Antioxidant- and Folate-Rich Foods for Depression

Antioxidant- and Folate-Rich Foods for Depression.jpeg

According to the Centers for Disease Control and Prevention, the rates of all of our top 10 killers have fallen or stabilized except for one, suicide. As shown in my video, Antioxidants & Depression, accumulating evidence indicates that free radicals may play important roles in the development of various neuropsychiatric disorders including major depression, a common cause of suicide.

In a study of nearly 300,000 Canadians, for example, greater fruit and vegetable consumption was associated with lower odds of depression, psychological distress, self-reported mood and anxiety disorders and poor perceived mental health. They conclude that since a healthy diet comprised of a high intake of fruits and vegetables is rich in anti-oxidants, it may consequently dampen the detrimental effects of oxidative stress on mental health.

But that study was based on asking how many fruits and veggies people ate. Maybe people were just telling the researchers what they thought they wanted to hear. What if you actually measure the levels of carotenoid phytonutrients in people's bloodstreams? The same relationship is found. Testing nearly 2000 people across the United States, researchers found that a higher total blood carotenoid level was indeed associated with a lower likelihood of elevated depressive symptoms, and there appeared to be a dose-response relationship, meaning the higher the levels, the better people felt.

Lycopene, the red pigment predominantly found in tomatoes (but also present in watermelon, pink grapefruit, guava and papaya) is the most powerful carotenoid antioxidant. In a test tube, it's about 100 times more effective at quenching free radicals than a more familiar antioxidant like vitamin E.

Do people who eat more tomatoes have less depression, then? Apparently so. A study of about a thousand older men and women found that those who ate the most tomato products had only about half the odds of depression. The researchers conclude that a tomato-rich diet may have a beneficial effect on the prevention of depressive symptoms.

Higher consumption of fruits and vegetables has been found to lead to a lower risk of developing depression, but if it's the antioxidants can't we just take an antioxidant pill? No.

Only food sources of antioxidants were protectively associated with depression. Not antioxidants from dietary supplements. Although plant foods and food-derived phytochemicals have been associated with health benefits, antioxidants from dietary supplements appear to be less beneficial and may, in fact, be detrimental to health. This may indicate that the form and delivery of the antioxidants are important. Alternatively, the observed associations may be due not to antioxidants but rather to other dietary factors, such as folate, that also occur in plant-rich diets.

In a study of thousands of middle-aged office workers, eating lots of processed food was found to be a risk factor for at least mild to moderate depression five years later, whereas a whole food pattern was found to be protective. Yes, it could be because of the high content of antioxidants in fruits and vegetables but could also be the folate in greens and beans, as some studies have suggested an increased risk of depression in folks who may not have been eating enough.

Low folate levels in the blood are associated with depression, but since most of the early studies were cross-sectional, meaning a snapshot in time, we didn't know if the low folate led to depression or the depression led to low folate. Maybe when you have the blues you don't want to eat the greens.

But since then a number of cohort studies were published, following people over time. They show that a low dietary intake of folate may indeed be a risk factor for severe depression, as much as a threefold higher risk. Note this is for dietary folate intake, not folic acid supplements; those with higher levels were actually eating healthy foods. If you give people folic acid pills they don't seem to work. This may be because folate is found in dark green leafy vegetables like spinach, whereas folic acid is the oxidized synthetic compound used in food fortification and dietary supplements because it's more shelf-stable. It may have different effects on the body as I previously explored in Can Folic Acid Be Harmful?

These kinds of findings point to the importance of antioxidant food sources rather than dietary supplements. But there was an interesting study giving people high dose vitamin C. In contrast to the placebo group, those given vitamin C experienced a decrease in depression scores and also greater FSI. What is FSI? Frequency of Sexual Intercourse.

Evidently, high dose vitamin C improves mood and intercourse frequency, but only in sexual partners that don't live with one another. In the placebo group, those not living together had sex about once a week, and those living together a little higher, once every five days, with no big change on vitamin C. But for those not living together, on vitamin C? Every other day! The differential effect for non-cohabitants suggests that the mechanism is not a peripheral one, meaning outside the brain, but a central one--some psychological change which motivates the person to venture forth to have intercourse. The mild antidepressant effect they found was unrelated to cohabitation or frequency, so it does not appear that the depression scores improved just because of the improved FSI.

