Food And Health, Some Thoughts About How Dietary Science And The Media Fail Us.
"I mind my belly very studiously, and very carefully; for I look upon it, that he who does not mind his belly will hardly mind anything else." Samuel Johnson
Food should not be a source of angst.
But for many of us food is scary. We fret about what we eat. We worry that our food will make us sick or worse. So we are susceptible to a steady bombardment of news, facts, myths, research, newer research, and pseudo research.
Food is my life. I love it, I wallow in it, I think about it constantly. I read everything I can find on the subject. In the process I have learned some things about health and our diets. Although I am not a scientist or dietician I am well informed. I am married to a PhD microbiologist, FDA research division head, editor of a food microbiology magazine, with extensive food safety expertise, and highly respected in the field. We talk about these matters.
In addition, I have a good enough background in science that I can read science journals, I am good at collecting information, asking experts, and sifting through it all with skepticism (if you spend any time on this site you know I question everything). In more than four decades as a reporter, some of it for publications like the Washington Post and Chicago Tribune, I have a well tuned BS meter and it is switched on high at all times. When I want facts I look for the original research, not second hand interpretations.
Here is what I have learned about food and health:
The most important word is risk
Everything we do carries risk. There is no such thing risk-free living. Or eating. We can try to reduce the risk of something, but it is hard to eliminate it altogether. What we need to understand is that some actions are riskier than others.
Eating arsenic is pretty high risk. Eating undercooked chicken is lower risk, but still risky. Eating a medium rare hamburger is lower risk still, but still risky. Eating a medium rare steak is not very risky at all. The risk of being killed in an airplane crash is practically zero. You have a much higher risk of being killed by lightning. The problem is that we don't know the risks for sure. Your risk of being struck by lightning goes down if you never go outdoors and if you stay out of the rain. Who knows what is the risk of death or disease from high fructose corn syrup (HFCS)? Despite the hysteria on the food blogs, nobody knows because the data isn't in yet (click the link to read what we do know). The problem is that, as consumers, we don't know what the risk really is. We can only guess. In the words of Dirty Harry "You've got to ask yourself one question: Do I feel lucky? Well, do ya, punk?"
We don't want pathogenic microbes in our meals. To reduce risk we ask our government to test food for pathogens in the slaughter houses and inspect restaurants. We also ask our government to test for non-microbial contaminants such as mercury in fish. But the danger from pathogens is is something we can prevent when we cook (please read my article on food safety). If we handle food properly, food-borne illness is very low risk. But when we eat out, we can't control food handling so the risk is slightly higher. In a fine dining establishment where the staff is properly trained, it is lower than at a food cart on the street.
It would be nice if there was a chart assessing the risks for us to put on our smartphones. But it is nigh impossible. It is too complex.
Alas, most of what we hear about food and health is written by people who do not understand science or risk assessment. They rarely read the original research because they don't know how to interpret it. Worse, many are hunting for headlines and soundbites, or are looking to bolster their preconceived notions.
There are so many misconceptions about food. For example, we have this sense that organic food is healthier. Is it? The rules say that organic fruits can only be fertilized with animal manure, not synthetic fertilizers. Not a problem for apples and peaches which grow high up in trees. But what about strawberries? They grow on the ground. Right on top of the manure. Now the manure is supposed to be sterilized, but that's almost impossible to do without heating it with petroleum products. So organic farmers pile the manure on high and let it ferment so the temps in the middle of the pile are high enough to pasteurize it. But what about the manure on the outside of the pile? What if they don't mix it thoroughly? So which do you want to feed your children? Organic strawberries grown on top of manure that has hopefully been pasteurized properly, or strawberries grown with synthetic fertilizers?
Here's another. Everybody knows that undercooked or raw ground meat is risky. But did you know that most food-borne illnesses are caused by raw vegetables? That's because fields of vegetables are exposed to contamination from Tweety, Thumper, Bambi, Pumbaa, and Mickey as well as irrigation water contaminated by Porky and Elsie.
Did you know that sprouts may be the most risky food in the grocery store? That's because the conditions under which sprouts are grown, wet and warm, are exactly the conditions that pathogens love.
