Foods Linked to ALS

Foods Linked to ALS.jpeg

As explored in my video ALS (Lou Gehrig's Disease): Fishing for Answers, there may be a link in the consumption of the neurotoxin BMAA, produced by algae blooms, and increased risk of ALS. It now appears that BMAA could be found in high concentrations in aquatic animals in many areas of the world.

This could explain ALS clustering around lakes in New Hampshire--up to 25 times the expected rate of ALS with some families eating fish several times a week. Or in Wisconsin, where the most significant ALS risk factor was the past consumption of fish out of Lake Michigan. Or clustering in Finland's Lakeland district, or seafood eaters in France, or around the Baltic sea, building up particularly in fish, mussels and oysters.

When I think of algae blooms I think of the Chesapeake bay near where I live, that gets choked off thanks in part to the poultry industry pollution. And indeed there was a recent report linking BMAA exposure to ALS in Maryland. The ALS victims, all of whom ate Chesapeake Bay blue crabs every week, lived within a half mile of each other, which raised some eyebrows at the Hopkins ALS center. And so researchers tested a few crabs, and two out of three tested positive for BMAA, indicating that the neurotoxin is present in the aquatic food chain of the Chesapeake Bay and is a potential route for human exposure.

To bring the story full circle, things in Guam, where the link between BMAA consumption and ALS was first discovered, are looking up. The ALS epidemic there may have been triggered by their acquisition of guns. Now though, the epidemic appears to be over thanks to near-extinction of the fruit bats they were eating due to over-hunting. But while the rates decline in Guam, neurodegenerative diseases like ALS around the rest of the world are on the rise.

It's plausible that humans have been exposed to some level of BMAA throughout their evolutionary history, but the increase in algae blooms as a result of human activities is probably increasing this exposure. There is a general consensus that harmful algal blooms are increasing worldwide thanks in part to industrialized agriculture (as shown in my video Diet & Amyotrophic Lateral Sclerosis-ALS). More people means more sewage, fertilizer, and manure, which can mean more algae, which may mean more exposure to this neurotoxin, leading to a possible increased incidence of neurodegenerative diseases such as Alzheimer's, Parkinson's, and ALS.

BMAA is considered a strong contender as the cause of, or at least a major contributor to the cause of both endemic and sporadic ALS and Alzheimer's disease, and possibly conferring risk for Parkinson's diseases as well. The ramifications of this discovery are enormous.

As researchers from Australia stated, "With substantial and ever growing evidence that BMAA does play a role in the onset and progression of neurodegenerative diseases, the most important question is, what mode of activity does BMAA exert?" Huh? That's not the most important question we should be asking. The most important question is "How can we reduce our risk?"

We know that the presence of BMAA in aquatic food chains could be a significant human health hazard. There may even be a synergistic toxicity between mercury and BMAA, making certain fish even riskier. Until more is known about the possible link of BMAA to Alzheimer's and ALS, it may be prudent to limit exposure of BMAA in the human diet.

For other neurotoxins found in the food supply, see Amnesic Seafood Poisoning, Essential Tremor and Diet, Ciguatera Poisoning & Chronic Fatigue Syndrome.

Other toxic substances can also build up in the aquatic food chain, for example:

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: Peter Miller / Flickr. This image has been modified.

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Foods Linked to ALS

Foods Linked to ALS.jpeg

As explored in my video ALS (Lou Gehrig's Disease): Fishing for Answers, there may be a link in the consumption of the neurotoxin BMAA, produced by algae blooms, and increased risk of ALS. It now appears that BMAA could be found in high concentrations in aquatic animals in many areas of the world.

This could explain ALS clustering around lakes in New Hampshire--up to 25 times the expected rate of ALS with some families eating fish several times a week. Or in Wisconsin, where the most significant ALS risk factor was the past consumption of fish out of Lake Michigan. Or clustering in Finland's Lakeland district, or seafood eaters in France, or around the Baltic sea, building up particularly in fish, mussels and oysters.

When I think of algae blooms I think of the Chesapeake bay near where I live, that gets choked off thanks in part to the poultry industry pollution. And indeed there was a recent report linking BMAA exposure to ALS in Maryland. The ALS victims, all of whom ate Chesapeake Bay blue crabs every week, lived within a half mile of each other, which raised some eyebrows at the Hopkins ALS center. And so researchers tested a few crabs, and two out of three tested positive for BMAA, indicating that the neurotoxin is present in the aquatic food chain of the Chesapeake Bay and is a potential route for human exposure.

