Myth Busters

Bacteria and your gut: Do probiotics and prebiotics help?

What about probiotics and prebiotics? These are HOT in health and wellness at the moment. They come in the form of expensive powders, pills, and beverages as well as vegetables, yogurt, and tasty kimchi among others. However, like most health products, there is more to the story, especially when it comes to probiotics and prebiotics.

This article provides evidence-based information about pre- and probiotics so you can make informed decisions.

Before we dive into what pre-and probiotics are, here is a little background information. Did you know that your body is home to trillions of bugs? Thousands of species of bugs, or microorganisms, live on your skin, in your gut, and just about all parts of your body. The bugs include bacteria, fungi, parasites, and viruses. Collectively, these bugs are called the microbiome, and you would not exist without it.

The cool thing is that, like DNA, no 2 people have the same microbiome. The composition of the bugs that live on your body is unique to you. Bugs started living on you the second you entered this world through the birth canal and by drinking breast milk or formula. ALthough initially, your microbiome comes from your mother, your environment and diet affect the composition of your microbiome later on.

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The gut inhabits its own microbiome called the gut microbiome. Humans have over 1000 different species of bacteria in the gut, mostly belonging to one of 2 bacteria families, the Bacteroidetes and Firmicutes families. There are tens of billions of bacteria living in the human colon alone. That is 10 times the number of cells that make up the human body. Even in seemingly healthy people, researchers have found that the gut microbiome is quite diverse.

Simply put, we are a sack of cells and bacteria that eat, poop, and have sex.  

So how do the bugs in your gut affect you? They are crucial to digestion and acquiring nutrients from foods you eat. For example, you cannot digest some of the food you eat, however the bugs can, like components of vegetables such as lettuce and onion. Fiber is a critical component in the human diet, but some of the fiber eaten is only digested by the gut bugs. In fact, they thrive on it and in turn, release compounds called short chain fatty acids (SCFA). SCFA are a great energy source for the cells of your intestines, improve gut health, and may even prevent tumor growth.

Whether you know it or not, you have a very intimate relationship with the bugs that live on and in you. You must be a good host. Like leaving a mint on their pillow, you must feed them high quality, nutritious food and, in turn, you will attract only the best kind of bugs that will provide you with all the nutrients you need for a healthy gut, heart, liver, brain and immune system. In other words, what you eat matters!

Prebiotics and Probiotics

That’s right…what you eat matters, especially when it comes to the bugs that live in your gut. These bugs have the power to greatly affect your health and wellbeing. Prebiotics and probiotics are two components that promote healthy gut bugs and their functions.

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Probiotics are bacteria in foods and supplements that are alive. These bacteria are naturally created by the process of fermentation in foods like yogurt, sauerkraut, miso soup, and kimchi. While you already have live bacteria in your gut, consuming a probiotic may improve the gut bacteria composition by increasing the amount of the good bacteria. Research has shown that probiotics may help repopulate the colon with healthy gut bugs after antibiotic (which wipe out the gut microbiome), improve symptoms of Irrital Bowel Syndrome and other gastrointestinal disorders, and may even be beneficial to treatment of obesity, type-2 diabetes, insulin resistance, and non-alcoholic fatty liver disease.

However, there are a few things to know about probiotics before you buy the expensive supplements or stock up on yogurt. Probiotics are only effective if they are alive. In fact, probiotics are fragile and can be killed by heat, stomach acid, and sitting too long on the shelf at the grocery store. Additionally, there are hundreds of probiotic species, however the best species for the average person is still unknown. Once ingested, probiotics must compete with hundreds of thousands of other bacteria in the gut to survive and flourish.

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Prebiotics are food for the bacteria in the gut. They are non-digestible fibers in food that you eat that pass through the stomach and small intestine undigested. The bacteria in the colon ferment these fibers and use them for energy. These fibers area found in food like bananas, onions, skin of apples, beans, and many others. *Notice these are non-processed foods 😉. Prebiotics are FIBERS* that provide food for the good kind of gut bugs causing them grow in number, improve your health, and reduce risk of disease.

