Visceral Fat May Indicate Alzheimer's Risk Decades Before Symptoms - Neuroscience News

https://neurosciencenews.com/visceral-fat-alzheimers-28152/

Visceral Fat May Indicate Alzheimer's Risk Decades Before Symptoms

Neuroscience News

Summary: A new study links visceral fat, a deep layer of abdominal fat, to increased brain amyloid and tau proteins—key markers of Alzheimer's disease—decades before dementia symptoms arise. Researchers found that visceral fat accounted for 77% of the relationship between high BMI and amyloid accumulation, while other fat types showed no similar impact.

The study highlights how managing visceral fat through lifestyle changes or medication could reduce Alzheimer's risk. Midlife interventions are especially critical, as participants in their 40s and 50s exhibited these pathologies early on. The findings further reveal that metabolic factors like insulin resistance and cholesterol levels amplify obesity-related brain damage. This research emphasizes the urgent need for targeted prevention strategies against obesity-related Alzheimer's risk.

Key Facts:

• Visceral fat is strongly associated with amyloid and tau protein buildup in the brain.
• Insulin resistance and low HDL cholesterol worsen obesity-related Alzheimer's pathology.
• Managing visceral fat through weight loss or metabolic treatments may reduce dementia risk.

Source: RSNA

Researchers have linked a specific type of body fat to the abnormal proteins in the brain that are hallmarks of Alzheimer's disease up to 20 years before the earliest symptoms of dementia  appear, according to a study being presented today at the annual meeting of the Radiological Society of North America (RSNA).

The researchers emphasized that lifestyle modifications targeted at reducing this fat could influence the development of Alzheimer's disease.

The effects of visceral fat on amyloid pathology were partially reduced in people with higher HDL. Credit: Neuroscience News

"This crucial result was discovered because we investigated Alzheimer's disease pathology as early as midlife—in the 40s and 50s—when the disease pathology is at its earliest stages, and potential modifications like weight loss and reducing visceral fat are more effective as a means of preventing or delaying the onset of the disease," said lead study author Mahsa Dolatshahi, M.D., M.P.H., post-doctoral research associate at Mallinckrodt Institute of Radiology (MIR) at Washington University School of Medicine in St. Louis, Missouri.

An estimated 6.9 million Americans, aged 65 and older, are living with Alzheimer's disease, according to the Alzheimer's Association. The association estimates this number could grow to 13 million by 2050, barring the development of medical breakthroughs to prevent or cure the disease.

For the study, the researchers focused on the link between modifiable lifestyle-related factors, such as obesity, body fat distribution and metabolic aspects, and Alzheimer's disease pathology.

A total of 80 cognitively normal midlife individuals (average age: 49.4 years, female: 62.5%,) were included in the study. Approximately 57.5% of participants were obese, and the average body mass index (BMI) of the participants was 32.31.

The participants underwent brain positron emission tomography (PET), body MRI and metabolic assessment (glucose and insulin measurements), as well as a lipid (cholesterol) panel.

MRI scans of the abdomen were performed to measure the volume of the subcutaneous fat (the fat under skin) and visceral fat (deep hidden fat surrounding the organs).

"We investigated the association of BMI, visceral fat, subcutaneous fat, liver fat fraction, thigh fat and muscle, as well as insulin resistance and HDL (good cholesterol), with amyloid and tau deposition in Alzheimer's disease," said Dr. Dolatshahi, a member of the Raji Lab at MIR's Neuroimaging Labs Research Center.

Thigh muscle scans were used to measure volume of muscle and fat. Alzheimer's disease pathology was measured using PET scans with tracers that bind to amyloid plaques and tau tangles that accumulate in the brains of people with Alzheimer's disease.

The findings revealed that higher levels of visceral fat were related to increased amyloid, accounting for 77% of the effect of high BMI on amyloid accumulation. Other types of fat did not explain obesity-related increased Alzheimer's pathology.

"Our study showed that higher visceral fat was associated with higher PET levels of the two hallmark pathologic proteins of Alzheimer's disease—amyloid and tau," Dr. Dolatshahi said.

"To our knowledge, our study is the only one to demonstrate these findings at midlife where our participants are decades out from developing the earliest symptoms of the dementia that results from Alzheimer's disease."

The study also showed that higher insulin resistance and lower HDL were associated with high amyloid in the brain. The effects of visceral fat on amyloid pathology were partially reduced in people with higher HDL.

