The Best Way to Wash Fruit and Vegetables

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How might we reduce our exposure to pesticide residues on fruits and vegetables? What about staying away from imported produce? Well, it turns out domestic produce may be even worse, dispelling the notion that imported fruits and vegetables pose greater potential health risks to consumers.

Buying organic dramatically reduces dietary exposure to pesticides, but it does not eliminate the potential risk. Pesticide residues are detectable in about one in ten organic crop samples, due to cross-contamination from neighboring fields, the continued presence of very persistent pesticides like DDT in the soil, and accidental or fraudulent use.

By choosing organic, one hopes to shift exposures from a range of uncertain risk to more of a range of negligible risk, but even if all we had to eat were the most pesticide-laden of conventional produce, there is a clear consensus in the scientific community that the health benefits from consuming fruits and vegetables outweigh any potential risks from pesticide residues. And we can easily reduce whatever risk there is by rinsing our fruits and vegetables under running water.

There are, however, a plethora of products alleged by advertisers to reduce fruit and produce pesticide residues more effectively than water and touted to concerned consumers. For example, Procter & Gamble introduced a fruit and vegetable wash. As part of the introduction, T.G.I. Friday's jumped on board bragging on their menus that the cheese and bacon puddles they call potato skins were first washed with the new product. After all, it was proclaimed proven to be 98% more effective than water in removing pesticides.

So researchers put it to the test and it did no better than plain tap water.

Shortly thereafter Procter & Gamble discontinued the product, but numerous others took its place claiming their vegetable washes are three, four, five or even ten times more effective than water, to which a researcher replied, "That's mathematically impossible." If water removes 50%, you can't take off ten times more than 50%. They actually found water removed up to 80% of pesticide residues like the fungicide, Captan, for example. So, for veggie washes to brag they are three, four, five, ten times better than water is indeed mathematically questionable.

Other fruit and vegetable washes have since been put to the test. Researchers compared FIT Fruit & Vegetable Wash, Organiclean, Vegi-Clean, and dishwashing soap to just rinsing in plain tap water. 196 samples of lettuce, strawberries, and tomatoes were tested, and researchers found little or no difference between just rinsing with tap water compared to any of the veggie washes (or the dish soap). They all just seemed like a waste of money. The researchers concluded that just the mechanical action of rubbing the produce under tap water seemed to do it, and that using detergents or fruit and vegetable washes do not enhance the removal of pesticide residues from produce above that of just rinsing with tap water alone.

That may not be saying much, though. Captan appears to be the exception. When plain water was tried against a half dozen other pesticides, less than half the residues were removed.

Fingernail polish works better, but the goal is to end up with a less toxic, not a more toxic tomato.

We need a straightforward, plausible, and safe method for enhanced pesticide removal. Is there anything we can add to the water to boost its pesticide-stripping abilities? Check out my video, How to Make Your Own Fruit & Vegetable Wash.

If you soak potatoes in water, between about 2% to 13% of the pesticides are removed, but a 5% acetic acid solution removes up to 100%. What's that? Plain white vinegar. But 5% is full strength.

What about diluted vinegar? Diluted vinegar only seemed marginally better than tap water for removing pesticide residues. Using full strength vinegar would get expensive, though. Thankfully there's something cheaper that works even better: salt water.

A 10% salt solution appears to work as good or better than full-strength vinegar. To make a 10% salt solution you just have to mix up about one-part salt to nine-parts water (though make sure to rinse all of the salt off before eating!).

There's not much you can do for the pesticides in animal products, though. The top sources of some pesticides are fruits and vegetables; but for other pesticides, it's dairy, eggs, and meat because the chemicals build up in fat. What do you do about pesticides in animal products? Hard boiling eggs appears to destroy more pesticides that scrambling, but for the pesticides that build up in the fat in fish or chicken, cooking can sometimes increase pesticide levels that obviously can't just wash off. In fact, washing meat, poultry, or eggs is considered one of the top ten dangerous food safety mistakes.

For more on organic foods, see:

The most important reason to wash produce is to reduce the risk of food-borne illness. Ironically, the food poisoning viruses may be found in the pesticides themselves. Check out my video Norovirus Food Poisoning from Pesticides.

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. This image has been modified.

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Ciguatera Poisoning & Chronic Fatigue Syndrome

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Ciguatera is one of the most common forms of food poisoning, which occurs after the consumption of fish contaminated with neurotoxins produced by certain microalgae that build up the food chain. Just a few bites can be sufficient to induce the condition. Disturbingly, affected fish looks, smells, and tastes normal, and ciguatoxins are resistant to all forms of cooking. So, there is no straightforward method to predict whether a seafood meal can turn into a ciguatera nightmare.

