The Brain Health Kitchen Guide to a Healthy Metabolism
Plus, are artificial sweeteners really all that bad?
Hello, everyone. I am writing to you from San Diego where I have been spending time with my mom. Many of you have asked me how she is doing and I really appreciate that. As you may already know, she has been living with Alzheimer’s for the past 9 years. One of the latest developments is that she no longer remembers who I am. I know this sounds devastating, and believe me, I was dreading this. After all, no longer recognizing family members is common in later stages of Alzheimer’s. And yet, even though I knew this was coming it blindsided me. It’s a good lesson, for me, to remember that knowing something will happen isn’t the same as knowing how it will make me feel.
Even so, my mom and I really enjoyed each other’s company this week. We played some version of Scrabble by moving tiles around to spell the names of her children. We dabbled watercolors onto paper just for fun. And when she saw all the signatures I have collected in my book, she became determined to sign it too. I admired her focus as she practiced writing her name.
Today, we are wrapping up the discussion of the impact of metabolic health on your brain health with a discussion of artificial sweeteners. And, I’ve put together a downloadable guide of takeaways for keeping metabolic health top of mind. Find it at the end of this post.
There’s still time to enter to win a copy of The Menopause Brain by Lisa Mosconi, PhD. I’ll be accepting comments on this post until Wednesday, March 13 at 9 pm MST.
Non Nutritive Sweeteners
If you grew up drinking Diet Coke (or Fresca or Tab), you probably never thought twice about the safety of artificial sweeteners. Back then, soft drinks without sugar were the healthier choice. Artificial sweeteners are now more likely to be called non-nutritive sweeteners (NNSs) because they include both artificial (such as sucralose (Splenda), aspartame (NutraSweet, Equal), saccharin (Sweet’N Low)) and natural sources like stevia and monk fruit. NNSs produce an intense sweet taste at a very low concentration compared to sucrose (table sugar). They have low- or zero-calorie counts and have been marketed to help people lose weight or normalize blood sugar. But do they? And, could these ubiquitous food additives be actually harmful to metabolic health?
After decades of study, there are a few things we can say with certainty about the impact of NNSs on health:
Non-nutritive sweeteners (NNSs) do not help people achieve or maintain long-term weight loss. The World Health Organization (WHO) released the definitive statement on this topic in May of 2023. Even though artificial sweeteners may help people achieve short-term weight loss, follow-up after 10 years suggested an increase in body fat—the dangerous visceral kind—associated with their use.
NNSs do not help people living with diabetes control blood glucose. In the same statement, the WHO reviewed all the available data on this subject, and came to the conclusion that NNSs do not help improve the metabolic health of people with diabetes.
NNSs are unlikely to be carcinogenic in humans. According to the National Institute of Health’s latest statement based on a review of all the studies to date, previous concerns about NNSs causing cancer have been debunked. Those studies were based on animal data using supranormal doses of artificial sweeteners. This is one instance in which animal data does not pertain to human outcomes.
Daily drinking of beverages containing NNSs has been linked to increased dementia and stroke risk. In the past, both sugar sweetened and artificially sweetened drinks were associated with poor brain health outcomes. In a recent observational trial of the Framingham participants, only artificially-sweetened soft drinks were associated with an increased risk of stroke and dementia. The last word on this, however, comes from the recent UK Biobank study that used brain scans to measure brain volume in 178,000 people. Drinking 2 or more artificially- or sugar-sweetened drinks a day compared to someone who had less than 2 per month was associated with more brain shrinkage and an increased risk of developing dementia.
NNSs all have unique actions on health. Saccharin, sucralose, aspartame, etc. all have different chemical structures. This is one of the reasons it makes them so difficult to study in humans.
The “natural” NNSs (stevia and monk fruit) are generally recognized as safe (GRAS) by the FDA but they are not well studied in humans. Neither have been found to elicit a glucose or insulin response in limited studies, like this one of 30 male participants.
Here are the growing concerns about the impact of NNSs on metabolism and health:
NNSs pose insidious long term harm to metabolic health. Because these products alter the perception of sweetness, they mess with the brain and the gut in complex feedback loops related to how the body regulates satiety. In other words, a steady dose of artificially sweetened food products may have a long term impact on how your body keeps metabolic factors (like glucose, insulin, and the appetite hormone ghrelin) in check. This data is still evolving.
