Phytoestrogens: Helpful or harmful?

Q. I consume about 1-2.5 tbsp of ground flaxseeds per day. I know from my symptoms (breast tenderness etc) that I have a bit of estrogen dominance. Could the phytoestrogens be negatively impacting my estrogen balance?

A. Does flax contain phytoestrogens? Yes.  In fact, flax seeds are a more potent source of phytoestrogens than soybeans. Is the ground flax causing your symptoms? Hard to say.

The whole issue of phytoestrogens (estrogen-like compounds found in plant sources including soy and flax) continues to bedevil researchers. Do they block the effects of estrogen, thereby protecting against things like breast cancer? Or, do they exert weak estrogenic effects, thereby protecting against things like heart disease and osteoporosis? Both? Sometimes one and sometimes the other?

Despite copious research, we still don't have a definitive answer on how phytoestrogens behave in the human body and why.  

Searching for clues in a sea of conflicting and confounding information, it appears that phytoestrogens probably don't do much for hot flashes but may help preserve bone density and reduce risk of heart disease.  The findings on cancer are even less conclusive. Phytoestrogens may protect some people against cancer,  but those with hormone-sensitive cancers are usually advised to avoid them. 

I have fewer concerns about whole foods like flaxseed and soybeans than I do about supplements which extract, isolate, and concentrate the bioactive compounds.

Returning to your question: I don't know if your symptoms are due to "estrogen dominance" or not. But the easiest way to find out whether flaxseed is contributing to them might be to stop eating flax for several weeks (try to keep everything else about your diet the same) and see if you notice any improvement.

More evidence that saturated fat has been falsely accused?

What if cancer, heart disease, and diabetes are really all the same disease?

An excellent commentary in this month's issue of the Journal of the American Dietetic Association lays out a compelling and detailed map showing how obesity and insulin resistance interact to promote the growth of cancerous tumors. The authors argue that weight loss (if appropriate) should be a central feature of cancer prevention and treatment. Going a step further, the journal's editors suggest that obesity (and insulin resistance) is the common culprit in all of the Dreaded Three: cancer, diabetes and heart disease. 

Now, if you ask the dietary establishment how to prevent obesity, cancer, and heart disease, they will most likely advise you to reduce your intake of total fat, saturated fat, and red meat. (See, for example, the American Cancer Society, the American Institute for Cancer Research, and the American Heart Association.)

Yet another study in the same issue of JADA tells a different story:

Saturated fat and red meat seem to prevent expanding waistlines

Danish researchers studied the links between consumption of various food groups and change in waist size.  Why are they worried about waist size? An increase in waist size signals an increase in visceral, or abdominal, fat. This is considered the most dangerous pattern of weight gain because abdominal fat is strongly linked to increased risk of heart disease, cancer, insulin resistance, and diabetes.  In fact, the association is so strong that a waist measurement of more than 35"  (for women) or 40" (for men) is an independent risk factor for heart disease.

Surprisingly (to some), they found that women who ate more butter and high fat dairy products gained less weight around the waist than those whose diets are lower in saturated fat. A similar association was observed with red meat--that is, those who ate more red meat had smaller waistlines. The researchers seem to be at a loss to explain these findings.

Some would argue that a diet higher in fat and protein may be lower in carbohydrates and that carbohydrates drive insulin resistance and obesity.

No consistent link found between animal fat and breast cancer

Then there was this study in the American Journal of Clinical Nutrition: Researchers from several European countries collected and analyzed dietary records for 319,000 women and found "no consistent association" between the consumption of eggs, meat, or dairy products with breast cancer. This, of course, contradicts previous observations.

I'm reminded of our extended debate over whether or not eating red meat increases your risk of cancer. And many of the same observations apply here: trying to draw definitive conclusions about the impact of diet on disease using diet records is a very tricky proposition. It's possible that red meat may be a red herring. For one thing, any category that lumps a char-grilled fast food hamburger (and the fries likely to accompany it) together with a grass-fed bison filet is completely meaningless.

Should you start eating more meat?

I'm not making any blanket recommendations one way or another.  Some thoughts:

The prevailing wisdom that meat and saturated fat are unhealthy is based on the same sort of inconclusive, circumstantial evidence as the studies I've noted here.  But if we really want to get to the truth, we're going to need to consider ALL the (flawed) evidence, not just that which supports our point of view.