For more mental health video, see:

Anything else we can do to enhance our sexual health and attractiveness? 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:

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

Original Link

Antioxidant- and Folate-Rich Foods for Depression

Antioxidant- and Folate-Rich Foods for Depression.jpeg

According to the Centers for Disease Control and Prevention, the rates of all of our top 10 killers have fallen or stabilized except for one, suicide. As shown in my video, Antioxidants & Depression, accumulating evidence indicates that free radicals may play important roles in the development of various neuropsychiatric disorders including major depression, a common cause of suicide.

In a study of nearly 300,000 Canadians, for example, greater fruit and vegetable consumption was associated with lower odds of depression, psychological distress, self-reported mood and anxiety disorders and poor perceived mental health. They conclude that since a healthy diet comprised of a high intake of fruits and vegetables is rich in anti-oxidants, it may consequently dampen the detrimental effects of oxidative stress on mental health.

But that study was based on asking how many fruits and veggies people ate. Maybe people were just telling the researchers what they thought they wanted to hear. What if you actually measure the levels of carotenoid phytonutrients in people's bloodstreams? The same relationship is found. Testing nearly 2000 people across the United States, researchers found that a higher total blood carotenoid level was indeed associated with a lower likelihood of elevated depressive symptoms, and there appeared to be a dose-response relationship, meaning the higher the levels, the better people felt.

Lycopene, the red pigment predominantly found in tomatoes (but also present in watermelon, pink grapefruit, guava and papaya) is the most powerful carotenoid antioxidant. In a test tube, it's about 100 times more effective at quenching free radicals than a more familiar antioxidant like vitamin E.

Do people who eat more tomatoes have less depression, then? Apparently so. A study of about a thousand older men and women found that those who ate the most tomato products had only about half the odds of depression. The researchers conclude that a tomato-rich diet may have a beneficial effect on the prevention of depressive symptoms.

Higher consumption of fruits and vegetables has been found to lead to a lower risk of developing depression, but if it's the antioxidants can't we just take an antioxidant pill? No.

Only food sources of antioxidants were protectively associated with depression. Not antioxidants from dietary supplements. Although plant foods and food-derived phytochemicals have been associated with health benefits, antioxidants from dietary supplements appear to be less beneficial and may, in fact, be detrimental to health. This may indicate that the form and delivery of the antioxidants are important. Alternatively, the observed associations may be due not to antioxidants but rather to other dietary factors, such as folate, that also occur in plant-rich diets.

In a study of thousands of middle-aged office workers, eating lots of processed food was found to be a risk factor for at least mild to moderate depression five years later, whereas a whole food pattern was found to be protective. Yes, it could be because of the high content of antioxidants in fruits and vegetables but could also be the folate in greens and beans, as some studies have suggested an increased risk of depression in folks who may not have been eating enough.

Low folate levels in the blood are associated with depression, but since most of the early studies were cross-sectional, meaning a snapshot in time, we didn't know if the low folate led to depression or the depression led to low folate. Maybe when you have the blues you don't want to eat the greens.

But since then a number of cohort studies were published, following people over time. They show that a low dietary intake of folate may indeed be a risk factor for severe depression, as much as a threefold higher risk. Note this is for dietary folate intake, not folic acid supplements; those with higher levels were actually eating healthy foods. If you give people folic acid pills they don't seem to work. This may be because folate is found in dark green leafy vegetables like spinach, whereas folic acid is the oxidized synthetic compound used in food fortification and dietary supplements because it's more shelf-stable. It may have different effects on the body as I previously explored in Can Folic Acid Be Harmful?

These kinds of findings point to the importance of antioxidant food sources rather than dietary supplements. But there was an interesting study giving people high dose vitamin C. In contrast to the placebo group, those given vitamin C experienced a decrease in depression scores and also greater FSI. What is FSI? Frequency of Sexual Intercourse.

Evidently, high dose vitamin C improves mood and intercourse frequency, but only in sexual partners that don't live with one another. In the placebo group, those not living together had sex about once a week, and those living together a little higher, once every five days, with no big change on vitamin C. But for those not living together, on vitamin C? Every other day! The differential effect for non-cohabitants suggests that the mechanism is not a peripheral one, meaning outside the brain, but a central one--some psychological change which motivates the person to venture forth to have intercourse. The mild antidepressant effect they found was unrelated to cohabitation or frequency, so it does not appear that the depression scores improved just because of the improved FSI.

