Five things you didn’t know about health and the human body
Reporting on health topics for the Wellness column over the past few years has left me with a deep respect for the human body. From its tireless, homeostasis-seeking cells to the mysteries of its gray matter, it’s an incredible machine that we get to walk around the world in.
Many of the things I learn interviewing locals with expertise in all areas of the human experience filter down to the bottom of my brain, never to be heard from again (though they are still there, I hope). The weirdest, hardest-to-believe and downright most useful information stays at the surface the longest, and it’s from this seething pool that I’ve skimmed the contents of this article. From brain plaque to the scientifically proven benefits of “forest baths,” here are five useful facts you probably didn’t know about your body and brain.
1. Plaque Builds Up in the Brain, Too
Humans have known about brain plaque since around 1892, thanks to the teamwork of a Romanian neurologist and a French pathologist. The correlation between Alzheimer’s disease and plaques in the brain, however, is much newer.
Not to be confused with the biofilm in our mouths, beta-amyloid plaque is formed from protein fragments which may kill cell-to-cell signaling of synapses long before it accumulates in detectable clumps of plaque, according to research from Stanford’s School of Medicine. This plaque is believed to be a main culprit in the brain-tissue loss that makes Alzheimer’s fatal.
A 2009 Science report noted that beta-amyloid production follows a circadian rhythm, rising when we are awake and falling during sleep—a possible explanation for the association of chronic sleep deprivation with early onset of Alzheimer’s.
A 2012 study printed in Neurology found that people with more brain plaque showed a greater and more rapid decline in memory. While brain plaque remains mysterious, studies show that “certain nootropics [smart drugs]—such as centrophenoxine and galantamine‚ which can improve memory and cognitive functioning—can also help to prevent the buildup of sticky lipofuscins and beta-amyloid plaque deposits in the brain,” according to local science writer and author David Jay Brown.
And while there is no causal association between oral bacteria and Alzheimer’s, keep flossing—there is a link between periodontal disease and heart disease. “We say ‘bad heart, bad brain,’ because there is increasing evidence of a deadly link between these two diseases,” says Chauncey Crandall, M.D., one of the nation’s leading cardiologists and author of the Heart Health Report newsletter.
2. The Truth About Probiotics
By now, most people know that the average human body carries 2 to 6 pounds of bacteria, which act as a metabolically active organ, and outnumber our cells by about 10 to one.
“The highest density of ancient bacteria, archaebacteria—the oldest bugs found anywhere on Earth—is in your colon,” says Dr. Dawn Motyka, who hosts KUSP’s radio show Ask Dr. Dawn. Receptors and surface flora allow bacteria to sense nutrients in their environment—and the colon appears to be their ultimate fertile crescent.
Lucky for us, because we couldn’t live without them, either. It’s the bacteria in our bodies that produce the life-crucial vitamins B12 and K. The same goes for many polyphenols—antioxidants found in coffee, tea, fruits, and vegetables. And, of course, it goes both ways: “Charred red meat has long been called a carcinogen, but in fact it is only the raw material for making carcinogens. Without the gut bacteria that break it down, the raw goods are harmless,” writes Mary Roach in Gulp: Adventures on the Alimentary Canal.
Rising consciousness about the importance of healthy gut flora has fueled a voracious market for probiotics. But unfortunately, the strains you can buy are not likely to be the most beneficial. “Probiotics that you buy are all aerobic organisms,” says Motyka, explaining that these are easy to grow and keep alive in the oxygen environment of a lab. “But 90 percent of our microbiome are anaerobic, they are the ones that do most of the heavy lifting as far as making the vitamins and controlling the immune system.”
Science has not quite figured out how to grow anaerobic bacteria—which only thrive in the colon—in the lab. So for now, there’s no simple pill that can deliver these good guys—only the emerging field of fecal transplants, which is exactly what it sounds like.
“Your diet and the amount of fiber in your diet has a huge influence on whether you grow the right anaerobes or not. That’s probably where a lot of the ‘fruits and vegetables are good for you’ [concept] comes from,” says Motyka. “When we take supplements that are extracts of vegetables, we’re messing up if we don’t get that fiber because we have to tend the garden inside ourselves, and make sure we get enough of the right kinds of fiber that are the right fuel.”
3. Trees May Heal Humans
The act of smelling comes from inhaling actual molecules in the air. For instance, the key aroma in grapefruit, basil, green tea and Cabernet comes from the molecule MMP. We “smell” when molecules connect with olfactory receptors, which then pass information to the brain. Because the olfactory bulb is part of the limbic system—associated with memory and feeling—smells can call up memories almost instantaneously, as well as influence mood.
