The Secret Ingredient

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The paper on the physics of fluids was interesting, although the math was way beyond my ability. Researchers from four European countries took part in the research study on Cacio e Pepe to find the precise texture of the pasta, starch content of the water, and temperature of the water to get the perfect sauce from cheese and pasta water (the starchy water in which the pasta’s been cooking).

It all comes down to something called phase separation. That is the critical point where the starchy pasta water emulsifies the cheese so that it becomes creamy instead of separating into a lumpy mess. The scientists called the clumping the mozzarella stage. Not everyone has an Italian grandmother that they can watch and learn from, and nonnas didn’t use fancy instruments to test the water starch content—they knew from experience after making the dish hundreds of times.

If you’ve never thought about the physics of cooking, I’m with you on that. But the interaction of the starch being released from the pasta and visually assessing the starch content to get it right is just that: physics. The number of attempts the scientists used with varying starch content, water temperature, and cheese, and the resultant mathematical calculations to get to a solution were amazing. They actually came up with the correct recipe, but believe me, it’s too complicated to just post because it requires so much explanation. So they looked for another way to prepare the cheese sauce.

The Secret to Cheese Sauce: Sodium Citrate

The scientists came up with a natural solution: a natural substance, sodium citrate, that helps with the emulsification of the cheese. That’s the step the physicist chef talked about on the podcast. At the point where the starchy water is added to the cheese, a pinch of sodium citrate will help the emulsification process and instead of goo, you’ll get a creamy and smooth sauce. When I try it, I’ll let you know how it went.

Sodium citrate will add some tartness, but it’s also good for you if you’re not sodium sensitive. The citrate is a natural anticoagulant as well as emulsifier. The stumbling block may be the amount of sodium citrate. The recipe called for a pinch, which is usually an eighth of a teaspoon, but in the amount of pasta for two persons, the scientists used 5 grams, which is almost a teaspoonful.

So even after all the science that went into it, it’s still going to come down to trial and error. But you now have a solution for homemade cheese sauces. Ever try to make your own mac and cheese and end up with clumps? If it works for Cacio e Pepe, it should work for other cheese sauces that may separate.

The Bottom Line

What’s the point to all of this? Cooking enhances the flavor of the simplest ingredients. I would wager that if people knew how to cook better, they would use healthier ingredients. I think we can all relate to hating Brussel sprouts, but when baked with a little cheese and bacon, they’re amazing (check out the recipe on the Health Info page at drchet.com). We can argue whether a three-ingredient pasta dish is healthy, but if cooked properly, we may be satisfied with less, while vegetables cooked properly may mean we eat a little more. Remember, no one ever said that vegetables, fruits, and whole grains had to taste bad. The goal is to eat better. If cooked well, we may eat less.

What are you prepared to do today?

        Dr. Chet

Reference: Physics of Fluids 37, 044122 (2025)

Cheesy Pasta: My Gooey Mess

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Last Saturday I said that with all the heavy health news going on, it was time to change it up and talk about something a little lighter. Nothing could be lighter than cooking with just three ingredients to get a magnificent pasta dish. The dish is called Cacio e Pepe (Cheese and Pepper in English), and all you need is pasta, fresh ground pepper, and pecorino cheese although Parmesan also works. What you may not realize is that you also need to watch an Italian nonna cook it about 100 times before you even try to cook it.

When done correctly, the sauce is delicious. I’ve tried making it twice. The first ended up with the cheese reformulating and making a gooey mess. The second was the same but was inedible because I put in way too much pepper, together with the gooey instead of smooth and glistening sauce. I wasn’t going to threaten the creations of Italian nonnas any time soon. (By the way, we thought Nonnas was a fun movie.)

That is until I listened to a podcast that mentioned the physics of cooking pasta. A guest on the podcast, a chef with a PhD in physics, mentioned the elusiveness of cooking this recipe. That caught my attention and led me to read a paper titled “Phase behavior of Cacio e Pepe sauce” in the journal Physics of Fluids. Not only did I find out a lot about how pasta loses starch, but I also found out about a secret ingredient that makes the sauce work—and it may be good for you as well! That’s Saturday’s Memo.

What are you prepared to do today?

        Dr. Chet

Reference: Physics of Fluids 37, 044122 (2025)

Folinic Acid and Autism

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The other news related to autism was talk about the potential benefits of a pharmacological form of folate called folinic acid, an active form of vitamin B9; it’s being described as a cure for autism. In fact, the new CDC administration is fast-tracking a change in label use for the drug so it can be prescribed more often. Here’s why I think that would be a mistake.

While doing background research on an updated webinar on pregnancy, I found a paper that discussed the potential impact of mutations of the methylenetetrahydrofolate reductase (MTHFR) gene of the mother on the development of the baby. If the mother had both mutated genes, her body wouldn’t process folate very well, resulting in the over production of homocysteine as well as other issues. That could be related to the development of neurological disorders in their babies, including autism spectral disorders and ADHD.