For more mental health video, see:

Anything else we can do to enhance our sexual health and attractiveness? 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:

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

Original Link

What to Eat to Protect Against Kidney Cancer

NF-Sept8 Can Diet Protect Against Kidney Cancer_.jpeg

58,000 Americans are diagnosed with kidney cancer every year, and 13,000 die. And the numbers have been going up. Approximately 4 percent of cases are hereditary, but what about the other 96 percent? The only accepted risk factor has been tobacco use, but cigarette smoking has been declining.

Nitrosamines are one of the most potent carcinogens in cigarette smoke. One hot dog has as many nitrosamines and nitrosamides as five cigarettes. And these carcinogens are also found in fresh meat as well: beef, chicken and pork. So even though smoking rates have dropped, perhaps the rise in kidney cancer over the last few decades may have something to do with meat consumption. But would kidney cancer just be related to the processed meats like bacon, sausage, hot dogs and cold cuts that have nitrate and nitrite additives, or fresh meat as well?

The NIH-AARP study featured in my video Can Diet Protect Against Kidney Cancer? is the largest prospective study on diet and health ever performed--about 500,000 followed for nine years. In addition to examining nitrate and nitrite intake from processed meat, they also looked at intake from other sources such as fresh meat, eggs and dairy. Nitrite from animal sources, not just processed meats, was associated with an increased risk of kidney cancer, and total intake of nitrate and nitrite from processed meat sources was also associated with kidney cancer risk. The researchers found no associations with nitrate or nitrite intake from plant sources, but nitrates from processed meat was associated with cancer.

When meat producers advertise their bacon or lunch meat as "uncured," this means no nitrites or nitrates added. But if you look at the small print you'll see something like, "except for celery juice." That's just a sneaky way to add nitrites. Processed meat producers ferment the nitrates in celery to create nitrites, then add it to the meat; a practice even the industry admits "may be viewed as incorrect at best or deceptive at worst."

But that same fermentation of nitrates to nitrites can happen thanks to bacteria on our tongue when we eat vegetables. So why are nitrates and nitrites from vegetables on our tongue harmless, but nitrates and nitrites from vegetables in meat linked to cancer? The actual carcinogens are not nitrites, but nitrosamines and nitrosamides. In our stomach, to turn nitrites into nitros-amines, and nitros-amides we need amines and amides, which are concentrated in animal products. And vitamin C and other antioxidants in plant foods block the formation of these carcinogens in our stomach. That's why we can safely benefit from the nitrates in vegetables without the cancer risk. In fact some of the highest nitrate vegetables like arugula, kale, and collards are associated with decreased risk of kidney cancer. The more plants, it appears, the better.

Plant-based diets and fiber-rich diets are recommended to prevent cancer directly, as well as chronic conditions associated with kidney cancer, such as obesity, high blood pressure and diabetes. It's similar to sodium intake and kidney cancer. Sodium intake increases kidney disease risk, but that's not just because sodium intake increases blood pressure. It appears the salt is associated with increased cancer risk even independently of hypertension. What about plant-based diets? Turns out the protective association remains even in people who are not obese and have normal blood pressure. So overall, plant-based and fiber-rich diets appear to do both: decrease cancer risk directly and indirectly.

I briefly address kidney health in Preventing Kidney Failure Through Diet and Treating Kidney Failure Through Diet, but have a whole series of more in-depth videos dealing with various kidney issues.

More on the fascinating nitrate/nitrite story in my 17-part series about improving athletic performance with nitrate-rich vegetables such as beets and arugula. Here are a few short highlights:

More on carcinogens caused by cooking meat in videos like:

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: RDSVS / Flickr

Original Link

Preserving Male Reproductive Health With Diet

NF-June14.jpeg

In 1992 a controversial paper was published suggesting sperm counts have been dropping around the world over the last 50 years. However, this remains a matter of debate. It's notoriously difficult to determine sperm counts in the general population for obvious reasons. If you just go ask men for samples, less than 1 in 3 tend to agree to participate.

