Issue 23: Nutrition made simple - 50% off this week

In partnership with

Welcome to Weekly.health’s 23rd issue. Every week, we explore cutting-edge research, actionable advice, and science-backed nutrition insights to help you live longer and healthier.

Our aim is to help you live another 10 healthy years and cut your risk of age-related disease.

🗒️ In This Issue:

• 🆕 Foundations of Nutrition Is Now Live: 50% Off This Week

• 📚 Books We’re Reading Right Now

• 🕒 Longevity Digest: Recent research on ageing

• 📈 Research Digest: What’s new in nutrition science

• 💊 Supplement Deep Dive: Magnesium

• 🛍️ Purchases We Recommend

• ❤️ Support Weekly.health: Help us keep the research flowing

• 📘 Glossary of Terms: Definitions for technical terms in this issue

🆕 Foundations of Nutrition Is Now Live - 50% Off This Week

Our first course, Foundations of Nutrition, is now available, and for this week only it’s 50% off with the code BLACKFRIDAY.

If you're looking for a clear, science-based way to understand nutrition properly - without rules, confusion, or overwhelm - and in just 10 minutes a day… this course is for you.

📚 Books We’re Reading Right Now

🕒 Longevity Digest: Recent Research on Ageing

🌱 Ageing well is surprisingly lifestyle-driven
This review of 35 trials (25,000 adults aged 50+) shows that small, everyday habits genuinely slow age-related decline. A Mediterranean-style diet cut cardiovascular risk by 22%, aerobic exercise improved fitness (VO₂ max +3.6 mL/kg/min), and mindfulness reduced stress by 35%. Seven to eight hours of sleep lowered cognitive decline risk by 25%. Combine these habits for the biggest impact. (source)

📈 Research Digest: What’s New in Nutrition Science

Here’s the best of recent nutrition research:

🍇 Mediterranean diet helps brains without the daily wine
In 75 Portuguese adults aged 55–85 at high dementia risk, a Mediterranean diet score only predicted better cognitive test results when low wine intake scored higher. When wine was counted as “healthy”, the link disappeared. Takeaway: enjoy a Mediterranean-style diet rich in plants and olive oil, but don’t rely on a daily glass of wine for brain health. (source)

🍽️ Eat like it’s sunny, even when the air isn’t clear
In 17,254 UK adults exposed to common air pollutants, shifting towards healthier patterns - Mediterranean-style, plant-rich, diverse, antioxidant and anti-inflammatory diets - was estimated to prevent up to ~10 diabetes cases, ~16 kidney disease cases, ~12 dementia cases and ~10 deaths per 1,000 people over 13 years. Build plates around veg, fruit, whole grains, beans, nuts and olive oil, while cutting ultra-processed foods and red meat. (course)

🧠 Daily lifestyle coaching helped older adults with memory issues maintain their cognitive health. 
Over 52 weeks, participants with mild cognitive impairment logged every meal with nutrition feedback three times a week, set personal weekly activity goals with tailored coaching, and received monthly checks on blood pressure, weight and blood sugar, plus extra guidance when readings were off. This steady support kept their cognition stable while the control group declined. Takeaway: build a simple routine, track your meals, move daily, and monitor key health numbers, to meaningfully protect long-term brain health. (source)

🌱 Foundations of Nutrition - Now Live (50% Off This Week)

If you’ve ever felt like nutrition is confusing or contradictory, you’re not alone.
This course was built to give you complete clarity, without overwhelm - a calm, practical, science-based foundation you can actually use in daily life.