As many of you know, I'm not a big meat eater myself--although this is more for environmental, ecological, and ethical reasons than nutritional concerns.  But I'm pretty sure that no one food or group of foods causes disease. In fact, to circle back to the beginning of this post (and a recurring theme around here), it seems that plain overconsumption of food in general is a bigger problem.  The fact that so much of that food is over-processed and nutrient-poor sure doesn't help.

If you're eating a calorically-appropriate diet made up mostly of whole foods, I'm prepared to be pretty darned flexible about the details.

Four steps to a longer healthier life?

A giant study (involving over 20,000 subjects over 8 years) looked at how four "healthy lifestyle habits" affected the risk of common diseases like heart disease and cancer. The four habits they chose to track?

1. Never smoking

2. Maintaining a BMI of 30 or lower (Calculate your BMI here.)

3. Engaging in at least 3 1/2 hours of physical activity per week

4. Eating a healthy diet, which was defined as one high in fruits, vegetables, and whole grains and low in meat. (Don't shoot the messenger!)

Less than 4% of the subjects had zero healthy behaviors. About twice as many (9%) could take credit for all four.  Here's what's making headlines: The Four-Behavior Group had:

• 93% lower risk of diabetes
• 81% lower risk of heart attack
• 50% lower risk of stroke
• 36% lower risk of cancer

Of course, this study was purely observational, and there may be (and probably ARE) other unmeasured variables that came into play. 

But, for what it's worth, the correlation between these four behaviors (especially in combination) and the risk of the four most common diseases is notable.  Note that diabetes appears to be almost three times more "responsive" to lifestyle than cancer.

It's also interesting that of the four factors, diet had the weakest effect on risk.  Avoiding obesity was the strongest factor, followed by never smoking, exercise, and (in last place) diet. Of course, that could have something to do with the way they defined "healthy" diet.

But it does underline something I've been saying a lot lately in comments and discussion on the blog.  I suspect that obesity has a stronger impact on health than the details of dietary composition. In other words, it's an oversimplification to say that a certain diet (low-fat, low-carb, whatever) is healthier than another.  Whatever diet (within reason) helps you achieve and maintain a healthy body weight has my vote. And, obviously, we're not all the same.

Just for kicks, how do Nutrition Data readers stack up against the German subjects in this study?

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Source: Archives of Internal Medicine

Seven out of ten kids have low vitamin D levels

A new report reveals that 70 million American kids (ranging in age from toddlers to teens) are at increased risk of heart disease, diabetes, and bone problems due to deficient or insufficient levels of vitamin D.  Low vitamin D levels are about 6 times more common in young black Americans because darker skin produces less vitamin D when exposed to sunlight. See also this story in the Washington Post.)

This storm has been gathering for quite some time.  Vitamin D levels in adults are also low and vitamin D deficiency is being linked to an increasing number of serious, chronic conditions and auto-immune diseases. (See also my post "Vitamin D. Now I'm a believer").

Everyone seems to agree on what's causing the problem. We spend less time outdoors, we've been drilled by dermatologists (and cosmetic companies) on the use of sunscreen to protect our skin against skin cancer and premature aging. We (and our kids) get a lot less vitamin D from our diet, chiefly because we drink less milk and more soda than we used to.

(Milk does not contain vitamin D naturally, of course. It's fortified with vitamin D. Fish are the best natural sources of vitamin D.)

It's harder to agree on the solution.  Some argue that high dose vitamin D supplements are the answer. It's a logical leap, but it's still a leap. While we have evidence linking low vitamin D levels to many diseases, there's less evidence to prove that taking vitamin D supplements reduces those risks.  (Correlation does not equal causation.)

It also takes a heck of a lot of vitamin D supplementation to correct a vitamin D deficiency. While the current RDA for vitamin D is 400IU, it can take 10,000 to 50,000IU a day to replenish depleted vitamin D stores in the body. High doses of vitamin D have been found to be safe and well-tolerated. Nonetheless, many experts are wary of this kind of super-high-dose supplementation without medical oversight.

Exposing the unprotected skin to sunlight is a much more efficient way to raise vitamin D levels in the body, but it proves very difficult to make recommendations about how much sunlight a given person needs. It depends on how much skin is exposed, your latitude, your altitude, the time of day, the time of year, atmospheric conditions, and your skin color. (Yikes!).  Plus, you have to weigh the benefits of vitamin D production against the risk of skin cancer and/or sun damage.