Finally though, a study of tens of thousands of men studied over a 17-year period was published. It indeed found a significant decline in sperm concentration, about a 30 percent drop, as well as a drop in the percentage of normal looking sperm. Most sperms looked normal in the 90's, but more recently that has dropped to less than half. This may constitute a serious public health warning.

Semen quality may actually be related to life expectancy. In a study of more than 40,000 men visiting a sperm lab during a 40-year period, they found a decrease in mortality was associated with an increase in semen quality, suggesting that semen quality may therefore be a fundamental biomarker of overall male health. Even when defective sperm are capable of fertilizing an egg, creating a child with abnormal sperm may have serious implications for that child's future health.

What role may diet play? I profiled a first-of-its-kind Harvard study suggesting that a small increase in saturated fat intake was associated with a substantially lower sperm count, but not all fat was bad. Higher intakes of omega-3's were associated with a more favorable sperm shape. This may help explain why researchers at UCLA were able to improve sperm vitality, movement, and shape by giving men about 18 walnuts a day for 12 weeks. Walnuts have more than just omega 3's, though. They also contain other important micronutrients. In a study of men aged 22 through 80, older men who ate diets containing lots of antioxidants and nutrients such as vitamin C had the genetic integrity of sperm of much younger men.

The antioxidants we eat not only end up in our semen, but are concentrated there. The amount of vitamin C ends up nearly ten times more concentrated in men's testicles than the rest of their bodies. Why? Because sperm are highly susceptible to damage induced by free radicals, and accumulating evidence suggests that this oxidative stress plays an important role in male infertility. So, more fruits and vegetables and perhaps less meat and dairy, but the Harvard data were considered preliminary. They studied fewer than 100 men, but it was the best we had... until now.

A much larger follow-up study, highlighted in my video, The Role of Diet in Declining Sperm Counts, found that the higher the saturated fat intake the lower the sperm count, up to a 65 percent reduction. These findings are of potentially great public interest because changes in diet over the past decades may be part of the explanation for the recently reported high frequency of subnormal human sperm counts. In any case, the current findings suggest that adapting dietary intake toward eating less saturated fat may be beneficial for both general and reproductive health.

Why is high dietary intake of saturated fat associated with reduced semen quality? What's the connection? Sex steroid hormones in meat, eggs, and dairy may help explain the link between saturated fat intake and declining sperm counts. That's the subject of my video, Dairy Estrogen and Male Fertility.

More on male infertility in my videos Fukushima and Radioactivity in Seafood and Male Fertility and Diet.

Diet also has a role to play in sexual dysfunction:

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: Julia Mariani / Flickr

Original Link

Which Nut Suppresses Cancer Cell Growth the Most?

NF-Dec22 Which Nut Fights Cancer Better?.jpg

People who eat nuts in their adolescence may have a better chance of fighting off breast cancer later in life, according to data from the Harvard Nurse's Study. A follow-up study involving the daughters of the nurses corroborated the findings. Those eating more peanut butter, nuts, beans, lentils, soybeans, or corn were found to have just a fraction of the risk for fibrocystic breast disease, which places one at higher risk of cancer. The protective effects were found to be strongest for those most at risk, such as those with a family history of breast cancer.

Another study out of the British Journal of Cancer found that even two handfuls of nuts a week may protect against pancreatic cancer, one of our most fatal malignancies.

Nuts are described as "nutritionally precious," which may explain some of the mechanisms by which nut components induce cancer cell death and inhibit cancer growth and spread in vitro. But which nuts work the best? In my video #1 Anticancer Vegetable, we learned that two classes of vegetables--the broccoli family vegetables and the garlic family vegetables--most effectively suppressed breast cancer cell growth. In Which Fruit Fights Cancer Better?, cranberries and lemons took the title.

What about nuts? In terms of antioxidant content, walnuts and pecans steal the show. Twenty-five walnuts have the antioxidant equivalent of eight grams of vitamin C (the vitamin C found in a hundred oranges).

But how do they do against cancer? In the video, Which Nut Fights Cancer Better?, you can see a graph of human cancer cell proliferation versus increasing concentrations of the ten most common nuts eaten in the United States. If you drip water on these cancer cells as a control, nothing happens. Hazelnuts, pistachios and Brazil nuts don't do much better. Pine nuts, cashews and macadamias start pulling away from the pack. Almonds appear twice as protective, halving cancer cell growth at only half the dose as pine nuts, cashews, and macadamias. Walnuts, pecans, and peanuts come out as the clear winners, causing a dramatic drop in cancer proliferation at just tiny doses.

