trying to help, but the presence of alcohol counteracts and erases the benefit.

Drinking really high antioxidant coffee, by preparing it Greek style for example (where we actually drink the grounds), coffee drinkers may actually be at an advantage

It might not be the caffeine in caffeinated coffee that appears to be harmful, though. In a randomized, double-blind, placebo-controlled, cross-over study, researchers found that caffeine alone--about two and a half cups of coffee worth--significantly improved arterial function in both people with and without heart disease.

Coffee contains more than a thousand different compounds other than caffeine, many of which are also removed by the decaffeination process, so there must be something else in the coffee bean that's causing the problem. In fact, caffeine may even enhance the repair of the fragile inner lining of our arteries by enhancing the migration of our endothelial progenitor cells, the stem cells that patch up potholes in our artery walls.

But how might we get the potential benefit of caffeine without the risky compounds in caffeinated coffee? Tea consumption enhances artery function, and there are substantial beneficial effects of both green tea and black tea. Instead of other components in tea leaves undermining caffeine's potential benefits, they appear to boost the benefit in healthy individuals, as well as heart disease patients, reversing some of their arterial dysfunction, both immediately and long-term.

All the measurements in the studies I've talked about so far were done on the brachial artery, the main artery in the arm (just because it's easier to get to). What we care about, though, is blood flow to the heart. And caffeine appears to impair blood flow to our heart muscle during exercise even in healthy folks, but especially in those with heart disease. Thankfully caffeine in tea form appears to have the opposite effect, significantly improving coronary blood flow, suggesting that tea consumption has a beneficial effect on coronary circulation, though the addition of milk may undermine the protective effects.

I'm fascinated by how complicated such a simple question can get. The take-home is that water is the healthiest beverage, followed by tea.

The effects of coffee on cancer risk are more salutary:

I've previously covered Walnuts and Artery Function and Dark Chocolate and Artery Function. Stay tuned for a few more coming up further exploring the effects of tea, olive oil, and plant-based diets on our lovely endothelium.

Low Carb Diets and Coronary Blood Flow is one of the few other studies I've done that measured blood flow within the coronary arteries themselves. For more background on the brachial artery test, see my video The Power of NO.

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--2013: Uprooting the Leading Causes of Death, More Than an Apple a Day, 2014: From Table to Able: Combating Disabling Diseases with Food, 2015: Food as Medicine: Preventing and Treating the Most Dreaded Diseases with Diet, and my latest, 2016: How Not To Die: The Role of Diet in Preventing, Arresting, and Reversing Our Top 15 Killers.

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No More Than a Quart a Day of Hibiscus Tea

NF-May17 How Much Hibiscus Tea is Too Much?.jpeg

Over the counter antacids are probably the most important source for human aluminum exposure in terms of dose. For example, Maalox, taken as directed, can exceed the daily safety limit more than 100-fold, and nowhere on the label does it say to not take it with acidic beverages such as fruit juice. Washing an antacid down with orange juice can increase aluminum absorption 8-fold, and citric acid-the acid found naturally concentrated in lemon and limes--is even worse.

Just as sour fruits can enhance the absorption of iron (a good thing), the same mechanism they may enhance the absorption of aluminum (a bad thing). This raises the question of what happens when one adds lemon juice to tea? Previously, I concluded that the amount of aluminum in tea is not a problem for most people because it's not very absorbable (See Is There Too Much Aluminum in Tea?). What if we add lemon? Researchers publishing in the journal Food and Chemical Toxicology found no difference between tea with lemon, tea without lemon, or no tea at all in terms of the amount of aluminum in the bloodstream, suggesting that tea drinking does not significantly contribute to aluminum getting inside the body.

The researchers used black tea, green tea, white tea, oolong tea, but what about the "red zinger" herbal tea, hibiscus? The reason hibiscus tea is called "sour tea" is because it has natural acids in it like citric acid. Might these acids boost the absorption of any hibiscus's aluminum? While a greater percentage of aluminum gets from the hibiscus into the tea water than from the other teas, there's less aluminum overall.

