jm.drome-portdeplaisance.com
New recipes

Study Says High-Fat Diets Are Bad for Your Gut Health

Study Says High-Fat Diets Are Bad for Your Gut Health


We are searching data for your request:

Forums and discussions:
Manuals and reference books:
Data from registers:
Wait the end of the search in all databases.
Upon completion, a link will appear to access the found materials.


The keto diet may not be the healthiest way to lose weight after all.

Low-carb, high-fat diets (such as the keto diet) may be all the range right now, but more studies continue to show the negative long-term effects that can fester after you lose the weight. While fat is an extremely important component of our diets, and we should seek to enjoy heart-healthy options each day, a new study shows too much fat could seriously disrupt your microbiome.

Stay up to date on what healthy means now.

Sign up for our daily newsletter for more great articles and delicious, healthy recipes.

Researchers from Harvard, Australia, New Zealand, and China studied the effects of dietary fat intake in healthy young adults and how differing amounts affected their microbiomes and cardiovascular health. Their findings, published in the journal, Gut, showed those who followed a high-fat diet experienced unfavorable changes in gut bacteria, leading to long-term gastrointestinal issues and an increased risk for metabolic diseases, such as Type 2 diabetes.

The researchers took 217 healthy adults between the ages of 18 and 35, and split them up into three groups with varying fat and carbohydrate intakes. Those on the low-fat diet consumed 20 percent of their daily calories from fat and 66 percent from carbs, while the high-fat dieters consumed 40 percent of their calories from fat and 46 percent from carbohydrates. The moderate-fat group ate a diet consisting of 30 percent fat and 56 percent carbohydrates. Every participant ate the same amount of protein and fiber. Participants were also required to give blood and stool samples at the beginning and end of the study.

Results showed those on the low-fat diet plan had higher levels of Blautia and Faecalibacterium, good bacteria that produce butyrate, a fatty acid with anti-inflammatory properties that’s known for positively influencing bowel movement. The low-fat diet group also saw a decrease in bacteria associated with metabolic disorders. The high-fat diet group saw a reverse effect, with a decrease in the anti-inflammatory bacteria and an increase in long-chain fatty acids, known for being inflammatory and linked to metabolic disorders.

Interested in learning more about boosting your gut health?

All three diet groups lost weight throughout the month, but the low-fat diet group lost the most on average. The authors of this study noted it is still unclear as to whether weight loss in this study was associated with metabolic markers, or changes in gut bacteria.

The bottom line: Both fat and carbs are essential nutrients to keep our bodies healthy and strong, but it is possible to have too much of a good thing. While some high-fat diets do provide amazing weight loss results, it is important to abide by a less restrictive, balanced lifestyle with more attainable goals and realistic principles.


  • Our gut health is important for digestive and immune function.
  • What we eat can affect the immune cells in the gut.
  • Researchers observe in mice how a diet high in fat and sugar may disrupt immune cell function.

Our diets affect our health, we’ve understood that for some time. But how does it affect us in specific ways? That’s trickier. One group of researchers examined the effects of a high fat, high sugar diet, which is common in Western countries, on the gut.

The digestive system, besides having the job of processing all the food you eat, also has important links with the immune system. Diet can also affect how the immune cells in the gut function, although how it does that has not been very well understood.

Experts are interested in the diet’s connections to gut health because of what can happen when the gut isn’t functioning as well as it could. In a new paper published in Cell Host & Microbe , a group of researchers study what happens in mice to try to learn more about this connection. “Inflammatory bowel disease has historically been a problem primarily in Western countries such as the U.S., but it's becoming more common globally as more and more people adopt Western lifestyles,” says lead author Ta-Chiang Liu, who is an associate professor of pathology and immunology at Washington University.

In the experiments, the researchers focused specifically on Paneth cells. These are immune cells in the gut that help to keep inflammation under control. They studied laboratory mice that were bred to overeat and observed what happened with the Paneth cells. Some mice were given a normal diet and others a diet in which 40 percent of the calories came from fat or sugar.

America is changing faster than ever! Add Changing America to your Facebook or Twitter feed to stay on top of the news.