More nuttiness:

-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: Mariya Chorna / Flickr

Original Link

Where Do You Get Your Fiber?

NF-Sep29 Do Vegetarians get enough Protein?.jpg

Vegetarians and vegans are all too familiar with the question: Where do you get your protein?

Well, we can finally put to rest the question of whether vegetarians get enough protein thanks to a large study that compared the nutrient profiles of about 30,000 non-vegetarians to 20,000 vegetarians and about 5,000 vegans, 5,000 flexitarians (vegetarian most of the time), and 5,000 pescetarians (no meat except fish). The average requirement is 42 grams of protein a day. As you can see in the graph in the video, Do Vegetarians Get Enough Protein, meat eaters get way more than they need, and so does everyone else. Vegetarians and vegans average 70% more protein than the recommendation every day.

It's surprising that there's so much fuss about protein in this country when less than 3% of adults don't make the cut, presumably because they're on extreme calorie-restricted diets and aren't eating enough food period. But 97% of Americans get enough protein.

There is a nutrient, though, for which 97% of Americans are deficient. That nutrient is fiber.

Less than 3% of Americans get even the recommended minimum adequate intake of fiber. That's something we really have to work on.

On average, we get only about 15 grams a day. The minimum daily requirement is 31.5, so we get less than half the minimum. Men are particularly deficient. If we break down intake by age and gender, after studying the diets of 12,761 Americans, the percent of men between ages 14 and 50 getting the minimum adequate intake is zero. (The only nutrient Americans may be more deficient in than fiber is potassium. See 98% of American Diets Potassium Deficient.)

This deficit is stunning in that dietary fiber has been protectively associated in population studies with the risk of diabetes, metabolic syndrome, cardiovascular disease, obesity, and various cancers as well high cholesterol, blood pressure, and blood sugars. Therefore, it is not surprising that fiber is listed as a nutrient of concern reported by the Dietary Guidelines Advisory Committee. Protein is not.

One problem is that most people have no idea what's in their food; more than half of Americans think steak is a significant fiber source. By definition, fiber is only found in plants. There is no fiber in meat, dairy or eggs, and little or no fiber in junk food. Therein lies the problem. Americans should be eating more beans, vegetables, fruits, and whole grains--but how are they doing?

96% of Americans don't eat the minimum recommended daily amount of beans, 96% don't eat the measly minimum for greens, and 99% don't get enough whole grains. Nearly the entire U.S. population fails to eat enough whole plant foods.

Even semi-vegetarians make the fiber minimum, though. Those eating completely plant-based diets triple the average American intake. When closing the fiber gap, you'll want to do it gradually though, no more than about five extra grams a day each week until you can work your way up. But it's worth it. "Plant-derived diets tend to contribute significantly less fat, saturated fat, cholesterol, and food-borne pathogens, while at the same time offering more fiber, folate, vitamin C, and phytochemicals, all essential factors for disease prevention, optimal health, and well being." And the more whole plant foods the better. If we compare the nutritional quality of vegan versus vegetarian, semi-vegetarian, pesco-vegetarian and omnivorous diets, traditional healthy diet indexing systems consistently indicate that the most plant-based diet is the healthiest one.

For more on how S.A.D. the Standard American Diet is, see Nation's Diet in Crisis.

Americans eating meat-free diets average higher intakes of nearly every nutrient. See my video Nutrient-Dense Approach to Weight Management.

Isn't animal protein higher quality protein though? See my videos:

For more on protein, see: Plant Protein Preferable and Prostate Cancer Survival: The A/V Ratio.

And for a few on fiber:

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: Nathan Rupert / Flickr

Original Link

Eliminate Most of Your Chronic Disease Risk in Four Steps

NF-Sep17 Turning the Clock Back 14 years.jpg

In 1903, Thomas Edison predicted that the doctor of the future will give no medicine, but instead "instruct his patient in the care of the human frame in diet and in the cause and prevention of disease." A hundred and one years later, the American College of Lifestyle Medicine was born. Lifestyle docs like myself still prescribe meds when necessary, but, based on the understanding that the leading causes of disability and death in the United States are caused mostly by lifestyle, our emphasis is particularly on what we put in our mouths: food and cigarettes. An "impressive number of studies have shown that lifestyle is the root cause of what ails us." The good news is that by changing our lifestyle we can dramatically improve our health.

