Eat walnuts for healthy breasts

Shopping for vegetables at my local farm shop this morning, my eyes lit on an unexpected find: wet walnuts! "Walnuts - already?!" I exclaimed, realizing with a pang that fall is imminent.

Before I had a chance to lament the passing of summer with its juicy peaches, sun-ripened tomatoes and chilled cucumber soups, I succumbed to the charms of those juicy golden kernels whose season lasts only a week or three. I rushed home with my brown paper bag of fresh walnuts, dug around for the nutcracker that had slumbered for months at the back of my kitchen drawer and got cracking.

When they are this fresh - their shells cool and damp, the kernels so moist they melt in your mouth - walnuts are simply amazing. They have a creamy, sweet flavor and lack the mouth-puckering bitterness of their aged counterparts. Paired with spicy farmhouse cheddar, chopped and sprinkled over oatmeal or fresh applesauce or simply on their own they make a delectable snack.

Even if you can't lay your hands on fresh walnuts - few supermarkets sell them as they are prone to molding - they are just as delicious dried. And in addition to their gastronomic appeal, walnuts are a nutritional powerhouse with cancer-protective qualities thanks to their high content of omega-3 fatty acids and antioxidants.

With impeccable timing, a new animal study in the journal Nutrition and Cancer and jointly funded by the American Institute for Cancer Research and the California Walnut Commission (according to the study's authors, neither funding agency had input on the design, collection or interpretation of the data) has found that eating walnuts may reduce the risk of breast cancer.

The study compared the effects of a typical American diet - among others, rich in cancer-promoting omega-6 fatty acids - to that of a diet containing walnuts across the lifespan: Through the mother from conception through weaning, and subsequently by eating the food directly. The amount of walnut in the test diet equated to about 2 ounces (or 28 walnut halves) a day for humans.

"We found that consumption of a walnut diet reduced mammary tumors in mice," said W. Elaine Hardman, PhD, the study's lead investigator and associate professor at the Marshall University's Joan C. Edwards School of Medicine. "The best tumor reduction was when both the mother consumed walnuts and her offspring consumed walnuts throughout life."

For the study, a test group of female mice genetically predisposed to breast cancer was fed a diet containing ground walnuts. The offspring whose diets also included walnuts developed breast cancer at less than half the rate of the group consuming no walnuts. In addition, the number of tumors and their sizes were significantly smaller.

A second group of mice fed walnuts only after weaning (their mothers did not eat walnuts during gestation) were less well-protected, but nonetheless showed approximately one-third fewer tumors compared to the mice not exposed to walnuts at all. A third group of mice whose only source of fat was corn oil - rich in omega-6 fatty acids - experienced the fastest tumor developments.

Walnuts' main nutritional appeal has long thought to lie in its beneficial omega-6-to-3 ratio (about 4:1, close to the 3:1 ratio considered ideal for human health; by comparison, the omega 6-to-3 ratio for corn oil is around 50:1). Walnuts contain the highest fraction of omega-3-rich alpha-linolenic acid of all tree nuts, and omega-3s have been shown previously to slow cancer growth.

But walnuts' anti-cancer effects aren't just limited to omega-3s. Additional cancer-protective compounds in walnuts include vitamin E (especially gamma tocopherol, associated with slowing cancer cell growth), ellagic acid (an antioxidant present in various nuts and fruits that encourages the self-destruction of cancer cells) and phytosterols, plant compounds with a range of cancer-inhibiting mechanisms.

"With walnuts, as with other foods, it is likely the synergism between the components that leads to reduced cancer incidence," said Hardman.

Another piece of good news: although they are rich in calories, the addition of a moderate amount of walnuts to the diet does not appear to cause weight gain in humans, according to this study.

But before you, too, rush out to buy a bag of walnuts, a few caveats. Because of their high omega-3 content, walnuts can easily go rancid if stored incorrectly. (Rancid walnuts smell like paint thinner; if this happens, throw them away.) Protect them from heat, light and oxygen (buy them vacuum-packed and store in the refrigerator - or better still, buy them whole, store in a cool, dark place and crack them yourself.) It's fine to bake muffins or fruit loaves with chopped walnuts, but avoid toasting them in a pan or a hot oven as this can damage their fragile oils. When buying walnut oil, always choose the smallest bottle you can find, refrigerate and use up quickly.