It literally can cause nightmares; about one in six may experience signs of hallucinatory poisoning: lack of coordination, hallucinations, depression, and nightmares. Most suffer some kind of neurological symptoms such as tingling, numbness, and a burning cold sensation. Sometimes a reversal of temperature sensation occurs, where cold objects feel hot and vice versa. For instance, ciguatera sufferers have reported that a refreshing dive in the ocean actually caused burning pain, or that drinking cool beer felt like too hot coffee.

The toxin may also be apparently sexually transmitted, or as one of my favorite public health bloggers put it, "when hot sex turns cold and painful, blame it on dinner."

As seen in my video Ciguatera Poisoning & Chronic Fatigue Syndrome, the symptoms can persist for months or even years. Ongoing research has shown that people with chronic fatigue syndrome may actually be suffering the long-term effects of this fish food poisoning or a condition called polymyositis, which causes diffuse muscle aches, pains, and inflammation. Some individuals intoxicated by fish consumption 25 years previously experience a recurrence of the main neurological disturbances during periods of overwork, fatigue, or stress. You can still find the toxins stuck in your body decades later.

Recent outbreaks in New York City have drawn attention to the problem. For example, a man ate grouper at a Manhattan restaurant and went from swimming two miles a day to having difficulty walking that lasted for months. But these aren't just rare anecdotes. Ciguatera fish poisoning affects an estimated 15,000 Americans every year, causing hundreds of hospitalizations and even a few deaths. Because the toxins are colorless, odorless, tasteless, and not destroyed by cooking, CDC scientists suggest "education aimed at the prevention of seafood intoxication by avoidance of high-risk fish altogether."

The AMA put out a similar advisory, suggesting that the only way to prevent it is to avoid eating fish like red snapper or grouper, but the problem is that a third of fish sold in the United States is mislabeled, so we don't know what we're getting. Some suggest first feeding a portion of the fish meal to a cat, treating them like a court tester, and if they're okay six hours later, we can dig in -- but this was considered inhumane. But if it's inhumane to feed it to your cat, how is it not inhumane to feed it to other members of the family?

Many more are killed by more conventional food poisoning bugs (Chicken Salmonella Thanks to Meat Industry Lawsuit), but how scary that you can get these toxins stuck in you and ruin your life? Reminds me of my Amnesic Seafood Poisoning video.

Other neurotoxin videos include Preventing Parkinson's Disease With Diet and Essential Tremor and Diet.

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: Pen Waggener / Flickr

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Are Sprouted Lentils Healthier Than Canned Lentils?

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Beans, chickpeas, split peas and lentils are packed with nutrients and play a role in the prevention of chronic disease, but most can't be eaten raw. Some can be sprouted, though. Boiling is the most common cooking method, which is used for canned beans. Which is healthier, though, cooked or sprouted?

The easiest way to compare healthfulness is to measure nutrient levels--such as the anthocyanin pigments that make kidney beans so pretty--thought to account for some of beans' protective benefits against chronic disease. Sprouted beans have more of some anthocyanins, but less than others. We find this same pattern across the board with the other phenolic phytonutrients: sprouted beans have more of some, less of others. Because the positive effects of these compounds may be related to their antioxidant capacity, we can compare the overall antioxidant power of boiled versus sprouted beans. In that case, boiled appears to have a marginal edge.

Ideally, though, rather than merely comparing concentrations of phytochemicals, we'd measure physiological effects. For example, we might look at the effect of boiled versus sprouted beans against cancer cell growth. That's exactly what researchers did. In my video Cooked Beans or Sprouted Beans?, you can see the concentrations of bean extract needed to cut the breast cancer growth rate in half in a petri dish. Boiled beans do about 40 times better than raw beans--the same cancer growth inhibition at just a fraction of the concentration. Sprouted beans do about the same.

We can't eat most beans raw, but I wanted to include them to show you a fascinating phenomenon. No amount of raw bean extract appears to totally stop the growth of breast cancer cells, but just small amounts of cooked or sprouted beans can. We find the same thing with killing off cancer. No amount of raw bean extract can fully kill off breast cancer cells, but both boiled and sprouted beans can.

Similar results were found for melanoma cells, a type of malignant skin cancer. Processing the beans--either cooking or sprouting--boosted anticancer activity in vitro. However, against kidney cancer, raw and boiled worked, but sprouted didn't at all.

