DR. MICHAEL MOSLEY: Sugar Cravings? Your Gut Bacteria Are To Blame

Despite everything I’ve done to improve my diet, like most people, I still get those occasional crazy, crazy cravings for junk food, the stuff we all know is bad for us, but that despite our best intentions, we just can. not resist.

In my case it is chocolate, cookies or cake. That’s why we rarely have them around the house, otherwise I could easily eat a whole pack or most of a cake in one sitting.

However, I have found that this craving usually goes away when I “surf the urge”. The urge to surf means that instead of trying to fight it, I try to sit it out by drinking a tall glass of water, practicing deep breathing, and trying to focus on other things. It usually takes me about 30 minutes to regain control.

But where do these crazy cravings come from? Junk food manufacturers are partly to blame for being adept at creating foods with just the right mix of fat, sugar, salt, and flavors that we find irresistible.

However, recent research from Pittsburgh University in the US has also revealed for the first time how the microbes that live in the gut trigger cravings for certain foods.

This happens, among other things, via the vagus nerve, the longest nerve in the body that connects the brain and intestines. It behaves like a busy internet cable and sends lots of messages in both directions. There is evidence, mostly from animal studies, that your gut microbes can hack into this system, much like cyber attackers, and talk directly to your brain.

These microbes, who are brilliant chemists, can also convert the food we eat into a variety of hormones and chemical messengers that reach the brain through the bloodstream, thereby affecting our mood and eating habits.

There are many examples of microbes manipulating other animals. When mice become infected with a bacteria called Toxoplasma gondii, they become strangely ruthless. Usually, a mouse will stay in the shade and avoid anything cat-related. But when infected with Toxoplasma, they are attracted to the smell of cat urine and boldly venture out to be killed and eaten.

This happens because the Toxoplasma bacteria need to infect a cat to complete its life cycle and the only way to do that is to manipulate the mouse’s behavior and turn it into a kamikaze mouse.

However, recent research from Pittsburgh University in the US has also revealed for the first time how the microbes that live in the gut trigger cravings for certain foods [File photo]

How the bacteria do this is a bit of a mystery, but one theory has it that they disrupt the mouse’s reward centers in the brain, producing surges of dopamine and serotonin, “feel-good hormones” that create the unexpectedly irresistible smell of cat pee.

A similar mechanism appears to be at play in the most recent study examining how gut microbes manipulate food preferences. The researchers infected laboratory mice with microbes from the guts of wild mice, chosen because they have very different natural diets.

Some wild mice, given choices, opt for a high-protein, low-carb diet, while others prefer a lower-protein, higher-carb diet. When their gut microbes were transplanted into the lab mice, the mice switched their diets to match the donor mice’s preferences.

Those fed microbes from protein-loving rodents now opted for a high-protein diet, while the mice fed microbes soon went from carb-lovers to carb-lovers.

And the researchers also noticed that the introduction of these new gut microbes also altered their levels of tryptophan, a substance that gets converted into serotonin in our brains. This strongly suggests that microbes living at least in the mouse gut made and used tryptophan to manipulate what their host ate.

The message we can take from all of this is that a junk food diet is likely to encourage the growth of junk food-loving microbes in your gut — and they’ll encourage you to eat more.

But if you instead increase the amount of fiber in your diet (eating more veggies and whole grains), it encourages the growth of other, healthier bacteria, and these should, over time, help drown out the alluring chemical messages the junk food-loving microbes are telling you that you should eat that cookie, you know you want it.

Another thing that can help fight cravings is exercise. As you get more active, your mood improves, which should help reduce cravings and encourage the growth of “good” bacteria.

Another recent study showed that rats that were encouraged to run vigorously on a treadmill for a month ate far fewer unhealthy treats when offered them than rats that led a more sedentary life. Although junk food cravings will likely never go away entirely, changing your microbiome should make it easier to resist.

Daily washing used to be a rare luxury – Queen Elizabeth I is said to have bathed once a month “whether she needed it or not”.

Nowadays, that would be considered antisocial – but how often should you wash?

dr Robert Shmerling, writing in Harvard Health, says daily washing can remove healthy oils. So if you’re not sweaty or dirty, then “several times a week is fine for most people” — even then, “quick showers, focusing on the armpits and groin, can suffice.”

I love spicy food and, much to my wife Clare’s chagrin, I often sprinkle chili flakes on her carefully prepared meals. I’ve also entered chili-eating contests.

But as I always remind Clare, eating chili isn’t just pure machismo. They’re high in antioxidants — a review published last month found that people who regularly eat chilies have an 8 percent lower risk of cancer and a 13 percent lower risk of dying from heart disease than those who avoid the fiery food .

Diver oxygen therapy that could help treat long Covid

Covid’s long tail was graphically highlighted by new figures showing just 29 per cent of those hospitalized with it had fully recovered a year later.

At the moment treatment for people with long Covid is limited because we still don’t know what’s going on.

Some think it’s due to blood clot damage, others believe the bad guy is long-term inflammation.

Regardless, one of the more unusual therapies being explored is the use of a hyperbaric oxygen chamber. These are typically used to treat deep sea divers with “jowls,” but also patients with wounds that won’t heal

These claims are being tested in a study at Cambridge University examining potential preventive treatments for long Covid. Recently discharged patients are offered apixaban (a blood thinner), atorvastatin (a statin), or usual care (ie standard treatment appropriate to their symptoms). The statin was included because it not only lowers cholesterol but also has anti-inflammatory effects.

Last week I met Dr. Michael Gonevski, a hyperbaric and diving specialist who is leading research into the use of such chambers in long Covid in the UK. He believes the extreme fatigue some are experiencing is because Covid has damaged their mitochondria, the powerhouses in our cells that convert food into energy: the theory is that hyperbaric oxygen therapy (HBOT) is helping restart mitochondria.

So far, he and his colleagues have treated more than 120 patients with good results.

“We’ve had people who haven’t been able to leave their homes for over a year and who showed radical improvement within a few days,” Dr. Gonevski. He and researchers from University Hospitals Coventry and Warwickshire NHS Trust recently published a small study showing that ten HBOT sessions conducted over 12 days can reduce fatigue and improve verbal skills and information processing speed.

One patient, Catherine Finnis, a 39-year-old teacher and mother of two, used to run half marathons until she contracted Covid two years ago. She was unable to move and coughed constantly, was tired and mentally “very slow,” she told me.

After three sessions, she noticed improvements and was able to return to work. She’s not back to her old self yet, “but I’m feeling better every day.” HBOT is not yet available in the NHS and Dr. Gonevski is very interested in obtaining funding for larger studies. With so many people affected, there is clearly an urgent need to find effective treatments, so fingers crossed.