In Zest for Life I have included a recipe for walnut Tarator, a garlicky-herby paste of ground walnuts from Turkey that can be enjoyed as dip, diluted with yogurt and water to make a chilled summer soup, or spooned onto hot pasta. The California Walnut Commission's website provides a multitude of other recipes (avoid the ones that contain large amounts of sugar). Enjoy!

Four ways to add 15 years to your life

The Mediterranean diet is once again making headlines with this week's publication of a study showing that this way of eating, paired with other healthy lifestyle habits, can extend our lifespan by more than a decade!

Women, especially, stand to benefit from adopting healthy habits: by eating a Mediterranean diet, exercising regularly, not smoking and maintaining a healthy body weight, they can extend their life by up to 15 years, according to a study from Maastricht University in the Netherlands published in the American Journal of Clinical Nutrition. For men, the effect of such healthy lifestyle habits is a smaller but nonetheless substantial lifespan increase of 8.5 years.

In this Netherlands Cohort Study (NLCS) the nutritional and lifestyle habits of 120,000 research participants were measured in 1986. The information was used to calculate a healthy lifestyle score that combined four factors: not smoking, being physically active for more than 30 minutes per day, adhering to a Mediterranean diet, and having a healthy body weight (BMI between 18.5 and 25).

In this study, the Mediterranean diet was defined as involving a high intake of vegetables, fruit, legumes, nuts, fish, whole grains, monounsaturated fat rather than saturated fat, low meat intake and alcohol consumption of between a half and two glasses per day.

The article confirms findings by previous investigations. Another European study showed that elderly people eating a Mediterranean diet who hadn't smoked for 15 years or longer, undertook regular physical activity and drank a moderate amount of alcohol were 65% more likely to outlive those who had none of these healthy habits and were 60% less likely to die of cancer.

Elsewhere, the famous Lyon Diet Heart Study found that eating a Mediterranean diet not only protected its 605 participants from cardiovascular disease, but also from cancer. Patients in the experimental group were encouraged to follow a regimen rich in fruits, vegetables and whole grains, to replace some meat with fish, to use healthy oils (especially omega-3 fats), and were allowed to drink moderate amounts of red wine with meals. After four years, they were found to be 61% less likely to develop cancer than members of the control group they were being compared to and who were eating the American Heart Association's so-called prudent diet!

According to the new study's author, Piet van den Brandt, Professor of Epidemiology at Maastricht University, those elements of the Mediterranean diet that appeared to have the biggest impact on the lower mortality rates in women are nuts, vegetables and alcohol intake.

This may be something of a simplification, and lest you rush off to cook up a huge pile of vegetables topped with nuts and washed down with a glass of red, I'd like to suggest that several additional factors may be just as important, especially when it comes to cancer prevention.

As many studies bear out (they are discussed in Zest for Life), a wide variety of vegetables, rather than the outright amount, may most effectively enhance our health. So rather than eating a pound of kale every day, you're better off enjoying an ever-changing variety of multi-colored, multi-flavored vegetables prepared in lots of different ways and combinations.

One of the best ways to ensure variety is to eat with the changing seasons. For example, you might choose asparagus, spring onions and peas in springtime; peppers, tomatoes, eggplants, zucchini, cucumbers and sweet lettuces in the summer; mushrooms, squash, cabbages, sweet potatoes or onions during fall and more cabbages, carrots, leeks, bitter leaves and celery root in the winter. (Some of these grow during more than one season, thus further increasing your choice.)

If you don't know what's in season, start shopping at a farmers' market or sign up to a community supported agriculture (CSA) scheme - local farmers are pretty good at knowing what's in season because they're growing it! (For more information, see the USDA's CSA information page.)

Quality is another important factor. Vegetables grown in rich, healthy soil under open skies and sometimes harvested only hours before you eat them (farmers' markets or CSAs make this possible) are more likely to give your body what it needs than intensively reared hot-house vegetables that were trucked half-way around the world to a supermarket near you. Similarly, there is increasing evidence that eggs, dairy products and meat from pastured, free-ranging animals is more nutritious than those of their intensively reared counterparts.