You have the power.

We've known for a long time that for most of the leading causes of death our genes account for at most 10 to 20% of risk, given that rates of killers like heart disease and major cancers differ up to a 100-fold among various populations, and that when people migrate from low- to high-risk countries, their disease rates almost always change to those of the new environment. For example, at least 70% of strokes and colon cancer are avoidable, as are over 80% of coronary heart disease and over 90% of type 2 diabetes. So maybe it's "time we stop blaming our genes and focus on the 70% that is under our control." That may be the real solution to the health care crisis.

It doesn't take much. Adhering to just four simple healthy lifestyle factors can have a strong impact on the prevention of chronic diseases: not smoking, not being obese, exercising half an hour a day, and eating healthier (more fruits, veggies, whole grains, less processed foods and meat). Four simple things cut our risk of developing a chronic disease by 78%. 95% of diabetes risk out the window, 80% of heart attack risk, gone. Half of stroke risk, a third of cancer risk, simply gone. Think of what that means in terms of the numbers. As it stands now, each year a million Americans experience their first heart attack or stroke, a million get diabetes, a million get cancer.

Do we actually get to live longer, too? The CDC followed about 8,000 Americans 20 years or older for about six years. They found that three cardinal lifestyle behaviors exerted an enormous impact on mortality. People who do not smoke, consume a healthy diet, and engage in sufficient physical activity can substantially reduce their risk for early death. By "not smoking" they just meant not currently smoking; by "healthy diet" they just meant in the top 40% in terms of complying with the rather wimpy federal dietary guidelines; and by being "physically active" they just meant averaging about 21 minutes a day or more of at least moderate exercise. Those that managed at least one of the three had a 40% lower risk of dying. Those that hit two out of three cut their chances of dying by more than half. Those that scored all three threw 82% of their chances of dying in those six years out the window.

What does that mean in terms of how much longer we get to live? A similar study on health behaviors and survival, highlighted in my video, Turning the Clock Back 14 Years, didn't just take people's word for how healthfully they were eating, they measured the level of vitamin C in people's blood, a biomarker for how many plants they were eating, and the drop in mortality risk in those nailing all healthy behaviors was equivalent to being 14 years younger.

I discuss the role diet may play in preventing the 15 leading causes of death in my 2012 annual review video Uprooting the Leading Causes of Death.

How does your diet compare? Calculate Your Healthy Eating Score.

I go into depth into the exercise component in my video Longer Life Within Walking Distance.

For more on slowing the aging process, see my videos:

And more on my chosen clinical specialty, lifestyle medicine, in:

In health,
Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my videos for free by clicking here and watch my full 2012 - 2015 presentations Uprooting the Leading Causes of Death, More than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: Marlon E / Flickr

Original Link

Why Deep Fried Foods May Cause Cancer

NF-Jul21 Cancer Risk from French fries.jpg

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

Original Link

Treating Asthma With Plants vs. Pills

NF-July7 Treating Asthma with Plants vs. Supplements.jpg

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

Original Link

How Fruits and Vegetables Can Prevent Asthma

NF-June30 Preventing Asthma with Fruits and Vegetables.jpg

Asthma is the most common chronic disease in children and the prevalence is increasing around the world. Despite this, most research dollars are spent on adult chronic disease. "One might ask," a group of researchers posited "whether this is because our politicians and senior administrators feel themselves to be more likely to suffer from the latter, and thus ignore allergic diseases as they mostly impact children and young adults" - who don't vote.

An enormous study about asthma and allergies in childhood, highlighted in my video, Preventing Asthma with Fruits and Vegetables, was published that includes more than a million children in nearly a hundred countries, making it the most comprehensive survey of asthma and allergies ever undertaken. The researchers found striking worldwide variations in the prevalence and severity of asthma, allergies, and eczema--a 20 to 60-fold difference in prevalence of symptoms of asthma, allergic runny nose, and atopic eczema around the world. The large variability suggests a crucial role of local characteristics that are determining the differences in prevalence between one place and another.