The mice that overate on a regular mouse diet had normal Paneth cells, but the mice who were fed a more Western diet had abnormal Paneth cells. What’s interesting is that the abnormal Paneth cells returned to normal after shifting to a normal diet. “Our research showed that long-term consumption of a Western-style diet high in fat and sugar impairs the function of immune cells in the gut in ways that could promote inflammatory bowel disease or increase the risk of intestinal infections,” says Liu.

This experiment was short, just eight weeks. For mice, that is a good proportion of their lifespan, but for humans that is very little time. In reality, it takes a long time for the health effects of their diet to affect their bodies. The researchers are interested in what those long-term impacts might be. “It's possible that if you have a Western diet for so long, you cross a point of no return and your Paneth cells don't recover even if you change your diet,” says Liu. “We'd need to do more research before we can say whether this process is reversible in people.”


Study Finds That Western Diet Might Be Increasing Gut Inflammation, Infection

Highlights

A western diet usually contains high sugar foods, pre-packaged foods, butter, candy, fried foods, high-fat dairy products, etc. While knowingly or unknowingly we consume these foods almost every day, we ignore the harmful effects of it. Recently, a research conducted by Washington University School of Medicine in St. Louis and Cleveland Clinic found that a Western diet weakens the immune system in the gut, potentially increasing the risk of infection and inflammatory bowel disease. The study was conducted in mice and humans. It found that a high-sugar, high-fat diet damages Paneth cells, which are immune cells in the gut that help keep inflammation in check. When Paneth cells are not working usually, the gut immune system becomes overly vulnerable to inflammation, increasing the risk of inflammatory bowel disease and eroding effective control of disease-causing microbes.

According to Ta-Chiang Liu, MD, PhD, associate professor of pathology and immunology at Washington University- "Inflammatory bowel disease has historically been a problem primarily in Western countries such as the U.S., but it's becoming more common globally as more and more people adopt Western lifestyles" Adding to that he also said "Our research showed that long-term consumption of a Western-style diet high in fat and sugar impairs the function of immune cells in the gut in ways that could promote inflammatory bowel disease or increase the risk of intestinal infections."

The research examined a database containing demographic and clinical information on 400 people and an assessment of each individual's Paneth cells. The researchers discovered that having a high body mass index (BMI) was linked to Paneth cells that appeared abnormal under a microscope. The worse a person's Paneth cells looked, the higher was their BMI.

Infection that attacks the gut area

To better clarify their findings, the researchers studied two strains of mice that are genetically predisposed to obesity. These mice regularly over ate because they have mutations that prevent them from feeling full even when fed a regular diet. Surprisingly, the researchers discovered that the obese mice had Paneth cells that appeared normal.

Obesity in people is frequently the result of a high-fat, high-sugar diet. As a result, the scientists fed normal mice a diet containing 40% fat or sugar, similar to the typical Western diet. After two months on this diet, the mice were obese, and their Paneth cells were noticeably abnormal. Later, when the mice were put back on the healthy mouse diet, their paneth cells returned to normal.

Ta-Chiang Liu, also said "In people, obesity doesn't occur overnight or even in eight weeks. People have a suboptimal lifestyle for 20, 30 years before they become obese. It's possible that if you have a Western diet for so long, you cross a point of no return, and your Paneth cells don't recover even if you change your diet. We'd need to do more research before we can say whether this process is reversible in people."

Further research revealed that a molecule known as deoxycholic acid, a secondary bile acid formed as a by-product of gut bacteria metabolism, links a Western diet and Paneth cell dysfunction. Bile acid increases the formation of two immune molecules that inhibit Paneth cell function: farnesoid X receptor and type 1 interferon.


&ldquoIf you&rsquore somebody who&rsquos prone to gas and bloating, you may need to reduce your consumption of fructose, or fruit sugar,&rdquo says Lee, pointing out that foods like apples, pears and mango are all high in fructose.

Berries and citrus fruits, such as oranges and grapefruit, contain less fructose, making them easier to tolerate and less likely to cause gas. Bananas are another low-fructose fruit that are fiber-rich and contain inulin, a substance that stimulates the growth of good bacteria in the gut.


Observational study suggests low-carb diets are associated with higher coronary calcium scores

A new observational study published in Arteriosclerosis, Thrombosis, and Vascular Biology concludes that low-carb diets and animal-based foods are associated with greater progression of coronary calcium scores.

On the surface, this sounds very concerning for those following low-carb diets. However, rest assured that this study does not use an accurate definition of low carb, so it is flawed from the start.