Folinic acid is a pharmacological form of folate that has been prescribed for use with chemotherapy patients. Some forms of chemo block the MTHFR gene, and folinic acid helps ameliorate the problems related to the chemotherapy. It seemed obvious to me that it could potentially help pregnant women with the mutated MTHFR genes and thus maybe prevent the neurological disorders in the baby. That’s where it ended because there’s not enough research to suggest it will work. The research has to happen now. Simply changing the uses for the drug based on small studies and testimonials isn’t good enough without research to support it.

As far as a treatment for autism, the same holds true. We don’t know whether the impact is dependent on, or independent of, the MTHFR mutation. Perhaps in people without the gene mutation it wouldn’t be effective, or worse, detrimental in some way that is not apparent right now.

I hope reason rules the day, as exciting as the potential seem to be, but treatments should not be based on a few case studies or worse, solely on potential. We need at least some conventional proof.

Next week, I’ll turn to a couple of cooking topics to lighten things up a little.

What are you prepared to do today?

        Dr. Chet

Acetaminophen and Pregnancy

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There have been statements circulating in the health news related to autism in the past couple of weeks, and I want to provide some perspective on both. Today it’s about a link between autism and acetaminophen, the generic name for Tylenol, also known in other countries as paracetamol. Acetaminophen is also an ingredient in OTC meds such as Nyquil, Alka-Seltzer Plus, Theraflu, Goody’s Powder, Pamprin, and so on.

The controversy surrounds a recently published study that concluded pregnant women should use acetaminophen with caution under the supervision of a physician for short periods of time—which is exactly what the major medical associations already recommend.

The researchers used a statistical technique called navigation guide analysis. Essentially, it’s a meta-analysis typically used to assess environmental toxins; whether it should be used in a pharmacological analysis is not clear. In addition, there’s always the risk of bias when selecting studies for inclusion in any meta-analysis, and this is no different.

It’s especially difficult to ignore bias when three of the four researchers have provided expert evidence for plaintiffs in prior lawsuits against acetaminophen manufacturers. Even if that were not a concern, the methodology for assessing acetaminophen use depended on recall questionnaires from the mothers-to-be or their healthcare providers—not medical records. We know how well that works in Food Frequency Questionnaires, so let’s go: Did you take any pain meds in the last year? Which ones? Don’t remember? I’m not surprised—neither would I expect a woman who’s busy growing another person to remember every OTC med she took.

One more thing? Acetaminophen has been recommended for pain since the 1950s. If it were directly linked to the risk of autism or other neurological issues, it would have become apparent before this, some 75 years later. It doesn’t mean research shouldn’t continue, but for now, acetaminophen appears to be safe when taken as recommended for short periods of time under the direction of a physician. Pregnancy comes with a host of worries—which diapers, which car seat, which baby vitamins—but I’d take acetaminophen off that list.

On Saturday: is there a new treatment for autism?

What are you prepared to do today?

        Dr. Chet

Reference: Environmental Health (2025) 24:56

BMI: Still Relevant

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The study I reviewed on Tuesday was trying to establish that body fat as assessed by BIA was a better predictor of the 25-year death rate than BMI. Researchers made their case by using data collected in the 1999–2000 NHANES wave to establish that a measure of body fat that can be collected with a device such asse a scale or wrist monitor was better than hard data like height and weight as used in calculating BMI.

BIA and Body Fat

I have a unique perspective on BIA because I was part of a laboratory that collected validation data on the original devices. The researchers continuously stated that BIA was a direct measurement of body fat, but that’s not correct. BIA measures the body’s resistance to a low electrical current through the body; then that number is put into an equation combined with other measures—primarily height and weight—to calculate a percentage of body fat. In that wave of the NHANES study, they also collected waist circumference and skin-fold measures to obtain the best predictive equation for use in future studies.

I’m certain that the equations have been updated over the years, but at that time, the model for calculation of body fat was 95% dependent on height and weight. Recent standard errors of the measurement of BIA for body fat range from 3.6% to 6%. There are many reasons for errors of that size, but impedance is particularly sensitive to changes in hydration and alcohol consumption. And to be clear, BIA is not a direct measurement of body fat—it’s just simple to use.

BMI Is Still Relevant

BMI is measure of surface area. It would be nice if more surface area indicated increased muscularity, but for 99.5% of us it’s not. It’s an indication, not a direct measurement, of our body fatness. It does tell us whether we are at a normal weight for our height.