"A key implication of our work is that managing Alzheimer's risk in obesity will need to involve targeting the related metabolic and lipid issues that often arise with higher body fat," said senior study author Cyrus A. Raji, M.D., Ph.D., associate professor of radiology at MIR.

Although previous studies have shown the role of high BMI in damaging the cells of the brain, no similar study has investigated the differential role of visceral and subcutaneous fat or metabolic profile, especially in terms of Alzheimer's amyloid pathology as early as midlife, Dr. Dolatshahi pointed out.

"This study goes beyond using BMI to characterize body fat more accurately with MRI and, in so doing, reveals key insights about why obesity can increase risk for Alzheimer's disease," Dr. Dolatshahi said.

Drs. Raji, Dolatshahi and colleagues are also presenting a study at RSNA 2024 that shows how obesity and visceral fat reduce blood flow in the brain.

In that study, the researchers performed brain and abdominal MRI on cognitively normal midlife individuals with a wide range of BMI and compared whole-brain and regional cerebral blood flow on brain MRI in individuals with high vs. low visceral and subcutaneous fat. 

The high visceral fat group showed lower whole-brain blood flow. No significant difference was observed in cerebral blood flow in the groups with high vs. low subcutaneous fat.

"This work will have a considerable impact on public health because nearly three out of four Americans are overweight or obese," Dr. Raji said.

"Knowing that visceral obesity negatively affects the brain opens up the possibility that treatment with lifestyle modifications or appropriate weight-loss drugs could improve cerebral blood flow and potentially lower the burden of and reduce the risk for Alzheimer's disease."

Other co-authors are Paul K. Commean, B.E.E., Mahshid Naghashzadeh, M.S., Sara Hosseinzadeh Kassani, Ph.D., Jake Weeks, B.S., Caitlyn Nguyen, B.S., Abby McBee-Kemper, B.S., Nancy Hantler, B.S., LaKisha Lloyd, M.Sc., Shaney Flores, M.S., Yifei Xu, M.S., Jingxia Liu, Ph.D., Claude B. Sirlin, M.D., Bettina Mittendorfer, Ph.D., Joseph E. Ippolito, M.D., Ph.D., John C. Morris, M.D., and Tammie L.S. Benzinger, M.D., Ph.D.

This study was awarded the RSNA Trainee Research Prize.

About this Alzheimer's disease research news

Author: Linda Brooks
Source: RSNA
Contact: Linda Brooks – RSNA
Image: The image is credited to Neuroscience News

Original Research: The findings will be presented at the 110th Scientific Assembly and Annual Meeting of the Radiological Society of North America

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Cataracts - Symptoms and causes - Mayo Clinic

https://www.mayoclinic.org/diseases-conditions/cataracts/symptoms-causes/syc-20353790

Cataracts

Overview

A cataract is a clouding of the lens of the eye, which is typically clear. For people who have cataracts, seeing through cloudy lenses is like looking through a frosty or fogged-up window. Clouded vision caused by cataracts can make it more difficult to read, drive a car at night or see the expression on a friend's face.

Most cataracts develop slowly and don't disturb eyesight early on. But with time, cataracts will eventually affect vision.

At first, stronger lighting and eyeglasses can help deal with cataracts. But if impaired vision affects usual activities, cataract surgery might be needed. Fortunately, cataract surgery is generally a safe, effective procedure.

Symptoms

Symptoms of cataracts include:

• Clouded, blurred or dim vision.
• Trouble seeing at night.
• Sensitivity to light and glare.
• Need for brighter light for reading and other activities.
• Seeing "halos" around lights.
• Frequent changes in eyeglass or contact lens prescription.
• Fading or yellowing of colors.
• Double vision in one eye.

At first, the cloudiness in your vision caused by a cataract may affect only a small part of the eye's lens. You may not notice any vision loss. As the cataract grows larger, it clouds more of your lens. More clouding changes the light passing through the lens. This may lead to symptoms you notice more.

When to see a doctor

Make an appointment for an eye exam if you notice any changes in your vision. If you develop sudden vision changes, such as double vision or flashes of light, sudden eye pain, or a sudden headache, see a member of your health care team right away.

Request an appointment

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Causes

Most cataracts develop when aging or injury changes the tissue that makes up the eye's lens. Proteins and fibers in the lens begin to break down. This causes vision to become hazy or cloudy.

Some disorders passed down from parents that cause other health problems can increase your risk of cataracts. Cataracts also can be caused by other eye conditions, past eye surgery or medical conditions such as diabetes. Long-term use of steroid medicines also may cause cataracts to develop.