The study authors inaccurately define low carb as less than 40% of calories from carbohydrate.

As we have written before, 40% of calories from carbs equates to 200 grams of daily carbs for a 2,000-calorie diet. That’s more carbs than most low-carb eaters have in an entire week!

I hope the authors can understand the difference between someone who eats 20 grams or even 50 grams of carbs per day and someone who eats 200 grams. But by reading the paper, it is hard to be certain that they do.

There are many other issues with this study. Since it is a nutritional observational study, it can only show an association, not a cause-and-effect relationship. It is also subject to the usual inaccuracies introduced by using food frequency questionnaires, in this case collected at only two time points. In addition, like most observational analyses, this study suffers from healthy user bias.

The paper shows that 54% of the group labeled as “low carb” were active or former smokers compared to just 27% in the group defined as “balanced carb.” Since smoking is the most significant risk factor for heart disease, it seems like a much more likely contributing factor than reducing carbohydrate or eating animal foods.

Low-carb eaters were also more likely to be male and have less education, two other factors that are associated with greater risk for heart disease.

Lastly, the group labeled “low carb” averaged 600 more calories per day than the high-carb group. Low-carb eaters consuming more calories directly conflicts with studies that show people following a properly designed low-carb diet naturally decrease caloric intake. In fact, it is often argued that low-carb diets work primarily by lowering calorie intake.

It would be inaccurate to interpret this study as one more study in a large body of evidence showing that low-carb diets are dangerous. In truth, it is one more study showing that people who eat a mixed high-carb and high-fat diet tend to be less healthy than their counterparts.

It says nothing about the benefits or risks of an appropriately designed low-carb diet.

As long as researchers continue to define low-carb diets inaccurately, we will continue to see misleading headlines. Perhaps the best we can do is to continue to point this out.

That said, I hope that sooner or later researchers begin to recognize that low-carb diets deserve to be studied — and that future research will be designed to help us understand where they are most useful for improving health.

More posts

Start your FREE 30-day trial!

Get delicious recipes, amazing meal plans, video courses, health guides, and weight loss advice from doctors, dietitians, and other experts.


7 Keto Foods for a Healthier Gut

While the ketogenic diet indirectly promotes gut health, eating more gut-friendly food on this diet will definitely have a direct impact on gut health. But what foods are both keto-friendly and good for your digestive system? Below are top 7 choices to consider.

1. Avocados

The mighty avocado is a major keto diet staple. This popular fruit is high in fat, low in digestible carbohydrates, high in fiber, and dense in essential nutrients.
One whole avocado contains around 13g of fiber, which is 54% of the daily value for this nutrient.

You need fiber in your diet to feed good gut bacteria and help give stool bulk so it passes more quickly. Avocados are also rich in monounsaturated fatty acids (MUFAs), for which studies show support gut microbiota balance.

2. Nuts and Seeds

There are at least dozens of nuts and seeds are allowed on a keto diet. Most are rich in fiber and MUFAs, and there’s evidence their regular consumption leads to a better microbiome. However, fiber and fat content can vary significantly among different nuts and seeds. A handful of walnuts, for example, provides only 1.9g of fiber and over 2.500 mg of omega-3 fatty acids. The same serving of pistachio nuts provides 3g of fiber and only 73mg of omega-3s. Eat a variety of nuts and seeds to get the most benefits.

3. Cruciferous Vegetables

Most cruciferous vegetables are low in carbohydrates, which is why they’re recommended on keto. Examples of cruciferous vegetables include broccoli, cauliflower, Brussel sprouts, bok choy, kale, and cabbage. Studies on cruciferous veggies found they contain antioxidant compounds that support gut lining health and immunity. They also found cruciferous vegetables change gut bacteria for the better.

4. Butter

Butter is a natural source of butyric acid, a short-chain fatty acid that gut bacteria produce and that provide energy for cells in the gut lining. Butter contains 3-4% butyric acid, which is high compared to other cultured dairy. Other sources of butyric acid include cheddar cheese, parmesan cheese, goat’s cheese, and ghee.