To bring the story full circle, things in Guam, where the link between BMAA consumption and ALS was first discovered, are looking up. The ALS epidemic there may have been triggered by their acquisition of guns. Now though, the epidemic appears to be over thanks to near-extinction of the fruit bats they were eating due to over-hunting. But while the rates decline in Guam, neurodegenerative diseases like ALS around the rest of the world are on the rise.

It's plausible that humans have been exposed to some level of BMAA throughout their evolutionary history, but the increase in algae blooms as a result of human activities is probably increasing this exposure. There is a general consensus that harmful algal blooms are increasing worldwide thanks in part to industrialized agriculture (as shown in my video Diet & Amyotrophic Lateral Sclerosis-ALS). More people means more sewage, fertilizer, and manure, which can mean more algae, which may mean more exposure to this neurotoxin, leading to a possible increased incidence of neurodegenerative diseases such as Alzheimer's, Parkinson's, and ALS.

BMAA is considered a strong contender as the cause of, or at least a major contributor to the cause of both endemic and sporadic ALS and Alzheimer's disease, and possibly conferring risk for Parkinson's diseases as well. The ramifications of this discovery are enormous.

As researchers from Australia stated, "With substantial and ever growing evidence that BMAA does play a role in the onset and progression of neurodegenerative diseases, the most important question is, what mode of activity does BMAA exert?" Huh? That's not the most important question we should be asking. The most important question is "How can we reduce our risk?"

We know that the presence of BMAA in aquatic food chains could be a significant human health hazard. There may even be a synergistic toxicity between mercury and BMAA, making certain fish even riskier. Until more is known about the possible link of BMAA to Alzheimer's and ALS, it may be prudent to limit exposure of BMAA in the human diet.

For other neurotoxins found in the food supply, see Amnesic Seafood Poisoning, Essential Tremor and Diet, Ciguatera Poisoning & Chronic Fatigue Syndrome.

Other toxic substances can also build up in the aquatic food chain, for example:

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: Peter Miller / Flickr. This image has been modified.

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Bile Acids and Breast Cancer

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Why do constipated women appear to be at higher risk for breast cancer? The results of a 1989 study out of the American Journal of Public Health suggested a slight increased risk of breast cancer for both decreased frequency of bowel movements and firm stool consistency. Women who had three or more bowel movements a day appeared to cut their risk of breast cancer in half. This could be because constipation means a greater contact time between our waste and our intestinal wall, which may increase the formation and absorption of fecal mutagens--substances that cause DNA mutations and cancer--into our circulation, eventually ending up in breast tissue.

The concept that more frequent bowl movements decrease breast cancer risk dates back more than a century, where severe constipation, so-called "chronic intestinal stasis," was sometimes dealt with surgically. Figuring that the colon was an inessential part of the human anatomy, why not cure constipation by just cutting it out? After the surgery, they noticed that potentially precancerous changes in the breasts of constipated women seemed to disappear.

It would take another 70 years before researchers followed up on the clues by those distinguished surgeons who claimed breast pathology cleared when constipation was corrected. A 1981 study published in The Lancet investigated the relation between potentially precancerous changes in the breast and the frequency of bowl movements in nearly 1,500 women (See Breast Cancer and Constipation). The researchers found that the risk of precancerous changes was four times greater in women reporting two or fewer bowel movements a week compared to more than once daily.

We know that even the non-lactating breast actively takes up chemical substances from the blood. We also know that there are mutagens in feces. It is not unreasonable to suggest that potentially toxic substances derived from the colon have damaging or even carcinogenic effects upon the lining of the breast. Toxic substances like bile acids. Bile acids were first shown to promote tumors in mice in 1940, but subsequent experiments on rats led to the mistaken belief that bile acids just promoted existing cancers and couldn't initiate tumors themselves. However, there is a fundamental difference between the rodent models and human cancer. Rats only live a few years while humans can live dozens, so the opportunity for cancer causing mutations may be at least 30 times greater in humans. We now have at least 15 studies that show that bile acids can damage DNA, strongly suggesting they can initiate new cancers as well.

Bile acids are formed as a way of getting rid of excess cholesterol. Our liver dumps bile acids into the intestine for disposal, assuming our intestines will be packed with fiber to trap it and flush it out of the body. But if we haven't been eating enough fiber-rich whole plant foods, bile acids can be reabsorbed back into the body and build up in the breast.

