Some Gut Bugs May Help Lower Your Cholesterol

Dennis Thompson . . . . . . . . .

Changes in gut bacteria have been linked to a variety of different diseases, including type 2 diabetes, obesity and inflammatory bowel disease.

Now, a new study indicates that gut bacteria also might play a role in a person’s risk of developing heart disease.

Certain species of bacteria actively consume cholesterol in the gut, which might help lower cholesterol levels and heart disease risk in people, researchers reported recently in the journal Cell.

In particular, people with higher levels of Oscillibacter bacteria in their gut have lower levels of cholesterol, because those bacteria drink in and process cholesterol from their surroundings, results show.

These findings could serve as “starting points to improve cardiovascular health” by tweaking a person’s gut bacteria, also known as the microbiome, said senior researcher Ramnik Xavier, co-director of the Broad Institute Infectious Disease and Microbiome Program in Boston.

Prior studies have linked the gut microbiome to heart disease risk factors like triglyceride or blood sugar levels, but they have failed to completely explain the means by which these bacteria affect heart health.

For the study, researchers analyzed the gut bacteria of more than 1,400 participants in the Framingham Heart Study, a decades-long effort to investigate risk factors for heart disease.

They found that people with several Oscillibacter species tended to have lower cholesterol than those who didn’t.

They also found that Oscillibacter is surprisingly abundant in the gut, representing, on average, one in every 100 bacteria.

To see how Oscillibacter affects cholesterol, researchers grew the bacteria in a laboratory from stool samples.

Analysis showed that the bacteria breaks down cholesterol into byproducts that are then further processed by other bacteria and excreted from the body.

They also found that another gut bacterial species, Eubacterium coprostanoligenes, also contributes to decreased cholesterol levels. That species carries a gene that is involved in cholesterol metabolism, the researchers explained.

In fact, Oscillibacter and Eubacterium might even boost each other’s impact on cholesterol levels, results show.

This research could lead to more studies that figure out why gut microbes have other effects on human health, the researchers said.

“There are many clinical studies trying to do fecal microbiome transfer studies without much understanding of how the microbes interact with each other and the gut,” said lead researcher Chenhao Li, a postdoctoral researcher in Xavier’s lab.

“Hopefully stepping back by focusing on one particular bug or gene first, we’ll get a systematic understanding of gut ecology and come up with better therapeutic strategies like targeting one or a few bugs,” Li added in a Broad Institute news release.

Source: HealthDay

 

 

 

 

Here’s the Latest on Dietary Cholesterol and How It Fits In With a Healthy Diet

Michael Merschel wrote . . . . . . . . .

For more than half a century, scientists have debated the role of dietary cholesterol in a healthy diet. Because it was often associated with saturated fat, limiting dietary cholesterol – especially by restricting egg consumption – seemed to benefit heart-health efforts.

More recently, accumulating data has caused researchers to broaden their thinking about how dietary cholesterol – and eggs – fit into a healthy eating pattern. “We’ve advanced considerably,” said professor Linda Van Horn, chief of the nutrition division in the department of preventive medicine at Northwestern University’s Feinberg School of Medicine in Chicago. “And we proceed on these issues as we learn more.”

Change can be confusing. So here are answers to a few common questions.

Are dietary cholesterol and blood cholesterol the same thing?

No. Dietary cholesterol is found in food. Blood cholesterol – which includes HDL (“good”) and LDL (“bad”) – is one of eight essential measures of heart health identified by the American Heart Association. A diet high in saturated fat can lead to high LDL cholesterol levels and further lead to plaque buildup in the walls of your arteries. This restricts blood flow and can lead to a heart attack or stroke.

Your doctor can check your blood cholesterol levels with a blood test.

What is dietary cholesterol, then?

Dietary cholesterol comes from animal-based foods. According to a 2019 AHA science advisory on dietary cholesterol and cardiovascular risk – which Van Horn helped write – high-fat meat, eggs, butter and full-fat dairy products are major sources. It’s especially abundant in processed meats – “sausages, burgers, hot dogs or similar foods,” Van Horn said.