What you’ll learn in just 10 minutes a day

• How energy balance and metabolism really work

• How to build satisfying, balanced meals without tracking or rules

• What protein, fibre, carbs, fats, and micronutrients actually do

• How to turn knowledge into habits through worksheets and a 6-week plan

What you get when you join

• Short, focused lessons designed for a busy life

• 21 actionable lessons over 5 modules

• The essentials of nutrition and how to implement it into your life

• Practical worksheets + habit tools

• A complete step-by-step framework

• Lifetime access

Here’s a sneak peak at lesson 1

Launch offer - 50% off this week only

Use code: BLACKFRIDAY

• £59 → £29.50 (UK)

• $75 → $37.50 (US & elsewhere)

🟢 Sponsors: AG1 & Medik8

The daily health habit you’ll actually stick with…

This time of year, it’s SO hard to stay in control of your health.

Holiday travel (and meals!), big family gatherings, dark and cold days, it’s easy to skip that workout, sleep in later than you should, or have just one more cookie.

That’s why you need a daily health habit that’s easy to stick with.

Meet AG1: With just one quick scoop every morning, you’ll get over 75 ingredients that help support your immune health, gut health, energy, and close nutrient gaps in your diet.

Right now is the best time to get started - with every new subscription, they are giving away $126 in free gifts for the holidays.

Give AG1 a try today and take control of your health this holiday season.

Give AG1 a try today

30% off Medik8 Starts NOW

Black Friday is here, but these deals won’t last long! Shop Medik8 and save 30% off your must-have products*

Shop Now

_{*Terms & Conditions Apply}

💊 Supplement Deep Dive: Magnesium

Should you be taking taking magnesium supplements?

1-minute verdict

Try (targeted): Small but valuable benefits to those with low consumption of nuts, seeds, wholegrains, and legumes, and who experience poor sleep or low mood.

• Outcomes that matter;

  • Reduced time to fall asleep in older adults with insomnia (avg 17 minutes)

  • Reduced depression scores in small trials moderately

  • Small improvements in anxiety and stress scores in some trials

• Time to benefit: 2–12 weeks for sleep and mood

• Who might skip or adjust: Those with moderate-severe kidney disease. Those already using magnesium-containing laxatives/antacids.

• Upper limit: 350 mg/day elemental magnesium from supplements (check labels). Food sources generally unrestricted.

Does it actually do anything?

Sleep

• A 2025 evidence review pooling three RCTs in adults with insomnia symptoms found that magnesium supplementation reduced sleep onset latency by ~17 minutes vs placebo – a modest but clinically relevant effect. (source)

• In a 2024 RCT, 1 g/day magnesium L-threonate in adults with self-reported sleep problems improved subjective sleep quality, deep/REM sleep, mood, energy and daytime functioning vs placebo. (source)

Anxiety, stress & mood

• A 2017 systematic review (18 RCTs) found magnesium may reduce subjective anxiety and stress, especially in people with mild–moderate anxiety and low baseline magnesium, but study quality was variable. (source)

• A 2023 meta-analysis reported a significant reduction in depression scores with magnesium supplementation versus control, though heterogeneity and small sample sizes mean this is still “promising” rather than definitive. (source)

Cognition (L-threonate)

• RCTs in older adults and middle-aged adults with poor sleep and subjective memory complaints show improvements in composite cognitive scores and working memory with 1.5–2 g/day Mg L-threonate over 12 weeks vs placebo. (source)

Our take: effects are small to moderate, not dramatic. Magnesium is best thought of as a foundational co-factor, especially helpful if your intake is low or stress load is high, less noticeable if you’re already consuming adequate amounts through diet.

Who is most likely to benefit?

People who might get the most out of magnesium are those who:

• Have a low intake of nuts, seeds, wholegrains, pulses and greens.

• Have a high stress load, frequent muscle tension, migraines or cramps (as part of a broader plan).

• Are perimenopausal or post-menopausal women with sleep disruption and anxiety.

• Are endurance or high-volume athletes with heavy sweat losses.

Dose & form

• Effective dose range:

  • Typical recommended intakes from diet: 310–320 mg/day (women) and 400–420 mg/day (men) in the US; similar reference values in Europe.

  • Upper limit for supplements/medicines in adults is usually set around 350 mg/day elemental magnesium (food doesn’t count towards this).