Carcinogenic bile acids are found concentrated in the fluid of breast cysts at up to a hundred times the level found in the bloodstream. By radioactively tagging bile acids, researchers were able to show that intestinal bile acids rapidly gain access to the breast, where they can exert an estrogen-like cancer-promoting effect on breast tumor cells. This would explain why we see 50% higher bile acid levels in the bloodstream of newly diagnosed breast cancer victims. These findings support the concept of a relationship between intestinally-derived bile acids and risk of breast cancer. So how can we facilitate the removal of bile acids from our body?

Slowed colonic transit can increase bile acid levels. Therefore, to decrease absorption of bile acids, we can speed up the so-called "oro-anal transit time," the speed at which food goes from mouth to toilet, by eating lots of fiber. A diet packed with plants greatly increases bile acid excretion.

Fiber can bind up and remove other toxic elements like lead and mercury as well as cholesterol and bile acids. But plants can bind bile acids even independent of fiber. Vegan diets bind significantly more bile acid than lacto-ovo or non-vegetarian diets even at the same fiber intake, which could explain why individuals eating vegetarian might excrete less mutagenic feces in the first place.

I touched on this in my live presentation From Table to Able: Combating Disabling Diseases with Food, but what I didn't get to discuss is the relative bile acid binding abilities of different foods. I cover that in my video Which Vegetable Binds Bile Best?

What intestinal transit time should we be shooting for? See Food Mass Transit. That may be why Stool Size Matters. Also, How Many Bowel Movements Should You Have Every Day? We can improve speed and size by Bulking Up on Antioxidants and eating lots of whole plant foods (Prunes vs. Metamucil vs. Vegan Diet).

Fiber may also help women remove excess estrogen from their body. See my video Fiber vs. Breast Cancer. For more on the wonders of fiber, see Dr. Burkitt's F-Word Diet.

For more of my latest videos on breast cancer prevention and survival, 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, and Food as Medicine.

Image Credit: Photocapy / Flickr

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How to Reduce Your Dietary Cadmium Absorption

NF-Oct15 Cadmium and cancer- plant vs animal food .jpg

Cadmium is known as a highly toxic metal that represents a major hazard to human health. It sticks around in our body for decades because our body has no efficient way to get rid of it and may contribute to a variety of illnesses, including heart disease, cancer, and diabetes.

Most recently, data suggests that cadmium exposure may impair cognitive performance even at levels once thought to be safe. Recent studies also suggest that cadmium exposure may produce other adverse health effects at lower exposure levels than previously predicted, including increased risk of hormonal cancers. For example, researchers on Long Island estimated that as much as a third of breast cancer in the U.S. might be associated with elevated cadmium levels.

Inhalation of cigarette smoke is one of the major routes for human exposure to cadmium. Seafood consumption is another route of human exposure. The highest levels, though, are found in organ meats. But how many horse kidneys do people eat? Since people eat so few organs, grains and vegetables actually end up contributing the largest amount to our collective diets.

However, don't drop the salad from the menu yet.

Whole grains and vegetables are among the major dietary sources of fiber, phytoestrogens, and antioxidants that may protect against breast cancer. Indeed, even though the risk of breast cancer goes up as women consume more and more cadmium, and even though on paper most cadmium comes from grains and vegetables, breast cancer risk goes down the more and more whole grains and vegetables women eat. So are animal sources of cadmium somehow worse, or do the benefits of plant foods just overwhelm any adverse effects of the cadmium?

A study out of the Journal of the Medical Association of Thailand highlighted in my video, Cadmium and Cancer: Plant vs. Animal Foods, may have helped solve the mystery. It's not what we eat, it's what we absorb.

Cadmium bioavailability from animal-based foods may be higher than that from vegetable-based foods. There appears to be something in plants that inhibits cadmium absorption. In fact, researchers found when they added kale to boiled pig kidneys, they could cut down on the toxic exposure. Just one tablespoon of pig kidney, and we may exceed the daily safety limit--unless we add kale, in which case we could eat a whole quarter cup. The pronounced effects of the inhibitory factors in kale point out, as the researchers note, "the importance of vegetable foods in terms of prevention of health hazard from [cadmium] ingested as mixed diets in a real situation."