There has also been interest in brain protection. Given that elderly persons who report always eating legumes may be significantly less likely to experience cognitive decline, a group of Chinese researchers decided to compare the protective effects of boiled versus sprouted beans on astrocytes.

Astrocytes are the most abundant type of cell in our brain. They are star-shaped cells that keep our brain running smoothly. Should they become damaged, though, they may play an important role in the development of neurodegenerative disorders such as Lou Gehrig's disease, Alzheimer's, or Parkinson's. So if we're thinking clearly, we should thank our lucky stars.

To see if beans help protect astrocytes from damage, we'd have to first make sure bean extracts wouldn't cause any damage. Cooked beans don't seem to hurt cells at all, and sprouted beans seem to even help them grow a little. If we add an oxidative chemical to the cells, we can kill off about a quarter of them. However, if we add that chemical along with some boiled bean extract, the astrocytes were partially protected at higher doses. Sprouted bean extract didn't appear to offer significant benefit.

What's the takeaway? As far as I'm concerned, we should eat beans in whichever way will get us to eat the most of them.

I do love my lentil sprouts, one of the healthiest snacks on the planet (along with kale chips). I can grow my own in just 2 to 3 days. But using canned beans I can get similar nutrition in about 2 to 3 seconds.

Sprouting is so much fun, though! I've got a bunch of videos on broccoli sprouts, for example: Biggest Nutrition Bang for Your Buck.

But again, whichever way we like them we should eat them. Why? See:

Mostly I just used canned. See Canned Beans or Cooked Beans?

Other videos on practical prep tips 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 Uprooting the Leading Causes of Death, More Than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: Veganbaking.net / Flickr

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How to Cook Broccoli

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When I used to teach medical students at Tufts, I gave a lecture about this amazing new therapeutic called "iloccor-B." I'd talk about all the new science, all the things it could do, its excellent safety profile. Just as they were all scrambling to buy stock in the company and prescribe it to all their patients, I'd do the big reveal. Apologizing for my "dyslexia," I would admit that I'd got it backwards. All this time I had been talking about broccoli.

The main active ingredient in broccoli is thought to be sulforaphane, which may protect our brains, protect our eyesight, protect our bodies against free radicals, boost our detoxification enzymes, and help prevent and treat cancer.

In my videos The Best Detox and Sometimes the Enzyme Myth is the Truth, I talked about how the formation of sulforaphane is like a chemical flare reaction, requiring the mixing of a precursor compound with an enzyme, which is destroyed by cooking. This may explain why we get dramatic suppression of cancer cell growth from raw broccoli, cauliflower and Brussels sprouts, but hardly anything from boiled, microwaved or steamed (except for microwaved broccoli, which actually retains some cancer fighting abilities). But who wants to eat raw Brussels sprouts?

There is a strategy to get the benefits of raw in cooked form. In raw broccoli, the sulforaphane precursor, called glucoraphanin, mixes with the enzyme (myrosinase) when you chew or chop it. If given enough time--such as when sitting in your upper stomach waiting to get digested--sulforaphane is born. The precursor and sulforaphane are resistant to heat and therefore cooking, but the enzyme is destroyed. No enzyme = no sulforaphane.

That's why I described the "hack and hold" technique--if we chop the broccoli, Brussels sprouts, kale, collards, or cauliflower first and then wait 40 minutes, we can cook them all we want. The sulforaphane is already made; the enzyme has already done its job, so we don't need it anymore.

When most people make broccoli soup, for example, they're doing it wrong. Most people cook the broccoli first, then blend it. We now know it should be done the exact opposite way. Blend it first, wait, and then cook it.

What if we're using frozen broccoli, though? In my video, Second Strategy to Cooking Broccoli, you can see the amount of sulforaphane in someone's body after they eat broccoli soup made from fresh broccoli versus from frozen broccoli. The difference is dramatic. Commercially produced frozen broccoli lacks the ability to form sulforaphane because vegetables are blanched (flash-cooked) before they're frozen for the very purpose of deactivating enzymes. This prolongs shelf life in the frozen foods section, but the myrosinase is dead by the time you take it out of your freezer. It doesn't matter how much you chop it, or how long you wait, no sulforaphane is going to be made. This may be why fresh kale suppresses cancer cell growth up to ten times more than frozen.

The frozen broccoli is still packed with the precursor--remember that's heat resistant--and we could get lots of sulforaphane out of the frozen broccoli by adding some outside enzyme. Where do we get myrosinase enzyme from? Researchers just buy theirs from a chemical company. But we can just walk into any grocery store.