5. Coconut oil

Another gut-friendly fat to include in your keto diet is coconut oil. Coconut oil has unique effects on overall health, but especially the gut microbiome. A study in mice published recently found that virgin coconut oil increased the abundance of probiotic bacteria, such as Lactobacillus, Allobaculum, and Bifidobacterium. Coconut oil antifungal properties were also found to reduce candida overgrowth in the gut.

6. Berries

Blueberries, strawberries, raspberries, and goji berries are some of the rare fruits allowed on keto. Berries can help boost your daily fiber intake. However, berries also contain phenolic compounds that studies found inhibit the growth of bad gut bacteria while increasing good bacteria such as Bifidobacterium and Lactobacillus acidophilus.

7. Kefir

Cultured dairy products like kefir are also allowed on keto. Kefir is one of the best dairy foods to consume for better gut health. It’s relatively low in lactose while containing over 50 different bacteria and yeast cultures. It reduces oxidative stress, inflammation, and colon cancer risk also by improving digestion and stool frequency.


The Three Major Players

For good gut health, experts suggest eating more foods that contain fiber, probiotics, prebiotics, or a combination of the three.

Fiber, found in plant foods, helps to regulate the speed at which food moves through your gut, making it a crucial factor when it comes to staying regular.

Probiotics in foods are beneficial microorganisms that are created through fermentation. You might think of them as “good” bacteria that can combat infection-causing microbes that are sometimes in the foods we eat or that thrive when we’re sick.

Prebiotics, simply put, are plant fibers that you can't digest but that serve as food for healthy bacteria in the gut. “They’re necessary in order for the good flora to flourish,” King says.

Here are some easy ways to work these three compounds into your diet.


Western diet may increase risk of gut inflammation, infection

A tiny, 3D model of the intestines formed from anti-inflammatory cells known as Paneth cells (green and red) and other intestinal cells (blue) is seen in the image above. Researchers at Washington University School of Medicine in St. Louis and Cleveland Clinic used such models, called organoids, to understand why a Western-style diet rich in fat and sugar damages Paneth cells and disrupts the gut immune system.

Eating a Western diet impairs the immune system in the gut in ways that could increase risk of infection and inflammatory bowel disease, according to a study from researchers at Washington University School of Medicine in St. Louis and Cleveland Clinic.

The study, in mice and people, showed that a diet high in sugar and fat causes damage to Paneth cells, immune cells in the gut that help keep inflammation in check. When Paneth cells aren’t functioning properly, the gut immune system is excessively prone to inflammation, putting people at risk of inflammatory bowel disease and undermining effective control of disease-causing microbes. The findings, published May 18 in Cell Host & Microbe, open up new approaches to regulating gut immunity by restoring normal Paneth cell function.

“Inflammatory bowel disease has historically been a problem primarily in Western countries such as the U.S., but it’s becoming more common globally as more and more people adopt Western lifestyles,” said lead author Ta-Chiang Liu, MD, PhD, an associate professor of pathology & immunology at Washington University. “Our research showed that long-term consumption of a Western-style diet high in fat and sugar impairs the function of immune cells in the gut in ways that could promote inflammatory bowel disease or increase the risk of intestinal infections.”

Paneth cell impairment is a key feature of inflammatory bowel disease. For example, people with Crohn’s disease, a kind of inflammatory bowel disease characterized by abdominal pain, diarrhea, anemia and fatigue, often have Paneth cells that have stopped working.

Liu and senior author Thaddeus Stappenbeck, MD, PhD — chair of the Department of Inflammation and Immunity at Cleveland Clinic, and former co-director of the Division of Laboratory and Genomic Medicine at Washington University — set out to find the cause of Paneth cell dysfunction in people. They analyzed a database containing demographic and clinical data on 400 people, including an assessment of each person’s Paneth cells. The researchers found that high body mass index (BMI) was associated with Paneth cells that looked abnormal and unhealthy under a microscope. The higher a person’s BMI, the worse his or her Paneth cells looked. The association held for healthy adults and people with Crohn’s disease.

To better understand this connection, the researchers studied two strains of mice that are genetically predisposed to obesity. Such mice chronically overeat because they carry mutations that prevent them from feeling full even when fed a regular diet. To the researchers’ surprise, the obese mice had Paneth cells that looked normal.

In people, obesity is frequently the result of eating a diet rich in fat and sugar. So the scientists fed normal mice a diet in which 40% of the calories came from fat or sugar, similar to the typical Western diet. After two months on this chow, the mice had become obese and their Paneth cells looked decidedly abnormal.

