12 Enlightening Facts About Body Fat

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The human body is an amazing thing. For each one of us, it’s the most intimate object we know. And yet most of us don’t know enough about it: its features, functions, quirks, and mysteries. Our series The Body explores human anatomy, part by part. Think of it as a mini digital encyclopedia with a dose of wow.

Let’s face it: Fat gets a bad rap. Entire industries have been built upon the criticism and attempted reduction of body fat. But fat, formally known as adipose tissue, is a crucial part of your hormonal and metabolic processes. Adipose tissue is a major site of energy storage, and has a key role in the regulation of metabolism and insulin production in your body—not to mention, it helps keep you warm. Having too much fat can be a bad thing, but having too little can pose problems as well.

Fat is stored in the body in the form of triglycerides, free fatty acid (FFA) molecules that are held together by a molecule called glycerol, a type of alcohol. Most of our body fat is stored in fat cells called adipocytes, but fat can also be stored as droplets within skeletal muscle cells. In addition, some triglycerides even roam freely in your blood stream. (These are the ones most easily broken down through exercise.)

Before you demonize fat, take a look at these 12 facts about your adipose tissue.

1. FAT IS AN ORGAN …

Your fat is not just a layer of padding—it’s actually an organ of the endocrine system. “Fat secretes a lot of hormones, while activating or deactivating many more,” Indraneil Mukherjee, a doctor at The Southeastern Center for Digestive Disorders and Pancreatic Cancer, Florida, tells Mental Floss. It’s comprised of adipocytes and fat cell types called the stroma-vascular fraction, which are made up of growth factors—messengers the body uses to signal cells—as well as stem cells, blood cells, and a host of other cell types.

2. … AND IT PLAYS A KEY ROLE IN YOUR METABOLISM.

Adipose tissue is “a metabolically dynamic organ,” according to a study in Archives of Medical Science, whose primary job is to store excess energy. It also synthesizes “a number of biologically active compounds that regulate metabolic homeostasis.” In other words, it controls your body’s energy balance by regulating appetite signals from the central nervous system and metabolic activity in peripheral tissues. Chronic over-nutrition—eating too much on a regular basis—can cause inflammatory responses and metabolic disorders that can lead to disease: most obviously, obesity.

3. WHITE FAT GIVES YOU ENERGY.

White adipose tissue stores your body’s reserves of energy, and the endocrine cells mentioned above, which secrete crucial hormones and molecules. There are even “adipose depots” where white adipose tissue tends to gather more easily, located around organs such as the heart, lung, and kidney.

4. BROWN FAT KEEPS YOU WARM—AND IS NEWLY DISCOVERED IN ADULTS.

Brown adipose tissue is typically found in newborn human babies and hibernating mammals, according to a study in Frontiers in Endocrinology. Its main function is to generate heat—keeping you warm—and to do so, it contains more mitochondria and capillaries than white adipose tissue.

Up until recently, researchers weren’t sure brown fat existed in adults. “There's a lot of excitement around the discovery,” Yi Sherry Zhang, an assistant professor at the TOPS Obesity and Metabolic Research Center at the Medical College of Wisconsin, tells Mental Floss. “It helps to regulate energy expenditure. This is important because drugs that target this type of fat may provide a new way to treat obesity.”

5. TOO MUCH OR TOO LITTLE FAT CAN INCREASE YOUR RISK OF DIABETES.

While it is now commonly known that obesity—when a person carries more weight than is considered healthy for their height—can predispose a person to type 2 diabetes, too little fat has a similar effect, according to the American Diabetes Association. Type 2 diabetes is a group of diseases in which the body has an impaired ability to produce or respond to the hormone insulin. And it turns out having too little fat is due in part to a lack of a lipid-storing “compartments,” which leads to an imbalance of triglyceride and free fatty acid levels, leading to insulin resistance.