All cruciferous vegetables have this myrosinase. Mustard greens, a cruciferous vegetable, grow out of little mustard seeds, which we can buy ground up in the spice aisle as mustard powder. If we sprinkled some mustard powder on our cooked frozen broccoli, would it start churning out sulforaphane? We didn't know...until now.

Boiling broccoli prevents the formation of any significant levels of sulforaphane due to inactivation of the enzyme. However, researchers from the University of Reading found that the addition of powdered mustard seeds to the heat processed broccoli significantly increased the formation of sulforaphane. In the video I mentioned earlier, Second Strategy to Cooking Broccoli, you can see the amount of sulforaphane in boiled broccoli versus the amount after half a teaspoon or a teaspoon of mustard powder is added. Both a half teaspoon and a full teaspoon increase sulforaphane by the same amount, suggesting that we could use even use less mustard powder for the same effect. Therefore, although domestic cooking leads to the deactivation of myrosinase and stops sulforaphane formation, the addition of powdered mustard seeds to cooked cabbage-family vegetables provides a natural source of the enzyme such that it's practically like eating them raw.

So, if we forget to chop our greens in the morning for the day, or are using frozen, we can just sprinkle some mustard powder on top at the dinner table and we're all set. Daikon radish, horseradish, or wasabi--all cruciferous vegetables packed with the enzyme--work as well. Just a quarter teaspoon of Daikon radish root for seven cups of broccoli worked--just a tiny pinch can do it. Or you can add a small amount of fresh greens to your cooked greens, because the fresh greens have myrosinase enzyme that can go to work on the cooked greens.

I love kitchen chemistry--it totally revolutionized my daily greens prep. One of the first things I used to do in the morning is chop my greens for the day, so when lunch and supper rolls around they'd be good to go. But now with the mustard powder plan, I don't have to pre-chop.

This helps explain the results I presented in Raw Broccoli and Bladder Cancer Survival.

OK, but what's so great about this sulforaphane stuff? For a taste, 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: Jessica Spengler / Flickr

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Bile Binding Beets

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In my video Breast Cancer and Constipation, I discussed how fruits and veggies bind carcinogenic bile acids in our gut. Since bile acids are absorbed back into our systems, they may increase our risk of not only colon cancer but also other cancers as well. In light of this, researchers publishing in the journal, Nutrition Research, concluded that to "lower the risk of diet and lifestyle-related premature degenerative diseases and to advance human nutrition research, relative bile acid-binding potential of foods and fractions need to be evaluated."

They found that some vegetables bind bile acids better than others. We know that those eating more plant-based diets are at a lower risk of heart disease and cancer. This could partly be because of phytonutrients in plants that act as antioxidants and potent stimulators of natural detoxifying enzymes in our bodies. Veggies can also lower cholesterol and detoxify harmful metabolites, functions that can be predicted by their ability to bind bile acids.

A group of USDA researchers studying this topic discovered three important things. First, they found an over five-fold variability in bile acid binding among various vegetables that had similar fiber content, suggesting that bile acid binding is not just related to total dietary fiber content (as previously thought), but instead some combination of unique phytonutrients yet to be determined.

Second, they discovered that steaming significantly improves the bile acid binding of collards, kale, mustard greens, broccoli, peppers, cabbage, beets, eggplant, asparagus, carrots, green beans, and cauliflower, suggesting that in this way steaming vegetables may be more healthful than those consumed raw.

Finally, they ranked multiple vegetables for bile binding ability. Which vegetables kicked the most bile butt? (in my video, Which Vegetable Binds Bile Best?, you can see a visual comparison of bile binding ability.) Turnips turned up last. Then came cabbage, cauliflower, bell peppers, spinach, asparagus and green beans. Mustard greens and broccoli were better. Eggplant, carrots and Brussels sprouts basically tie for the #5 slot. Then collards at #4. Kale got the bronze, okra the silver, and beets the gold. Kale, surprisingly, got beet.

The researchers concluded that inclusion of all these vegetables in our daily diets should be encouraged. When consumed regularly, they concluded, these vegetables may lower the risk of premature degenerative diseases and improve public health.

More raw versus cooked comparisons in

Beets also have a number of other remarkable properties. Check out my video series on Doping with Beet Juice as well as Hearts Shouldn't Skip a Beet, and Whole Beets vs. Juice for Improving Athletic Performance.