What kind of environmental factors? Why does the prevalence of itchy eyes and runny noses range anywhere from 1% in India, for example, and up to 45% of kids elsewhere? There were some associations with regional air pollution and smoking rates, but the most significant associations were with diet. Adolescents showed a consistent pattern of decreases in symptoms of wheeze (current and severe), allergic rhinoconjunctivitis, and atopic eczema with increases in per capita consumption of plant foods. The more their calories and protein came from plant sources, the less allergies they tended to have.

In general, there seems to be an association between an increase in asthma prevalence and a decrease in consumption of fresh fruits, green vegetables, and other dietary sources of antioxidants, helping to explain why the prevalence of asthma and respiratory symptoms are lower in populations with high intake of foods of plant origin. High intakes of fat and sodium, and low intakes of fiber and carbohydrates, are linked with asthma, while traditional and vegetarian diets are associated with lower rates. For example, if we look closer within India, in a study of more than 100,000 people, "those who consumed meat (daily or occasionally) were more likely to report asthma than those who were strictly vegetarian." This also meant avoiding eggs.

Eggs have been associated (along with soft drink consumption) with increased risk of respiratory symptoms and asthma in schoolchildren. On the other hand, consumptions of soy foods and fruits were associated with reduced risk of respiratory symptoms. In fact, removing eggs and dairy from the diet may improve lung function in asthmatic children in as little as eight weeks. Therefore, it may be a combination of eating fewer animal foods and more plants.

High vegetable intake, for example, has been found protective in children, potentially cutting the odds of allergic asthma in half. And fruit has also shown a consistent protective association for current and severe wheeze and runny nose in adolescents, and for current and severe asthma, allergies, and eczema in children.

Why is this? I've talked about the endocrine-disrupting industrial pollutants (see Dietary Sources of Alkylphenol Endocrine Disruptors) building up in the meat supply that may increase the risk of allergic disease, but the increase in asthma may be a combination of both a more toxic environment and a more susceptible population. One review notes that, "The dietary changes which have occurred over recent years may have led to a reduction in these natural antioxidant defenses, resulting in a shift of the antioxidant status of the whole population and leading to increased susceptibility to oxidant attack and airway inflammation."

In adults, for example, the risk of airway hyper-reactivity may increase seven-fold among those with the lowest intake of vitamin C from plant foods, while those with the lowest intake of saturated fats may have a 10-fold protection, presumably because of saturated fat's role in triggering inflammation.

The protective effect of plant-based food may also be mediated through effects on intestinal microflora. It turns out that differences in the indigenous intestinal flora might affect the development and priming of the immune system in early childhood. Kids with allergies, for example, tend to be less likely to harbor lactobacilli, the good bacteria that's found in fermented foods, and naturally on many fruits and vegetables. Lactobacillus probiotics may actually help with childhood asthma, which may help explain why children raised on largely organic vegetarian diets may have a lower prevalence of allergic reactions. Infants raised this way tend to have more good lactobacilli in their guts compared to controls, though they were also more likely to have been born naturally, breastfed longer, and not been given antibiotics, so we can't really tell if it's the diet until we put it to the test (See Treating Asthma with Fruits and Vegetables).

More on preventing allergic diseases can be found in my videos Preventing Childhood Allergies and Preventing Allergies in Adulthood.

More on protecting lung function with fruits and vegetables can be found in Preventing COPD With Diet.

Surprised probiotics can affect immune function? Check out my video Preventing the Common Cold with Probiotics? And if you think that is wild, wait until you see Gut Feelings: Probiotics and Mental Health.

What might be in plants that's so beneficial? See Anti-inflammatory Antioxidants.

What might be in animal products that is harmful to lung function? There are endocrine-disrupting industrial pollutants that build up in the food chain that may be playing a role. See my video Alkylphenol Endocrine Disruptors and Allergies. Also there's an inflammatory omega-6 fatty acid found predominantly in chicken and eggs that may contribute to inflammation as well. See Inflammatory Remarks About Arachidonic Acid.

Choosing fragrance-free personal care products may also help reduce airway reactivity: Throw Household Products Off the Scent.

I compare the efficacy of plants to pills (Treating Asthma With Plants vs. Supplements?) and explore the role an entire diet filled with plants might play in Treating Asthma and Eczema With Plant-Based Diets.

-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: EdTech Stanford University School of Medicine / Flickr

Original Link