How a cataract forms

A cataract is a cloudy lens. The lens sits behind the colored part of your eye, called the iris. The lens focuses light that passes into your eye. This produces clear, sharp images on the back part of the eye, called the retina.

As you age, the lenses in your eyes become less flexible, less clear and thicker. Aging and some medical conditions can cause proteins and fibers within the lenses to break down and clump together. This is what causes the clouding in the lenses.

As the cataract grows, the clouding becomes worse. A cataract scatters and blocks the light as it passes through the lens. This prevents a sharply defined image from reaching your retina. As a result, your vision becomes blurred.

Cataracts usually happen in both eyes, but not always at the same rate. The cataract in one eye may be worse than the other. This causes a difference in vision between eyes.

Types of cataracts

Cataract types include:

• Cataracts affecting the center of the lens, called nuclear cataracts. A nuclear cataract may at first cause objects far away to be blurry but objects up close to look clear. A nuclear cataract may even improve your reading vision for a short time. But with time, the lens slowly turns more yellow or brown and makes your vision worse. It may become difficult to tell colors apart.
• Cataracts that affect the edges of the lens, called cortical cataracts. A cortical cataract begins as white, wedge-shaped spots or streaks on the outer edge of the lens cortex. As the cataract slowly grows, the streaks spread to the center and affect light passing through the lens.
• Cataracts that affect the back of the lens, called posterior subcapsular cataracts. A posterior subcapsular cataract starts as a small spot that usually forms near the back of the lens, right in the path of light. A posterior subcapsular cataract often affects your reading vision. It also may reduce your vision in bright light and cause glare or halos around lights at night. These types of cataracts tend to grow faster than others.

• Cataracts you're born with, called congenital cataracts. Some people are born with cataracts or develop them during childhood. These cataracts may be passed down from parents. They also may be associated with an infection or trauma while in the womb.

  These cataracts also may be due to certain conditions. These may include myotonic dystrophy, galactosemia, neurofibromatosis type 2 or rubella. Congenital cataracts don't always affect vision. If they do, they're usually removed soon after they're found.

Risk factors

Factors that increase your risk of cataracts include:

• Increasing age.
• Diabetes.
• Getting too much sunlight.
• Smoking.
• Obesity.
• Family history of cataracts.
• Previous eye injury or inflammation.
• Previous eye surgery.
• Prolonged use of corticosteroid medicines.
• Drinking excessive amounts of alcohol.

Prevention

No studies have proved how to prevent or slow the growth of cataracts. But health care professionals think several strategies may be helpful, including:

• Regular eye exams. Eye exams can help detect cataracts and other eye problems at their earliest stages. Ask your health care team how often you should have an eye examination.
• Do not smoke. Ask a member of your health care team how to stop smoking. Medicines, counseling and other strategies are available to help you.
• Manage other health problems. Follow your treatment plan if you have diabetes or other medical conditions that can increase your risk of cataracts.

• Choose a healthy diet that includes plenty of fruits and vegetables. Adding fruits and vegetables to your diet ensures that you're getting many vitamins and nutrients. Fruits and vegetables have antioxidants. Antioxidants help maintain the health of your eyes.

  Studies haven't proved that antioxidants in pill form can prevent cataracts. But a large population study recently showed that a healthy diet rich in vitamins and minerals reduced the risk of developing cataracts. Fruits and vegetables have many proven health benefits. Eating them is a safe way to get enough minerals and vitamins in your diet.

• Wear sunglasses. Ultraviolet light from the sun may cause cataracts. Wear sunglasses that block ultraviolet B rays when you're outdoors.
• Reduce alcohol use. Drinking too much alcohol can increase the risk of cataracts.

By Mayo Clinic Staff

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massaging accupoints

https://www.facebook.com/share/r/15Lu4P6GEL/?mibextid=N9fs7i

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total cholesterol, triglycerides, HDL-C and LDL-C.

just so that you have a better idea about my beliefs regarding cholesterol, here's the rest that I did not get to finish. There are 4 components to the usual lipid panel: total cholesterol, triglycerides, HDL-C and LDL-C. Most doctors are trained to respond to high LDL-C levels (the bad cholesterol) and suggest a drug to lower it.
However, other doctors, mostly overseas ones, now prefer to use the ratio of triglycerides over HDL and decide if action is needed. Assuming the units are given in mg/dl, the preferred ratio is 2 or less. I am using this to decide if I should take action as well. So, I am not taking any meds to lower cholesterol because my ratio is good enough. It was 1.2 from a lab test done last October.
It might also help to know that the body makes 80% of it's cholesterol with about 20% coming from the foods. It is not likely you can eat excess cholesterol. Lastly, it might also be useful to know that the body naturally turns excess carbs into fats and stored.
Under normal circumstances, the body only has 4g of glucose circulating in the blood; that's about 1 teaspoon of sugar. 1 serving size of white bread has about 8 teaspoons and 6 for brown bread.
The only macronutrients that MUST be eaten are proteins and fats! Carbs are optional.
Do let me know if I have been unclear or if you have questions.