Lastly, pleasure is, to me, a vital ingredient in any healthy diet. The traditional Mediterranean diet, which treasures mealtime conviviality and the guilt-free enjoyment of tasty home-cooked  food, certainly provides it. Taking time to shop for healthy ingredients, to prepare simple  meals and to savor them - ideally with people whose company we enjoy - is a thoroughly life-affirming process. How many years this might add to our lives is anybody's guess; but that it will enhance our enjoyment of our time on earth is certain.

Low-carb, high-protein eating may curb cancer risk

Hitherto known mostly as a weight-loss method, low-carb eating may also protect us against cancer. A new study highlights how heavy intakes of sugar and refined carbohydrates typical of the industrialised Western diet could be a factor fueling the worldwide cancer epidemic.

The study, published next month in Cancer Research, indicates that eating a low-carbohydrate, high-protein diet may reduce the risk of cancer and slow the growth of tumors already present.

Although the study was conducted in mice, its authors said the findings are relevant to humans:  “The fact that human blood glucose can be significantly reduced with low-carbohydrate diets, and the association of many cancers with high blood glucose levels, suggest that our findings are very relevant to human cancers, particularly cancers that have been associated with higher blood glucose and/or insulin levels, such as pancreatic, breast, colorectal, endometrial and esophageal cancers.”

Cancer cells need significantly more glucose than healthy cells to grow and thrive. Restricting carbohydrate intake can significantly limit blood glucose and insulin, a hormone that is released in response to rising blood glucose and that promotes tumor growth in both humans and mice.

For the study, Gerald Krystal of the British Columbia Cancer Research Centre and his team implanted various strains of mice with human or mouse cancer cells and assigned them to one of two diets. The first diet, a typical Western diet, contained about 55% carbohydrate (mostly sucrose, or table sugar), 23% protein and 22% fat. The second contained 15% carbohydrate (mostly in the form of starches that were about 70% amylose, a more slowly digested sugar typically found in whole grains, legumes, bananas, sweet potatoes, radishes and parsnips), 58% protein and 26% fat.

The low-carb mice exhibited lower blood-glucose and insulin levels and their tumor cells grew consistently slower than in those fed the high-carbohydrate western diet. They also had lower lactate levels – a chemical that fuels cancer growth and metastasis.

In addition, mice genetically predisposed to breast cancer were put on the two diets and almost half of those on the Western diet developed breast cancer within their first year of life while none on the low-carbohydrate, high-protein diet did. Only one mouse on the Western diet reached a normal life span (approximately two years), with 70% dying from cancer. Only 30% of those on the low-carbohydrate diet developed cancer and more than half of them reached or exceeded their normal life span.

In addition to lowering blood glucose levels, a low-carbohydrate, high-protein diet can both boost the immune system’s ability to kill cancer cells and prevent obesity. “Certain amino acids (i.e., arginine and tryptophan) play a very important role in allowing killer T cells to kill tumor cells,” says Krystal.

Moreover, high protein diets lead to more rapid satiety, which reduces obesity. “Obesity has a dramatic effect on cancer incidence, likely, at least in part, by increasing chronic inflammation,” he explains.

All this doesn’t mean we need to banish carbohydrates forever; however, we need to differentiate between less-healthy carbohydrates that cause a sharp increase in blood glucose and healthier carbs with a gentler glycemic impact.

The former include starchy foods like baked goods made with white flour, potatoes and white rice – all of which make up a large proportion of the calories a typical Westerner eats every day.

The latter tend to be unrefined, natural foods such as vegetables, fruits, legumes, nuts or whole grains that are converted more gradually into blood glucose. (Similar to the carbs the healthier mice ate.) These foods also generally contain important anti-cancer plant chemicals; thus they play an important role in an anti-cancer diet. In Zest for Life I recommend that people stick to low-glycemic carbohydrates – especially non-starchy vegetables – and eat protein with every meal to keep blood glucose levels stable.

Does increasing protein intake mean eating more meat? Such a conclusion could be problematic, for red and processed meats are thought to increase the risk of colorectal cancer. (See this post.) My view is that we should eat some high-quality protein at every meal, but should aim to vary its sources as much as possible, alternating between fish, white and occasional red meat, eggs, legumes, nuts and minimally processed soy foods; Dr Krystal  uses whey protein isolate powder to boost his protein intake.