Reesearchers have concluded: "Even if a vegetarian diet contains more lead and cadmium than a mixed diet, it is not certain that it will give rise to higher uptake of the metals, because the absorption of lead and cadmium is inhibited by plant components such as fiber and phytate." Having whole grains in our stomach up to three hours before we swallow lead can eliminate 90% of absorption, thought to be due to phytates in whole grains, nuts, and beans grabbing onto it.

So vegetarians may have lower levels of lead and cadmium even though they have higher intakes.

In fact, there is a significant decrease in the hair concentrations of lead and cadmium after the change from an omnivorous to a vegetarian diet, indicating a lower absorption of the metals. Researchers took folks eating a standard Swedish diet and put them on a vegetarian diet. The vegetarians were encouraged to eat lots of whole, unrefined plant foods, with no meat, poultry, fish, and eggs. Junk food was also discouraged. Within three months on a vegetarian diet, their levels significantly dropped, and stayed down for the rest of the year-long experiment. The researchers came back three years later, three years after the subjects stopped eating vegetarian, and found that their levels of mercury, cadmium, and lead had shot back up.

Since the cadmium in plants is based on the cadmium in soil, plant-eaters that live in a really polluted area like Slovakia, which has some of the highest levels thanks to the chemical and smelting industries, can indeed build up higher cadmium levels, especially if they eat lots of plants. It's interesting that, "in spite of the significantly higher blood cadmium concentration as a consequence of a greater cadmium intake from polluted plants, all the antioxidants in those same plants were found to help inhibit the harmful effects of higher free radical production caused by the cadmium exposure." Still, though, in highly polluted areas it might be an especially good idea not to smoke or eat too much seafood or organ meats. But even if we live in the Slovak Republic's "black triangle of pollution," the benefits of whole plant foods would outweigh the risks. For people in highly polluted areas, zinc supplements may decrease cadmium absorption, but I'd recommend against multi-mineral supplements, as they have been found to be contaminated with cadmium itself.

There are other toxins in cigarette smoke also found in food. See:

Toxic metals have also been found in dietary supplements. See for example, Get the Lead Out and Heavy Metals in Protein Powder Supplements.

Mercury is also a serious problem. See:

More on pollution in seafood can be found in:

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: Julie / Flickr

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Salmon May Be the Greatest Source of Dietary Pollutants

NF-Aug6 Pollutants in Salmon and Our Own Fat.jpg

In my video Diabetes and Dioxins, I explored a nationwide study that found a strong dose-response relationship between industrial toxins and diabetes. Since then, Harvard researchers have reported a link between persistent pollutants like hexachlorobenzene and diabetes in their Nurse's Health Study (See Food Sources of Perfluerochemicals). This is supported by an analysis they did of six other studies published since 2006 that showed the same thing. The Harvard researchers conclude that "past accumulation and continued exposure to these persistent pollutants may be a potent risk factor for developing diabetes."

Where is hexachlorobenzene found? In a U.S. supermarket survey, salmon and sardines were most heavily tainted with hexachlorobenzene, with salmon "the most contaminated food of all." Farmed salmon specifically is perhaps the greatest source of dietary pollutants, averaging nearly ten times the PCB load of wild-caught salmon.

Wait, isn't there a flaw in this argument? Since many of these chemicals were banned in the 70's, the levels inside people have been going down, whereas the rates of diabetes have been shooting straight up. Therefore, how could pollutant exposure be causing diabetes? This puzzle may be explained by our epidemic of obesity. The nationwide study found that the association between these toxins and diabetes was much stronger among obese subjects than among lean subjects. As people get fatter, the retention and toxicity of pollutants related to the risk of diabetes may increase.

So we're not just exposed by eating the fat of other animals; our own fat can be a continuous source of internal exposure because these persistent pollutants are slowly but continuously released from our fat stores into our circulation.

They don't call them "persistent pollutants" for nothing. These chemicals have such a long half-life that people consuming regular (even just monthly) meals of farmed salmon might end up retaining these chemicals in their bodies for 50 to 75 years.

Hexachlorobenzene in fish has been tied to diabetes; what about the mercury? A 1995 study highlighted in my video, Pollutants in Salmon and Our Own Fat, out of Japan found that diabetics do seem to have higher mercury levels in their body. Mercury alone does not seem to increase diabetes risk, though. It may be the simultaneous exposure to both dioxins and mercury that increases risk, so the safety limits for dioxins and mercury individually may underestimate the risk when they're consumed together in seafood.