Here, for example, are two very different points of view:

UV Advantage,org

SunProtection.net

For what it's worth, here's how I'm balancing the two, pending further findings. 

1. Because my face, neck, and chest have received an awful lot of sun over the years, I always apply sunscreen there to prevent further damage.

2. In the summer, If I'm going to be outside for any length of time between 10AM or 4PM in the summer, I put sunscreen on all exposed skin. Before and after those hours or during the winter, I don't put sunscreen on except if I'm going to be out for a long time.

3. I keep track of and have my doctor check any suspcious moles.

4. I take 1,000IU of vitamin D every day.

If you have children, you might want to ask your pediatrician about it at your next appointment. I'd probably ask whether he/she thinks it would be worthwhile to test your child's vitamin D levels and about guidelines for appropriate sun exposure and/or supplementation.

Red meat and cancer link questioned

I'm sure this won't end the debate over the nutritional merits or demerits of meat, which continues here (Meat and mortality) and here (Saturated fat no longer the villain?).  

But the authors of a widely-cited study linking the consumption of red meat to colorectal cancer now say their analysis contained "errors and omissions" and overstated the links. The study was conducted by the American Institute for Cancer Research (AICR) and World Cancer Reserach Fund (WCRF). See Errors found in cancer report for more details.

That the National Cattleman's Beef Association (NCBA) objected to the AICR/WCRF study is not surprising.  That the USDA decided to defer to the judgment of the AICR/WCRF over that of the NCBA in the matter is also not surprising.

That the AICR/WCRF met with the NCBA, acknowledged that their criticisms had merit and agreed to inform the USDA of errors is, well, surprising.

To me it says that 1) we all need to remember that no "study" ever really closes the case; 2) industry-funded research is not ALWAYS less reliable than "independent" research; 3) ideology can be just a potent a bias as commercial interest; and 4) true scientists are more interested in getting it right than getting the "right" results.

All in all, the apparent cooperation and good faith between the parties adds up to a triumph for the scientific process in which we all try to get closer to the truth.

Protect your skin without blocking vitamin D production

July is UV Safety Month, an opportunity to remind everyone that using sunscreen will reduce your risk of skin cancer and prevent premature skin aging.  As with so many things, however, it may be possible to overdo it with the suncreeen. A limited amount of sun exposure (without sunscreen) may help to prevent vitamin D deficiency. See also this related post: Sunscreen, Vitamin D, and Cancer.

Eating certain foods can help protect your skin from the inside without interfering with vitamin D production in the skin. A combination of responsible sun exposure, an antioxidant-rich diet, and appropriate use of sunscreen may be the best of all worlds.

Foods that prevent and repair UV damage

Vitamins C and E are particularly effective in preventing and repairing ultraviolet damage to the skin.  Eating foods rich in these nutrients has actually been shown to help prevent or lessen the extent of a sunburn!

Here's the tricky part: These vitamins are much more effective together than either is by itself, but there aren't many foods that are high in both nutrients. Foods high in vitamin C include red and green bell peppers, guava, kale, parsley, collard greens, turnips, and broccoli.  Vitamin E is found in wheat germ oil, sunflower seeds, safflower and sunflower oils, almonds, and avocados.

To give your skin maximum protection, you'll need to combine foods from both groups.  Guacamole with fresh red and green pepper strips would make a delicious, skin-loving snack! Try this guacamole recipe from Epicurious.com. Or, how about a crisp broccoli salad topped with slivered almonds? Here's my own personal recipe.   

These foods help nourish and protect your skin, but remember to wear your sunscreen if you will be out in the sun for an extended period of time.

Tips and recipes for a healthier Memorial Day cookout

This weekend is the traditional opening of the summer grilling season (although we pretty much grill year-round at my house, snow or no!).  Grilling is a quick, convenient, and delicious way to prepare many foods. However, grilling also presents a health risk. Two separate types of carcinogenic compounds are produced by high-temperature grilling:

• heterocyclic amines (HCAs)
  HCAs form when a meat is directly exposed to a flame or very high-temperature surface. The creatine-rich meat juices react with the heat to form various HCAs, which have been shown to cause DNA mutation, and may be a factor in the development of certain cancers.
• polycyclic aromatic hydrocarbons (PAHs)
  PAHs form in smoke that's produced when fat from the meat ignites or drips on the hot coals of the grill. Various PAHs present in the resulting smoke adhere to the outside surface of the grilled meat. PAH exposure is also believed to be linked to certain cancers.