*Fiber is a crucial part of the human diet and most Americans do not consume enough. The recommended daily intake of fiber is 25g/say from food. However, this number is extremely low. Increase your fiber intake through having a serving of vegetables at every meal. This is ideal food for the good bacteria that inhabits your gut!

You can think of probiotics as the seeds of a garden and the prebiotics as the fertilizer that help the seeds grow and flourish.Unlike probitioics, prebiotics are not affected by heat, stomach acid, or time and studies have shown that prebiotics may help improve immunity, digestive health, bone density, weight management, and brain health

While there are many prebiotic pills and supplements, there is one simple thing to know about prebiotics; they are easily acquired. Just eat your fruits and veggies!

Should you consume probiotics?

While probiotics may exist in many tasty foods, the true effect on health (if any) is not fully understood. Buying expensive supplements may not be worth it. Spend your money on food sources of probiotics such as kimchi and sauerkraut. If you love yogurt, stick with plain Greek yogurt. Many other yogurts are loaded with added sugar and artificial flavors. However, if you have undergone a round of antibiotics, a probiotic may help repopulate your gut with goods bugs. As always, consult a gastroenterologist before trying something too crazy.

Should you consume prebiotics?

Simple. YES! Prebiotics are easily acquired through eating a healthy diet with plenty of vegetables and fruits. Increase your daily fiber intake by incorporating a serving of vegetables in every meal.

Move more, gym less?

As you know, proper nutrition and exercise are important to health and wellbeing. It is important to nourish your body and exercise daily. The two truly go hand in hand – from losing fat and building muscle, to the complex cellular level where your body uses food to make energy for movement.

If it sounds like a tall order to increase exercise and improve nutrition, you can stop stressing. There are several ways to increase your daily activity and incorporate nourishing foods into your daily life.

In the motivating article below titled, Humans, Made to Move, Dr. David Katz discusses how “sitting is the new smoking” and how more daily movements, not necessarily exercise, can improve your health. 

Humans, Made to Move It

You might be wondering where nutrition comes in to play in this discussion. First, the more you move, the more energy you expend, thus, you increase your total daily energy expenditure (TDEE). Expending more energy than you consume can help with weight loss.

Second, and more complex, moving more improves your metabolism (or, what your body does with what you eat). This occurs at the cellular level. Increasing movement, also referred to as physical activity, increases the demand for energy in muscle tissue and other tissues and organs throughout the body. Your cells must provide that energy; therefore, they adjust and adapt to meet the increased energy demand.

Adaptations to physical activity include:

  • Increased mitochondria in the cells to provide energy from fat stores

  • Increased glucose receptors on cell membrane to facilitate glucose uptake

  • Increased capillary density to supply blood and oxygen to muscles

  • Increased activation of neuromuscular units that result in increased muscle strength and power

  • Decreased resting heart rate and blood pressure

From a nutritional standpoint, your body becomes better at using the food you eat and have stored to make energy. This is referred to as metabolic flexibility. For example, someone who uses a stand-up desk most of the day, takes the stairs, and walks around the office a few times in the morning and afternoon is more metabolically flexible than someone who sits at their desk for 8 hours a day. The active person expends more energy and makes energy from the food they eat and have stored better than the sedentary person because they have trained their body to do so. This is likely reflected in their health markers such as blood pressure and lipid profile.

Ways to increase movement or physical activity throughout the day include:

  • Take the stairs

  • Using a standing desk

  • Sit on a stability ball instead of an office chair

  • Take a walk after lunch

  • Walk while you meet with a co-worker

  • Stretch for 5 minutes a few times throughout the day

  • Get creative! Even fidgeting expends energy!

Nourishing your body with nutrient-dense foods enhances these adaptations in addition to other physiological benefits. Whole, non-processed foods are the best sources of nutrients and your body and metabolism thrive on.