Dietary cholesterol also can be found in baked goods made with eggs, butter or cream.

Although dietary cholesterol was once singled out as a contributor to heart disease, the 2019 science advisory said studies have not generally supported an association between dietary cholesterol and cardiovascular risk.

How much dietary cholesterol can I eat?

Federal dietary guidelines recommend keeping dietary cholesterol consumption “as low as possible without compromising the nutritional adequacy of the diet.”

The good news is, that leaves room for flexibility. But it is not a free pass to eat all the dietary cholesterol you want.

“The general recommendation is to eat less than 300 milligrams of dietary cholesterol per day,” Van Horn said.

But focusing on that number, or the lack of evidence linking dietary cholesterol to health risks, could be a misstep, she said. That’s because foods high in dietary cholesterol also tend to be high in saturated fat. The exception is shellfish, such as shrimp and lobster. Despite being high in dietary cholesterol, shellfish is relatively healthy when not fried.

Overall, Van Horn said, “research has shown that you really cannot isolate dietary cholesterol from that total fat intake.” And eating too much saturated fat – along with too much sugar and sodium, and too little fiber – raises the risk of heart disease.

Instead of thinking about how much dietary cholesterol you can get away with, try thinking about eating an all-around healthy diet, with lots of fruits and vegetables, whole grains, healthy sources of protein and low-fat or fat-free dairy products, Van Horn said.

Put another way: If you’re eating a healthy diet, Van Horn said, a little butter now and then (and its 31 mg of dietary cholesterol per tablespoon) on your toast should not pose a major risk.

While cholesterol-rich foods are not recommended, she said, “they are better tolerated as a food source when they are the exception and not the rule.”

Does that mean I can eat eggs?

First, go back and read the part about the importance of an all-around healthy diet.

One large, whole egg contains around 200 mg of dietary cholesterol. Because of that, Van Horn said it once was considered wise to eat no more than two or three yolks per week. Egg whites are not high in dietary cholesterol.

But research regarding the effects of eggs was complicated by the fact that eggs often are eaten with high-fat foods such as bacon, sausage and butter. These days, Van Horn said, if your LDL cholesterol level is low, a few eggs per week are considered tolerable, depending on the overall content of the diet.

The 2019 science advisory says healthy people can include up to a whole egg or the equivalent in their diets each day; given the nutritional benefits and convenience, older people with healthy cholesterol levels can have two.

What if I have high blood cholesterol?

Anyone with a high LDL cholesterol level should consider reducing sources of both saturated fat and dietary cholesterol, Van Horn said, because together they are considered more likely to contribute to arterial plaque. This is especially a concern among people with overweight, obesity or other risk factors.

Some people are genetically predisposed to high blood cholesterol levels. Health care professionals often advise such patients to pay extra attention to what they eat, control their weight and increase their level of physical activity, Van Horn said.

People with healthy blood cholesterol levels should recognize that as they age, their risk increases and tolerance for less-healthy foods can change, she said.

So, it’s best to keep the emphasis on “more plant-based eating, including whole grains, fresh fruits and vegetables, along with more fish combined calorie-conscious eating and regular physical activity,” Van Horn said.

Why has dietary cholesterol advice changed over the years?

Scientists learn stuff.

Decades ago, nutrition research was focused on an isolated nutrient or a specific food, Van Horn said. “Nutrition research has shifted that focus to the broader totality of eating patterns and food frequency,” she said. “Since nobody eats a nutrient or a food in isolation, the overall dietary intake over the day, the week or the year influences biological factors. These include blood cholesterol, blood pressure, blood glucose – all the risk factors that are examined, evaluated and studied to prevent heart disease.”

While dietary cholesterol remains important to researchers, it’s of less concern now, Van Horn said. That’s because the average American’s blood cholesterol level has gone down in recent decades, and some of that is thanks to statin medications and a better understanding of diet, she said.

“Now, the resounding benefit of a diet higher in plant-based foods continues,” she said. “Typically, those are not high sources of dietary cholesterol.”

Put another way, the foods once shunned due to their high dietary cholesterol content only come from animal products, and they should still not be the focus of your diet.