“Obesity wasn’t the problem per se,” Liu said. “Eating too much of a healthy diet didn’t affect the Paneth cells. It was the high-fat, high-sugar diet that was the problem.”

The Paneth cells returned to normal when the mice were put back on a healthy mouse diet for four weeks. Whether people who habitually eat a Western diet can improve their gut immunity by changing their diet remains to be seen, Liu said.

“This was a short-term experiment, just eight weeks,” Liu said. “In people, obesity doesn’t occur overnight or even in eight weeks. People have a suboptimal lifestyle for 20, 30 years before they become obese. It’s possible that if you have a Western diet for so long, you cross a point of no return and your Paneth cells don’t recover even if you change your diet. We’d need to do more research before we can say whether this process is reversible in people.”

Further experiments showed that a molecule known as deoxycholic acid, a secondary bile acid formed as a byproduct of the metabolism of gut bacteria, forms the link between a Western diet and Paneth cell dysfunction. The bile acid increases the activity of two immune molecules — farnesoid X receptor and type 1 interferon — that inhibit Paneth cell function.

Liu and colleagues now are investigating whether fat or sugar plays the primary role in impairing Paneth cells. They also have begun studying ways to restore normal Paneth cell function and improve gut immunity by targeting the bile acid or the two immune molecules.

Liu TC, Kern JT, Jain U, Sonnek NM, Xiong S, Simpson KF, VanDussen KL, Winkler ES, Haritunians T, Lu Q, Sasaki Y, Storer C, Diamond MS, Head RD, McGovern DPB, Stappenbeck TS. Western Diet Induces Paneth Cell Defects through FXR and Type I Interferon. Cell Host & Microbe. May 18, 2021. DOI: 10.1016/j.chom.2021.04.004

The study was supported by the National Institutes of Health (NIH), grant numbers U01DK062413, R01 DK125296, R01 DK124274, DK109081, R01 AI143673, R01 AI127513 and R01 AI123348 the Helmsley Charitable Trust, grant number 2014PGIBD010 and Washington University’s Genome Technology Access Center and Digestive Disease Research Core Center.


How a low-carb diet might impact gut health

New research uses a “human gut simulator” to study the effects of two different diets on the composition of gut microbiota. Its findings illuminate the harms of having no carbs in the diet.

Share on Pinterest The diet we adopt has complex effects on our intestines, gut bacterial composition, and overall health.

Recently, there has been a lot of debate over the role of carbohydrates in one’s diet.

On one hand, a diet low in carbs has been shown to stave off insulin resistance and metabolic syndrome.

Low-carb, high-fat diets such as the keto diet — which more and more people are adopting to lose weight — have been suggested to have several benefits.

These range from improving cardiovascular health to keeping the brain healthy.

On the other hand, recent studies have suggested that too few carbs in our diet may raise mortality risk, while other researchers have downright discouraged people from adopting low-carb diets, deeming them “unsafe.”

Most studies in the latter category are observational studies, but new research helps elucidate the effects of a diet low in carbs and high in fat on gut microbiota by using an artificial intestine.

Scientists led by Richard Agans, of the Department of Biochemistry and Molecular Biology at the Wright State University in Dayton, OH, conducted the new study.

Its findings were recently published in the journal Applied and Environmental Microbiology.

Agans and colleagues designed an artificial intestine, or human gut simulator, whose main purpose was to simulate the environment found inside the human colon.

The researchers used fecal samples from donors to recreate this bacterial environment and added nutrients first from a balanced Western diet, and then from a no-carb, no-protein diet made exclusively of fats.

Then, they applied a range of cutting-edge technologies to examine and measure the composition of metabolites resulting from changing the nutrients.

The study revealed that switching from a balanced diet to a high-fat, no-carb diet increased strains of bacteria that metabolize fatty acids. The switch also lowered bacteria such as Bacteroides, Clostridium, and Roseburia, which are responsible for degrading proteins and carbs.

In turn, this reduced the production of short-chain fatty acids and antioxidants, which are chemical compounds that fight DNA damage and aging by countering the harmful effects of free radicals.

When gut bacteria metabolize carbs, say the researchers, they release short-chain fatty acids, which have positive health effects such as reducing inflammation and colon cancer risk.