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: Robert Couse-Baker / Flickr

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How Learning to Cook Can Save Your Life

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The eating habits of modern Americans have been described as, "eating breakfast in their cars, lunch at their desks and chicken from a bucket." Within the last few decades, Americans are eating out more and more, and cooking fewer meals at home, which are typically healthier. Home-cooled meals tend to contain less saturated fat, cholesterol, and sodium, and more fiber. Therefore, the benefits to preparing healthy food at home may include the prevention of chronic disease. Just because food is prepared at home doesn't mean it's healthy, though. Microwaving a frozen pizza isn't exactly home cooking.

One of the problems is many people no longer know how to cook. For example, one study reported that 25% of the men in the study had absolutely no cooking skills whatsoever. Another study in the UK compared the nutritional content of meals created by television chefs to TV dinners, and both were then compared to the nutritional guidelines published by the World Health Organization. The researchers looked at a hundred of each, and not a single one complied with the nutrition standards. And the TV chef recipes were even less healthy than the TV dinners!

Many people don't know how to make healthy food taste good. This is not a new problem; an editorial in the Journal of the American Medical Association bemoaned the same issue back in 1913. In the United States, "vegetables are frequently boiled in a way which deprives them of their characteristic odor and their toothsomeness. 'Villainous and idiotic' are the only adjectives that can describe our methods of cooking vegetables."

Researchers in Taiwan recently found that in a group of elderly Taiwanese people, those who cooked their own food were not only healthier, but also lived longer. In a ten year study, highlighted in my video, Cooking to Live Longer, those who cooked most frequently had only 59% of the mortality risk. This took into account the exercise people got grocery shopping, physical function, and chewing ability. So why did they live longer? Those that cooked typically ate a more nutritious diet with a higher consumption of vegetables.

The effect on mortality was much more evident in women than in men. It turns out that "men were, with doubtful justification, more positive about the nutritional value of convenience foods compared with women." Women who cooked made better food choices in general.

As one author noted in the book Something from the Oven, over the last century:

"we began the long process of turning over to the food industry many of the decisions about what we eat...Today our staggering rates of obesity and diabetes are testimony to the faith we put in corporations to feed us well. But the food industry is a business, not a parent; it doesn't care what we eat as long as we're willing to pay for it. Home cooking these days has far more than sentimental value; it's a survival skill."

With the onslaught of health information out there, access to simple, healthy recipes has never been easier. While cooking at home requires more effort, energy, and cleaning, the results, health aside, are often more rewarding. Learning to cook is a simple art, and with the right amount of patience and delicious ingredients, it can help us take back control of our own lives.

Check out your local public library for cookbooks--I've been amazed at the selection in all of the cities I've lived. Or for those for which books are just so 20th century, the online Rouxbe Cooking School holds healthy cooking classes.

More on fast food:

Some other unsavory bits about the food industry:

I think this is the only other mention of celebrity chefs I have:
Paula Deen: diabetes drug spokesperson

-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.

Picture by Moyan Brenn on Flickr

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Is it Better to Bake, Boil, or Steam Sweet Potatoes?

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I previously talked about the cancer fighting properties of sweet potatoes (See Anti-Cancer Potential of Sweet Potato Proteins) and what would happen if you centered your diet around them (The Okinawa Diet: Living to 100). It seems that the only potential downside to eating too many sweet potatoes is that you could get yellow palms (or nose as you can see in the video, The Best Way to Cook Sweet Potatoes), a harmless condition called "carotenemia." Caused by elevated levels of beta carotene in the blood, it was first noticed a century ago when carrots were introduce into infant diets. It's treated mostly by just reassuring parents that it's harmless, but if we don't want our child's nose to be yellow, we can decrease their beta carotene intake and in a few months it will be gone.

When picking out varieties at the supermarket, the intensity of the yellow or orange flesh color of the sweet potato is directly correlated to its nutritional content, so the more intense the better. Though if you really want intensity, sweet potato varieties don't just range from white to yellow and orange, but from pink to deep purple. The natural pigments that cause these colors may have special anticancer effects.

What is the best way to cook sweet potatoes? Boiling may actually retain most of the antioxidant power of sweet potatoes, compared to roasting and steaming. If we compare baking to boiling microscopically, boiling helps thin out the cell walls and gelatinize the starch, which may enhance the bioavailability of nutrients. At the same time, the glycemic index of boiled sweet potatoes was found to be about half that of baking or roasting, so boiled sweet potatoes give us less of a blood sugar spike.

Make sure to keep the skin on, though. The peel of a sweet potato has nearly ten times the antioxidant power as the flesh (an antioxidant capacity comparable to that of blueberries). However, the peel's nutrition really takes a hit when baked, which wipes out over two thirds of the antioxidants, whereas microwaving or boiling are comparatively much gentler. The same is true for the rest of the sweet potato. Baking can also cause an 80% drop in vitamin A levels, twice as much as boiling. Therefore, from a nutritional standpoint, boiling rather than baking should be recommended for cooking sweet potato.

