December 2023 Research Roundup: Influencing Future Generations and The Impact of Lifestyle Choices on Offspring Health

Today's episode is a recap and "roundup" of research articles that were published in December 2023. Although we cannot take one single paper and make broad-sweeping claims, I do believe there are practical considerations and takeaways for each one of the papers that I chose for the episode.

The first paper tackles how lifestyle choices (even those of the father) might impact future generations. The authors of the study urge men to consider the potential shadow that paternal alcohol use has on future offspring. The research presents a compelling case for pre-conception alcohol abstinence, linking a father's drinking habits to potential birth defects due to sperm alterations. Moreover, I will discuss the surprising cognitive boosting effects of Lion's Mane mushroom in young people after one-time administration.

Next, I will go over the nuances of pain-relieving medication and pregnancy health, scrutinizing recent findings on acetaminophen use in the third trimester of pregnancy and childhood outcomes. From there I will shift gears to discuss a systematic review that outlines the benefits of glycine supplementation in healthy populations, highlighting its role in enhancing sleep quality and cognitive function, along with possible implications for aging research. Lastly, the conversation goes into advances in personalized nutrition. Specifically, how fiber might be differently affecting gut bacteria, and how those same bacteria matter for what fibers it is you consume.

Be sure to subscribe for future episodes covering specific nutrients and strategies for achieving optimal nutrient adequacy.

Papers cited in the podcast:
Paternal alcohol use: https://onlinelibrary.wiley.com/doi/10.1111/andr.13566
Lions mane: https://www.mdpi.com/2072-6643/15/22/4842
Acetaminophen use during pregnancy: https://www.nature.com/articles/s41390-023-02924-4
Glycine: https://link.springer.com/article/10.1007/s11357-023-00970-8
Fiber: https://pubmed.ncbi.nlm.nih.gov/37942526/

Transcript

Speaker 1: 0:10

Hello everyone, my name is William Wallace and I will be your host today as we perform our first research review from the month of December for the year 2023. We're going to take a look at what I personally thought were some interesting studies published in the month of December in the realm of nutrition science. Obviously, there's a lot to choose from every month, ranging from notable cell and mechanistic data, animal data and human clinical trials, not to mention all the genres of research design that could be included under the umbrella of each of those categories. My primary criterion for choosing here is really what I think is interesting and what I want to share with people. It's really that simple for this go-around. For this episode, I chose a total of five articles, some that were published from November and December, and I'm wrapping it up into this December recap video. I'm going to put the links to the articles themselves in the show notes for reference for anyone that wants to go find them and read them over for themselves.

Speaker 1: 1:10

Before we go any further, I must preface with the disclaimer that this podcast is being generated purely for educational purposes. Students of this broadcast do not constitute medical advice and are not meant to substitute for standard medical practice. Please consult with your primary healthcare practitioner before beginning any nutrition or supplement-based protocols that may be mentioned in this episode. The first article calls out a very interesting topic, that being alcohol-related birth defects. This particular study is going to help change the conversation around alcohol-related birth defects, with the historical emphasis being placed almost solely on maternal responsibility. Really, up to this point, there's not been much of any consideration given to male alcohol use when couples are trying to conceive or when a potentially alcohol-related birth defect is being considered in a child by a clinician.

Speaker 1: 2:09

This study is telling us that male alcohol consumption around the time of conception does, in fact, matter. This study was published out of Texas A&M in the Journal of Andrology and was titled Alterations in Sperm RNAs Persist After Alcohol Cessation and Correlate with Epidedymal Mitochondrial Dysfunction. That's mouthful. The results of this study suggest that men should abstain from drinking at least three months prior to conceiving. What the authors found was that it takes much longer than previously believed longer than one month actually for the effects of moderate alcohol consumption to leave a father's sperm. Now I do have to note that this study was conducted using an animal model and then extrapolating to human outcomes, while using approximate human equivalent dosing for alcohol consumption in mice.