So while the pharmaceutical industry works on coming up with drugs to help mediate the impact of these pollutants, a better strategy might be to not get so polluted in the first place.

Unfortunately, because we've so contaminated our world, we can't escape exposure completely. You have to eat something. Some foods are more contaminated than others, though. Exposure to these pollutants comes primarily from the consumption of animal fat, with the highest levels found in fatty fish like salmon. Farmed Atlantic salmon may be the single largest source of these pollutants, and that's the kind of salmon we most commonly find in supermarkets and restaurants.

We hear about advisories warning pregnant women to avoid the consumption of food containing elevated levels of pollutants and mercury, but as a public health journal article points out, since these toxins bio-accumulate in the body for many years "restricting the exposure to these pollutants only during pregnancy would not protect the fetus or future generations against the harmful effects of these hazardous chemicals."

For the existing links between seafood and diabetes risk, see Fish and Diabetes and I explored this concept of our own body fat as a reservoir for disease-causing pollutants in Diabetes and Dioxins.

More on hexachlorobenzene in my video Food Sources of Perfluorochemicals.

Our body has a tougher time getting rid of some toxins than others:

The best way to detox is to stop toxing in the first place.

-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: Sharon Mollerus / Flickr

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How Contaminated Are Our Children?

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In a study highlighted in my video, California Childen Are Contaminated, researchers analyzed the diets of California children ages two through seven to determine the cancer and non-cancer health effects from food contaminant exposures. It turns out food may be the primary route of exposure to toxic heavy metals, persistent pollutants, and pesticides. "Though food-borne toxic contaminants are a concern for all ages, they are of greatest concern for children, who are disproportionately impacted because they're still developing and have greater intake of food and fluids relative to their weight. Pediatric problems that have been linked to preventable environmental toxin exposures include cancer, asthma, lead poisoning, neurobehavioral disorders, learning and developmental disabilities, and birth defects."

The good news is that changing one's diet can change one's exposure. Quoting from the study, "A diet high in fish and animal products, for example, results in greater exposure to persistent pollutants like DDT and dioxins and heavy metals than does a plant-based diet because these compounds bioaccumulate up the food chain." Plants are at the bottom of the food chain. The sample of California kids, however, was not eating a plant-based diet. Cancer benchmark levels were exceeded by all 364 children for arsenic, the banned pesticide dieldrin, a metabolite of DDT called DDE, and dioxins.

Children exceeded safety levels by a greater margin than adults. This is especially of concern for children because all of these compounds are suspected endocrine disruptors and thus may impact normal development. Cancer risk ratios were exceeded by over a factor of 100 for both arsenic and dioxins.

Which foods were the worse? For preschoolers, the number one food source of arsenic was poultry, though for their parents, it was tuna. The number one source of lead was dairy, and for mercury it was seafood. And the number one source of the banned pesticides and dioxins was dairy. (See Preventing Parkinson's Disease With Diet.)

The researchers also recommended children should eat lower quantities of chips, cereal, crackers, and other crispy carbs to reduce acrylamide intake.

The California study didn't split up the groups by gender, but a similar study in Europe found that men had higher levels of some of these pollutants than women. For example, levels of the banned pesticide chlordane were higher in men, but women who never breastfed were right up there alongside men, with the lowest levels found in women who breastfed over 12 months. Therefore, it is likely that the lactation-related reduction in blood pollutant levels partly explains the lower body burdens among women compared with men. So cows can lower their levels by giving some to us, then we can pass it along to our children.

What non-cancer effects might some of these pollutants have? They can affect our immune system. Studies clearly demonstrate the "ability of dioxins and related compounds to have a long-lasting and deleterious impact on immune function." This manifests as increased incidences of respiratory infections, ear infections, cough, and sore throat. At first, most of the data was for during infancy, but now we have follow-up studies showing that the immunosuppressive effects of these toxins may persist into early childhood, so we should try to reduce our exposure as much as possible. Because these pollutants accumulate in animal fat, consuming a plant-based diet-decreasing meat, dairy, and fish consumption-may reduce exposure for children and adults alike.

These findings should come as no surprise to those who saw my video Pollutants in California Breast Tissue. For an overview see CDC Report on Environmental Chemical Exposure and President's Cancer Panel Report on Environmental Risk.