The real question is whether the aluminum then gets from the tea water into our bodies. We don't have that data, so to be on the safe side we should assume the worst: that hibiscus tea aluminum, unlike green and black tea aluminum, is completely absorbable. In that case, based on this data and the World Health Organization weekly safety limit, we may not want to drink more than 15 cups of hibiscus tea a day, (based on someone who's about 150 pounds). If you have a 75 pound 10-year-old, a half-gallon a day may theoretically be too much. Recent, more extensive testing highlighted in my video, How Much Hibiscus Tea is Too Much?, suggests that levels may reach level twice as high. Therefore, to be safe, no more than about two quarts a day for adults, or one quart a day for kids or pregnant women. Hibiscus tea should be completely avoided by infants under six months--who should only be getting breast milk--as well as kids with kidney failure, who can't efficiently excrete it.

There is also a concern about the impressive manganese level in hibiscus tea. Manganese is an essential trace mineral, a vital component of some of our most important antioxidant enzymes, but we probably only need about two to five milligrams a day. Four cups of hibiscus tea can have as much as 17 milligrams, with an average of about ten. Is that a problem?

One study from the University of Wisconsin found that women given 15 milligrams of manganese a day for four months, saw, if anything, an improvement in their anti-inflammatory, anti-oxidant enzyme activity. Another study using 20 milligrams a day similarly showed no adverse short-term effects, and importantly showed that the retention of dietary manganese is regulated. Our bodies aren't stupid; if we take in too much manganese, we decrease the absorption and increases the excretion. Even though tea drinkers may get ten times the manganese load (10 or 20 milligrams a day) the levels in their blood are essentially identical. There is little evidence that dietary manganese poses a risk.

These studies were conducted with regular tea, though, so we don't know about the absorption from hibiscus. To err on the side of caution we should probably not routinely exceed the reference dose of ten milligrams per day, or about a quart a day for adults and a half-quart for a 75 pound child.

I've actually changed my consumption. Given the benefits of the stuff, I was using it as a substitute for drinking water, drinking around two quarts a day. I was also blending the hibiscus petals in, not throwing them away, effectively doubling the aluminum content, and increasing manganese concentrations by about 30%. So given this data I've cut back to no more than a quart of filtered hibiscus tea a day.

Lemon can actually boost the antioxidant content of green and white tea. See Green Tea vs. White. For a comparison of their cancer-fighting effects in vitro, Antimutagenic Activity of Green Versus White Tea.

Before that I covered another potential downside of sour tea consumption in Protecting Teeth From Hibiscus Tea, and before that a reason we should all consider drinking it in: Hibiscus Tea vs. Plant-Based Diets for Hypertension.

For more on the iron absorption effect, see my video Risks Associated with Iron Supplements.

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 Uprooting the Leading Causes of Death, More Than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: mararie / Flickr

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Aluminum Levels in Tea

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While aluminum is the third most abundant element on Earth, it may not be good for our brain, something we learned studying foundry workers exposed to particularly high levels. Although the role of aluminum in the development of brain diseases like Alzheimer's is controversial, to be prudent, steps should probably be taken to lessen our exposure to this metal.

There are a number of aluminum-containing drugs on the market (like antacids, which have the highest levels), though aluminum compounds are also added to processed foods such as anti-caking agents in pancake mix, melting agents in American cheese, meat binders, gravy thickeners, rising agents in some baking powders and dye-binders in candy. Therefore, it's better to stick to unprocessed, natural foods. Also, if you cook those natural foods in an aluminum pot, a significant amount of aluminum can leach into the food (compared to cooking in stainless steel).

When researchers tried the same experiment with tea, they got a few milligrams of aluminum regardless of what type of pot they used, suggesting that aluminum was in the tea itself. Indeed, back in the 1950's researchers noticed that tea plants tended to suck up aluminum from the soil. But it's the dose that makes the poison. According to the World Health Organization, the provisional tolerable weekly intake--our best guess at a safety limit for aluminum--is two mg per healthy kilogram of body weight per week, which is nearly a milligram per pound. Someone who weighs around 150 pounds probably shouldn't ingest more than around 20 mg of aluminum per day.