But smell can also affect us physically, and researchers in the Far East who believe forests hold a chemical secret to health could be onto something. Shinrin-yoku, or forest bathing, is a bona fide field of study in Japan, Russia and Korea, “aimed at understanding what’s at work in the moist, fragrant air of an old-growth forest,” writes science writer Jim Robbins in The Man Who Planted Trees.
A 2000 study at the Nippon Medical School tested the blood and urine of 12 healthy Tokyo men after three consecutive days hiking in the forest. For a week following their return to the city, the samples showed a reduction in adrenaline in the urine, an increase in anti-cancer proteins, and a significant increase in “natural killer” cells, which prevent the formation of tumors.
“One of the sharp, pungent smells in the air during a walk through a pine forest on a warm day is pinene, a monoterpene that has been shown to relieve asthma, perhaps by reducing lung inflammation caused by ozone trapped in the lungs,” writes Robbins.
Other widely studied forest aerosols are limonene and perillyl alcohol, which demonstrate the ability to dissolve cholesterol and gallstones and prevent asthma, writes Robbins. Inhalation therapy with perillyl alcohol is even being used in promising trials by Clovis O. Fonseca, a Brazilian doctor and professor in neuro-oncology, to treat brain tumors that don’t respond to surgery or chemotherapy.
4. Meditation Grows Your Brain
Of all of the health trends to rise to cult status, meditation is probably the one I most confidently feel deserves its hype—and it’s finally been proven to physically change the brain.
Most recently, an eight-week Harvard University study of 16 subjects who had meditated for 30 minutes a day found an increase in gray matter density in the hippocampus, which
is responsible for learning and memory, as well as in areas associated with compassion, introspection and self-awareness.
“Although the practice of meditation is associated with a sense of peacefulness and physical relaxation, practitioners have long claimed that meditation also provides cognitive and psychological benefits that persist throughout the day,” says Sara Lazar, a Harvard Medical School instructor in Psychology. “This study demonstrates that changes in brain structure may underlie some of these reported improvements and that people are not just feeling better because they are spending time relaxing.”
The hardest part of meditating is actually doing it. To get over that hurdle, forget the 30 minutes those Harvard students spent in lotus position and go with Dan Harris’ advice: “Start with five minutes a day and tell yourself you’ll never do more.” Set your smartphone timer, sit with your back against a couch or bed, and just observe your thoughts without entertaining them. In doing this, you’re activating the nervous system’s “rest and digest” circuit, which lowers anxiety and helps with stress management.
“There’s no magic or mysticism required—it’s just exercise. If you do the right amount of reps, certain things will happen, reliably and predictably,” writes Harris, a former skeptic and author of (the tongue-in-cheek-titled) 10% Happier.
5. The Detox Deception
As the health of any of the body’s detoxifying organs—liver, kidneys, lungs and skin—declines, the health of the entire body slips as well. While it’s crucial to keep these tireless organs functioning well in order to feel our best, detoxing doesn’t necessarily mean forking over money for juice cleanses, pills or the trend of the minute in an ever-widening detox market. Detoxing can really be much simpler than that—our bodies know exactly what to do.
“I’m repeatedly amazed at how people are positively impacted by cleaning up their diets—and, of course, their incredible resistance to it. Moving away from processed foods, taking breaks from coffee, sugar, alcohol never disappoints,” says Dr. Aimée Shunney of Santa Cruz Integrative Medicine, who says periodic breaks from coffee, sugar and alcohol are like much-needed vacations for your detox organs.
Eating lots of fruit and vegetables while detoxing gives the organs the nutrients they need to clean house—and some foods like cilantro, garlic and ginger can help the process along. But Shunney cautions from taking it too far. “I’m seeing more and more orthorexia, which is an unhealthy obsession with healthy eating that leads to malnourishment,” says Shunney. “It’s an interesting duality, especially here in Santa Cruz.”
Even attempts to improve one’s eating habits can go awry if they are done haphazardly, she says.
“One of the most common things I see is that people want to be vegan or vegetarian for various reasons, many of which I completely get, but they become completely unhealthy in the process,” says Shunney. “It takes a real commitment to eat that way well. I see so many patients trying to eat less meat who end up increasing sugar and processed foods, and who don’t get enough protein and good quality fat to stay nourished.”