Pollutant exposure may affect the ability to have children in the first place (Male Fertility and Diet and Meat Hormones & Female Infertility). Such a delay, though, may allow one an opportunity to reduce one's toxic burden through dietary change (Hair Testing for Mercury Before Considering Pregnancy and How Long to Detox From Fish Before Pregnancy?).

During pregnancy, pollutants can be transferred directly (DDT in Umbilical Cord Blood), and after pregnancy through breastfeeding (The Wrong Way to Detox). Once our kids are contaminated, How Fast Can Children Detoxify from PCBs? The chemicals have implications for older children too: Protein, Puberty, and Pollutants.

Seafood is not the only source of toxic heavy metals. See:

Videos on primary food sources of other industrial pollutants include:

There are some things we can eat, though, to counteract some of the toxins:

-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: Kevin Krejci / Flickr

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Who Should be Careful About Curcumin?

NF-Feb5 Who Shouldn't Consume Curcumin or Turmeric?.jpg

Following flax and wheatgrass, turmeric is the third best-selling botanical dietary supplement, racking up $12 million in sales. Currently, sales are increasing at a rate of 20%.

"Curcumin is a natural plant product extracted from the turmeric root and is used commonly as a food additive popular for its pleasant mild aroma and exotic yellow color. It is widely considered unlikely to cause side effects." However, just because something is natural doesn't mean it's not toxic. Strychnine is natural; cyanide is natural. Lead, mercury and plutonium are all elements--can't get more natural than that! But turmeric is just a plant. Surely plants can't be dangerous? Tell that to Socrates.

"In considering the validity of the widely accepted notion that complementary and alternative medicine is a safer approach to therapy, we must remind ourselves and our patients that a therapy that exerts a biologic effect is, by definition, a drug and can have toxicity." It cannot be assumed that diet-derived agents will be innocuous when administered as pharmaceutical formulations at doses likely to exceed those consumed in the diet.

Traditional Indian diets may include as much as a teaspoon of turmeric a day. Doses of turmeric that have been used in human studies range from less than just a 16th of a teaspoon a day to two tablespoons a day for over a month. On the other hand, the curcumin trials have used up to the amount found in cups of the spice, around 100 times more than what curry lovers have been eating for centuries.

Studies have yet to show overt serious side effects in the short-term. However, if we combine high dose curcumin with black pepper, resulting in a 2000% boost in bioavailability (See Boosting the Bioavailability of Curcumin), it could be like consuming the equivalent of 29 cups of turmeric a day. That kind of intake could bring peak blood levels to the range where you start seeing some significant DNA damage in vitro.

So just incorporating turmeric into your cooking may be better than taking curcumin supplements, especially during pregnancy. The only other contraindication cited in the most recent review on curcumin was the potential to trigger gallbladder pain in individuals with gallstones.

If anything, curcumin may help protect liver function and help prevent gallstones by acting as a cholecystokinetic agent, meaning that it facilitates the pumping action of the gallbladder to keep the bile from stagnating. In one study, profiled in my video, Who Shouldn't Consume Turmeric or Curcmin?, researchers gave people a small dose of curcumin, about the amount found in a quarter teaspoon of turmeric and, using ultrasound, were able to visualize the gallbladder squeezing down in response, with an average change in volume of about 29%. Optimally, though we want to squeeze it in half. So the researchers repeated the experiment with different doses. It took about 40 milligrams to get a 50% contraction, or about a third of a teaspoon of turmeric every day.

On one hand that's great--totally doable. On the other hand, that's some incredibly powerful stuff! What if you had a gallbladder obstruction? What if you had a stone blocking your bile duct? If you eat something that makes your gallbladder squeeze so much, it could cause pain. So patients with biliary tract obstruction should be careful about consuming curcumin. For everyone else, these results suggest that curcumin can effectively "induce the gallbladder to empty and thereby reduce the risk of gallstone formation and ultimately even gallbladder cancer."

Too much turmeric, though, may increase the risk of kidney stones. As I mentioned in Oxalates in Cinnamon, turmeric is high in soluble oxalates which can bind to calcium and form insoluble calcium oxalate, which is responsible for approximately 75% of all kidney stones. "The consumption of even moderate amounts of turmeric would therefore not be recommended for people with a tendency to form kidney stones." Such folks should restrict the consumption of total dietary oxalate to less than 40 to 50 mg/day, which means no more than at most a teaspoon of turmeric. Those with gout, for example, are by definition, it appears, at high risk for kidney stones, and so if their doctor wanted to treat gout inflammation with high dose turmeric, he or she might consider curcumin supplements, because to reach high levels of curcumin in turmeric form would incur too much of an oxalate load.