Here are some tips for dramatically reducing HCA and PAH content in grilled meats:

1. Select leaner meats.
   Leaner cuts of meat are less likely to drip fat on the grill and produce PAH-laden smoke.
2. Marinate meats before grilling.
   Researchers have determined that marinating meat prior to grilling, even for just a few minutes, can reduce HCA formation by 90% or more.
3. Grill at lower temperatures.
   Lower temperature "roasting" also greatly reduces HCA formation.
4. Prevent flare-ups.
   Flames from grill flare-ups cause the formation of both HCAs and PAHs. Keep an eye on your grill and turn meats frequently to minimize the chance of flare-ups.
5. Don't overcook meats.
   While it's important to cook poultry and ground meats thoroughly, be careful not to overcook any meat. Well-done or burnt meats contain higher levels of HCAs than less cooked meats.

Or, opt for a vegetarian cookout.  HCAs and PAHs are not formed when grilling  and the options are virtually unlimited: Try veggie kabobs, portobella mushrooms, or black bean burgers.

Here are a variety of recipes (both veggie and non) for a healthy, gourmet Memorial Day cookout. (Click on "see nutritional analysis" for a complete ND analysis of each recipe!

Grilled Asian Flank Steak with Sweet Slaw

Yogurt-Marinated Chicken Kebabs

Grilled Shiitakes with Ginger and Scallions

Bulgur Veggie Burgers with Lime Mayonnaise

Spicy Grilled Chicken with Green Onions

Grilled Lemons, Baby Artichokes, and Eggplant

Grilled Pork Loin with Fire-Roasted Pineapple Salsa

Meat and mortality: What does color have to do with it?

"High intakes of red or processed meat may increase your risk of mortality."  So conclude the authors of a ten-year study involving half a million people, published in this week's Archives of Internal Medicine.

The authors found that those who ate the most red meat were about 20% more likely to die of cancer than those who ate the least. The risk of cardiovascular disease was also elevated in those who ate more red meat. (Eating more white meat appeared to have a protective effect.) You can access the entire article here: "Meat Intake and Mortality." 

Whenever you have big studies like this, there are always questions about whether the results are skewed by confounding variables.  In this study, the researchers attempted to "adjust" for as many variables as they could. They took into account the subjects' age, race, physical activity, vegetable intake, vitamin supplements, alcohol use, body weight, smoking habits, and family health history.   

But you can never account for everything. For example, they did NOT account for things like sugar, sodium, monounsaturated fat, or trans fat intake--dietary factors that all have a strong link to either cancer, heart disease, or both.  I wish we could see how adjusting for those factors affected the findings.

Seeing Red

But my main complaint with this study is not whether they accounted for enough (or the right) confounders but with the most basic aspect of the study's design. The division of meat into "red" and "white" categories seems completely arbitrary to me.

In this study, "red" meat included anything made with beef or pork, including steaks, bacon, liver, cold cuts, burgers, ham, sausage, and hot dogs.   "White" meat included anything made from chicken, turkey, or fish.   Although these categories have some cultural significance, they make absolutely no sense from a nutritional, or even a zoological, perspective.  How is canned tuna more nutritionally similar to turkey sausage than it is to a filet of beef?

In other words, someone who ate grass-fed beef five times a week would be in the same category as someone who ate a fast food hamburger every day.  Someone who ate wild-caught salmon three times a week would be in the same category as someone who ate chicken nuggets just as often. Even if you controlled for things like saturated fat content (which they did), how much could comparing these dietary "patterns" possibly reveal about human health and disease?

I can think of several ways to analyze meat consumption that would have shed more light on connections between meat consumption, cancer, and heart disease.  For example, how about categorizing meat based on the percentage of monounsaturated fat it contains?  What would these groups look like?

Some meats containing more than 40% of total fat as monounsaturated fat
Beef tenderloin
Pork Roast
Sablefish

Some meats containing less than 40% of total fat as monounsaturated fat
Skinless roasted chicken breast
Canned white tuna
Steamed shrimp

Intake of omega-3 and omega-6 fats is also linked to both heart disease and cancer; specifically, it appears beneficial to increase the ratio of omega-3 to omega 6 fats in the diet. So why not categorize meats according to their omega-3/omega-6 ratios?