6. YOUR LEVEL OF BODY FAT MAY BE INFLUENCED BY YOUR MICROBIOME.

Researchers at McMaster University have begun studying a new realm of therapies known as postbiotics, the by-products that bacteria leave behind, which help the body synthesize insulin more effectively. In a new study, scientists discovered that administering postbiotics to mice with obesity reduced their insulin sensitivity—without any need for weight loss—heralding promising potential treatments for obesity with type 2 diabetes.

7. EXCESS FAT IS THE PERFECT ENVIRONMENT FOR CANCER.

Adipose tissue also secrets “hormones that make cancer cells grow quicker,” says Mukherjee. In fact, when adipose tissue expands, it also allows more immune cells to enter the tissue. These B and T immune cells secrete pro-inflammatory molecules such as adipokines [PDF]—peptides that signal other organs—and cytokines, which create the perfect microenvironment for tumor growth, according to a study in Frontiers in Physiology.

8. YOU CAN MOVE YOUR FAT AROUND.

If you are so inclined, Mukherjee points out that “fat transplant is legal”—so you can technically surgically move it from one body part to another without any harm done, “for vanity,” he says. These so-called fat transfers can augment a formerly flat part of your body, but buyer beware—not only can you experience the side effects of surgery such as swelling, bruising, several weeks of recovery time, you can develop lumps.

9. DIETING DOESN’T REDUCE THE NUMBER OF FAT CELLS YOU HAVE.

The number of your fat cells can increase, but once the cellular structures have developed, they never go away. “With dieting, they just get smaller,” Mukherjee says. Zhang adds, “Each of us has 10 billion to 30 billion fat cells in our body.” Obese people can eventually have up to 100 billion fat cells.

10. YOUR FAT COMMUNICATES WITH OTHER ORGANS ALL OVER THE BODY.

It does so by sending out small molecules called microRNAs (miRNAs) that control gene activity, according to a study in Nature. After injecting genetically modified mice with fluorescent liver cell miRnas, researchers saw a significant drop in liver cell fluorescence, which suggested that the fat tissue was communicating with the liver to regulate gene expression. They hope to further study this process to discover new treatment methods for obesity and type 2 diabetes.

11. THE GENETIC UNDERPINNINGS OF FAT MAY HELP TREAT OBESITY.

“We are beginning to understand the genetic basis for fat distribution and obesity,” says Zhang. “We have recently published genes that play a role in determining how body fat is distributed,” she continues. She hopes that these discoveries will help researchers understand the genetic component of common disorders like metabolic syndrome, type 2 diabetes, and obesity.

12. IN FACT, EPIGENETICS IS THE NEW FRONTIER OF FAT RESEARCH.

Researchers studying fat to better understand metabolic disorders recently focused on the field of epigenetics, which is the study of “the various elements that regulate which genes are active in particular cells and how they are regulated,” Zhang says. She believes that epigenetic changes are likely to play a critical role in the development of chronic disorders like metabolic syndrome and type 2 diabetes. “Unlike the genetic code, it is possible to reverse and alter these elements, which means we can potentially develop new ways to prevent and treat these common disorders.”

10 Facts About Your Tonsils

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Most of us only become aware of our tonsils if they become swollen or infected. But these masses of lymphatic tissue in the mouth and throat are important immunological gatekeepers at the start of the airways and digestive tract, grabbing pathogens and warding off diseases before they reach the rest of your body. Here are some essential answers about these often-overlooked tissues—like what to do when your tonsils are swollen, and whether you should get your tonsils removed.

1. People actually have four kinds of tonsils.

The term tonsils usually refers to your palatine tonsils, the ones that can be seen at the back of your throat. But tonsillar tissue also includes the lingual tonsil (located in the base of the tongue), tubal tonsils, and the adenoid tonsil (often just called adenoids). "Collectively, these are referred to as Waldeyer's ring," says Raja Seethala, the director of head and neck pathology at the University of Pittsburgh Medical Center and a member of the College of American Pathologists Cancer Committee.

2. Tonsils are one of the body's first responders to pathogens.

The tonsils are a key barrier to inhaled or ingested pathogens that can cause infection or other harm, Seethala tells Mental Floss. "These pathogens bind to specialized immune cells in the lining—epithelium—to elicit an immune response in the lymphoid T and B cells of the tonsil," he says. Essentially, they help jumpstart your immune response.