NNSs alter the gut microbiome. Since NNSs get metabolized by gut microbiota, which in turn alters how our friendly gut bugs behave and what they do—namely synthesizing hormones that regulate metabolism and appetite.
NNSs may have an “antibiotic effect” on gut health. A few studies have shown that chronic consumption of NNSs in food may lead to antibiotic resistance to common therapeutic drugs.
The Takeaway on NNSs
The study of artificial and natural NNSs is complicated by many factors, including reverse causation—those who tend to include foods containing these additives may already have poor metabolic health. After decades of study to tease out these factors, however, it looks like NNSs have a negative impact on long term metabolic health. In my book, both sweetened and artificially sweetened drinks are on my list of foods to limit or avoid.
Based on very limited study, NNSs derived from natural sources—stevia and monk fruit—do not appear to have a negative impact on health. These NNSs, used judiciously, are probably the best choice for sweetening foods. (I sometimes use monk fruit to sweeten non-alcoholic drinks. Find my recipe for monk fruit simple syrup here.)
We are born hard-wired to crave sweets, a fact that gets exploited by food companies throughout our lives. But this preference for sweets is malleable—it is something we can change. Part of the shift to a brain-healthier way of eating, in my opinion, is to stop expecting food to be sweet. Hone your taste buds to enjoy foods that are on the bitter end of the spectrum such as green tea, black coffee, bitter greens (like radicchio), dark chocolate, citrus peel. Many bitter foods contain tannins, potent brain health nutrients.
Recap of Metabolic Health Takeaways
Glucose is your brain’s best friend and worst enemy. That’s because the brain thrives on glucose as its primary source of fuel, but it only needs a small dose for optimal function. Too much blood glucose in circulation becomes a source of chronic inflammation in the body and the brain. Our brain health perspective on keeping your metabolism in tip top shape, then, is built upon a short list of glucose-centric concepts.
Chronically high glucose is bad for the brain. When fasting glucose levels run higher than 100 mg/dL for long periods of time, the excess glucose in circulation is especially harmful to the part of the brain where memories are (literally) made: the hippocampus. The hippocampus is a vulnerable structure; it is sensitive to too much blood sugar and shuts down its ability to respond to insulin to meet its glucose needs. The result: impaired memory and thinking skills.
Abnormal glucose metabolism falls on a spectrum. It progresses over years from insulin resistance to pre-diabetes to metabolic syndrome to type 2 diabetes.
Diabetes doubles the risk of Alzheimer’s. Chronically high blood sugar over time damages blood vessels, especially the small blood vessels that supply the brain. And, the earlier one gets diabetes, the greater the dementia risk.
Prediabetes can impair healthy brain function, too, and increase Alzheimer’s risk later in life. Fasting blood sugar levels consistently in the high-normal range—greater than 100 mg/dL—have been proven to substantially increase dementia risk.
Get these tests each year: a fasting blood glucose and hemoglobin A1c. Hemoglobin A1c (HgbA1c) reflects an average of blood sugar over the previous 3 months. If your health care practitioner suspects you may be insulin resistant, he or she may also measure fasting insulin. Target blood sugar levels are different for people with and without diabetes. For those over age 40 without diabetes, normal blood sugar is:
Fasting: 70-99 mg/dL
Before eating: 80—130 mg/dL
1-2 hours after eating: 80-140 mg/dL
Target hemoglobin A1c: Below 5.7%
Pay attention to numbers that are drifting up over time, not just the absolute values. If your fasting blood sugar has been under 90 mg/dl for years, for example, take note if it is rising, even if it is under the cut-off of 100 mg/dl.
There are pros and cons to wearing a continuous glucose monitor (CGM). Tracking the ups and downs of your blood sugar can be a learning experience especially if your testing is in prediabetic or diabetic ranges. It can help you clue into your unique biology and alert you when you may need additional testing. Wearing a CGM can also be a source of stress and may not be necessary if you are metabolically healthy. Getting minute by minute feedback on glucose peaks and valleys can elicit a stress response that in turn may feed into abnormal glucose levels. Micromanaging what you eat like this can lead to an overly stressful—and less joyful—approach to eating.