If we are going to take a supplement, how do we choose? The latest review recommends purchasing from Western suppliers that follow recommended Good Manufacturing Practices, which may decrease the likelihood of buying an adulterated product.

I previously discussed the role spices play in squelching inflammation and free radicals in Which Spices Fight Inflammation? and Spicing Up DNA Protection. Then out of the lab into the clinic with attempts to test the ability of turmeric extracts to treat joint inflammation with Turmeric Curcumin and Rheumatoid Arthritis and Turmeric Curcumin and Osteoarthritis.

I wish there was more science on wheatgrass. I just had that one unhelpful anecdote in my video How Much Broccoli Is Too Much? There is good science on flax though. See:

More on gallbladder health can be found in my video Cholesterol Gallstones. And those who are susceptible to kidney stones should try to alkalinize their urine by eating lots of dark green leafy vegetables. See Testing Your Diet with Pee & Purple Cabbage.

Based on this new science on turmeric (lots more to come!), I now try to include it in my family's daily diet.

-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: sean dreilinger / Flickr

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How Long to Avoid Fish Before Conception?

NF-Dec25 How Long to Detox from Fish Before Pregnancy?.jpg

Mothers' increased consumption of fish before and during pregnancy leads to increased exposure to both mercury and the long-chain omega 3 DHA. Mercury may negatively affect brain development in one's unborn baby, whereas DHA may stimulate brain development. However, the negative effect of mercury appears to outweigh the beneficial effect of DHA for most species of fish (see Mercury vs. Omega-3s for Brain Development).

Unfortunately, women of childbearing age appear less aware and knowledgeable about this problem than other women, despite FDA and EPA campaigns to inform every OB/GYN and pediatrician in the country about the potential risks of mercury in fish.

Since mercury sticks around in the body, women may want to avoid fish with high levels of mercury for a year before they get pregnant, not just during pregnancy. The rationale for avoiding fish for a year before pregnancy is because the half-life of mercury in the body is estimated to be about two months. In a study I profile in my video How Long to Detox from Fish Before Pregnancy a group of researchers fed subjects two servings a week of tuna and other high mercury fish to push their mercury levels up, and then stopped the fish. Slowly but surely their levels came back down (see the video for the graph). I know a lot of moms are concerned about exposing their children to mercury containing vaccines, but if they eat even just a serving a week of fish during pregnancy, the latest data shows that their infants end up with substantially more mercury in their bodies than if they were injected with up to six mercury-containing vaccines.

Given the two-month half-life of mercury, within a year of stopping fish consumption our bodies can detox nearly 99% of the mercury. Unfortunately the other industrial pollutants in fish can take longer for our body to get rid of. Certain dioxins, PCBs, and DDT metabolites found in fish have a half-life as long as ten years. So getting that same 99% drop could take 120 years, which is a long time to delay one's first child.

The fact that we can still find DDT in umbilical cord blood decades after the pesticide was banned speaks to the persistence of some pollutants. There's a shortcut for moms, but it's The Wrong Way to Detox.

What effects do these other pollutants have? Well, high concentrations of industrial contaminants are associated with 38 times the odds of diabetes--that's as strong as the relationship between smoking and lung cancer! Isn't diabetes mostly associated with obesity though? Well, these pollutants are fat-soluble, so "as people get fatter the retention and toxicity of persistent organic pollutants related to the risk of diabetes may increase." This suggests the shocking possibility that obesity "may only be a vehicle" for such chemicals.

Now the pollutants could just be a marker for animal product consumption, which may be why there's such higher diabetes risk, since more than 90% of the persistent organic pollutants comes from animal foods. And indeed, in the U.S. every additional serving of fish a week is associated with a 5% increased risk of diabetes, which makes fish consumption about 80% worse than red meat. PCBs are found most concentrated in fish and eggs (Food Sources of PCB Chemical Pollutants), which may be why there are lower levels of Industrial Pollutants in Vegans. This may also help explain the remarkable findings in Eggs and Diabetes.

More on the risks of mercury can be found in these videos:

-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.