It’s worth noting that the low-carb, high-protein diet tested in this study is also low in fat (26%, as compared with around 35% in the traditional Mediterranean diet and 50% in the Atkins diet).  While hungry, captive mice will eat this kind of diet, humans struggle to stick to low-carb, low-fat diets for long. (A recent survey found that 80% of Dukan dieters regained the weight they had shed on this low-fat, high-protein regimen within three years.)

“It is likely that we could still attain very beneficial effects if we raised the fat slightly and reduced the protein slightly,” says Dr Krystal. Such a diet (say 20% carbohydrate, 40% fat and 40% protein) would also be easier to maintain than the 15% carb, 25% fat and 60% protein model used in the mouse studies, he says.

Again, the ancestral Mediterranean diet may offer the best solution: it is rich in low-glycemic vegetables and fruits, provides plenty of protein through fish, lean meat, legumes and nuts, offers healthy fats in the form of olive, nut and fish oils and is low in sugar and refined grains.

Best of all, it is simple and tasty, making it a pleasure to follow long-term.

Am I a Food Fascist?

It's not often that I am called a "Food Nazi," but it happened last week - for the first time - after I published this post relating my decision to bake "Faux-reo cookies" for my daughter, rather than buy her a packet of mass-produced Oreos.

Apparently, some people get upset when you suggest that feeding children high-sugar confections is a bad idea. The vehemence of two commenters' reactions - accusing me of "food Nazism," and predicting that my daughter will develop an eating disorder because I limit her intake of junk food - prompted some reflection.

Returning briefly to the "Oreo episode:" I did not heavy-handedly overrule my daughter's wish for the branded article. I simply told her that I had gone to the supermarket to buy the cookies she had requested, saw that they contained lots of unhealthy ingredients and asked her how she would feel if we baked a batch of healthier cookies instead.

Her response was highly enthusiastic. Like many children, she loves to bake with mommy, an activity that is often curtailed by lack of time on my part. She was delighted at the prospect of not only getting a sweet treat closely resembling Oreo cookies, but also spending "quality time" with me.

Meanwhile, I would like to reassure the commenter who fears that a lack of junk food will turn my daughter food-phobic. The "no junk food" rule in our home means no sugary breakfast cereals, no pre-made meals, no candy, no factory-made cookies and cakes and no soft drinks.

This is because my kids - and most others - inevitably get regular doses of junk outside the home, at friends' houses and birthday parties, for example. On family outings, we will occasionally let them have an ice cream or a non-caffeinated soft drink as a rare treat. In restaurants, they are allowed dessert and any of the "kiddie treats" handed to them. A few years ago, even our dentist handed them candy after their first dental check-up, as a reward for having caries-free teeth! (Prompting confused head-shaking from my children.)

At home, however, we have learned that letting even occasional junk foods creep in simply opens the door to endless begging for more, and so we put a stop to it some years ago. For breakfast we eat home-made porridge with chopped nuts, Bircher muesli with fresh fruit and whole milk yogurt, fruit and nut smoothies, a variety of eggs served alongside mashed sweet potatoes, or whole grain toast topped with sardines, cheese or nut butter. The children drink water or herbal tea sweetened with honey. Lunch is eaten at school (and is generally moderately nutritious as best). On weekends, at home, lunch or dinner will feature fish, meat or pulses with salad and/or vegetables and water.

We do eat desserts at home (fruit cobblers, tarts and compotes, egg puddings, etc.), cakes (cheesecake, chocolate cake, apple cake, etc.) and cookies, but these are home-made (often together with the kids) and usually contain whole grain flour and half (or less) the sugar of their store-bought counterparts.

This blog isn't about feeding kids, it's about dietary cancer prevention. So why am I yammering on about what I feed my offspring?

Because teaching children about healthy food choices, and showing them how to prepare delicious home-made alternatives to unhealthy branded foods is one of the most important gifts we can offer them for a long life of good health. (That cancer prevention starts in the womb and that childhood eating patterns influence our chances of developing cancer later in life, was illustrated eloquently by Ricardo Uauy, Professor of Public Health Nutrition at the London School of Hygiene and Tropical Medicine, in this fascinating presentation at the 2010 World Cancer Research Fund conference.)