If you are struggling with your eating habits, set a goal for the rest of the week to have protein, fat, and vegetables for each meal. Here is a quick guide:

  • A serving of protein is 4oz of uncooked meat or palm of your hand.

  • A serving of fat is 1-2 tablespoons.

  • A serving of vegetables is approximately 1 cup or handful.

Men: 6-8oz of protein, 1-2 servings of fat, 1-2+ servings of vegetables

Women: 4-6oz protein, 1 servings of fat, 1-2 servings of vegetables

To summarize, simply moving more throughout the day can improve the way your body makes and uses energy from the food you eat. You also get better at using the fat and carbohydrates you have stored. Second, when it comes to nutrition. Think simple. Stick with non-processed foods and have protein, fat, and vegetables at every meal.

Diabetes: Let’s not sugar-coat the pill

When talking with a friend recently who was diagnosed with Type-2 Diabetes (T2D) about a year ago, I was appalled to find out he had no idea what T2D was. His doctor never explained it to him, rather just said his blood sugar was high and wrote him a prescription for metformin.

T2D, and pre-diabetes, are serious conditions with growing prevalence. Do you have a relative or friend with diabetes? It is a complex condition with multiple risk factors The good news is that T2D can be prevented and even reversed with lifestyle modifications.

Here are the facts and what you can do to manage and prevent the disease.

The stats

According to surveys by the Center of Disease Control, the prevalence and cost of diabetes are astonishing.

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  • There are 29.1 million people in the United States that have diabetes. That is 1 out of every 11 people.

  • 1 out of 4 people don’t know they have diabetes.

  • 86 million people (that’s 1 out of 3 adults) have prediabetes.

  • However, 9 out of 10 people do not know they have prediabetes.

  • 15-30% of people with prediabetes will develop prediabetes within 5 years.

  • The total medical costs and lost work and wages for people with diagnosed diabetes is estimated to be $245 billion.

  • The risk of death for adults with diabetes is 50% higher than those without.

  • Medical costs of people with diabetes are twice as high as for those without diabetes.

  • People with diabetes have a higher risk of developing serious health complications such as blindness, kidney failure, heart disease, stroke, and loss of toes, feet, or legs.

What is Type 2 Diabetes?

Type 2 Diabetes is a condition that causes blood glucose (sugar) to rise higher than normal. High blood glucose is the result of improper use of insulin, called insulin resistance.

What is insulin resistance?

The progression to type 2 diabetes begins long before the actual onset of the disease. It begins with insulin resistance.

To understand insulin resistance, it is important to review the normal physiological process that occurs in response to eating.

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When we eat foods that contain carbohydrates (anything from pasta, bread, crackers, and cake to fruit, fruit juice, soda, and oatmeal), it is broken down in the stomach into glucose. Glucose is absorbed through the small intestine into the blood stream causing an increase in blood glucose. When glucose enters the blood stream, it triggers the pancreas to secrete the hormone insulin. Insulin is secreted from the beta cells of the pancreas. In a lock and key manor, insulin stimulates (unlocks) muscle cells to allow glucose to enter and be stored within the cell and used for energy and the concentration of glucose in the blood decreases. Glucose is also produced by the liver and released into the blood stream when blood glucose gets low. Thus, blood glucose levels are kept in a tightly regulated range.

When there’s too much sugar floating in the blood after a meal, (for example, you ate that hi-carb meal, washed it down with a soda and went back to your chair in front of the computer) the cells refuse to let insulin bring the extra sugar in. The result? Insulin production shoots up as the body tries to “muscle” the sugar into the cells. When the muscle cells don’t budge, excess sugar goes away into the fat cells, where it begins to accumulate.

In other words, over time, a sedentary lifestyle, poor eating habits, genetic predisposition, and other factors can result in insulin resistance. This occurs when the muscle cells become desensitized or resistant to the effects of insulin. The beta cells of the pancreas must then secrete more insulin to dispose of the same amount of glucose.  This is the first step in the progression of Type 2 Diabetes.

The development of Type 2 Diabetes

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1.        Insulin resistance.