Up to a fifth of aluminum intake may come from beverages, so what we drink probably shouldn't contribute more than about four mg a day, the amount found in about five cups of green, black, or oolong tea. So should we not drink more than five cups of tea a day?

It's not what you eat or drink, it's what you absorb. If we just measured how much aluminum was in tea, it would seem as though a couple cups could double aluminum intake for the day. But if we measure the level of aluminum in people's bodies after they drink tea, it doesn't go up. This suggests that the bioavailability of aluminum in tea is low, possibly because most of the extractable aluminum in brewed tea is strongly bound to large phytonutrients that are not easily absorbed, so the aluminum just passes right through us without actually getting into our bodies. Probably more than 90 percent of the aluminum in tea is bound up.

One study out of Singapore, highlighted in my video, Is There Too Much Aluminum in Tea? did show a large spike in aluminum excretion through the urine after drinking tea compared to water. The only way for something to get from our mouth to our bladder is to first be absorbed into our bloodstream. But the researchers weren't comparing the same quantity of tea to water. They had the study subject chug down about eight and a half cups of tea, or drink water at their leisure. Therefore, the tea drinkers peed a lot more, so the aluminum content cup-for-cup was no different for tea versus water. This suggests that gross aluminum absorption from tea is unlikely and that only a little aluminum is potentially available for absorption.

So although as few as four cups of tea could provide 100 percent of our daily aluminum limit, the percentage available for absorption in the intestine may be less than 10 percent. It is therefore unlikely that moderate amounts of tea drinking can have any harmful effects--for people with normal aluminum excretion. Tea may not, however, be a good beverage for children with kidney failure, since they can't get rid of aluminum as efficiently. For most people, though, tea shouldn't be a problem.

On a special note, if you drink tea out of a can, buy undented cans. The aluminum in dented cans can leach into the liquid, boosting aluminum levels by a factor of eight while sitting on store shelves for a year.

What about the levels and absorbability of the aluminum in my other favorite type of tea? Find out in my video, How Much Hibiscus Tea is Too Much?

The tea plant also sucks up fluoride. So much so that heavy tea drinking can stain the teeth of children. See my video Childhood Tea Drinking May Increase Fluorosis Risk.

Why should we go out of our way to drink tea? See:

Is Caffeinated Tea Dehydrating? Find out by watching the video!

For more on metals in our food supply, 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 year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: Toshiyuki IMAI / Flickr

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Rinse Your Mouth After Sour Foods and Drinks

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Hibiscus tea has been found to be as effective at lowering blood pressure as a leading hypertension drug without the potential side-effects (which include everything from lack of strength to impotence, including rare cases of potentially fatal liver damage). Hibiscus, though, may have adverse effects of its own.

As I've reviewed previously in Plant-Based Diets: Oral Health, people who eat plant-based diets appear to have superior periodontal health, including less gum disease and fewer signs of inflammation, like bleeding. However, they also have twice the prevalence of dental erosions, areas on the teeth where the enamel has thinned due to more frequent consumption of acidic fruits and vegetables. Therefore, after we eat something like citrus, we should swish our mouths with water to clear the acid from our teeth.

This includes beverages. I'm a big fan of hibiscus tea, but it's not called "sour tea" for nothing. In a study highlighted in my video, Protecting Teeth from Hibiscus Tea, researchers at the University of Iowa dental school tested 25 different popular teas and found two with a pH under 3 (as acidic as orange juice or coca cola): Tazo's passion and Bigelow's red raspberry, both of which contain hibiscus as their first ingredient.

To see if these teas could actually dissolve teeth, the researchers took 30 extracted molars from people and soaked them in different teas. And indeed, out of the five teas tested, the greatest erosion came from the tea with the most hibiscus. The researchers left the tooth sitting in the tea for 25 hours straight, but this was to simulate a lifetime of exposure. The bottom line is that herbal teas are potentially erosive, particularly fruity and citrusy teas like hibiscus. To minimize the erosive potential, we can use a straw to drink the beverage. And as I mentioned above, after consuming an acidic food or drink we should also rinse our mouth with water to help neutralize the acid.