As long as they are young and consume the majority of their meals at home, we can influence our children's taste buds and shape their metabolism in beneficial ways. It can only be hoped that that they will continue to eat this way once they fly the coop.

So to those of you who worry that I am raising a generation of orthorexics (i.e., people who obsess compulsively about eating only healthy foods), let me reassure you: I am anything but an austere food-fundamentalist. My children know that outside the home, they can make their own food choices. As my story above about the dentist confirms, junk food has an amazing power to find kids; you don't need to help them look for it.

Meanwhile, at home we revel in growing and gathering our food, preparing it and eating it. Ketchup and mayonnaise? French fries? Salad dressings? Oreo cookies? Hamburgers and hot dogs? We make ‘em all - and so can you!

Faux-reo cookies: kids like real food if you dare serve it to them!

My daughter's friends have recently begun bringing sweet snacks to school to brighten the mid-morning recess of this poor child, whose mother (me) deprives her of junk food. Oreo Cookies, now available in even the smallest of French supermarkets, have become my daughter's favorite snack, so much so that she recently asked for a packet of them for her ninth birthday.

In a moment of weakness, I made my way to the supermarket to purchase said cookies. Although I have a strict "no junk food" rule, I didn't want to seem like a food fundamentalist. I mean: one packet of Oreos - no big deal, right?

As I lifted the packet off the shelf, I couldn't help glancing at the ingredients and my heart sank. According to manufacturer Nabisco, these edible food-like discs contain (in this order) "sugar, enriched flour (wheat flour, niacin, reduced iron, thiamine mononitrate, riboflavin, folic acid) high oleic canola oil and/or palm oil and/or canola oil and/or soybean oil, cocoa (processed with alkali), high fructose corn syrup, cornstarch, leavening (baking soda and/or calcium phosphate), salt, soy lecithin, vanillin - an artificial flavor, chocolate."

 

As a rule, I avoid buying anything that lists sugar as its first ingredient. In my children, it causes highly-strung, jittery behavior followed by tearful irritability. In me, it causes the above symptoms plus bloating, exhaustion and sugar cravings. Sugar is not a food; it is at best a condiment. As a first ingredient, it's a no-no.

Next ingredient: enriched flour. Sounds nice: "enriched." How thoughtful of them to put all those extra nutrients in. But what it really means is: "We've taken all the natural goodness out of this grain when we refined it and now we're putting four vitamins and one mineral back in." Of course, this denatured flour bears little resemblance to the vast panoply of nutrients available from whole, unrefined grains.

As for the fats: why won't the manufacturer say which fats they used the day the cookies were made? Doesn't this vague list of oils, selected at the manufacturer's discretion, open the door to the cheapest, lowest-grade processed fats available on any given day?

Although scientists continue to argue about the health effects of dietary fats, few would dispute that denatured, mass-produced factory oils are unlikely to offer health benefits, and may well contain inflammation-fueling omega-6 fatty acids and trans fats.

Next ingredient: cocoa. This at least is healthy, right? Well, yes, when it's "raw" (i.e. naturally fermented, dried, defatted and ground into a powder), cocoa is chock-full of plant chemicals called procyanidins, thought to have powerful antioxidant, anti-inflammatory and tumor-growth-inhibiting properties.

However, the industrial process of "dutching" (i.e. treating cocoa with an alkalizing agent to modify its color and give it a milder flavor) sharply reduces the polyphenol content in cocoa. One study found that 60 per cent of natural cocoa's original antioxidants were destroyed by even light dutching, and 90 per cent were destroyed by heavy dutching.

High-fructose corn syrup, the next ingredient, doesn't offer much more hope of sustenance to my growing child. Along with sugar (above) it can disrupt blood-sugar metabolism, feed cancer cells (see this post) and contribute to weight gain - especially around the middle, the least healthy place to carry extra fat.

As for baking soda - sorry to be a party pooper, but researchers recently found that when combined with cocoa, the latter's polyphenol content is sharply reduced. One study found that in chocolate cakes leavened with baking soda, the amount of procyanidins declined by 84 per cent; the same recipe prepared with baking powder showed no loss at all.