3. Adenoid tonsils can obstruct breathing and cause facial deformities.

If the adenoid tonsils are swollen, they can block breathing and clog up your sinus drainage, which can cause sinus and ear infections. If adenoids are too big, it forces a person to breathe through their mouth. In children, frequent mouth breathing has the potential to cause facial deformities by stressing developing facial bones. "If the tonsils are too large and cause airway obstruction, snoring, or obstructive sleep apnea, then removal is important," says Donald Levine, an ear, nose, and throat specialist in Nyack, New York. Fortunately, the adenoids tend to get smaller naturally in adulthood.

4. As many of us know, sometimes tonsils are removed.

Even though your tonsils are part of your immune system, Levine tells Mental Floss, "when they become obstructive or chronically infected, then they need to be removed." The rest of your immune system steps in to handle further attacks by pathogens. Another reason to remove tonsils besides size, Levine says, is "chronic tonsillitis due to the failure of the immune system to remove residual bacteria from the tonsils, despite multiple antibiotic therapies."

5. Tonsillectomies have been performed for thousands of years ...

Tonsil removal is believed to have been a phenomenon for three millennia. The procedure is found in ancient Ayurvedic texts, says Seethala, "making it one of the older documented surgical procedures." But though the scientific understanding of the surgery has changed dramatically since then, "the benefits versus harm of tonsillectomy have been continually debated over the centuries," he says.

6. ... and they were probably quite painful.

The first known reported case of tonsillectomy surgery, according to a 2006 paper in Otorhinolaryngology, is by Cornélio Celsus, a Roman "encylopaediest" and dabbler in medicine, who authored a medical encyclopedia titled Of Medicine in the 1st century BCE. Thanks to his work, we can surmise that a tonsillectomy probably was an agonizing procedure for the patient: "Celsus applied a mixture of vinegar and milk in the surgical specimen to hemostasis [stanch bleeding] and also described his difficulty doing that due to lack of proper anesthesia."

7. Tonsil removal was performed for unlikely reasons.

The same paper reveals that among some of the more outlandish reasons for removing tonsils were conditions like "night enuresis (bed-wetting), convulsions, laryngeal stridor, hoarseness, chronic bronchitis, and asthma."

8. An early treatment for swollen tonsils included frog fat.

As early practitioners struggled to perfect techniques for removing tonsils effectively, another early physician, Aetius de Amida, recommended "ointment, oils, and corrosive formulas with frog fat to treat infections."

9. Modern tonsillectomy is much more sophisticated.

A common technique today for removing the tonsils, according to Levine, is a far cry from the painful early attempts. Under brief general anesthesia, Levine uses a process called coblation. "[It's] a kind of cold cautery, so there is almost no bleeding, less post operative pain, and quicker healing. You can return to normal activities 10 days later," Levine says.

10. Sexually-transmitted HPV can cause tonsil cancer.

The incidence of tonsillar cancers is increasing, according to Seethala. "Unlike other head and neck cancers, which are commonly associated with smoking and alcohol, tonsillar cancers are driven by high-risk human papillomavirus (HPV)," he says. "HPV-related tonsillar cancer can be considered sexually transmitted."

26 Amazing Facts About the Human Body

Mental Floss via YouTube
Mental Floss via YouTube

At some point in your life, you've probably wondered: What is belly button lint, anyway? The answer, according to Mental Floss editor-in-chief Erin McCarthy, is that it's "fibers that rub off of clothing over time." And hairy people are more prone to getting it for a very specific (and kind of gross-sounding) reason. A group of scientists who formed the Belly Button Biodiversity Project in 2011 have also discovered that there's a whole lot of bacteria going on in there.

In this week's all-new edition of The List Show, Erin is sharing 26 amazing facts about the human body, from your philtrum (the dent under your nose) to your feet. You can watch the full episode below.

For more episodes like this one, be sure to subscribe here.

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