For more on the effects of hibiscus on blood pressure, see the previous video, Hibiscus Tea vs. Plant-Based Diets for Hypertension.

Are there other potential downsides to tea drinking? That's the topic of my videos: Is There Too Much Aluminum in Tea? and How Much Hibiscus Tea is Too Much?

For more on avoiding drug side-effects by choosing more natural treatments can be found in videos like:

For more on diet and oral health, 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 year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: T.Kiya / Flickr

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Plant-Based Diets for Hypertension

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Recently, researchers from Taiwan pitted the herbal tea hibiscus against obesity. They gave hibiscus to overweight individuals and reported that subjects showing reduced body weight. However, after 12 weeks on hibiscus subjects only lost about three pounds, only one and a half pounds over placebo. Hibiscus is clearly no magic fix for obesity.

The purported cholesterol-lowering property of hibiscus tea looked a bit more promising. Some older studies suggested as much as an 8% reduction from drinking two cups a day for a month. When all the studies are put together, though, the results are pretty much a wash. This may be because only about 50% of people respond at all to drinking the equivalent of between two to five cups a day, though those that do may get a respectable 12% drop. That's nothing like the 30% one can get within weeks of eating a healthy, plant-based diet, though.

Hibiscus may really shine in treating high blood pressure, a disease affecting a billion people and killing millions. Up until 2010, there wasn't sufficient high quality research to support the use of hibiscus tea to treat hypertension, but there are now randomized double-blind, placebo-controlled studies where hibiscus tea is compared to artificially colored and flavored water that looks and tastes like hibiscus tea, and the tea lowers blood pressure significantly better.

We're still not sure how it works, but hibiscus appears to boost nitric oxide production, which could help our arteries relax and dilate better. Regardless, an updated review acknowledged that the daily consumption of hibiscus tea may indeed significantly lower blood pressures in people with hypertension.

How does hibiscus compare to other blood pressure interventions? The premier clinical trial when it comes to comprehensive lifestyle modification for blood pressure control is the PREMIER Clinical Trial. Realizing that nine out of ten Americans are going to develop hypertension, researchers from John Hopkins randomized 800 men and women with high blood pressure into one of three groups. One was the control group, the so-called "advice only group," where patients were just told to lose weight, cut down on salt, increase exercise and eat healthier. In the two behavioral intervention groups the researchers got serious. Eighteen face-to-face sessions, groups meetings, food diaries, physical activity records, and calorie and sodium intake monitoring. One intervention group just concentrated on exercise; the other included exercise and diet. Researchers pushed the DASH diet, which is high in fruits and vegetables and low in full-fat dairy products and meat. In six months subjects achieved a 4.3 point drop in systolic blood pressure, compared to the control, slightly better than the lifestyle intervention without the diet.

A few points might not sound like a lot--that's like someone going from a blood pressure of 150 over 90 to a blood pressure of 146 over 90--but on a population scale a five point drop in the total number could result in 14% fewer stroke deaths, 9% fewer fatal heart attacks, and 7% fewer deaths every year overall.

A cup of hibiscus tea with each meal didn't just lower blood pressure by three, four, or five points, but by seven points, from an average of 129 down to 122. In fact, tested head-to-head against a leading blood-pressure drug, Captopril, two cups of strong hibiscus tea every morning (five tea bags for the two cups) was as effective in lowering blood pressure as a starting dose of 25mg of captopril taken twice a day.

So hibiscus tea is as good as drugs, without side-effects, and better than diet and exercise? Well, the lifestyle interventions in the PREMIER study were pretty wimpy. As public health experts noted, the PREMIER study was only asking for 30 minutes of exercise a day, whereas the World Health Organization recommends a minimum of an hour a day.