Dispirited by my Oreo fact-finding mission, I decided I'd rather be branded a boring old food purist than feed my daughter a concoction of cheap sugars and fats. I replaced the cookies on the supermarket shelf, drove home and Googled "Homemade Oreo cookies".

And this is what I found: a fabulous recipe by French Laundry chef Thomas Keller. I made a few adjustments to the ingredients, swapping soured crème fraiche for heavy cream, reducing the amount of white chocolate, swapping baking powder for baking soda, whole spelt flour for white wheat flour, using raw cocoa and scraping a vanilla bean into the cream.

I also simplified the cookie-shaping: instead of rolling out the very sticky dough (which required angelic patience), I pinched off small portions of dough, rolled them into balls, placed them on the paper-lined baking tray and flattened them into discs with my fingertips - less precise, but mercifully quick.

Don't get me wrong; these cookies *do* contain sugar, fats and calories aplenty and are not something to eat every day. But I take comfort from the fact that all the ingredients are natural, minimally processed and - apart from the sugar - contain useful nutrients. They also taste amazing, the crunchy, bitter cookie contrasting beautifully with the sweet, sticky cream inside.

Best of all, my daughter loved them! "They don't look so great, but they taste much better than the real ones," my daughter opined. She took a few cookies into school the next day for her friends to taste. To my great surprise, they agreed with her. Guess who gets to provide the next round of Faux-reos at recess?

Photograph courtesy of "C" at www.projectmcb.com

Kick the can and eat fresh food

If you think that canned and packaged food isn't so bad for you, think again.

A study by the Breast Cancer Fund and the Silent Spring Institute published this week in the peer-reviewed journal Environmental Health Perspectives found that food packaging is a major source of hormone-disrupting chemicals such as bisphenol A (BPA) and plastic softener DEHP, and that a fresh food diet can reduce levels of these chemicals by half in just three days.

When 20 study participants ate food that had not been canned or packaged in plastic over three days, their urine contained two-thirds less BPA and about 55% less DEHP than when they were eating their usual diet which included packaged foods. When they returned to their normal eating habits, their levels of BPA and the DEHP compound rose significantly.

BPA is used to harden plastics. It is also found in the epoxy resin linings of food and soft drink containers and in the ink on most types of paper cash register receipts. DEHP is used to soften plastics and can be found in plastic food wrap.

According to the Centers for Disease Control and Prevention, some 93% of Americans have detectable levels of BPA in their bodies. This is problematic because some studies have linked BPA and phthalates such as DEHP to infertility, heart disease and cancer. One study found that even at weak concentrations BPA can block the effects of several commonly used chemotherapy agents on breast cancer cells.

There is much debate over the levels at which these chemicals are dangerous. The American Chemistry Council was quick to point out yesterday that "typical consumer exposure to BPA and DEHP, from all sources, is up to 1,000 times lower than government-established safe exposure levels."

However, the US government doesn't seem quite so confident about its "safe exposure levels" for BPA anymore. In January 2010, the Food and Drug Administration (FDA), which had for years insisted that BPA was safe, expressed "concern about the potential effects of BPA on the brain, behavior, and prostate gland in fetuses, infants, and young children." Two months later, the Environmental Protection Agency added the compound as a "chemical of concern" because of its possible harmful effects on the environment.

A small note of caution: although the BPA investigation above was peer-reviewed, it is a small study and was conducted by groups that are known to be critical about BPA and other chemicals. However, I can think of many reasons besides BPA and phthalate exposure why we should avoid canned and packaged foods.

The advantages of fresh over packaged food are manifold. In addition to being free from plastics, it is generally: -

• Cheaper (especially when you shop at farmers' markets, farm shops or through CSA schemes),
• Healthier (packaged food is often processed, which implies a decline in nutrients compared to fresh equivalents and often involves the addition of unhealthy fats, sugars and starch, excess salt, preservatives, flavorings, fillers, etc.),
• Environment-friendlier, both through the production and the disposal of packaging (all the waste you generate when preparing fresh vegetables, fruit, fish or meat is biodegradable), and
• Tastier (well, at least for those of us who remember the flavor of fresh, additive-free food...).