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ketosis helps with Alzheimer's

Would you believe we were born in "ketosis"? And that ketosis helps with Alzheimer's but you will need to "turn it on". Have a watch, if keen: https://youtu.be/yooNuOKsa1Q

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danger of high insulin production

(Re-?)Sharing. https://youtu.be/2lI3dM65Zqo
One cause suggested for the condition of insulin resistance is that too much insulin is released by the pancreas (which does so in response to high-carb/ ultra-processed foods). An easy way to appreciate this is ... we quickly and unconsciously ignore constant background sounds; the ears automatically tune them out after hearing them in the first moments. Similarly, our cells "tune out" the effect on "background" insulin when there is excess for an extended period of time.
The pancreas is super-efficient at producing insulin quickly because the body HAS to remove excess blood glucose. However, insulin's eventual breakdown is slow. So, snacking on sugar-added foods will just continue to keep insulin in the background longer than it is safe for us over the long haul.
Sadly, local doctors don't see the significance of knowing the body's insulin levels; they'd happily test for fasting blood glucose though. That's like prescribing panadol to treat a fever while ignoring the septic cut on the leg.
A low-carb diet's primary effect is to keep insulin levels low and, in doing so, reverse insulin resistance. Similarly, we can, once again, hear the constant background sound when the environment is (made) right.
The body is dynamic and while we are often given the message that insulin resistance is not good for us, not many know that insulin resistance occurs naturally; in pregnancy and goes off after birth.
In the case of regular excess high-carb meals, insulin resistance is a safety mechanism our cells employ; the cells are protecting you; otherwise, they will die and when enough dies, so will we. Take a moment for that to sink in; then wonder why your doctor is ambivalent about testing insulin levels!


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conversation on pyramid

Jim:
I like to expand on a bit on our conversation on the food pyramid and am sharing it because it has relevance to every here. Specifically, on the topic of fructose from fruits.
Historically, adults who develop fatty liver are those who drink a fair bit of alcohol. It doesn't develop overnight but with frequent consumption, a pot belly develops; the fat comprises those in the liver and beyond.
It was thus a surprise to the medical community when kids as young as 6 years old were diagnosed with fatty liver too. It was established that no alcohol was consumed. After much searching, the doctors concluded, with intervention studies that fructose also caused fatty liver. Perhaps, like me, you remember TV shows, movies and advertisements portraying family breakfasts a glass of orange juice associating it with being healthy.
Biologically, fructose cannot be used in the same way as glucose. Practically all cells in the body can use glucose for energy. Conversely, not only is there no biological use for fructose, the body treats it like a toxin and turns it into fat. With excess consumption, a fatty liver will eventually develop. This is the result once the subcutaneous (under the skin) fat cells become full.
So, you might wonder, why do we take fructose? Between glucose and fructose, it is actually the sweeter of the two. And sugar comes with both in equal amounts. That means with every 1 teaspoon of sugar, the body will happily take 50% and use it for energy and while the other half is treated as waste, converted to fat and stored.
50% ... is a lot and IMHO, suggest why we gain weight as we age.
Having taken sugar practically all our lives, it would be difficult to even conceive of depriving ourselves.
Nevertheless, awareness is a start. Some amongst us are now taking coffee without added sugar (not to be confused with sweeteners as they are chemically different). It would be good to be aware that the food industry uses our "sweet tooth" to their advantage and many processed foods will have added sugar. Hence, an impact way to counter this potential problem is with home-cooked meals using real whole foods, as opposed to canned/packaged/convenient read-to-cook/eat meals.
As for fructose, eat your fruits whole (instead of juice) and infrequently ... the recommendations to have fruits daily may not be intended nor wise; all fruits come with fructose.
Having a fatty liver is just another "peg" towards chronic problems. As explained by MD Jason Fung: https://youtu.be/UvlXa9jW3kE


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