Diet-wise, the lower the animal fat intake, and the more plant sources of protein the PREMIER participants were eating, the better the diet appeared to work. This may explain why vegetarian diets appear to work even better, and the more plant-based, the lower the prevalence of hypertension.

On the DASH diet, subjects cut down on meat, but were still eating it every day, so would qualify as nonvegetarians in the Adventist 2 study (highlighted in my video Hibiscus Tea vs. Plant-Based Diets for Hypertension) which looked at 89,000 Californians. It found that those who only ate meat on a weekly basis had 23% lower rates of high blood pressure. Those who cut out all meat except fish had 38% lower rates. Those eating no meat at all, vegetarians, have less than half the rate. The vegans--cutting out all animal protein and fat--appeared to have thrown three quarters of their risk for this major killer out the window.

One sees the same kind of step-wise drop in diabetes rates as one's diet gets more and more plant-based, and a drop in excess body weight, such that only those eating completely plant-based diets in the Adventist 2 study fell into the ideal weight category. Could that be why those eating plant-based have such great blood pressure? Maybe it's just because they're so skinny. I've previously shown how those eating plant-based just have a fraction of the diabetes risk even at the same weight. but what about hypertension?

The average American has what's called prehypertension, which means the top number of our blood pressure is between 120 and 139. We don't have hypertension yet, which starts at 140, but we may be well on our way. Compare that to the blood pressure of those eating whole food plant-based diets. In one study, those eating plant-based didn't have blood pressures three points lower, four points lower, or even seen points lower, but 28 points lower. However, the group eating the standard American diet was, on average, overweight with a BMI over 26, still better than most Americans, while the vegans were a trim 21--that's 36 pounds lighter.

Maybe the only reason those eating meat, eggs, dairy, and processed junk had such higher blood pressure was because they were overweight. Maybe the diet per se had nothing to do with it?

To solve that riddle we would have to find a group still eating the standard American diet, but as slim as vegans. To find a group that trim, researchers had to use long-distance endurance athletes, who ate the same crappy American diet, but ran an average of 48 miles per week for 21 years. Anyone who runs almost two marathons a week for 20 years can be as slim as a vegan--no matter what they eat!

How did the endurance runners compare to the couch potato vegans? It appears that if we run an average of about a thousand miles every year our blood pressures can rival some couch potato vegans. That doesn't mean we can't do both, but it may be easier to just eat plants.


Those who've been following my work for years have seen how my videos have evolved. In the past, the hibiscus results may have been the whole article or video. But thanks to everyone's support, I've been able to delegate the logistics to staff and concentrate more on the content creation. This allows me to do deeper dives into the literature to put new findings into better context. The posts are a bit longer, but hopefully they're more useful--let me know what you think!

For such a leading killer, hypertension has not gotten the coverage it deserves on NutritionFacts.org. Here's a few videos, with more to come:

So should we all be drinking hibiscus tea every day? This is the first of a four part series on the latest on hibiscus. Stay tuned for the next three:

For another comparison of those running marathons and those eating plants, see: Arteries of Vegans vs. Runners

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 Uprooting the Leading Causes of Death, More Than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: Amy / Flickr

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Treating Asthma With Plants vs. Pills

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In my video Treating Asthma With Fruits and Vegetables, I highlighted a landmark study on manipulating antioxidant intake in asthma. The study found that just a few extra fruits and vegetables a day can powerfully reduce asthma exacerbation rates. If the antioxidants in the plants are ameliorating asthma, then why can't we take antioxidant pills instead? Because antioxidant pills don't appear to work.

Studies using antioxidant supplements on respiratory or allergic diseases have mostly shown no beneficial effects. This discrepancy between data relating to fruit and vegetable intake compared with those using antioxidant supplements may indicate the importance of the whole food, rather than individual components. For example, in the Harvard Nurse's Health Study, women who got the most vitamin E from their diet appeared to be at half the risk for asthma, (which may help explain why nut consumption is associated with significantly lower rates of wheezing), but vitamin E supplements did not appear to help.