Boiling may theoretically be best, but sweet potatoes are so incredibly healthy that the actual best way to prepare them is whichever way will get you to eat the most of them! The exception is deep frying, which can lead to the formation of acrylamide, a potential human carcinogen.

What about cooking methods for other vegetables? See my video Best Cooking Method.

Want more information about acrylamide, the potential crispy carb carcinogen? See my video Cancer Risk from French Fries. And for why deep frying in general might not be good, Deep Frying Toxins and Carcinogens in the Smell of Frying Bacon.

-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: Avital Pinnick / Flickr

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Why Deep Fried Foods May Cause Cancer

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In the latest study on dietary patterns and breast cancer risk among women, healthier eating was associated with eliminating three-quarters of the odds of breast cancer, whereas less healthy eating was associated with up to nearly eight times the odds. Included in the unhealthy eating pattern was the consumption of deep-fried foods, which have previously been linked to breast cancer, pancreatic cancer, lung cancer, oral and throat cancers, esophageal cancer, and cancer of the voicebox. No deep fried foods? What's a Southern belle to do? Instead of deep fried foods, how about the traditional Southern diet, characterized by high intakes of cooked greens, beans, legumes, cabbage, sweet potatoes and cornbread, which may reduce the risk of invasive breast cancer significantly.

What about the consumption of deep-fried foods and risk of prostate cancer? Researchers at the Fred Hutchinson Cancer Research Center and the University of Washington found that eating French fries, fried chicken, fried fish, and doughnuts was associated with about a third greater odds of prostate cancer. After stratifying for tumor aggressiveness, they found slightly stronger associations with more aggressive disease, suggesting that regular intake of deep-fried foods may contribute to the progression of prostate cancer as well.

What in deep fried foods is so bad for us? Just heating oil that hot can generate potentially carcinogenic compounds, and then known carcinogens such as heterocyclic amines and polycyclic aromatic hydrocarbons form when the muscles of chickens and fish are cooked at that temperature. Deep-fried plants, on the other hand, can form acrylamide.

I did a video about acrylamide back in 2008, suggesting it's a probable human carcinogen (See Acrylamide in French Fries). Since then, studies have suggested pregnant women may want to cut back on French fries to protect the growth of their baby's body and brain. Based on a study (highlighted in my video, Cancer Risk from French Fries) feeding people a little bag of potato chips every day for a month, it now seems acrylamide may also cause inflammation as well, which could explain its purported role in cancer progression.

Acrylamide intake has been associated with endometrial cancer, ovarian cancer, lung cancer, kidney cancer, and esophageal cancer. How much cancer risk are we talking about? Taiwanese researchers examined lifetime cancer risk and French fry consumption. The researchers picked on French fries because they comprise by far the greatest percentage contribution of acrylamide to the diets of children. They estimated that, at most, one or two boys and girls out of every ten thousand would develop cancer eating French fries that they would otherwise not have developed if they hadn't eaten French fries. So it's not as bad as eating something like fried fish, or fried chicken, but how much is that saying?

The level of cancer risk in both boys and girls associated with French fries depends on how long and hot they're fried. In Europe, the food industry swore that they'd self-regulate and control fry times to decrease acrylamide levels, but we've yet to see any subsequent change in acrylamide levels in French fries.

Researchers continue to urge that the cooking temperature should be as low as possible and the cooking time should be as short as possible, "while still maintaining a tasty quality" of course. We wouldn't want to reduce cancer risk too much--they might not taste as good!

Blanching the potatoes first reduces acrylamide formation, but potato chip companies complain that, not only would it muck with the flavor, but it would reduce the nutritional properties by leaching away some of the vitamin C. But if we're relying on potato chips to get our vitamin C, acrylamide is probably the least of our worries.

More on heterocyclic amines:

There are some things we can do to counteract the effects of these carcinogens, though:

I touch on polycyclic aromatic hydrocarbons in Meat Fumes: Dietary Secondhand Smoke and Is Liquid Smoke Flavoring Carcinogenic?
Certain fats may play a role in breast cancer survival as well: Breast Cancer Survival, Butterfat, and Chicken and Breast Cancer Survival and Trans Fat.