At first, the pancreas compensates for insulin resistance by increasing insulin secretion, resulting in elevated levels of insulin in the blood (hyperinsulinemia). Glucose tolerance, or glucose levels in the blood, remains in the normal range because higher insulin secretion does the trick.

2.       Impaired glucose tolerance and beta-cell dysfunction.

The next progressing towards type 2 diabetes is an increase in blood glucose levels (hyperglycemia). Insulin secretion is reduced and this is reflected in blood glucose levels as insulin is no longer sufficient to dispose of glucose into the cells. The beta cells of the pancreas also begin to fatigue and stop working properly as less insulin is secreted.

3.       Type-2 diabetes

Lastly, the progression to full blown type-2 diabetes where the pancreatic beta cells fail. They secrete little to no insulin in response to blood glucose. Medications such as metformin and insulin injections are then prescribed. Symptoms include feeling tired because your cells have little glucose for energy, excess thirst. Diabetes is complex and affects multiple organ systems. It can lead to other conditions such as eye problems (retina damage), heart disease, and neuropathy or tingling/burning sensations in arms and feet.

How do you test for T2D or pre-diabetes?  There are a few ways to determine whether you have diabetes or pre-diabetes.  · Impaired glucose tolerance – This is step 2 in the development of T2D. Have you ever had a glucose tolerance test where you drink a very sugary drink then have your blood drawn before and after? This measures the glucose response to the sugar drink. If your glucose is elevated after 2 hours, depending on how high it is, you may be pre-diabetes or have T2D.  · Elevated fasting glucose – Also step 2 in the development of T2D. When you go to the doctor and they draw your blood in the morning before you have eaten anything (you are fasted). If your glucose is high, then this means you have impaired fasting glucose. Remember there are 2 sources of glucose, what you eat and your liver can make it. When you are fasted, your liver makes glucose. Insulin is secreted to keep this glucose level in a tight range. When fasting glucose is high, this means insulin is not doing its job and you are insulin resistant.  What about step one? Notice that these tests do not measure insulin levels. In these 2 cases, we miss step one. The only way to determine if you are insulin resistant but still glucose tolerant (meaning your pancreas has to secrete more insulin to get the cells to take to glucose out of the blood stream and store it) is to measure your insulin response to a glucose tolerance test. If your insulin is elevated, then you are hyperinsulinemic and insulin resistant. If you think you might be insulin resistant and on your way to prediabetes or T2D, ask you doctor about testing both your insulin and glucose response to an oral glucose tolerance test (OGTT).

How do you test for T2D or pre-diabetes?

There are a few ways to determine whether you have diabetes or pre-diabetes.

· Impaired glucose tolerance – This is step 2 in the development of T2D. Have you ever had a glucose tolerance test where you drink a very sugary drink then have your blood drawn before and after? This measures the glucose response to the sugar drink. If your glucose is elevated after 2 hours, depending on how high it is, you may be pre-diabetes or have T2D.

· Elevated fasting glucose – Also step 2 in the development of T2D. When you go to the doctor and they draw your blood in the morning before you have eaten anything (you are fasted). If your glucose is high, then this means you have impaired fasting glucose. Remember there are 2 sources of glucose, what you eat and your liver can make it. When you are fasted, your liver makes glucose. Insulin is secreted to keep this glucose level in a tight range. When fasting glucose is high, this means insulin is not doing its job and you are insulin resistant.

What about step one? Notice that these tests do not measure insulin levels. In these 2 cases, we miss step one. The only way to determine if you are insulin resistant but still glucose tolerant (meaning your pancreas has to secrete more insulin to get the cells to take to glucose out of the blood stream and store it) is to measure your insulin response to a glucose tolerance test. If your insulin is elevated, then you are hyperinsulinemic and insulin resistant. If you think you might be insulin resistant and on your way to prediabetes or T2D, ask you doctor about testing both your insulin and glucose response to an oral glucose tolerance test (OGTT).

What are the risk factors for Type 2 Diabetes?