Men who eat a lot of apples appear to have superior lung function, as do kids who eat fresh fruit every day, as measured by FEV1 (basically how much air you can forcibly blow out in one second). The more fruit, salad, and green vegetables kids ate, the greater their lung function appeared.

Researchers are "cautious about concluding which nutrient might be responsible." There's vitamin C in fruits, salads, and green vegetables, but there are lots of other antioxidants, such as "vitamin P," a term used to describe polyphenol phytonutrients found in grapes, flax seeds, beans, berries, broccoli, apples, citrus, herbs, tea, and soy. Polyphenol phytonutrients can directly bind to allergenic proteins and render them hypoallergenic, allowing them to slip under our body's radar. If this first line of defense fails, polyphenols can also inhibit the activation of the allergic response and prevent the ensuing inflammation, and so may not only work for prevention, but for treatment as well.

Most of the available evidence is weak, though, in terms of using supplements containing isolated phytonutrients to treat allergic diseases. We could just give people fruits and vegetables to eat, but then we couldn't perform a double-blind study to see if they work better than placebo. Some researchers decided to use pills containing plant food extracts. Plant extracts are kind of a middle ground. They are better than isolated plant chemicals, but are not as complete as whole foods. Still, since we can put whole foods in a capsule, we can compare the extracts to fake sugar pills that look and feel the same to see if they have an effect.

The first trial involved giving people extracts of apple skins. I've talked about the Japan's big cedar allergy problem before (See Alkylphenol Endocrine Disruptors and Allergies), so apple extract pills were given every day for a few months starting right before pollen season started. The results were pretty disappointing. They found maybe a little less sneezing, but the extract didn't seem to help their stuffy noses or itchy eyes.

What about a tomato extract? A randomized, double-blind, placebo-controlled eight-week trial was performed on perennial allergic rhinitis, this time not for seasonal pollen, but for year-round allergies to things like dust-mites. There are lots of drugs out there, but you may have to take them every day year-round, so how about some tomato pills instead? After oral administration of tomato extract for eight weeks, there was a significant improvement of total nasal symptom scores, combined sneezing, runny nose and nasal obstruction, with no apparent adverse effects.

Would whole tomatoes work even better? If only researchers would design an experiment directly comparing phytonutrient supplements to actual fruits and vegetables head-to-head against asthma, but such a study had never been done... until now. The same amazing study, highlighted in my video, Treating Asthma with Plants vs. Supplements?, that compared the seven-fruit-and-vegetables-a-day diet to the three-fruit-and-vegetables-a-day diet, after completion of its first phase, commenced a parallel, randomized, controlled supplementation trial with capsules of tomato extract, which boosted the power of five tomatoes in one little pill, and the study subjects were given three pills a day.

Who did better, the group that ate seven servings of actual fruits and vegetables a day, or the group that ate three servings a day but also took 15 supposed serving equivalents in pill form? The pills didn't help at all. Improvements in lung function and asthma control were evident only after increased fruit and vegetable intake, which suggests that whole-food interventions are most effective. Both the supplements and increased fruit and vegetable intake were effective methods for increasing carotenoid concentrations in the bloodstream, but who cares? Clinical improvements--getting better from disease--were evident only as a result of an increase in plant, not pill, consumption. The results provide further evidence that whole-food approaches should be used to achieve maximum efficacy of antioxidant interventions.

And if this is what a few more plants can do, what might a whole diet composed of plants accomplish? See Treating Asthma and Eczema with Plant-Based Diets.

I also dealt with preventing asthma in the first place: Preventing Asthma With Fruits and Vegetables.

The theme of whole foods being more efficacious than supplements seems to come up over and over again. See for example:

More on "vitamin P" in How to Slow Brain Aging by Two Years.

The anti-inflammatory effects of nuts may explain the Harvard Nurse's Health Study finding: Fighting Inflammation in a Nut Shell.

-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 Uprooting the Leading Causes of Death, More Than an Apple a Day, and From Table to Able.

Image Credit: Mike Mozart / Flickr

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