But it’s settled now, right?

Diet and dietary cholesterol remain important topics of nutrition research. Van Horn pointed out that the National Institutes of Health is currently funding the Nutrition for Precision Health study. It promises to unlock relationships between what we eat, the microbiome inside our bodies and biomarkers for assessing health status that have “never before been studied as comprehensively and systematically as they are now,” Van Horn said.

The study’s overarching goal is to identify preventive ways to tailor nutrition recommendations to each person’s genetic, lifestyle and environmental needs to achieve better health over the life span.

“So stay tuned,” she said.

Source: American Heart Association

 

 

 

 

Keeping Cholesterol Levels Stable May Help Shield You From Dementia

Steven Reinberg wrote . . . . . . . . .

Could swings in your blood fat levels increase your chances of being diagnosed with Alzheimer’s disease?

Yes, suggests a new study that found fluctuating cholesterol levels among older adults may increase the risk for Alzheimer’s disease and other dementias.

Those who had the most fluctuations in cholesterol had a 19% higher risk of developing Alzheimer’s or dementia, and those with the most fluctuations in triglyceride levels had a 23% increased risk, the researchers found.

Still, Dr. Marc Lawrence Gordon, chief of neurology at Northwell Health’s Zucker Hillside Hospital in Great Neck, N.Y., stressed this study can’t prove these variations actually cause Alzheimer’s disease or dementia.

“You don’t know whether the fluctuation is what’s driving the incidence of dementia or an increased incidence of dementia is somehow causing fluctuations,” said Gordon, who had no part in the study. “I could not advise any of my patients to do anything in particular on the basis of these data.”

However, lead researcher Suzette Bielinski, from the Mayo Clinic in Rochester, Minn., believes the findings could be helpful.

“Fluctuations in these results [cholesterol and triglycerides tests] over time could potentially help us identify who is at greater risk for dementia, help us understand mechanisms for the development of dementia, and ultimately determine whether leveling out these fluctuations could play a role in reducing dementia risk,” she said in a statement.

For the study, Bielinski and her colleagues collected data on more than 11,500 men and women aged 60 and older who did not have Alzheimer’s or other dementia.

The investigators found that over an average of 13 years of follow-up, those who had the most variation in their cholesterol levels saw a greater risk for mental decline.

Of the more than 2,400 people who developed Alzheimer’s or dementia, 515 with the most variations in cholesterol levels developed dementia, compared with 483 of those who had the least variation.

These results were after the researchers adjusted for factors such as sex, race, education and cholesterol-lowering medications.

“It remains unclear why and how fluctuating levels of cholesterol and triglycerides are related to the risk of Alzheimer’s disease,” Bielinski said.

The report was published online in the journal Neurology.

One expert said that heart health and brain health are intertwined, and that keeping your cholesterol and triglycerides in check might play a part in preventing dementia.

“Heart health and brain health are closely related,” said Christopher Weber, director of global science initiatives at the Alzheimer’s Association.

Cholesterol fluctuations can affect the brain’s vascular health and contribute to an increased risk of developing cognitive (mental) decline and dementia, including Alzheimer’s disease, he said.

Also, the dysfunction of blood vessels in the brain could contribute to the connection between cholesterol fluctuations and Alzheimer’s, Weber noted.

“This could affect cerebral blood flow and increase the risk of cognitive impairment and Alzheimer’s in later life,” he said.

Weber added that maintaining a low and stable level of cholesterol and triglycerides may be beneficial for reducing the risk of developing Alzheimer’s.

“You should always consult your doctor or health care provider if you are concerned about your cardiovascular health, cholesterol levels or cognitive decline. Know your heart health numbers, get treatment when you need it, and live an overall heart- and brain-healthy lifestyle,” Weber advised.

“Research is still evolving, but evidence is strong that people can reduce their risk of cognitive decline by making key lifestyle changes, including participating in regular physical activity, staying socially engaged and maintaining good heart health,” Weber said.

