As you know I’m overweight and I’m always reading about the health liabilities of fat. But recently, I saw something about brown fat being good for health. Can you elaborate?
Yes, I can, or at least I’ll give it my best shot. Adipose tissue (fat) is an underappreciated and misunderstood vital organ in the human body. It consists of two types of fat: white adipose tissue (WAT) and brown adipose tissue (BAT). In lean adults WAT accounts for 30 to 40% of total body mass in women and 15 to 25% of total body mass in men. While BAT accounts for roughly 1% of total body mass.
You are correct about the negative implications of too much WAT but it’s the “too much” which is the operant concept. The Goldilocks scenario of “just right” pertains to WAT. Believe it or not children born with congenital absences of fat have multiple severe health consequences and shorter lives. We all need the right amount of WAT. It subserves four main functions: thermal insulation, mechanical protection, storage of readily available fuel energy and hormonal function. Successful pregnancy requires the last two functions.
The problem with obesity is that the individual WAT cells expand from 30 to 100 µm in size. As they do so the swelling compromises blood delivery of oxygen to these cells which causes the cells to set off “fire alarm alerts” through a variety of mechanisms: altering the expression (function) of more than 1,000 genes, triggering insulin resistance (type II diabetes), releasing a spectrum of inflammation causing chemicals, impairing normal immune function (hence increased risk with COVID), and leading to deposition of triglycerides inside blood vessels and in the liver (leading to vascular disease and fatty liver).
BAT on the other hand, reduces inflammation in the body. It also improves insulin sensitivity, thus preventing diabetes. BAT generates heat (thermogenesis) when we are chilled and in doing so burns calories. BAT helps improve bone density. BAT releases a healthy hormone called adiponectin. Most centenarians (people aged 100 plus) have high levels of adiponectin. Regular exercise increases our stores of BAT even if the exercise does not lead to weight loss.
The last issue of this newsletter had an article about COVID brain studies in the UK. A recent article in Science adds to these preliminary findings. Neuroscientists in this country have noticed that the neurologic symptoms seen in many COVID patients (fatigue, brain fog, trouble remembering and headache) are very similar to those seen in other viral infections and with disorders such as myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and even with chemotherapy.
In addition to similar symptoms, the brains in all these cases show changes in the microglia. Microglia are the supporting and nurturing cells for the neuronal cells that allow us to think and act. It seems that immune activation of these cells in response to COVID infection causes the microglia to go into hyper drive and interfere with normal neuronal function.
Spinal taps done on patients with “COVID brain” show higher levels of immune activating proteins than normal patients. One of these proteins is CCL11, which is also found in the spinal fluid of patients with dementia.
Bacterial infections that don’t respond to antibiotics are becoming a major cause of death around the world. The British Medical Journal Lancet recently reported 1.3 million deaths globally due to antibiotic resistant infections. This translates to 16.4 deaths per 100,000 people. This is twice as many people than those who died from malaria (the fifth leading cause of death worldwide).
The bacteria that are the mischief makers include E. coli, Staph aureus, Clostridium difficile, Klebsiella spp, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterococcus faecium and Enterobacteriaceae.
The two main causes of the problem are bacteria’s innate ability to mutate to drug resistant forms and overuse of antibiotics. The overuse phenomenon is in both people and animals. The industrial nature of food production utilizes antibiotics in the food for chickens, turkeys, cows, pigs and cattle with the subsequent transfer to humans via their diet. The other overuse is in medical treatment of people. It is estimated that at least 2/3 of antibiotics prescribed for humans are not needed as the illness is viral in nature, not bacterial. Also, even in true bacterial infections such as pneumonia and urinary infections the length of antibiotic prescriptions is greater than necessary to resolve the infection. In this regard a recently published research study by John’s Hopkins University found a similar clinical cure rate in children with community acquired pneumonia with a five-day antibiotic regimen versus a standard ten-day regimen. Multiple research studies have found similar results in uncomplicated urinary tract infections.
JAMA (Journal of American Medical Association) just published research on this quit smoking project. After years of decline in the number of smokers in the US, sadly there is a major upsurge among American youth. Currently 14% of adults use tobacco (cigarettes or E. cigarettes) while 24% of teens do. The prevailing thought among psychologists has been that until a smoker is ready to quit the likelihood of motivating them or helping them is nil. The JAMA article reflects research into a new approach called brief abstinence games. Basically, the researchers asked smokers to “take a break”. As a control group they used non-inhalation nicotine in the form of nicotine lozenges.
The researchers were pleasantly surprised that taking a break for a very brief time (a day or so) over a period of time led to 18% of the smokers quitting. This study was done in adults, not teens. So, the next project will be aimed at this younger population.
Several years ago, this newsletter discussed a new form of anaphylaxis due to tick bites. The syndrome is peculiar in several ways. Most importantly the anaphylaxis is delayed from the exposure by several hours. Also, it occurs after eating mammalian meat such as beef and pork.
Alpha-gal is a glycoprotein that is found in mammalian meats. The patient becomes sensitized to the alpha-gal from a tick bite because the ticks secrete alpha-gal in their saliva when they bite humans. In order to diagnose the condition, the patient needs to be tested for alpha-gal. They do not show a positive response to the standard allergy tests for beef, pork, etc.
The new twist is that certain round worms, such as Ascaris lumbricoides also contain alpha-gal and infestation with these worms can lead to the same syndrome.
Another molecule (Clusterin) has been discovered that protects the brain from inflammation and is generated by exercise. Several years ago, neuroscientists discovered irisin as a protection for brain inflammation that is produced by exercise.
The current concept regarding dementia is that it occurs due to chronic inflammation in the brain with resultant scar tissue (amyloid plaque). In this regard scientists have studied patients with early dementia and have found an improvement in cognitive function via a daily exercise routine. The exercise leads to increased production of both irisin and Clusterin.