H E A L T H    L E T T E R

Issue No. 1 March 2024 

-Seattle Winters & Your Circadian Rhythm

-Gut Health & the Microbiome

-Exercise IQ

Hello & welcome to the inaugural Sequoia Project quarterly health letter.

It’s Been a Winter!

Rainy Seattle winters and months of gray skies are hard on the psyche. Now a study of 85,000 adults confirms you were right: adequate daylight exposure is indeed associated with better mental health. Researchers found that getting more daylight directly correlated with lower levels of depression, anxiety, bipolar disorder, PTSD, self-harm, and psychosis — literally, all of the things. 

During the dark months, your circadian rhythm may need more help telling the difference between day and night. Getting outdoors for even just ten minutes in the morning and again around twilight provides important cues for your brain — more than a day’s worth of bright indoor light. And scientists say ensuring adequate nighttime darkness is equally critical, if not more so. Turn lights down at bedtime, put screens away, and make sleeping quarters nice and dark.

If you have trouble sleeping, resetting your circadian rhythm should be the first step. 

Gut Health & The Microbiome

Many patients have been asking how to strengthen their microbiome, the 100 trillion or so microbes that live on the human skin, lungs, genuto-urinary tract, and gut.

Microbiome science is still very young. Shotgun metagenomics, the technology used to sequence a person’s entire microbiome, was invented just 15 years ago and is still being refined. But we already know the gut microbiome has major implications for health. There’s good evidence gut microbes trigger personalized food and alcohol cravings, reinforcing eating patterns in their own human host. Certain gut bacteria have been linked to a higher risk of diseases like obesity, diabetes, cancer, Parkinson’s, and autism — and many more.

We know antibiotics can totally wipe out the microbiome, and probiotics like Lactobacillus and Bifidobacterium, found in fermented foods like cultured yogurt, can help restore balance. We’re now on the cusp of using probiotics to target specific conditions. A recently published randomized controlled trial showed that Lactobacillus and Bifidobacterium supplementation reduces recurrent bladder infection in premenopausal women by as much as 50%. 

It could take years for science to fully catch up. Meanwhile, I'm betting we’ll find out that beneficial bacteria need adequate substrate to thrive in our gut, and in the end, evolving how you eat will be more effective than probiotic supplements.

One bacteria worth knowing about is Akkermansia muciniphila, which lives deep in the colon. Among its many roles, Akkermansia stimulates the release of Glucagon-like Peptide-1 (Glp-1), reducing food cravings and lowering blood sugar — this is the exact same peptide delivered by the next generation diabetes & weight loss drugs Ozempic and Mounjaro, which cost upwards of $1000/month.

Akkermansia loves insoluble fiber from vegetables, fruit, whole grains, and beans. The USDA recommends 30g of fiber for men and 25g for women; most people including me consume far less and can do better. Slowly increasing your fiber intake is the number one thing you can do to build this population of beneficial bacteria. (Rapidly increasing fiber intake can cause gut distress along with quickly abandoning your fiber-eating quest!) There’s strong evidence that microbes adapt very rapidly; you can change your entire microbiome during a one-week international trip, so even minor changes can make a short term difference.   

A favorite breakfast for me is a parfait with layers of plain yogurt, homemade granola, and berries. It’s a quick and delicious way to get probiotics, whole grains, and fruit to start the morning. Because like most people, who knows when the day will go sideways and there you are, stranded with a growling stomach and a bag of Doritos ...   

Exercise IQ

Quiz: What burns more fat — hard sprints on a hill or a speedy walk around Greenlake with a friend?

Answer: Intense exercise mostly burns carbs. Exercising at a pace where you can still talk but are somewhat out of breath burns mostly fat. Humans store far more fat than glucose, which is why intense exercise causes you to "bonk" much more quickly. 

Metabolic substrate analysis, which is often performed alongside VO2 max testing, identifies your particular profile for burning fat and carbs during exercise - and can help you understand how to broaden your metabolic range. If you're a patient wanting to optimize how you burn energy, please reach out to discuss.    

Audrey Young, MD

March 2024