By far, by a very long distance, the riskiest thing we do is get in a car. Do you buy only organic food and then use your cell phone when driving home? If you do, you are hereby authorized to eat bacon with every meal for the rest of your short life.
The anxiety caused by worrying about our food may be far more dangerous than what we eat.
Let's get our priorities straight.
The problem with dietary and nutrition science
In the world of quality science, a team starts out with a question they want to ask or they develop a hypothesis they want to test. And it is usually a team, not an individual. They then devise experiments that might answer the question. They don't know if the experiments will answer the question until they collect the data. They let the cards play out. Their experimental design always includes proper controls. That means that if they are testing the effect of a new cattle feed, they need to give it to half the animals and not to the others. And they have to chose the animals carefully. Then they must do many replications. They may need to do the experiment hundreds of times or apply it to hundreds of subjects.
Next they write up the results according to very specific rules and include their data in detail, the good, bad, and the ugly. Sometimes there is a clear answer. Sometimes the data is inconclusive. Sometimes it is not what they expected. Then they submit the paper to a respected journal. From there it is then sent to other scientists to review it. Some may even be competitors. This is called peer review. Not all journals are peer review. The best are and they are very tough to get into and they have very strict standards.
The peers comment on a paper's strengths and weaknesses and in some cases the journal may require the team to do further research and gather more data before they will publish. Sometimes they reject it. When it is approved for publication, then the scientific community at large has its shot at the data and conclusions. Finally, if the info is important, often another lab may attempt to duplicate the data, or do similar experiments with a twist to the design. If it all checks out, it's a pretty good bet that the experiment's conclusions are fact.
Until proven otherwise. And when it comes to dietary and nutrition science it seems like what is thought to be true is often being overturned. Results of physics and chemistry research are often definitive. They are easy to repeat and test and once proven are rarely overturned. This is not true of dietary and nutrition science because it is hard to apply the scientific method I just described.
Here's the problem: We can't take 1,000 people, divide them into two groups, feed them different diets for their entire lives, and see how it impacts their health and mortality. Or to put a finer point on it, as Dr. M.L. Tortorello of the FDA told me "You can't put humans in a rat cage." This restriction limits nutrition and dietary science to rudimentary. It is nowhere nearly as advanced as, say, physics, chemistry, agricultural, and other sciences. Witness:
- Since the 1960s we have been told steadily and consistently to reduce our fat intake. That if we ate fat it caused weight gain and cardiovascular disease. Nutrition and dietary scientsts now think this was a horrible mistake. They have learned that we need fats. That when we take them out of foods the stuff we replace them with is more harmful. That eating bad cholesterol is often accompanied by consumption of good cholesterol and the result is a wash. The whole system is far more complex than ""if you eat fat it goes straight to your hips." In fact, a well-run recent study showed that doubling saturated fat in your diet does not increase saturated fat in your blood. We've also learned that microbes in our guts are crucial players. Today they have taken down the most wanted posters on steaks and replaced them with posters for bagels. Today the enemy is carbs. An article in TIME magazine in June 2014 summarized the latest thinking rather well (if you're not a subscriber, just watch the summary video).
- People of a certain age remember when butter was bad and margarine good. Now we learn they both pack the same amounts of calories and some of the fats in butter substitutes may be worse than butter.
- Since the 1970s the American Heart Association has warned us that eating eggs would increase our risk of heart disease. In 2006 they lifted their ban and two large studies published in the Journal of the American Medical Association and BMJ say that consuming 5 to 6 eggs a week did not raise the risk of heart disease or stroke in healthy adults.
- For years we have been told to eat low salt diets. In January 2015 the Journal of the American Medical Association published research from a well-conducted 10 year study that concludes that sodium intake was not associated with mortality, incident cardiovascular disease, or incident heart failure. We are told that cutting out most salt can be dangerous.