There are both modifiable and non-modifiable risk factors for Type 2 Diabetes.

Non-modifiable risk factors are those that we have no control over:

  • Family history of diabetes

  • Age over 45 years

  • Race/ethnicity

  • History of gestational diabetes.

Risk factors we can change include:

  • Physical inactivity

  • Poor diet

  • Overweight and obesity

  • High blood pressure

  • High cholesterol

 

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Lifestyle treatments for Type-2 Diabetes

1.       First and foremost, the diagnosis must be treated with urgency.

Think back to the progression of diabetes. By the time high blood glucose (impaired glucose tolerance, high fasting glucose) occurs, you are already insulin resistant and on your way to full on diabetes. Now that you know there are factors you can modify, ask your doctor what factors (weight loss, diet, exercise) you need to focus on.

2.       Exercise

Exercise has many benefits. Exercise has numerous benefits. When it comes to diabetes, exercise works at the molecular level of our cells to increase glucose uptake and sensitivity to insulin. It also reduced harmful fats inside the cell that can promote insulin resistance and increase good fats that promote insulin resistance.

3.       Diet

Specific dietary changes should be adopted immediately when diagnosed with pre-diabetes or full on Type 2 Diabetes. The consumption of carbohydrates requires insulin. (Remember all carbohydrates are broken down to their basic molecules – glucose.) When the pancreas no longer produces or produces too little in response to glucose then insulin must be administered. This is essentially a band aid to the larger issue. Treatment with insulin as a medication (exogenous insulin) is not a cure. Reducing carbohydrate consumption, however, reduces the need for insulin. A lower carbohydrate diet is essential for reversing diabetes.

Numerous research studies have shown that even modest lower carbohydrate diets improve pancreatic beta-cell function and increase insulin sensitivity.

The take-away:

  • Diabetes and pre-diabetes are urgent diagnoses!

  • You CAN prevent and even reverse diabetes through lifestyle modifications – diet and exercise.

Lastly, consult your doctor before taking on any drastic lifestyle changes. Increases in insulin sensitivity through diet or exercise will likely change the need for medications such as insulin and metformin and should be medically supervised.

Have you been diagnosed with T2D or pre-diabetes? Do you have family history of diabetes? Want to know more about what you can do for T2D and how to prevent it? Contact SPINLab!

How history shaped the American diet Part 2: Big change backed by little science

Part 1 reviewed the swift progress and major events in history that influenced the American diet. Part 2 exposes a big, fat, juicy story that will make you question what you believe about what you eat.

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Once upon a time...

It came to light in the 1940s that the leading cause of death was coronary heart disease. Scientists, thus, sought to identify the cause and ways of prevention. Numerous research studies taking place over decades, and some still on-going, began collecting data. Among those was Ancel Key’s seven country study. This was an epidemiological study comparing how many people were dying of heart disease with how much fat they were eating. At the time, 22 countries had this data available and were included in the study.

Keys found that the countries with higher fat consumption had more deaths from heart disease (Fig.1). Japan, for instance, consumed less that 10% of total calories from fat and had a much lower death rate from heart disease than the US who consumed 40% of calories from fat. The conclusion drawn from this study was that the more fat in the diet, the more likely to die of heart disease.

Taking a deeper look, there were a number of things wrong with this study. First and foremost, the methods of data collection lacked rigor and would never fly in research today. There were two major issues with data collection. One, percent fat from total calories was determined by food availability per capita in each country. Basically, the amount of food available was divided by total number of people in each country. This is a poor estimate of what people were truly eating. Two, death by heart disease was determined by death certificate, however autopsies were not performed at this time and cause of death is many times confounded by multiple comorbidities. In the 1940s, cause of death was many times a guess. With so many flaws, this study design would not have a leg to stand on in research today. In fact, the original data has been destroyed, so forget reanalysis.