Some meats with a higher ratio of omega 3 to omega 6
Beef liver
Grouper
Braised shortribs

Some meats with a low ratio of omega 3 to omega 6
Ground turkey
Tuna salad
Chicken livers

Cooking meat over high or direct heat is known to promote the formation of carcinogens. So why not put hamburgers, grilled pork chops, and barbecued chicken into one group and pot roast, baked chicken, and poached fish in the other?

I could go on, but I'm sure you get my point.  None of these designations is perfect but ALL of them seem more valid than "red" and "white." At least there are actual criteria involved.

Mostly, I'm disappointed in this study because it reinforces our tendency to look at foods or nutrients (like fats, carbs, and now, so-called red meat) as "good or "bad," without enough consideration of the context of the entire diet or the substantial differences within these groups.  Despite the headlines being generated by this study, I'm not convinced that eating red meat (as opposed to white) categorically increases your risk of heart disease or cancer. 

Other (better?) reasons to reduce your meat intake

Aside from the impact of red meat consumption on disease risk--which I think this week's study does little to illuminate, there are other good reasons to consider cutting back on meat of all kinds. Many are outlined in an editorial by Barry Popkin, which appears in the same issue of the Archives:

• Over-consumption of animal protein increase the global food prices (including non-meat foods)
• Animal crops consume up to 5 times more of our dwindling water supplies than do plant crops
• Livestock production accounts for 55% of land erosion, 37% of pesiticide use, and 50% of antiobiotics consumed in the U.S.
• Livestock production consumes a large amount of fossil fuel and contributes to greenhouse gases

Personally, while I don't worry that red meat per se is increasing my risk of disease, I find these very compelling reasons to eat less meat of all colors. That's why I'm a new and enthusiastic supporter of the Meatless Monday campaign, a public (and planetary) health initiative that encourages consumers to enjoy one meatless day each week. Care to join me?

Are your drinking habits healthy or harmful?

My recent post on moderate drinking and breast cancer risk spurred a lot of comments.  So I thought you might also be interested in a new initiative from the National Institutes of Health called Rethinking Drinking. The goal is to help people assess the risks and/or benefits of their drinking habits.

I think some people will be suprised to see how low the threshold for "low-risk" drinking is, especially when you consider the size of a "standard" drink is just 1.5 ounces of hard liquor. The newly (or once again) popular martini drinks usually contain the equivalent of 2 to 4 servings of alcohol.

Our social norms make it completely unremarkable to have a drink before dinner and a couple of glasses of wine with dinner. This alone would put you in the high risk category.  If you're motivated by this to make a change, the site offers tools and ideas for cutting back your alcohol consumption.

What do you think? Is this too heavy-handed an approach? Are we American's showing our latent puritanism here?  Are the risks of moderate drinking being overstated?

I will say that, for those who are motivated to make a change in their drinking habits, the tools and strategies on this site are very well designed. They are consistent with the proven approach developed by James Prochaska and outlined in his excellent book Changing for Good.

Today's Poll: Will the recent news on alcohol and breast cancer risk affect your drinking habits?

British researchers this week announced findings from a seven year study of over a million women, finding that even low to moderate alcohol consumption increases the risk of some cancers; breast cancer, in particular.  At least one of the authors concludes that "there is no level of alcohol consumption that could be considered safe."

Yet moderate alcohol consumption (that's one drink per day for women and two for men) is associated with lower risk of heart disease and longer, healthier lives.  How do you weigh these seemingly contradictory findings?

I don't have the answer, but here are some questions to consider and discuss with your doctor to decide whether moderate alcohol consumption is a boon or bust for your health:

1. Is there a family history of breast cancer or heart disease? Either one might tip your decision.

2. Do you have other modifiable risk factors that might be more significant? 

For example, the recent study found that each daily drink increases your risk of breast cancer by about 1.5%.   On the other hand, regular exercise can decrease your risk of breast cancer by up to 30%. Eating more fiber can slash your risk by up to 50%.  Sleeping fewer than six hours a night can increase your risk by 60%, and so on.  Maintaining a healthy weight as you get older also has a substantial protective effect.

I'm also reminded of some research a couple of years ago that found that women who drank moderately had absolutely no increased risk of breast cancer, as long as they ate a diet high in folic acid.

My point is this: If you're 30 pounds overweight, are using your treadmill as a laundry-folding station, are chronically sleep-deprived, and/or have little time for green vegetables, that evening glass of wine may be the least of your worries.

There are a lot of pros and cons to weigh and any decision on how to respond to this latest news will be highly personal.   What's your take? 

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