• Forms:

  • Magnesium glycinate (bisglycinate) – sleep & calm

  • Magnesium malate – energy & muscles

  • Magnesium L-threonate (MgT) – brain & sleep depth

Our picks - what to buy

Stack sensibly (optional)

• Evening: magnesium glycinate ± extra glycine or a low-dose theanine as a gentle wind-down stack.

• Daytime energy/muscle: magnesium malate with electrolytes (sodium/potassium), especially in endurance athletes or heavy sweaters.

• Brain stack: Mg L-threonate alongside omega-3 (EPA/DHA) and choline-rich foods for general brain support (evidence is stronger for omega-3 than for any single “nootropic” supplement).

Mechanism minute (for the curious)

• Nervous system: magnesium sits in the NMDA receptor channel and helps prevent excessive glutamate signalling; it also supports GABAergic tone which underpins its calming and neuroprotective effects.

• Energy: it’s required for ATP to function (technically “Mg-ATP”), so low magnesium can show up as fatigue, muscle weakness and poor exercise tolerance.

• Stress axis: magnesium helps regulate the HPA axis and cortisol response, which may explain some benefits in stress and mild anxiety.

• Brain-specific (L-threonate): MgT appears to increase brain magnesium more than other forms in animal and early human work, supporting synaptic density and plasticity, basically making neurons more resilient and efficient.

Safety & cautions

• Main issue at higher doses = loose stools, cramping, nausea, especially with citrate/oxide; glycinate, malate and threonate are generally gentler.

• Next-day grogginess if dose is too high or taken very late at night (some people do better taking it 1–2 hours before bed, not right at lights-out).

• Some should not self-supplement heavily;

  • Significant kidney disease (reduced ability to clear magnesium).

  • On high-dose magnesium medicines already (e.g. some laxatives).

  • Children and teens – only under professional guidance.

🔧 Update: The Healthspan Academy

Last week we launched The Healthspan Academy, with a full suite of tools to help you optimise your health.

Our last issue was so popular, our email open-rate was 20% higher than normal, and our click-rate was more than double what we normally get.

Weekly.health readers calculated their BMI, TDEE, BMR, and other health metrics more than 500 times, and more than 200 recipes were generated using our AI Meal Plan Generator, for free.

We’re thrilled our platform got off to such a great start, but there’s still more to come, and The Healthspan Academy will make a regular appearance in these issues as a supporting platform to give you practical ways to use what you learn in Weekly.health.

🛍️ Purchases we recommend

Discover the products, services, and retailers we’ve mentioned in past Weekly Health issues, all in one place so you can explore at your own pace.

📥 Finding this newsletter useful so far?

Your friends could benefit, too!

It would really help us if you could share Weekly.health with your friends either in person or through social media. You could even just forward this email to them.

Every subscriber helps us towards our goal of improving lives and helping people live longer.

📥 Feedback or suggestions?
We really appreciate any feedback you can give. Your feedback can help shape Weekly.health to change lives.

Reply directly to this email - we'd love to hear from you and we’ll be sure to reply!

🙏 Thanks for Reading!

That’s the end of this issue of Weekly.health.

This newsletter is written by a small, independent team, led by James — who’s been following nutrition science for nearly 20 years and working on a formal, industry-recognised qualification.

We’re based in England, so if you’re over the pond, you might notice a few strange spellings.

Our goal is to make cutting-edge, evidence-based nutrition advice simple, useful, and genuinely applicable to everyday life.

We don’t want to bombard you with adverts, but a few of the links in this email may reward us when you click and make a purchase. This goes towards helping us to continue bringing you this newsletter.

We’ll keep improving with every issue. If you’ve got any feedback or suggestions, we’d love to hear them (just reply to this email).

See you next week!

Want to start your own newsletter like this? Join Beehiiv.

📖 Glossary of Terms in This Issue (Alphabetical Order)