- Research in the 1970s indicated that sodium nitrite could cause cancer in laboratory animals. Since then we have learned that the research was flawed and that we consume plenty of nitrites and nitrates in spinach and other natural foods. In 2003, the World Health Organization stated "In the studies on dietary nitrate, no association was found with oral, oesophageal, gastric, or testicular cancer. No other cancer sites have been studied." But millions still think hot dogs and bacon are carcinogens.
- Back in the 1960s somebody found saccharin caused cancer in male rats and the FDA slapped a warning label on it. But how many of us remember reading about the subsequent research that showed that the biological mechanism in rats that made the cancers possible doesn't exist in humans? How many remember that the warning label was removed in 2001? How many of us still think saccharin causes cancer?
- Likewise, millions of people are running around thinking that grilling causes cancer because of one research paper. But they never read the followups that said, pretty much, just don't burn your food and you'll be OK.
Science has new tools and methods and as they inspect the accepted wisdom of the past, occasionally they overturn the results. In the world of science, everything is always being questioned. That's why you will rarely find me calling a recipe "healthy". I just don't know for sure what is healthy or not.
And don't tell me that if it is "natural" it is healthy. Arsenic is natural. Salmonella is natural. Feces are natural. Nowadays the villains are red meats, processed foods, corn, high fructose corn syrup, salt, fats, sugars, and genetically modified organisms (GMOs). Surely someday somebody will find that carrots are risky.
The problem with epidemiological or observational studies
So many of the studies we hear about in the popular media are known as epidemiological studies or observational studies. These are not lab studies where a hypothesis is stated, variables are isolated, pristene conditions maintained, control groups studied, data collected, and analyzed. Lab studies are great sources of knowledge, but even they can be flawed, like the saccharin research. Epidemiological studies are also very useful, but they have a higher chance of being misleading.
Epidemiological studies are usually based on survey data or other data that can be observed. Researchers collect information from a group of subjects or events, carefully chosen to represent a larger population. They are then asked a bunch of questions, the data is punched into a computer, and the researchers look for correlations. For example, researchers have noticed that French people are not as obese as Americans, so they try to find out why by studying their diets and other factors. Often they find useful correlations - they drink much more wine than Americans - but the results are inconclusive until tested in the lab. But what is a correlation? If there are 10 people in the study group and six get sick, is that a correlation? If there are 1,000 and 600 get sick, is that a correlation? 650? 700? Researchers use statistical analysis tools and study standard deviations, but are they enough to make vast pronouncements that red meats cause cancer?
Epidemiological studies are a great way to develop hypotheses that can then be taken to the lab for further study. But on their own, they must be carefully studied. There are usually too many uncontrolled variables that could be influencing the data.
Here's an example. In several epidemiological studies it has been found that people who watch a lot of television are fatter than the rest of us. Therefore, one might conclude that television causes obesity, right? Perhaps it is the light emitting from TV screens? Perhaps it is invisible radiation from the screen? Electromagnetic fields? Vapors from the plastic? Subliminal mind control? Perhaps it is the flame retardants in our sofas? Perhaps we should ban television, or ration TV watching?
Or could the obesity be caused by something else? Like snacking while watching? Or cravings caused by commercials? Or lack of excercise?
On the other hand, epidemiological studies easily proved that lowering speed limits and wearing seat belts saved lives. So they are not to be totally discounted.
This is a crucial, vital, message: Correlation doesn't mean causation.
The biggest problem with food is that we can't do lab tests on humans very easily. There are laws to protect research subjects from abuse or poisoning. So the tests often have to be done on animals whose biology may not be similar to ours. And now there are animal activists who object to scientists using animals as subjects.
Here's a chart from the endlessly fascinating website Spurious Correlations. It shows a remarkable correlation between the number of non-commercial space launches around the world and the number of sociology doctorates awarded in the US. Hmmmmm. Post your theories in the comments below. And visit this fascinating website to see the correlations between the number people who drowned by falling into a swimming-pool and the number of films Nicolas Cage appeared in, or the per capita consumption of cheese in the US and the number of people who died by becoming tangled in their bedsheets, and more.
Also, beware of single-study syndrome. The gold standard measurement to establish a fact is to have multiple studies that produce the same data. Often one experiment is not enough.