“The relative beneficial and harmful effects of the high-carb and high-fat diets are a subject of many studies and debates,” says corresponding study author Dr. Oleg Paliy, an associate professor at Wright State University’s Boonshoft School of Medicine.

However, “One aspect rarely considered in the above debate,” point out the study authors, “is how macronutrient composition of a diet impacts the environment of the colon and the gut microbiota residing in that region.”

“Intestinal microbes mediate many dietary effects on human health,” adds Dr. Paliy. “There, most of these compounds are fermented by gut bacteria.”

“This happens,” he notes, “because a significant proportion of dietary carbohydrates, proteins, and fats escapes digestion in the small intestine, and reaches the colon, a section of the gut housing a dense population of microbes.”

The new study “showed that human gut microbiota can utilize dietary fatty acids to sustain growth.”

Changing to a fat-only diet, the authors explain, “led to a substantial decrease in the production of [short-chain fatty acids] and antioxidants in the colonic region of the gut, which might potentially have negative health consequences on the host.”


Good monounsaturated and polyunsaturated fats

Good fats come mainly from vegetables, nuts, seeds, and fish. They differ from saturated fats by having fewer hydrogen atoms bonded to their carbon chains. Healthy fats are liquid at room temperature, not solid. There are two broad categories of beneficial fats: monounsaturated and polyunsaturated fats.

Monounsaturated fats. When you dip your bread in olive oil at an Italian restaurant, you're getting mostly monounsaturated fat. Monounsaturated fats have a single carbon-to-carbon double bond. The result is that it has two fewer hydrogen atoms than a saturated fat and a bend at the double bond. This structure keeps monounsaturated fats liquid at room temperature.

Good sources of monounsaturated fats are olive oil, peanut oil, canola oil, avocados, and most nuts, as well as high-oleic safflower and sunflower oils.

The discovery that monounsaturated fat could be healthful came from the Seven Countries Study during the 1960s. It revealed that people in Greece and other parts of the Mediterranean region enjoyed a low rate of heart disease despite a high-fat diet. The main fat in their diet, though, was not the saturated animal fat common in countries with higher rates of heart disease. It was olive oil, which contains mainly monounsaturated fat. This finding produced a surge of interest in olive oil and the "Mediterranean diet," a style of eating regarded as a healthful choice today.

Although there's no recommended daily intake of monounsaturated fats, the Institute of Medicine recommends using them as much as possible along with polyunsaturated fats to replace saturated and trans fats.

Polyunsaturated fats. When you pour liquid cooking oil into a pan, there's a good chance you're using polyunsaturated fat. Corn oil, sunflower oil, and safflower oil are common examples. Polyunsaturated fats are essential fats. That means they're required for normal body functions but your body can't make them. So, you must get them from food. Polyunsaturated fats are used to build cell membranes and the covering of nerves. They are needed for blood clotting, muscle movement, and inflammation.

A polyunsaturated fat has two or more double bonds in its carbon chain. There are two main types of polyunsaturated fats: omega-3 fatty acids and omega-6 fatty acids. The numbers refer to the distance between the beginning of the carbon chain and the first double bond. Both types offer health benefits.

Eating polyunsaturated fats in place of saturated fats or highly refined carbohydrates reduces harmful LDL cholesterol and improves the cholesterol profile. It also lowers triglycerides.

Good sources of omega-3 fatty acids include fatty fish such as salmon, mackerel, and sardines, flaxseeds, walnuts, canola oil, and unhydrogenated soybean oil.

Omega-3 fatty acids may help prevent and even treat heart disease and stroke. In addition to reducing blood pressure, raising HDL, and lowering triglycerides, polyunsaturated fats may help prevent lethal heart rhythms from arising. Evidence also suggests they may help reduce the need for corticosteroid medications in people with rheumatoid arthritis. Studies linking omega-3s to a wide range of other health improvements, including reducing risk of dementia, are inconclusive, and some of them have major flaws, according to a systematic review of the evidence by the Agency for Healthcare Research and Quality.

Omega-6 fatty acids have also been linked to protection against heart disease. Foods rich in linoleic acid and other omega-6 fatty acids include vegetable oils such as safflower, soybean, sunflower, walnut, and corn oils.

Images:
wildpixel/Getty Images
AlexPro9500/Getty Images