Remember when eggs were bad for us before they were good for us? Or when certain heart disease was the devil’s bargain we made for loving a good cheeseburger? You may be excused for the vertigo you experience from all the flip-flops, twists and turns written over the years about the goodness or badness of any number of foods. For all of the “scientific” studies of nutrition and health, the bottom line is that we know something about the food we eat. But truthfully, the science behind what we ingest and how it affects our health is in its infancy.
There are numerous reasons why we are get conflicting information, partly because of how some journalists interpret scientific reports. Most reputable research papers are broken down the same way. There is an introduction/background, a methods section explaining how the research was performed, a results section, discussion/conclusion, and finally a summary. Journalists for the most part, not being scientists and on tight deadlines, read only the summary, which may have less scientific jargon and be more readily digestible than the rest of the paper. Many a journalist has fallen prey to accepting the summary without delving into the particulars. The result is a headline that screams Coffee Is Great for Your Health! when it should have said Coffee Is Great for Your Health—If You are Middle Class, Have Health Insurance, Don’t Smoke, Exercise, and Your Parents Don’t Have Cancer!
The problem is not always the journalism. Some studies are deeply flawed. Other studies cannot be duplicated and are therefore discredited. Sometimes the sample of people studied is too small. And then there are the studies sponsored by industries that have vested interests in the outcome.
Dietician Andy Bellatti wrote on Lifehacker, that:
"...increasingly, food companies are setting up 'institutes' (i.e. Coca-Cola's Beverage Institute for Health and Wellness, General Mills' Bell Institute) that are essentially PR efforts that oh-so-coincidentally frame these companies' products as healthful (or, in the case of soda, in no way problematic from a health standpoint).
"To make matters more confusing, these institutes have doctors, cardiologists, and dietitians on their payroll—as well as key media contacts—resulting in a health professional talking to media about, say, how soda is 'unfairly vilified.' Most times, the general public isn't aware that this isn't an objective health professional choosing to say that.”
Whatever the reason, once corrected, a study may come to conclusions that are diametrically opposed to previous studies.
Here are five nutritional flip-flops, and a few more where the jury is still out.
1. Eggs. There was a time not very long ago when eggs were looked upon as cardiovascular time bombs. High in dietary cholesterol, it was said that eating a lot of eggs would result in gummed-up arteries and a high risk of heart attack. Most recent studies, however, cast these assumptions aside. Unless you are diabetic, there is no evidence that dietary cholesterol results in plaque building up in your arteries (studies on diabetics have shown possible correlation but nothing definitive).
In addition to protein, eggs contain lots of great nutrition, including omega-3s and B-vitamins.
Bottom line: Eat your eggs.
2. Saturated fat/red meat. Good and bad news about saturated fat has been bouncing to and fro like a ping-pong ball for several decades. One of our primary sources of saturated fat is red meat (burgers, steaks, beef hot dogs and the like). From the early- to mid-20th century, we were encouraged to consume lots of meat because it was a great source of protein, B vitamins and numerous other nutrients. However, in the 1960s, studies began to link saturated fat with heart disease and cancer.
Back and forth the argument went, as conflicting studies linked and unlinked the dangers of red meat consumption. People read and worried, accepted that meat was bad (although did not stop eating it), and rejoiced whenever news came out that maybe meat was OK. In 2014, a study out of Harvard, comprised of over one million people, found no link between the consumption of unprocessed red meat and either heart disease or diabetes. Another study out of Europe of over 450,000 individuals came to the same conclusion.
However, both of these studies did find a link between processed meat (hot dogs, cold cuts and the like) and disease.
Bottom line: If you want a burger, eat one, but think twice about that salami (processed meat) sandwich. But health reasons aside, the consumption of meat in the world sustains factory-farming of animals, which is the source of horrendous misery for billions of cows and pigs and is literally killing the planet because of the carbon, air and land pollution it creates. If you are concerned about that, and you should be, cut down on your meat consumption or stick to meat obtained from sustainable farming practices.
3. Butter. Butter’s stock has gone up and down for 150 years. As far back as 1855, people were told to use oil instead of butter. Like a close-fought basketball game, the duel between margarine and butter has been classic, but it seems that butter has finally gained the upper hand.
The main beef against butter has mostly been that it is a saturated fat, which with prolonged consumption, would cause cardiovascular disease. The Harvard study referenced above seems to have put that fear to rest, and in fact it is margarine, with its high trans fat content, which studies have shown is the heart disease enabler.
Meanwhile, butter is a good source of fat-soluble vitamins like A, E and K2, and actually raises the good HDL level in your blood, while lowering the bad LDL. As for the extra calories? No worries. A 2012 study concluded there was no correlation between high fat dairy and obesity.
Bottom line: Butter your toast. But remember most dairy you consume comes from factory farms, so try to buy butter that comes from grass-fed cows.
4. Coffee. For many years, coffee was the victim of flawed studies linking it to cancer and heart disease. Problem was, these studies did not take into account other factors, like coffee-drinkers might also be cigarette smokers. The result was that many people gave up coffee, albeit reluctantly.