-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: Kim Love / Flickr

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Reducing Arsenic in Chicken and Rice

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In 2013, Maryland became the first state to ban the feeding of an arsenic-containing drug to chickens. This arsenic-containing drug is used to control parasites and gives chicken meat an "appealing pink color." In 2011, the FDA found that the livers of chickens fed this drug had elevated levels of inorganic arsenic, a known human carcinogen. In response, the drug's manufacturer, Pfizer, voluntarily pulled the drug off the U.S. market. However, it's still sold overseas--including to places that continue to export chicken back to us--and a similar arsenic-containing drug for use in poultry is still available in the United States. The Maryland ban was still some help, though; it kept Maryland farmers from using stockpiles of the drug.

How much arsenic gets into the actual meat and not just the internal organs? We didn't know until recently. In a study highlighted in my video, How Many Cancers Caused by Arsenic-Laced Chicken?, researchers at the Johns Hopkins School of Public Health coordinated the purchase of chicken breasts off grocery store shelves in ten cities across the country. They found that 70% of the samples of chicken meat from poultry producers that didn't prohibit arsenic drugs were contaminated with the cancer-causing form of arsenic at levels that exceeded the safety thresholds originally set by the FDA (before the FDA relented and admitted that there's really no safe level of this kind of arsenic).

When the drug was first approved, scientists believed that its organic arsenic base would be excreted unchanged (organic arsenic is much less dangerous than inorganic arsenic). Guess what appears to convert the drug into the carcinogenic form? Cooking. When chicken meat is cooked, levels of the arsenic-containing drug go down and levels of carcinogenic arsenic go up, suggesting the drug may degrade into the cancer-causing inorganic arsenic form during cooking.

How much cancer are we talking about? If we estimate that about three-quarters of Americans eat chicken, then the arsenic in that chicken has potentially been causing more than 100 cases of cancer every year. The John Hopkins researchers conclude that "eliminating the use of arsenic-based drugs in [poultry and pig] production could reduce the burden of arsenic-related disease in the U.S. population."

Arsenic-containing drugs fed to chickens is one of the ways arsenic gets into rice. When we feed arsenic to chickens, the resulting arsenic-bearing poultry manure is introduced to the environment, soil, and water, and rice sucks it up from contaminated soil and can transfer it to people who don't even eat chicken. There is massive environmental contamination from the poultry industry; nearly two million pounds of arsenic has been poured into the environment every year by the U.S chicken industry alone.

We're even seeing arsenic in foods sweetened with organic brown rice syrup. It reminds me of the arsenic in apple juice story. Although the U.S. made lead and arsenic-based pesticides illegal years ago, they still persist in the soil, so even organic products are not immune.

There are other sources of arsenic (such as naturally occurring arsenic deposits), but arsenic-containing poultry drugs have been deliberately administered to animals intended for human consumption for 70 years. Consequently, exposures resulting from use of these drugs are far more controllable than are exposures from environmental sources. And the good news is that, thanks to a lawsuit from the Center for Food Safety and other consumer groups, three out of the four arsenic-containing drugs fed to poultry have been officially pulled from the market.

I've previously addressed this issue in my video Arsenic in Chicken. It's nice to see there's been some progress!

The antibiotics the poultry industry continues to feed chickens present another public health hazard. See my videos:

Cooking may also create other carcinogens from the muscle itself:

-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: Stu Spivak / Flickr

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Is Liquid Smoke Safe?

NF-Apr14 Does Liquid Smoke Cause Cancer.jpg

We know smoke inhalation isn't good for us, but what about smoke ingestion? Decades ago, smoke flavorings were tested to see if they caused DNA mutations in bacteria--the tests came up negative. Even as more and more smoke flavoring was added, the DNA mutation rate remained about the same.

But the fact that something is not mutagenic in bacteria may have little predictive value for its effect on human cells. A group at MIT tested a hickory smoke flavoring they bought at the store against two types of human white blood cells. Unlike the bacteria, the mutation rate shot up as more and more liquid smoke was added. But, "there is no evidence that mutagenic activity in a particular human cell line is more closely related to human health risk than is mutagenic activity in bacteria." In other words: just because liquid smoke causes DNA mutations to human cells in a petri dish, doesn't mean that it does the same thing within the human body.

A good approach may be to just analyze liquid smoke for known carcinogens, chemicals that we know cause cancer.

Damaging DNA is just one of many ways chemicals can be toxic to cells. A decade later researchers tested to see what effect liquid smoke had on overall cell viability. If you drip water on cells, nothing happens, they keep powering away at around 100% survival, but drip on more and more wood fire smoke, and you start killing some of the cells off. Cigarette smoke is more toxic, but three out of four of the brands of liquid smoke they bought at the supermarket killed off even more cells, leading them to conclude that the cytotoxic potential of some commercial smoke flavorings is greater than that of liquid cigarette smoke, a finding they no doubt celebrated given that the researchers were paid employees of the R. J. Reynolds Tobacco Co.