The second major error in this study has to do with interpretation of the findings. In statistics, there is a little saying, “correlation does not equal causation.” Correlation analysis is simply a mathematical way to describe the relationship between two things. For example, height is correlated to weight because as we grow taller, we also weigh more. Another example is that there is a strong correlation between homicide rates and ice cream sales.  Does this mean that buying ice cream causes violent crime? No, that sounds foolish. However, there is plenty of evidence showing that warm temperatures cause an increase in crime, maybe because we are more likely to lose our temper in hot weather. In addition, ice cream is more appealing in warm weather, therefore, sales are higher in the summer vs winter months. This means that temperature and temper confound, or that there is merely more to the story in the relationship between homicide and ice cream sales.

Back to Key’s conclusions. Yes, the data says that people in the US ate more fat than people in Japan and more people in the US were dying of heart disease. However, is fat the cause of heart disease or just a confounder? Was there more to the story?

Nevertheless, in the 1950s, Ancel Keys went to the World Health Organization and American Health Association (AHA) promoting a low-fat diet claiming that a “fatty diet raised serum cholesterol, atherosclerosis, and myocardial infarction.” In 1961, Keys was featured on the cover of Time Magazine making the recommendation that the American diet should consist of 70% of calories from carbohydrates and 15% from fat – a drastic change from the 40% fat calories Americans were consuming. The AHA got on board and released a report that “the best scientific evidence of the time” suggests that Americans would reduce their risk of heart disease by reducing the fat in their diets.

True, though flawed, the best evidence at the time suggested that dietary fat consumption is related to heart disease. In the least, this observation called for further research.

When the fat hit the fire

Big money was put into more research on how and why fat consumption appeared to be linked to heart disease. One, the Western Electric Study by Paul Oglesby, was published in 1963. This study was conducted to identify factors associated with the risk of heart disease. Over 4,000 men age 40-55 years were selected to be in the study. Over a 4.5-year period, mortality rate was compared between those consuming the fattiest and those consuming the leanest diets. The findings were clear, 14 deaths due to heart disease in the high fat group and 16 in the low-fat group. No significant difference. These findings were not only ignored but later blatantly misreported. The AHA and National Heart, Lung, and Blood Institute (NHLBI) published “The Cholesterol Facts” which included the Western Electric Study as one of seven studies showing a correlation between saturated fat and heart disease. Exactly what it did not do.

What could have put an end to the low-fat ideology came in 1973 with The Minnesota Coronary Study. This was a highly controlled diet intervention study conducted on 9000 men and women in 6 mental institutions across Minnesota. While unethical to study this vulnerable population today, investigators were able to control what the participants ate – something that had not been done before on such a large scale. The researchers investigated the effect of saturated fat (thought to be “bad” fat) on heart disease over 4.5 years. The participants in the study were randomized to either a 9% saturated fat diet or control diet (18% saturated fat) for 4.5 years. Total fat was the same for both groups.

Contradicting Ancel Key’s findings, the investigators found no difference in heart disease or overall mortality between groups. In fact, there were 269 deaths due to heart disease in the treatment group while there were 206 deaths in the control group.

Why did this study not put an end to the low-fat diet? The lead investigator was not pleased with the results and the study sat unpublished until 1989!

Fat Chance

Evidence piled up that the amount of fat has no relationship to heart disease. However, the type of fat was found to be important.

There are different types of fat depending on chemical structure. These include saturated, unsaturated, and trans fats. There is some evidence, though controversial, that saturated fats (found in beef, pork, skin on poultry, whole-milk, cheese, butter, eggs, and palm and coconut oil) are related to heart disease. A number of studies have shown that consumption of omega-3 fatty acids actually reduces the risk of heart disease. Today, the AHA recommends no more than 5-6% of fat from saturated fat while unsaturated fats are healthy. The message that was heard, though, is that fat is bad, which was not just misleading but dangerous.