Another crucial message: Just because we have made a study of something doesn't mean we have studied it.
How the media, especially the internet, fails us
Much of what consumers think we know about diet and health is wrong.
Too often we glom onto one or two statements and overlook the caveats or forget the details. Yes, we devotees of The Omnivore's Dilemma by Michael Pollan, a superlative landmark book, have learned that corn products are everywhere and in practically all processed foods. It is mindblowing. But Pollan never says corn is evil.
So why are so many people worked up over corn derivatives, especially high fructose corn syrup (HFCS)? How did people get so freaked out over a product that has not been proven to be any more harmful that plain old white sugar? The facts is that HFCS ranges from about 42 to 55% fructose and the rest is mostly glucose. Table sugar, called cane sugar or sucrose, is 50% glucose and 50% fructose. Not much diff! And plain old corn syrup is different than HFCS. It is mostly a sugar called maltose. Why do we damn them both?
OK, I agree that we should probably lift the massive subsidies paid to corn farmers and let these products compete in the open marketplace. But just because the corn industry is big it doesn't mean it is bad.
Everyone who is agitated about HFCS and won't buy products containg it, raise your hands. I have some questions for you. Have you read my article (linked above)? Do you eat pink burgers? Do you eat eggs with runny yolks? Raw sprouts? Do you smoke cigarettes? Wear your seat belts? Speed? Have you compared the risks?
Then there are GMOs. Yes, I think we should have transparent food labeling, and that means labeling GMOs, but we have nothing to fear. The American Association for the Advancement of Science (AAAS), a truly august board, says "The science is quite clear: crop improvement by the modern molecular techniques of biotechnology is safe. The World Health Organization, the American Medical Association, the US National Academy of Sciences, the British Royal Society, and every other respected organization that has examined the evidence has come to the same conclusion: Consuming foods containing ingredients derived from GM crops is no riskier than consuming the same foods containing ingredients from crop plants modified by conventional plant improvement techniques." In other words, the tried and true method of breeding plants by dusting a little pollen on the female flowers as practiced for centuries by nature and by breeders is the same as breeding plants by transplanting genes in a petri dish. There are hundreds of legitimate research projects that have found GMOs perfectly safe and practically every test questioning them has been bogus.
Our disconnect is the byproduct of the internet and all the half truths it tells. It is from our fear of the unknown. It is our suspicion of big business. It is our fear of illness and mortality. It is the fact that science is complex and often written in jargon that we cannot understand. It is because we didn't pay attention in science class. It is because our BS meters are not running.
We must start by turning on our BS meters: Consider the source. Did it come to you in an email? Is it in a publication on a mission? Does the author speak in hyperbole? Are all sides represented? Are there facts and references to scientific research in peer reviewed journals? Who were the authors? Scientists or physicians? Physicians are usually not scientists. Their training and skill sets are very different. Show me a single respected scientific journal with peer review of its papers that has published anything showing that a GMO is more harmful than non GMO varieties.
And we must weigh risk and reward. Yes, the day may come when someone discovers that a single GMO product is problematic, but all of them? And what about the good they can do? Breeding for disease resistance means greater yields, and that is the only way the world can feed an exploding population. Or is war and genocide preferable?
People who are afraid of food have invented a myriad of regimens: Vegetarianism, veganism, ovo-lacto, lactovegetarian, pescetarian, semi-vegetarian, flexitarian, omnivore, the Atkins diet, African Mango diet, Paleo diet, South Beach diet, Oritikin diet, Mediterranean diet, Detox diet, Grapefruit diet. Then there are the elimination diets: Gluten free, soy free, sugar free, low sodium, egg free, dairy free, corn free, and who knows what else. Some of these go beyond goofy to downright dangerous.
What is vexing to me is that people become so devoted to their diets and eating habits they try to convince others to join them. They become prosthelytizers, evangelists, fascists, and preach their food philosophies with the zeal of a cult member. One epidemiological study becomes a fad, then a lifestyle, and then a religion. Like so much else in modern society, lines are drawn in the concrete, neither side listens to the other, and the only facts invited to the party are the ones that support your argument.