BMI should not be used with hard edges. I would be hard pressed to say that there is a significant risk of anything for someone who has a BMI of 25.9 versus a BMI of 24.9; the former indicates overweight while the latter indicates normal weight. That’s a difference of just six pounds, and a good bowel movement could account for half of that. It’s not relevant in the real world. But a BMI of over 30 indicates that someone is obese, and that affects an increasing number of people in the U.S. and other industrialized nations.

The Bottom Line

BMI is still the best metric we have for assessing whether someone is at a healthy weight for their height. We can try to account for bone size and muscularity, but that doesn’t apply to most people. Getting to a healthy weight and staying there is still the best way to live the longest and the healthiest life. There’s no splitting hairs over that.

Here’s a factoid for you: our email platform tells us how many clicks we get on whatever we send you, and by far the most-clicked page is the BMI chart in the Health Info section. And we include adjustments for frame size, so you’ll know for sure if you’re really big boned. We hope having that info easily available helps you make good decisions about your health, because a BMI chart is still the easiest way to determine whether your weight needs to come down.

What are you prepared to do today?

        Dr. Chet

Reference: Ann Fam Med 2025;23:Online. https://doi.org/10.1370/afm.240330

Are We Done with BMI?

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Body mass index has been used for decades as a way to assess whether someone is at a healthy body weight for their height. For just about as long, it’s been under attack for the people who feel it was not representative of their body composition; high muscle mass and bigger bones were two of the complaints. I’m not going to disagree, within reason, but as a way of assessing a population in large studies, it can give us some indication of how body mass is related to health.

A recently published study has called into question the use of BMI as a predictor of mortality. Researchers used the data from the 1999–2000 National Health and Nutrition Examination Survey (NHANES) to compare BMI with a method of measuring body fat called bioelectrical impendence analysis (BIA). The subjects had all metrics measured when that wave began and were 20–49. Then they obtained death certificates for everyone in the study who died in the 25 years since.

The results presented in hazard ratios demonstrated that BIA and waist circumference were significantly related to all-cause and CVD mortality while BMI was not significantly related to either. In the discussion, the researchers suggested that BIA for determining body fat percent be used in clinical settings to assess patients at risk for increased risk of dying. Is that a good idea? Should we throw out BMI? I’ll let you know on Saturday.

What are you prepared to do today?

        Dr. Chet

Reference: Ann Fam Med 2025;23:Online. https://doi.org/10.1370/afm.240330

Forever Chemicals: Maybe Not Forever

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The issue with forever chemicals, particularly PFAS, is that we can’t avoid exposure, especially because they are found in the water supply. That’s why a couple of recent studies provide some hope that a solution can be found in the foods we eat, specifically fiber.

Study One: Oat Fiber, Cholesterol, and PFAS

Canadian researchers examined the blood of 72 men who participated in a study of the use of oat fiber (beta-glucan) to lower cholesterol. They re-examined the blood samples taken for that study for PFAS levels collected before and after taking the fiber supplement for four weeks. They found that those taking the fiber showed reduced levels of some forms of PFAS in their blood.

That’s a very short study, and while done with a different purpose in mind, it still provided some direction for future research. The types of fiber and the forms of the PFAS that can be affected still need to be determined, but as I said, it provides direction.

Study Two: Inulin, PFAS, and Your Liver

Researchers began with several questions for this study in mice. First, was the damage caused by PFAS passed from mother to pups? Second, could adding a form of fiber called inulin to the diet of the pups reduce the damage from the PFAS exposure?

The answer to the first question was yes. Both liver damage and damage to the microbiome of the mice and their offspring were confirmed. Second, did the use of inulin fiber reduce and reverse the damage to both the liver and the microbiome? The answer again was yes.

This was a rodent study and humans are not rodents. However, it’s apparent that fiber supplementation was beneficial in reversing at least some of the damage caused by PFAS. Combining this with the earlier study, this is a direction that should be pursued by further research.

The Bottom Line

These two studies illustrate the benefit of basic research. It’s a beginning stage; we don’t yet know the complete mechanism of action of the fiber in relation to the microbiome and how that works with eliminating PFAS from our body, or even whether other types of fiber would work as well. As time goes on, if the research can go on, we’ll know more.

To me, we already have the direction in the recommendation of getting 25–35 grams of fiber every day. Fruit, vegetables, beans, nuts, and grains will provide us with the fiber we need every day, and a fiber supplement will give you extra insurance for those days you don’t eat as you should. If we start doing it now, we can wait for the research to catch up to our healthy lifestyle.

What are you prepared to do today?

        Dr. Chet

References:
1. https://doi.org/10.1186/s12940-025-01165-8
2. https://doi.org/10.1016/j.envpol.2025.126749

Should You Worry About Forever Chemicals?

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Per- and polyfluoroalkyl substances (PFAS for short) are found in water to the extent that 100% of the population has measurable PFAS in their blood. PFAS are synthetic chemicals that are used in many products such as fire and heat retardants and oil- and stain-resistant products. Teflon coating in cookware is the best example of the use of PFAS and why getting rid of that cookware is a good idea. Because they are chemically stable, they are called forever chemicals.