What about cholesterol? Cholesterol is essential for life and present in all tissues of the body. Eating cholesterol (such as egg yolks and shellfish) does not actually contribute much to blood cholesterol levels. In other words, you cannot get high cholesterol from eating foods high in cholesterol. Only about 25% of the cholesterol comes from diet because cholesterol in foods can’t be absorbed by our bodies. The other 75% is produced in the body by the liver. Cholesterol levels are tightly regulated in the body so that when cholesterol level in the diet goes up, the body makes less. It is wrong to say that high cholesterol causes heart disease.

In the 1970s, the NIH funded studies to investigate which specific fractions of cholesterol contributed to heart disease. It was found that total cholesterol does not predict heart disease. However, it was also found that different proteins carry cholesterol throughout the body dropping it off where it is used for cell metabolism. The amounts of these proteins does matter, though. These proteins include high density (HDL), low density (LDL), and very low density (VLDL). Cholesterol carried by LDL that is not used, is left to circulate in the bloodstream where it can then accumulate in the walls of the arteries, leading to plaque formations and atherosclerosis. LDL is therefore thought to be “bad” cholesterol. HDL acts more as a scavenger, collecting cholesterol and taking it back to the liver for reprocessing or excretion. HDL is the “good” cholesterol.

When it comes to heart disease, high LDL is only a “marginal risk factor,” however, low HDL was found to be a 4-fold better predictor of heart disease compared to LDL, and it was the only predictor of heart disease in men and women over age 50. Therefore, pay attention to your HDL and things that raise HDL may reduce the risk of heart disease.

Unfortunately, the findings for these NIH studies too were ignored for 20 years. Another tragedy in the bigger story.  

The Tipping Point

The tipping point came in 1977, though, when the government took hold of the low-fat hypothesis. That year, the US Senate’s Select Committee on Nutrition and Human Needs (aka the McGovern Report) published the “Dietary Goals in the United States.” For the first time in history, a branch of the government urged Americans to eat more fruits, vegetables, whole grains, poultry, and fish and to eat fewer high-fat foods, substitute nonfat for whole milk. In other words, eat more fruits and vegetables instead of fat.

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Tell people not to eat fat and you think they are going to eat more fruits and vegetables? What happened was the invention of a whole new food culture. The “Snackwells phenomenon.” ‘Low-fat,’ ‘fat-free,’ and ‘low-calorie’ foods which largely replaced fat with sugar were mass produced. However, many of these foods still have the same number of total calories as their full-fat counterparts.

Further fueling the low-fat movement, in the 1980s an article based on the Framingham Heart Study was published highlighting obesity as an independent risk factor of heart disease. Consequentially, it was believed that a low-fat diet might reduce the risk of heart disease and promote weight loss by reducing caloric intake (because of all macronutrients, fat has the most calories per gram). In other words, if it wasn’t fat, it wouldn’t make you fat and you won’t die of heart disease.

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Then, as if proven, the federal government incorporated the low-fat ideology into federal policy. In 1984, the National Institute of Health consensus stated “there is no doubt that a low-fat diet will afford significant protection against coronary heart disease to every American over the age of 2.” In 1988, the Surgeon General’s report emphasized the dangers of dietary fat. In 2000, the federal “Report on Nutrition and Health” labeled fat as the unhealthiest part of the American diet – not saturated or trans-fat, just fat. Shockingly, in 1992, the American Heart Association (AHA) began labeling low-fat products with their seal of approval, such as Kellog’s Frosted Flakes, Fruity Rice Krispies, and Low-Fat Pop-Tarts.

With this kind of support of course consumers (you and me) believed, and still believe, that a low-fat diet is healthy. Thanks to my mother trying to stay trim and raise healthy kids, I grew up a low-fat kid sustained on cereal, low-fat Wheat Thins, fat-free yogurt, and Reduced Fat JIF Peanut Butter!

The advice being fed to Americans was not only false, but actually dangerous as people were eliminating healthy fats that are important in reducing risk of heart disease. While fat consumption was reduced, carbohydrate consumption increased and so did the prevalence of obesity, heart disease, diabetes, and other metabolic diseases.

More on the consequences of the low-fat dogma in Part 3. Stay tuned!