Source: HealthDay

 

 

 

 

Combo of Bad Cholesterol and High Blood Pressure May Increase Heart Attack or Stroke Risk

High levels of lipoprotein(a), a type of “bad” cholesterol, may be associated with a 24% higher risk of cardiovascular disease among people who have hypertension, however, CVD risk was not higher among those without hypertension, according to new research published today in Hypertension, an American Heart Association journal.

“High blood pressure is a known cardiovascular disease risk factor, and lipoprotein(a) is a type of inherited ‘bad’ cholesterol that may also lead to cardiovascular disease,” said lead study author Rishi Rikhi, M.D., M.S., a cardiovascular medicine fellow at Atrium Health Wake Forest Baptist Medical Center in Winston-Salem, North Carolina. “We found that among people with hypertension who have never experienced a stroke or heart attack before, lipoprotein(a) seems to increase the risk of cardiovascular disease and risk of a major cardiovascular event like heart attack or stroke.”

Hypertension is a key risk factor for cardiovascular disease. In this study, hypertension was defined as a top number of 140 mmHg or higher, a bottom number of 90 or mmHg or the use of blood pressure medication. In 2017, the Association updated its definition of hypertension to be a top number of 130 mmHg or higher or a bottom number of 80 mmHg or higher. Previous studies have indicated that when a person has hypertension and lipid imbalance, or dyslipidemia, their cardiovascular disease risk substantially increases. According to the study’s authors, there is less information on how much of an affect lipoprotein(a) may have on cardiovascular disease risk among people with hypertension.

Lipoproteins, which are made up of protein and fat, carry cholesterol through the blood. The subtypes of lipoproteins include low-density lipoprotein (LDL), high-density lipoprotein (HDL) and lipoprotein(a), or Lp(a). Much like LDL cholesterol, lipoprotein(a) cholesterol may deposit and build up in the walls of blood vessels, thus increasing a person’s risk of a heart attack or stroke.

The research used health data from the Multi-Ethnic Study of Atherosclerosis (MESA) study, an ongoing community-based study in the U.S. of subclinical cardiovascular disease—meaning the disease is discovered before there are clinical signs and symptoms. MESA is a research study including nearly 7,000 adults that began in 2000 and is still following participants in six locations across the U.S.: Baltimore; Chicago; New York; Los Angeles County, California; Forsyth County, North Carolina; and St. Paul, Minnesota. At the time of enrollment in the study, all participants were free from cardiovascular disease.

The current study included 6,674 MESA participants who had lipoprotein(a) levels and blood pressure assessed and for whom there was documented cardiovascular disease event data throughout MESA’s follow-up exams in approximately 2001, 2003, 2004, 2006, 2010, 2017 and in telephone interviews every 9 to 12 months to gather interim data on new diagnoses, procedures, hospitalization and deaths. The study’s participants were from diverse racial and ethnic groups: 38.6% self-identified as white adults; 27.5% self-identified as African American adults; 22.1% self-identified as Hispanic adults; and 11.9% self-identified as Chinese American (n=791) adults. Additionally, more than half of the group was female (52.8%).

To evaluate the potential correlation between hypertension and lipoprotein(a) on the development of cardiovascular disease, the researchers first categorized the participants into groups based on their lipoprotein(a) levels and blood pressure measures obtained once at baseline:

• Group 1 (2,837 people): lipoprotein(a) levels less than 50 mg/dL and no hypertension.
• Group 2 (615 people): lipoprotein(a) levels greater than or equal to 50mg/dL and no hypertension
• Group 3 (2,502 people): lipoprotein(a) levels less than 50mg/dL and hypertension
• Group 4 (720 people): lipoprotein(a) levels ≥ 50mg/dL and hypertension

Participants were followed for an average of approximately 14 years and cardiovascular events, including heart attack, cardiac arrest, stroke or death from coronary artery disease, were tracked.