Glycemic index reflects the quality of carbohydrate. Glycemic load reflects the quantity of carbohydrate. Choosing foods that are low in both GI and GL is important for keeping blood sugar stable.
Does the order you eat your food matter for glycemic response? Perhaps. If you are living with diabetes, this strategy has solid science to back it up. Eating foods rich in protein and fat before a carbohydrate-rich food does blunt the post-meal glucose response.
Is intermittent fasting a good thing to do? Some people enjoy fasting and employ it to maintain a healthy weight and a stable blood sugar. But if you don’t like restricting your eating this way, it is not necessary for good metabolic health. Just try to finish up eating 3 to 4 hours before you go to bed.
Putting on muscle helps keep your blood sugar in check. Lifting weights and working out with resistance bands to build muscle helps your metabolism thrive. Think of muscle as a sponge that soaks up excess glucose that could otherwise lead to harm. By extension, making sure you consume adequate protein to build and maintain muscle is part of your strategy for a healthy metabolism. See: The BHK Guide To Getting Enough Protein and High-Protein Vegetarian Eating.
Foods to include that are high on my list for both brain health and low GI/GL: Berries, cruciferous vegetables, mushrooms, non-starchy vegetables, fatty fish, nuts and seeds, beans and legumes, whole grains, olives and olive oil, coffee and green tea, vinegar.
Limit or avoid foods containing non nutritive sweeteners (NNSs). Evolving data says these artificial sweeteners may be linked to poor metabolic health and alterations in healthy gut microbiota actions. Stevia and monk fruit sweeteners have limited human data to support their long term safety, but judicious use to sweeten foods is probably fine.
Perimenopause makes a woman more insulin resistant. Blood glucose can creep up during this time even when exercise and dietary habits stay the same. Once menopausal, the risk of type 2 diabetes goes up. Here’s a science-based strategy to make your metabolism more resilient during perimenopause and beyond:
Know your numbers. Keep track of your lipid profile, fasting glucose, and hemoglobin A1c on an annual basis. Ask for a fasting insulin level, too. Pay attention to results that drift up from year to year. Don’t hesitate to get out the tape measure and keep track of your waist/hip circumference.
Double down on your brain healthy dietary pattern. All the key components for your metabolic health are here: a diet that is low in sugar, packed with fiber, rich in protein, and includes the right balance of brain-friendly fats. Is there an aspect of brain healthy eating you could improve? The trick is to be mindful yet not overly obsessive about what you eat. Remember to enjoy your meals and that you don’t need to be a perfect eater to get results.
Get strong. Fighting back against prediabetes means resisting the tendency to lose muscle as we get older. For women at mid-life, strength training is no longer optional—it is essential to protect metabolic health, bone health, and brain health. Even two 30-minute sessions each week can help maintain the muscle mass needed for healthy aging.
Gather a team. You don’t have to muscle through perimenopause alone. Enlist the help of a registered dietician well-versed in this life stage. Jump start your exercise program with the help of a fitness specialist.
Consider HRT. One of the little-known facts about taking menopausal hormone therapy: it reduces the risk of developing type 2 diabetes. Not only does it help keep the body sensitive to insulin, it helps prevent the accumulation of visceral fat.
Founding Members Cooking Class: March 24th
I can’t even believe it myself, but I’ll be writing to you next from Sardinia—the big wild island off the coast of Italy that hosts dozens of centenarian villages. I will be attending Italian language school for 2 weeks then making my way over to Puglia (the heel of the boot) for the next Brain Health Retreat. I can’t wait to see some of you there!
Founding Members: I hope you can join our next Kitchen Chat and Cooking Class. Let’s meet for Sunday Lunch on March 24th at 12 pm MDT. I’ll be in touch to see what topics are on your mind.
Founding Members is a tier of the paid subscription that includes 4 live cooking classes and kitchen chats per year plus bonus content like additional recipes. I adore this group of BHKers and everyone is welcome to join. To do so, upgrade your subscription to Founding Member and I’ll get you on the list.
Thank you, everyone, for being a part of this community. I hope you all have a stellar week.
Love,
Annie
Once again thank you for your expertise!
sugar free desserts and spring salads using lots of asian greens
Stir fry entrees with tofu and asian greens
Thanks Annie - look forward to seeing you on Zoom.