 

How History Shaped the American Diet Part 1: From Scratch to TV Dinners

 

Factor or fiction?

Foods with cholesterol causes heart disease. Full fat foods cause weight gain. Low-fat, sugar-free, diet foods are the way to lose weight. What you eat doesn’t matter, it’s all about reducing calories. Fad diets, juice cleanses, and detoxes work. Eating small meals throughout the day is better. Healthy foods are expensive…

These and many other myths have influenced the American diet for much longer than you might think. But what are the foundations of these beliefs?

Looking back through history, there is a compelling story underlying what we believe about nutrition and how that shaped the American diet as we know it today.

Decades of change

Rapid change influencing daily life began over 100 years ago. The turn of the 20th century marked an era of great growth and optimism in the United States. Typical American families lived off the land and prepared meals from scratch. For some, vegetables were picked from the garden and meat was a mainstay. Others relied on rice or cornmeal. Thousands of Americans died of scurvy (vitamin C deficiency) and pellagra (vitamin B deficiency). Thus, the emphasis on eating your veggies!

America became a ‘melting pot’ in the 1910s as immigration was at an all-time high, bringing new flavors to the kitchen. How else can lasagna with American cheese and chop suey with American hamburger be explained?

Progress was rapid in the following decades. This set the stage for industrialization which was mirrored in the cuisine at the time. Processed foods such as mayonnaise, Oreo cookies, Crisco, puffed wheat and puffed rice, and hot dogs became increasingly available. Night life escalated as speakeasy dining and cocktail parties lead to the concoction of many of today’s popular mixed drinks. However, Prohibition crippled the night life and put many restaurants and hotels out of business in the 1920s. Not only did it put a stop to alcohol sales, but production of soft drinks, candy, and fruit cocktail increased and tea rooms and cafeterias took the place of restaurants and hotels.

Then, the 1930s were struck with the Great Depression. Food, however, was not sparse and hard to come by because there was an ample supply of inexpensive foods. People had the options of lesser grade meats (chuck instead of sirloin), cheaper cuts of animal (heart, brains, feet), and manufactured substitutes such as Crisco instead of butter. Despite this, protein, the most expensive part of the meal, was reduced and one-pot meals, such as mac and cheese, soups, and casseroles became popular. The Great Depression slowly waned, then the horrors of WWII hit in the 1940s. Women left the kitchen to work in factories and every family had to ration food. The government restricted each person to 28 ounces of meat per week and limited sugar, butter, milk, cheese, eggs, and coffee. Cookies were sugarless, cakes were made without eggs, and meals without meat. 

As America recovered from the war, cookbooks and magazines propagated simple, belly-filling meals made from pre-packaged foods. The Swanson TV dinner was introduced in 1953 starting an uprising of convenience items. In addition, time-saving appliances were increasingly prevalent in American households. Food science continues to evolve. In 1965, the popularity of artificial sweeteners soared. Its use increased threefold in the US, particularly in the form of soda. Also, around this time, scientists began developing an inexpensive method of extracting oils from corn, soybeans, cottonseed, and other oilseeds – called vegetable oil. Thus, the consumption of vegetable fats increased. Everything from TV dinners to fat-free, sugar-free, diet foods were mass produced. To say the least, variety of and convenience of foods grew swiftly while cost was reduced and America went from deaths due to vitamin deficiencies to food overload in only a few decades.

In short, American diet became more diverse and processed, less starchy, cheaper, and arguably more calorically dense. Based on nationally-represented surveys of food intake, the biggest difference in the American diet today versus 70 years ago is that the majority of calories come from refined high-fat foods and carbohydrates (Fig. 1). Simultaneously, physical demands at home and the workplace decreased due to labor-saving devices and industrialization, resulting in reduced physical activity. Therefore, both diet quality (and quantity) changed and daily energy expenditure decrease and then began a rise in the prevalence of obesity and chronic disease.

This is just the background to the meat of the story. Stay tuned for part 2 of How History Shaped the American Diet.