The study’s results include:

• A total of 809 of the participants experienced a cardiovascular disease event.
• Lipoprotein(a) levels had an effect on hypertension status that was statistically significant (meaning it was not due to chance).
• When compared to Group 1 (low lipoprotein(a) levels and no hypertension), Group 2 (higher lipoprotein(a) levels and no hypertension) did not have an increased risk for cardiovascular disease events.
• Less than 10% of Group 1 (7.7%) and Group 2 (participants 8%) had cardiovascular disease events.
• Participants in Groups 3 and 4, all of whom had hypertension, demonstrated a statistically significant increase in risk for cardiovascular disease events when compared to those in Group 1.
• Approximately 16.2% of the people in Group 3 (lower lipoprotein(a) levels and hypertension) had cardiovascular disease events, and 18.8% of the participants in Group 4 (higher lipoprotein(a) levels and hypertension) experienced cardiovascular disease events.

“We found that the overwhelming amount of cardiovascular risk in this diverse population appears to be due to hypertension,” Rikhi said. “Additionally, individuals with hypertension had even higher cardiovascular risk when lipoprotein(a) was elevated. The fact that lipoprotein(a) appears to modify the relationship between hypertension and cardiovascular disease is interesting, and suggests important interactions or relationships for hypertension, lipoprotein(a) and cardiovascular disease, and more research is needed.”

Everyone can improve their cardiovascular health by following the American Heart Association’s Life’s Essential 8: eating healthy food, being physically active, not smoking, getting enough sleep, maintaining a healthy weight, and controlling cholesterol, blood sugar and blood pressure levels. Cardiovascular disease claims more lives each year in the U.S. than all forms of cancer and chronic lower respiratory disease combined, according to the American Heart Association.

The study had limitations, including potential selection bias from participants – potentially disproportionately from one of the four subgroups – dropping out because the study was long-term. Additionally, the study participants may have developed hypertension during the follow-up period, which may have resulted in misclassification.

Source: American Heart Association

 

 

 

 

Experimental Pill May Be New Way to Control Cholesterol

Denise Mann wrote . . . . . . . . .

Millions of people take daily medication to lower their cholesterol levels and prevent heart attacks, but there hasn’t been a drug that targets a dangerous type of cholesterol in the blood known as lipoprotein(a), or Lp(a).

That’s why a new study of an investigational drug called olpasiran, which blocks the production of apolipoprotein(a) — a key component of Lp(a) — is generating a lot of excitement in scientific circles.

“Unlike other types of cholesterol, there is, unfortunately, no approved treatment that is currently available to lower Lp(a),” explained study author Dr. Michelle O’Donoghue, a cardiovascular medicine specialist at Brigham and Women’s Hospital in Boston.

Olpasiran binds to the body’s own mRNA, to prevent it from making apolipoprotein(a).

The study looked at different doses of the new drug in about 230 people with high levels of Lp(a). Folks who received the highest doses of olpasiran in the study reduced their Lp(a) concentration by more than 95% compared with placebo. The drug is given via injection every 12 weeks.

Study patients’ Lp(a) levels were about 260.3 nanomoles per liter of blood (nmol/L), on average, when the study started. The U.S. Centers for Disease Control and Prevention defines high Lp(a) levels as greater than 125 nmol/L. Most people in the study were also taking drugs to lower their cholesterol levels, mainly statins.

What’s more, the treatment was safe. Injection site reactions were more common with olpasiran than a placebo shot, but they tended to be mild and resolve on their own, O’Donoghue said.

A phase 3 trial will be launching in December to evaluate the efficacy and safety of olpasiran, she added.

Millions of people take statins or other drugs to lower their cholesterol levels, but these drugs mainly target low-density lipoprotein (LDL) cholesterol, she explained.

“Statins don’t lower Lp(a) [and] statins may even raise Lp(a),” O’Donoghue said. “That’s one of the reasons that it’s exciting to have a novel therapy in development that leads to such a marked and sustained reduction in Lp(a).”

The findings were presented Sunday at the American Heart Association (AHA) annual meeting, in Chicago, and were published simultaneously in the New England Journal of Medicine.

Lp(a) is potentially the most dangerous molecule in the blood, and high levels increase the risk of heart attack, stroke and death, said Dr. Manesh Patel, chief of the division of cardiology and the division of clinical pharmacology at Duke University School of Medicine in Durham, N.C. He is also the chair of the AHA’s 2022 council on scientific sessions programming.

Source: HealthDay