The problem is that there are known health issues associated with exposure to PFAS. Among them are a reduction in immune response and increased risk of infections of the liver and kidney damage, increased risk of cholesterol and high blood pressure, as well as issues related to reproductive health. There may be more specific issues with other organs and organ systems. Research will continue.

The question is this: if they are forever chemicals, will they stay in the body forever? There is no known detoxification system that directly eliminates PFAS from the liver, but there may be hope based on a few recent studies. We’ll take a look at those on Saturday.

In tomorrow’s Insider Conference Call, I’ll discuss a variety of topics related to vaccinations as well as whether the COVID infection impacts the health of arteries. If you become an Insider by 8 p.m. tomorrow, you can participate and get your questions answered.

What are you prepared to do today?

        Dr. Chet

Reference: https://bit.ly/3VhB612

Artificial Sweeteners—Still Your Choice

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The use of artificial sweeteners is always a contentious topic in the health field. Some people hate them, other people love them. I use them occasionally, but when it comes to benefits versus harms, I stick to the research. In this case, it’s what wasn’t stated in the headlines about the study that is important, but we can make a decision based only on what we read. This was an abstract of a presentation at a conference, so some details may have been left out that were included in the study.

The Rest of the Story

The authors established an increased risk of diabetes with artificially sweetened drinks and saccharin in any form, but there were no statistically significant diabetes symptoms linked with total intake of artificial sweeteners, sucralose, or aspartame in all foods. That means that artificial sweeteners used in other foods didn’t raise the risk of diabetes, such as added to coffee, used in ice cream or other dairy products, or used in baking. You have to wonder why it had no apparent impact.

It may be that the specific food delivery system has some impact on why it does or does not have an effect. One possibility is that if the sweetener reaches the gut bacteria, it’s modified in some way so that it doesn’t impact blood sugar or blood sugar release.

It seems odd that they used markers of diabetes as their criteria rather than physician diagnosis. They looked for fasting glucose of 126 mg/dl or more; oral glucose tolerance test 2-hour glucose of 200 mg/dl or more; hemoglobin A1C of 6.5% or more; or use of diabetes medications. The last one makes sense, because you don’t get the meds unless you have a diagnosis, but still, odd language.

FFQ—Again!

Even though the food frequency questionnaire is still a good assessment tool when used with interviews, I checked the validation studies. The correlations with food diaries and interviews for the food frequency questionnaire developed specifically for the CARDIA study were no better than 0.5, indicating a moderate positive relationship—maybe it did, maybe it didn’t. That’s much worse than other correlations used in large studies. Also, the first two nutritional assessments couldn’t have assessed sucralose because it wasn’t available until after they took place; I don’t know why sucralose was included when it wasn’t available for almost half the follow-up period.

The Bottom Line

The debate on artificial sweeteners will go on, because people love them or hate them. Based on the results of this observational study, nothing of worth has really been added to the knowledge base. The researchers called for more research to examine how artificial sweeteners impact glucose metabolism. We don’t know that it does from anything done in this study, but that doesn’t mean well-designed studies shouldn’t be done in the future. Until then, it’s up to you whether to use artificially sweetened drinks or not. Maybe a better idea is to give up the mega-burger and fries instead.

What are you prepared to do today?

        Dr. Chet

Reference:  Cur Devel in Nutr  https://doi.org/10.1016/j.cdnut.2025.107034

Artificial Sweeteners—Again

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“I’ll have the jumbo mega-burger with extra cheese, a large order of fries, and a diet cola.” Have you ever heard that when you’re standing in line? Have you maybe ordered that yourself? That’s what I thought of when I read the health headlines about the dangers of artificial sweeteners contributing to the development of diabetes.

The Coronary Artery Risk Development in Young Adults (CARDIA) study began in the early 1980s by recruiting and tracking young adults to determine which factors are associated with the development of heart disease. Nutrition was one of the primary factors that was tracked using a food frequency questionnaire with dietician interview. They tested the subjects at the beginning of the study, at year 7 of follow-up, and year 20 of follow-up.

After tracking the subjects for almost 25 years, they found that 14.8% of subjects developed metabolic changes that indicated diabetes. Comparing the highest quintile of artificially sweetened drink use with the lowest quintile, there was a 129% increased risk for developing diabetic symptoms in the highest quintile. The use of saccharin was also associated with 120% increased risk of developing diabetes.

Is there more to this study that wasn’t highlighted in the headlines? I’ll cover that in Saturday’s Memo.

What are you prepared to do today?

        Dr. Chet

Reference:  Cur Devel in Nutr  https://doi.org/10.1016/j.cdnut.2025.107034