Newsletter #162: The Limitations of Caffeine & The Power of Fruit
Good morning humanOS friends!
Hope y'all are having a delightful summer so far. This week, we stumbled upon an interesting mix of new studies, with some super useful findings. Here are the key takeaways:
🔹 Caffeine helps some, but it is definitely not a substitute for sleep;
🔹 Whole fruit consumption (but not fruit juice) is linked to better insulin sensitivity and lower risk of developing type 2 diabetes;
🔹 People living traditional lifestyles in the Amazon maintain incredible brain health as they get older.
To get the details, scroll on down 👇
This Week’s Research Highlights
☕ Caffeine does help you to stay alert when sleep deprived - but it has limited benefit for more complex cognitive tasks.
Researchers from Michigan State had participants visit their lab in the evening and complete two cognitive tests. The first was a simple attention task that measures sustained attention by testing how fast subjects react to a light appearing on a screen. The second was a more challenging cognitive test meant to measure placekeeping - the ability to perform steps of a complex task in a prescribed order without skipping or repeating steps. Afterwards, subjects were randomly assigned to either stay awake overnight in the lab, or go sleep as much as they wanted at home. The following morning, all participants convened at the lab and were given capsules that either contained caffeine (200 mg) or placebo, before performing the same cognitive tasks again. Caffeine did effectively counter the detrimental effect of sleep loss on the simple attention task, but it showed no benefit for the more complex placekeeping task. This is a pretty big problem since placekeeping is a fundamental function for work, driving, and other potentially risky activities. Lead author Kimberly Fenn said: “Caffeine may improve the ability to stay awake and attend to a task, but it doesn’t do much to prevent the sort of procedural errors that can cause things like medical mistakes and car accidents.”
🍓 Eating more fruit is linked to better insulin sensitivity and lower risk of developing type 2 diabetes.
Researchers at Edith Cowan University in Perth examined data from 7675 participants in a large population-based survey of diabetes prevalence, dietary intake, and risk factors in Australia. The researchers determined that total fruit intake was associated with lower serum insulin and higher insulin sensitivity, and reduced risk of developing type 2 diabetes.
Compared to participants with the lowest intake (less than one serving daily), those who consumed moderate amounts of fruit (about two servings per day) had 36% lower odds of having diabetes over the following five years. Notably, this only applied to whole fruit - fruit juice showed no association with insulin resistance or type 2 diabetes, in agreement with prior research on this topic.
🧠 Indigenous people in the Amazon experience dramatically slower age-related brain atrophy than Western counterparts.
Researchers recruited members of the Tsimane, a forager-horticulturalist population based in the Bolivian Amazon region, and performed CT scans on their heads to measure brain volume. The researchers then calculated how changes in brain volume associated with advancing age in the Tsimane, and compared the results to samples from industrialized populations in the US and Europe. The researchers found that the difference in brain volumes between middle age and old age was 70% less in the Tsimane than in Western populations, suggesting that the Tsimane experience less brain atrophy over the aging process. Cerebral atrophy is a hallmark of aging, and the rate of atrophy predicts whether a person will develop cognitive impairment and dementia. This finding may be due to their remarkable cardiovascular health - prior research has shown that the Tsimane have the lowest levels of coronary artery disease of any population recorded to date. Maybe we need to rethink our current baseline for healthy brain aging?
Random Trivia Question of the Week
🤔What creature produces the largest sperm in the animal kingdom?(You will seriously never guess )
💡 Answer
Videos We Loved This Week
- Jari Roomer: How To Protect Your Focus And Reach "Flow State." Via The Art of Improvement.
- Matthias Gruber: This is Your Brain on Curiosity. Via TEDx.
Products We Are Enjoying
Further Food Turmeric Tonic.
If you're looking for a good way to get a decent amount of turmeric into your diet without having to take a bunch of pills, this is a solid option. One tiny scoop of this powder blend contains 1.5 grams of turmeric (plus black pepper to boost absorption). It’s super easy to add to smoothies (just toss in the blender and voilà), or you can just blend it with almond milk to make a golden milk latte. Smells really good too!
humanOS Catalog Feature of the Week
How-to Guide - Chrononutrition (Eating Timing)
This week, we’d like to highlight our how-to guide for chrononutrition. We often fixate on what we are eating, when we are discussing diet and lifestyle, but we are gradually appreciating that when we eat also has a significant impact on our health and our daily performance.
This guide will help show you how to optimize your food timing, in alignment with the latest scientific research, to maintain robust circadian alignment and to ensure you are performing at your very best.
(PS: If you’re looking for a deeper dive into the subject of nutrient timing and other aspects of circadian physiology, please refer to our Circadian OS Program.)
Enjoy your weekend, and we'll have some more juicy science for y'all next week! 👀