It turns out that the dark side of coffee was greatly exaggerated. Yes, there are negative aspects of coffee. It is addictive, so if you want to stop, be prepared for a couple days of wicked headaches. It is a stimulant, so if you overdo it, expect to be tossing and turning in bed. If you are pregnant, don’t overdo it. There is some small correlation (not causation) between coffee and miscarriages, but opinion is nowhere near what it used to be, and most doctors now think a small cup or two a day, even if you are pregnant, is not a problem.
Now for the good stuff. Coffee is loaded with antioxidants (in fact, some Westerners actually get more antioxidants from coffee than from fruits and vegetables). Coffee enhances brain function (as do most stimulants), may protect your brain from degenerative diseases like Alzheimer’s and Parkinson’s, and may ward off Type 2 diabetes and even liver cancer. Want more? There are studies linking coffee to a lower risk of depression and suicide and to a longer lifespan. (It is important to note that these studies are not causative, i.e. they do not show coffee causes a reduction in disease, only that those who drink coffee seem to have less disease.)
Bottom line: A cup of joe, please.
5. Avocados. Only a few decades ago the avocado was considered a sinful treat. As studies coming out in the 1970s and '80s extolled the dangers of fat, the poor avocado suffered in silence as it was swept up in the low-fat tsunami of scientific opinion.
What we know now, is that the creamy fruit (yes, it is a fruit, not a vegetable) is a source of mono-saturated fat that does not clog your arteries or increase your cholesterol level, and in fact helps sweep away the bad LDL in your blood.
Bottom line: Eat as much guacamole as your heart desires.
On the Fence
Red wine: For a long time, scientists struggled with the so-called French paradox. Why is it that the French, whose diet includes lots of saturated fats, still manage to have less heart disease than Americans? The answer, researchers declared, was red wine. Red wine contains an ingredient called resveratrol, which studies point to as an active agent in protecting the cardiovascular system. Wine drinkers celebrated and drank a lot of wine, secure in the knowledge that they were doing their heart a solid. Alas, it seems we jumped the gun, or goblet as it were. More recent research has shown that the amount of resveratrol in the bodies of wine drinkers was not sufficient to provide any cardiovascular protection.
Since we now know that saturated fat is not the grim reaper we thought it was, it would seem that the lower level of heart disease in France would have other causative factors. A more likely cause, we now believe, is the higher amount of fresh fruits and vegetables that the French consume, as well as the lower amount of processed foods.
Bottom line: Drink up, but not to excess. A glass or two of wine a day might not protect your heart directly, but it certainly reduces stress and that’s a good thing. More than a couple glasses, though, and you are doing your body more harm than good.
Salt: Considered a contributor to high blood pressure and resulting heart attack and stroke risk, Americans have long been advised to limit their salt intake to about 2,300 milligrams of sodium a day (about a teaspoon of salt). Since we routinely consume over 3,500 milligrams a day, salt has been considered a major culprit contributing to America’s cardiovascular woes.
Here’s the thing, though: when we limit our salt intake, the resulting blood pressure drop is generally minimal (120/80 may drop to 118/79), not really enough to make much difference. And limiting salt too much has its own risks, since the human body needs salt to function properly. Now a major study, called the PURE study, published in the New England Journal of Medicine has concluded that there is insufficient evidence to show that limiting salt intake has any effect on health. Moreover, people in the study who limited their salt intake had more heart trouble than those who did not. There is still debate going on over the PURE results, and the American Heart Association, as well as the American government, has stuck to its guns that limiting salt is the better choice, but it would seem that the old orthodoxy may be cracking just a bit.
Bottom line: If you have very high blood pressure, limiting your salt intake might be the wise choice (for the moment, anyway), but the occasional potato chip shouldn’t overly concern you. For people without blood pressure issues, worrying about salt might raise your blood pressure more than the salt you are unnecessarily worrying about.
Sorry, These Are Still Bad For Us
Bacon: Unprocessed meat good. Processed meat bad. Because of the good news about saturated fat, bacon lovers of the world rejoiced, and there have been numerous articles claiming bacon is now good for you. Sorry, bacon lovers, but bacon is a cured, processed meat. There is plenty of evidence linking consumption of processed meats to heart disease, cancer and diabetes.
Bottom line: No scientific flip-flop on bacon. Bacon tastes great and is very bad for you.
Sugar: It's bad for you. It was then, it is now. And it’s not just the tooth decay or the obesity or the diabetic risk; studies increasingly point to sugar as a culprit in inflammation, which may link to autoimmune diseases, cancer, heart disease, and more.
Bottom line: Sugar tastes so good, and it is hidden in so many foods. But cut down on the sweet stuff.
The overall takeaway is that today’s good food may be tomorrow’s bad food. So listen to the old saw: everything in moderation. And no matter what, no one will ever say too many fruits and veggies are bad for you. Eat lots of those and you really won’t need to worry too much about the rest.