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How Seafood Can Impact Brain Development

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In my video Fish Intake Associated With Brain Shrinkage, I discussed evidence suggesting that mercury exposure through fish intake during pregnancy may decrease the size of the newborn's brain. However, just because fish-eating mothers may give birth to children with smaller brains doesn't necessarily mean their children will grow up with neurological defects. In the video, Mercury vs. Omega-3s for Brain Development, you can see real-time functional MRI scans of teens whose moms ate a lot of seafood when pregnant. Because these kinds of scans can measure brain activity, as opposed to just brain size, we can more accurately determine if exposure to mercury and PCBs affected these kids. You can see an MRI of what a normal brain looks like when you flash a light in someone's eyes, but the MRI is significantly different for the mercury and PCB exposed brains, suggesting toxicant related damage to the visual centers in brain. (For more on the effect of mercury on teens, see Nerves of Mercury). Fish consumption may also increase the risk of our children being born with epilepsy.

So does maternal fish consumption have an effect on how smart our kids turn out? The DHA in fish--a long chain omega 3 fatty acid--is good for brain development, but mercury is bad for brain development. So a group of researchers looked at 33 different fish species to see what the net effect of these compounds would have on children's IQ. For most fish species, they found that "the adverse effect of mercury on the IQ scores of children exceeded the beneficial effects of DHA." In fact, so much brainpower may be lost from fish consumption that the United States may actually lose $5 billion in economic productivity every year.

For example, if pregnant women ate tuna every day, the DHA would add a few IQ points. But the mercury in that very same tuna would cause so much brain damage that the overall effect of eating tuna while pregnant would be negative, wiping out an average of eight IQ points. The only two fish that were more brain-damaging than tuna were pike and swordfish.

At the other end of the spectrum, the brain boosting effect of DHA may trump the brain damaging effects of mercury in salmon by a little less than one IQ point. Unfortunately, IQ only takes into consideration the cognitive damage caused by mercury, not the adverse effects on motor function and attention and behavior deficits. We think that attention span may be particularly vulnerable to developmental mercury exposure, probably due to damage to the frontal lobes of the brain.

And the IQ study didn't take into account the relatively high levels of PCBs in salmon and the accompanying concerns about cancer risk. Sustainability concerns are another wrinkle, as farm-raised salmon are considered a "fish to avoid." While king mackerel is considered a best choice for sustainability, the mercury levels are so high as to warrant avoiding consumption--exceeding both the FDA and EPA action levels for mercury contamination. But why risk any loss in intelligence at all when pregnant women can get all the DHA they want from microalgae supplements without any of the contaminants? We can then get the brain boost without the brain damage.

More on PCBs in:

-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.

Images thanks to Dion van Huyssteen / Flickr

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Why Pregnant Women Should Avoid Tuna

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All fish contain small amounts of methylmercury, the most toxic form of mercury, and "fish consumption represents the main source of methylmercury exposure." In my videos Nerves of Mercury and Fish Fog, I discuss how mercury exposure through fish consumption, even within the government's safety limits, can have adverse neurological and behavioral effects on child development. Severe exposure can cause overt structural brain abnormalities like microcephaly, a shrunken brain disorder. But we didn't know whether low exposure could also affect brain size until recently.

Autopsy studies suggest mercury preferentially affects the developing cerebellum, so researchers used ultrasound to measure cerebellum size in newborns of mothers who had high body levels of mercury.

Let's put those levels into practical terms. In the video, Fish Intake Associated with Brain Shrinkage, you can see the results of a study measuring mercury concentration in human hair. Just one can of tuna a week raises human hair mercury concentration to levels nearly three times as high as the "high" group in the ultrasound study. So the bodies of the women suffering high mercury contamination were considered heavily contaminated, but even just a little canned tuna once in a while could bump our levels even higher. So the high really wasn't that high. But what did they find?

The researchers demonstrated that babies born to mothers with higher hair mercury levels had cerebellums up to 14% shorter than those born to mothers with lower hair mercury levels. They conclude that prenatal exposure to what may be considered low-levels of methylmercury does indeed influence fetal brain development as evidenced "by decreased size of a newborn's brain."

But what about the long chain omega-3 DHA in fish--isn't that necessary for healthy brain development? That's the topic of my video Mercury vs. Omega-3s for Brain Development.

For more on canned tuna in particular, check out:

-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.

Images thanks to Thomas Hawk / Flickr

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