Unfortunately they didn't name names of the offending brands. That's one of the reasons I was so excited about a new study, where they tested--and named--15 different brands of liquid smoke. This maximum "response" they were measuring was p53 activation.

P53 is a protein we make that binds to our DNA, you can see this illustrated in my video, Is Liquid Smoke Flavoring Carcinogenic?. It activates our DNA repair enzymes. So a big p53 response may be indicative of a lot of DNA damage,and a few of the liquid smoke flavorings activated p53 almost as much as a chemotherapy drug like etoposide, whose whole purpose is to break DNA strands.

Other flavorings didn't seem as bad, though there was a hickory smoke powder that ranked pretty high, as did the fish sauce, though smoked paprika didn't register at all.

The p53-activating property in liquid smoke was eliminated by standard baking conditions (350°F for 1h), so if you're baking something with liquid smoke for long enough, it should eliminate this effect, though just boiling--even for an hour, or slow cooking doesn't appear to work.

They conclude "If the DNA-damaging activities of liquid smoke were thought to be deleterious, it might be possible to replace liquid smoke with other safer, smoky substances." Why do they say if thought to be deleterious? That's because they're not really measuring DNA damage, they're measuring p53 activation, and that's not necessarily a bad thing.

P53 is considered "Guardian of our Genome," guardian of our DNA. It's considered a tumor suppressor gene, so if something boosts its activity is that good or bad? It's like the broccoli story. Cruciferous vegetables dramatically boost our liver's detoxifying enzymes. Is this because our body sees broccoli as toxic and is trying to get rid of it quicker? Either way, the end result is good, lower cancer risk.

It's a biological phenomenon known as hormesis - that which doesn't kill us may make us stronger. Like exercise is a stress on the body, but in the right amount can make us healthier in the long run. So, for example, teas and coffees caused p53 activation as well, but their consumption is associated with lower cancer risk. So it's hard to know what to make of this p53 data. Due to the limitations of the available tests it's hard to calculate the genotoxic potential of liquid smoke, or any other food for that matter. A better approach may be to just analyze liquid smoke for known carcinogens, chemicals that we know cause cancer.

This was first attempted back in 1971. One of the seven liquid smoke flavors researchers tested contained one polycyclic aromatic hydrocarbon known to be cancer-causing, but there's a bunch of similar carcinogens researchers didn't test for. A later study, however, tested across the board, looking specifically at five different carcinogens in retail liquid smoke seasonings.

The recommended daily upper safety limit for these carcinogens is 47. Hickory smoke flavoring has only 0.8 per teaspoon, so we'd have to drink three bottles a day to bump up against the limit. And mesquite liquid smoke has only 1.1.

It turns out that most of the carcinogens in smoke are fat soluble, so when we make a water-based solution, like liquid smoke, we capture the smoke flavor compounds without capturing most of the smoke cancer compounds. The only time we need to really worry is when eating smoked foods--foods directly exposed to actual smoke. For example, smoked ham has 21.3 per serving, and smoked turkey breast has 26.7 per serving. One sandwich and we may be halfway to the limit, and one serving of barbequed chicken takes us over the top. Eating less than a single drumstick and we nearly double our daily allotment of these carcinogens. Nothing, however, is as bad as fish. Smoked herring? 140 per serving. And smoked salmon? One bagel with lox could take us ten times over the limit.

I've touched on those cooked meat carcinogens before. In Estrogenic Cooked Meat Carcinogens I explored the role of these cooked meat chemicals in tumor growth. PhIP: The Three Strikes Breast Carcinogen explored their role in cancer invasion. Reducing Cancer Risk In Meateaters offered some mediation strategies. Heterocyclic Amines in Eggs, Cheese, and Creatine? showed how even vegetarians may be at risk and Cancer, Interrupted: Green Tea and Cancer, Interrupted: Garlic & Flavonoids explored some counter measures.

Some smoke compounds may be a concern even if we don't eat them. See Meat Fumes: Dietary Secondhand Smoke. Even the smell of frying bacon may be carcinogenic: Carcinogens in the Smell of Frying Bacon.

Some plant foods exposed to high temperatures may also present a concern. See Is Yerba Mate Tea Bad for You? and Acrylamide in French Fries. What about Carcinogens in Roasted Coffee?

The broccoli liver enzyme boost story is covered in The Best Detox.

-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: eric forsberg / Flickr

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