Silent Spring suggests some practical ways of cutting down exposure to potentially harmful chemicals. In Six Simple Steps to avoid BPA and Phthalates in Food they recommend --

• Eating fresh or frozen rather than canned food as much as possible
• Eating fresh meals at home (they cite studies showing that people who eat more meals prepared outside the home have higher levels of BPA)
• Storing food and drinks in glass or stainless steel containers rather than plastic containers - especially if they are fatty or acidic
• Not microwaving food in plastic containers (warmer temperatures increase the rate of chemicals leaching into food and drinks) but using heat resistant glass or ceramic containers instead
• Brewing coffee using a French press rather than automatic coffee makers, which may have BPA and phthalates in their plastic containers and tubing

For the rare occasions when canned food is the best option (I confess to eating canned sardines occasionally - they're so tasty and convenient!), it is good to know that some US food manufacturers are moving towards making cans without BPA-containing resins. They include Vital Choice, Oregon's Choice and Eden foods. (Click here for a fuller list.)

In Zest for Life I write extensively about the benefits of eating fresh, seasonal, locally grown, home-cooked food while avoiding processed, packaged food. Even "healthy" foods such as sardines or tomatoes are even healthier when fresh. While this may take some adjustments at first, the pay-back in terms of health and mealtime satisfaction can be tremendous!

Meat and Cancer: The Carnivore's Conundrum

The media are abuzz with conflicting reports about the possible cancer risks of eating red meat, reinforcing already widespread confusion among consumers. However, safe meat consumption is possible, provided you steer clear of processed meat and eat moderate amounts of red meat that's been carefully prepared, experts say.

A review published last week by the British Nutrition Foundation (and funded by the UK meat industry) found no evidence that eating moderate amounts of lean red meat has negative health effects. "Hurrah - eating red meat is good for you!" Britain's Daily Mail cheered.

At the other end of the spectrum, the British Vegan and Vegetarian Foundation issued a press release saying that women wishing to lower their risk of breast cancer "should reduce the amount of meat they eat and cut down - or even cut out - dairy produce."

The World Cancer Research Fund on its blog responded by pointing out that this recommendation was based on research that had not actually investigated the link between animal foods and breast cancer. "This press release is likely to hinder, rather than help, people's ability to make informed choices," it concluded.

In-between these poles, the British government said in its Iron & Health Report that while red meat is a valuable source of iron, eating too much could lead to cancer and heart disease. It recommended that people consuming more than 90g (3.2 oz) per day of red and processed meat should reduce intakes to 70g (2.5 oz) per day or less. (This is equivalent to two standard beef burgers; one lamb chop; two slices of roast lamb, beef or pork; or three slices of ham.)

This tallies with the WCRF's recommendation that adults should eat no more than 500g (1.1 lb; cooked weight) red meat per week, though the cancer research and education charity makes a clear distinction between "red" and "processed" meat, advising people to avoid the latter wherever possible.

Where does this leave the confused carnivore? Should we avoid red meat and only eat poultry and fish? Should we stop eating meat altogether? Or is there a safe way of enjoying red meat?

I asked Denis Corpet, Professor of Food Hygiene and Human Nutrition at the University of Toulouse, for his views on the matter. Professor Corpet heads the "Prevention and Promotion of Carcinogenesis by Foods" research team at the ToxAlim center of France's public agriculture research agency INRA.

CMW: What is the colon-cancer risk of eating red and processed meat?

DC: Meat is not carcinogenic, but people eating lots of meat develop cancer more often than those who eat it less. In Europe, twenty percent of people eat more than 80g beef per day, and they are more likely to develop colon cancer than those eating meat rarely. The risk increase is modest, between +20% and +30%. The same risk is observed in people eating more than 50g deli (cured meat) per day.

From an individual perspective, this is not a huge increase. It means that one person out of 20 will get colorectal cancer, and in big meat eaters this value becomes 1.2 person out of 20. But from a public health perspective, each day one hundred people in France are told they have colorectal cancer. The excess risk associated with a daily steak, +25%, now translates to an extra 25 people each day with cancer!

CMW : Is red meat implicated in any other cancers?

DC: The link between meat and cancer was discovered with stomach and colorectal cancer. The link seems much weaker with breast and prostate cancers, and did not show up even in the very large European EPIC study of half a million persons. In an American study of similar size, elevated risks (from 20% to 60%) were evident for esophageal, colorectal, liver, and lung cancer, but not breast or prostate.