So many diets mix politics and religious fervor with health. Whether killing animals for food is moral has absolutely nothing to do with our health and attempts to conflate them are plain and simple non sequiturs. One can make a legitimate argument against killing animals for food, but there is no room in this debate for health discussions. Likewise one can make a legitimate argument that eating animal products may be unhealthy, but there is no room in that debate for morality issues. Click here to read a pretty thorough debate on the topic that I conducted on Huffington Post. Does PETA really think its irritating tactics are working on thinking adults? Probably they don't. They're after impressionable teenagers and insecure grownups, and in the process they pissing a lot of us off with their exaggerations.
Barbecue and health
Barbecue is a form of roasting, which means cooking in warm dry air. "Roasting is probably the premier and probably the healthiest way to cook," says Chef Art Smith, highly respected restaurateur, chef to Oprah, and Southern cuisine specialist. He has made healthy eating a mission, shedding, and keeping off 120 pounds. "I don't think anything blanched or boiled has any flavor. Roasting intensifies the color and the flavor of food." This is a proven fact.
Likewise grilling over direct heat develops tremendous flavor without the fats of frying.
The problem with barbecue and grilling is that they have their roots in fatty gristly foods, cheap undesireable cuts left to peasants and slaves while the tender cuts went to the wealthy. Add to that fact the rich sweet spice rubs and sauces, and you can end up with a lot of tasty calories. That makes ribs, pulled pork, skin-on chicken and other staples of the barbecue canon special occasion food. Too rich for everyday eating. Like dessert, classic fatty sweet barbecue should not be overused.
So what's a person to do? Love food! Don't fear it! Take what you hear from the media, from your friends, and especially from the internet, with a, ahem, grain of salt, literally. Keep your BS meter turned on high. You doctor is not infallible, but she knows better than the TV news reporter. When you chose your diets, consider the actual level of risk and before you become devoted to it remember how the landscape changes and how that which is good today can be bad tomorrow. Before you obsess over your lunch, compare the risk of eating a bologna sandwich with putting makeup on your eyes. Or driving your car. Or putting on your makeup while driving your car. Select your food carefully, but don't give yourself an ulcer worrying about it.
If you live to 79, the average life US expectancy, you will eat 86,505 meals. It is really doubtful that a few bologna sandwiches, an occasional hot dog or high fat burger, or even a few bags of Cheetos will dent that. Even if you went on a bender and ate a hot dog for lunch every day for a week. If you at one hot dog a week for your entire life, that would be 4,108 hot dogs out of 86,505 meals. A pittance! Even a dietician will tell you that an occasional small bag of potato chips, a hot dog, a candy bar, a martini, or barbecue sauce with HFCS are not going to hurt you. Just don't make them mainstays of your diet.
All my reading and studying has led me to conclude this: Mom was probably right. Eat a balanced diet and everything in moderation.
It is probable that "Standard American Diet" (SAD) probably includes too much meat, too little vegetable, and too few whole grains and nuts. We should probably reduce our portion sizes and eat more meals without meat. We eat too many foods made in factories so we can't control what is in our meals. We should probably cook from scratch as often as possible. (Notice how I cover my butt with the word probably because what we know to be fact today is sure to be false tomorrow. Given that the nutrition and diet sciences seem to be so rudimentary, we might someday learn that one of the ingredients in Cheetos is good for you.)
And please please please, when you find a diet that works for you, don't oppress your friends with your food religion. Just swallow your tongue.
A final thought
We all want a long, healthy life, but life should not be an ascetic journey of denial of pleasure so that we can arrive at the end with a perfect body. I plan to watch my diet and take everything in sensible proportion, but deny myself of no opportunity for great pleasure because of some research paper that will be invalidated in a year. As Dr. David Katz, the founding director of Yale University's Prevention Research Center has said "The cold hard truth is that the only way to eat well is to eat well."
I plan to arrive at the pearly gates with a bottle of French Burgundy in one hand and a rib bone in the other, laughing and regaling anyone within earshot with tales of how great my life was.