The year is off to a busy start. In the past month, new thinking has emerged around sugar, fiber, espresso, and the many bacteria in your gut. Oh, and a lady’s growing human brains from scratch. Here’s a look at it all.
A microbiome “fact” reversed
It’s good to get a reminder now and then that science isn’t fact – it’s simply a collection of the best theories we have right now.
Such a reminder came earlier this month, when Nature put out a report debunking the idea that you have 10 times as many bacteria in your body as you do human cells. For the past 44 years, scientists have quoted the 10:1 ratio and educators have taught it in biology courses, but new evidence suggests that it’s way off.
It looks like the ratio is closer to 1:1. An average person has ~30 trillion cells and ~39 trillion bacteria, and that second number can vary, depending on factors like what you eat and where you live. Taking antibiotics, for example, wages war on your gut biome and kills off trillions of bacteria, good and bad. Your bacteria count could drop to 20 trillion if you’re just coming off a course of antibiotics. On the other hand, if you’re outside in the dirt all the time and you don’t wash your hands often, your gut biome could be much more diverse than your neighbor’s. That may be why babies chew on everything in sight – the habit diversifies their gut bacteria.
We’re beginning to understand how your gut bacteria and your cells work together to run your body. Your gut has more say than you might think – it can affect your happiness, your weight, and your brain function, among other things. To learn more about how your gut interacts with the rest of you, and how you can manipulate your gut bacteria to improve your performance, check out this article.
How to grow a brand new brain
Scientists are already working on 3D printing ears, bones, and organs using live cells as the ink, and they’re hoping to reach a day when they can implant them into people without issue. English researcher Madeline Lancaster is taking things to the next level: she’s working on growing human brains in a dish.
Not to mislead: Lancaster hasn’t made a full brain. She is creating what she calls “mini-brains,” though. Every dish she cultivates produces a small and specialized part of a human nervous system. Lancaster starts with stem cells and keeps them under careful conditions. She hasn’t figured out how to control what part of a brain the stem cells turn into yet, so each dish is like a grab bag; she doesn’t know what it is until she opens it. Memorable surprises have included a retina and a cerebral cortex.
Perhaps the most exciting thing about Lancaster’s research is that it offers the opportunity to watch how brains grow, and to see which genes drive growth. That insight could lead to a much deeper understanding of how we function – and how to function better.
The USDA’s new dietary guidelines are out
And while they still have a long way to go, they’re better than the last set of guidelines was.
The USDA updates its dietary recommendations every five years. The most recent ones are a commendable step in the right direction. In fact, the government is on a general upward trend when it comes to diet. A few months ago they reversed their anti-cholesterol stance, and their latest dietary advice gives a green light to lean red meat and whole eggs. They also name sugar as a cause of obesity, and recommend limiting refined sugar intake to 10% instead of 15%.
The government’s recommendations are far from Bulletproof. They still recommend a low-fat, moderate-to-high-carb diet with lots of whole grains and they’re against saturated fat. However, they deserve credit for recognizing the dangers of refined sugar, and for recognizing eggs and meat as healthy foods.
Eat fiber – your grandkids will thank you
Speaking of dietary recommendations, new research suggests that the diet of mice permanently affects their offspring. Scientists found that mice fed a low-fiber diet had decreased bacterial diversity in their guts. That’s no surprise – prebiotic fiber is an important source of food for your gut bacteria, and without it, certain species of bacteria die. What’s more interesting was the effect parents’ low-fiber diets had on their kids’ gut bacteria.
When 3-4 generations of mice in a row ate low-fiber diets, certain species of gut bacteria went extinct in their guts, and their children were born without those bacteria, too. Decreased gut diversity correlates with decreased immune response and greater risk of infection.
This study was done in mice, but their guts were populated with bacteria from human colons, so the results apply to humans more than the results of most mouse studies do. Green veggies are a good source of fiber; the Bulletproof Diet Roadmap recommends that you eat 6-11 servings per day. Do it for the children.
The study’s authors have their own recommendations for increasing gut biodiversity. They suggest avoiding antibiotics and washing less, especially after touching soil or cuddling with pets.
They also entertain the idea of mass fecal transplants. Let’s hope it doesn’t come to that.
Your espresso machine could be taxing your health
When was the last time you cleaned the coffee/espresso maker? If it’s been a few weeks, take action. Researchers swabbed the waste trays of 10 espresso machines and analyzed the coffee residues within, and the results weren’t pretty. It turns out bacteria like coffee as much as we do. The trays were full of them, and some species were pathogenic. Coffee and caffeine have antibacterial properties, but the bacteria in the coffee machines had actually adapted to survive in coffee. Crazy stuff.
Moral of the story: clean out your coffee maker, or at least wipe down your waste tray from time to time. With many coffee makers, you can run vinegar through the system in place of water and it will kill off unwanted bacteria. Just check with the company to make sure it won’t damage the machine or get stuck anywhere. Vinegar-flavored coffee is pretty horrific.
That’s it for this month. Thanks for reading!