CMW: What are the cancer risks inherent in red meat?

DC: Nobody knows exactly why red meat is (slightly) toxic, but we have "hypotheses," that is, various paths to track down the villain. A tasty BBQ steak could be bad for you because it's fatty, grilled, or "red."

Yes, too much fat increases our risk of obesity, which is a cause of cancer. But dietary fat in itself is not carcinogenic.

Yes, the black-brown part of a grilled steak contains potent carcinogens (named, for instance, PhIP, MeIQx, BaP), but the doses are very low and it is hard to believe they could give us cancer.

Yes, beef is red because it contains heminic iron, which our body needs to make our own red blood and red muscles. In my laboratory we found that that rats given heminic iron (or beef meat) after being injected with carcinogens had more tumors than controls given the shot but not the iron-rich diet. Thus "the red" in red meat clearly promotes cancer.

CMW : What are the cancer risks inherent in processed meat?

DC: Most processed meats are made from red meat (pork is red, even if it has less iron than beef), and ham and sausages are often fatty and grilled; thus the same risks are present in beef and in cured meat.

In addition, cured meat is made by adding salt (no effect on the colon, but bad for the stomach) and nitrites. Nitrites provide four benefits: fewer bacteria (particularly the killer botulism), less oxidation (no rancidity), better color (red instead of brown, pink instead of grey when cooked) and better flavor (the "deli" taste). But nitrites may form carcinogenic substances called nitrosamines, or related toxic compounds we call NOCs, and my lab has shown that these promote tumors in rats.

CMW : Are there risks in not eating red or processed meat?

DC: Meat is good for you. We need protein, and meat provides excellent proteins, though we can also get protein from other foods. We need iron, zinc and vitamin B12, and it is very hard to find those elsewhere than in meat. This is why I would not advise people to give up red meat, but to eat at least one steak a week. Many young women dislike red meat and become anemic: as the iron stores in their bodies decline they cannot make enough red blood cells and this can lead to constant tiredness and a pale complexion.

In contrast we do not NEED to eat cured meat. Its benefits are the same as those of red meat, but because it seems twice as toxic, it's better to eat fresh than processed meat.

CMW: Observational studies show that red meat consumption is associated with a higher risk of cancer; are these studies reliable? What experimental evidence is there for the meat/cancer link?

DC: Epidemiological observations do not "prove" the cause and effect link. This is why I chose to work experimentally on this question about ten years ago. The problem is that this type of research cannot be done on humans. We thus provide strong evidence that red meat, cured meat, and heminic iron, promote tumors in rats and mice. This does not translate directly to humans, but bringing together observations in people and experiments in rodents seems to provide a compelling picture.

CMW: How can people who eat red meat regularly cut their cancer risk?

DC: It is wise not to eat red meat too often, and to have small portions in line with the WCRF's guidelines. In addition, people who are afraid of fat should choose lean meat. And people who worry about carcinogens should not fry, grill or barbeque their steak, but eat slowly cooked red meat instead.

For those who think, as I do, that heminic iron could be the villain, a good way to reduce their risk is by consuming calcium with an iron-rich meal (calcium lowers the absorption of iron from food); for instance, by eating a yogurt or a piece of cheese after a steak.

CMW : Is there a way of lowering the risks from processed meat?

DC: In my laboratory we are testing specific substances that could be added during the curing process to "protect" meat so it does not promote tumors in rats. We already have shown, but not yet published, that added calcium and vitamin E can block the toxic process. We are now investigating the possible protective effects of natural polyphenols, like those that lend red wine and green tea their color and flavor.

I would advise against eating processed meat without nitrites (preservatives) because the deadly botulism bacterium remains a risk. Overall, it's enough to eat cured meat rarely: For instance I never buy ham or sausage, nor do I chose it at the cafeteria. But when I am invited to dinner at a friend's house, I eat whatever they serve me, most often with delectation (I just love the French "saucisson").

Professor Corpet's personal website provides articles he has published about his work (http://fcorpet.free.fr/Denis/Science.html), lecture notes and some of his favourite healthy recipes (http://fcorpet.free.fr/SalmonRecipe.html).