Speaker 1: 2:57

It turns out that if you're a regular alcohol consumer, when you stop drinking, the liver is still experiencing similar stress responses from the drinking time period. This, in theory, sends a signal through the rest of the male body that even impacts the reproductive system, essentially communicating to the body hey, this environment is very stressful, and so we need to help program our children to be able to adapt to that environment. Because of this, sperm seems to develop an adaptation that we would term a maladaptation, in other words, an adaptation that results in unfavorable consequences. In this case, adaptations that a male sperm make might increase the risk for something like fetal alcohol syndrome. Actually, this same research group previously showed that drinking habits of the father before conception can harm fetal development, with semen from men impacting fetal alcohol syndrome, brain defects and in vitro fertilization outcomes.

Speaker 1: 4:01

The concept that paternal alcohol consumption as a stressor can cause changes to male physiology that affect the fetus is not a new concept. It involves the idea that environmental factors or stressors like the stress imposed from alcohol consumption, can cause changes in an organism that are then passed down to subsequent generations. This is called the transgenerational effect. Now for a practical takeaway. The model they use would suggest that having three to four drinks regularly can induce these negative changes in male sperm, because sperm are made over the course of 90 days and it takes one month for the negative impacts of regular alcohol consumption to leave the sperm. The researcher suggests that three months of alcohol abstinence prior to planned conception is wise. Now you might ask what does drinking regularly look like? And fair enough, the CDC states that regular drinking looks like three to 14 drinks per average per week from men. As a practical guideline, falling underneath this limit, then ceasing alcohol consumption three months prior to trying to conceive, seems like a reasonable recommendation.

Speaker 1: 5:15

The next study up is one of those that I referred to that was published in November of 2023. This one I find especially interesting because a lot of my doctoral work and professional work interests around the time of my doctorate was spent learning about purported cognitive enhancement agents that could be obtained legally over the counter in the United States. This study was the first to show that the popular mushroom Lion's Mane does in fact, positively impact cognitive performance in young, healthy people after only a single dose. There is some past research showing Lion's Mane did improve cognitive functions and mood, but those studies are typically using routine dosing, for weeks at a time and in a much more elderly population. This study, for the first time, shows improvements in young people and after a single dose. This study was titled the acute and chronic effects of Lion's Mane mushroom supplementation on cognitive function, stress and mood in young adults a double blind parallel groups pilot study.

Speaker 1: 6:20

For this study, 1.8 grams of Lion's Mane mushroom powder so it was a powder, non extract or a placebo was given to a group of 41 people aged 18 to 45 years old. The powder was taken every day for a period of 28 days and yielded very intriguing results in the short term. That's one time administration participants exhibited improved performance in what's called the strupe test, indicating enhanced processing speed and selective attention. Selective attention would be focusing on a specific aspect of information while simultaneously ignoring other irrelevant information. One example of selective attention would be the cocktail party effect. This is the phenomena that occurs when you're at a party and, despite the multitude of noises around you and all the other distractions that you can actually tune in and listen, listen to and understand a single conversation that you might be engaged in. You're effectively able to filter out and ignore competing stimuli. However, the cocktail party effect usually refers to auditory stimulus and, as is the case with this test, we're referring more to a visual stimulus. Now, after four weeks of using the lion's man powder, there was a notable trend towards reduced subjective stress reported in the people receiving the supplement.

Speaker 1: 7:42

The theoretical mechanism for lion's man's ability to affect learning and memory is its ability to increase brain derived neurotrophic factor, more popularly known as BDNF. As is implied in the name, this is a neurotrophin. Neurotrophins are a group of proteins that help brain cells survive, function and develop throughout life. Some of the top factors influencing the release and activity of BDNF in the brain include stress, exercise, nutrition, as well as environmental novelty. So do the results of this study mean that you should go out and buy a tub of lion's man's powder? Well, not necessarily. Although the results of this study are exciting and promising, I do have to note that studies with larger sample sizes are needed to replicate and confirm these findings.

Speaker 1: 8:32

And lastly, it had been brought to my attention that there's some kind of internet movement to discredit lion's man, on the basis of some Reddit users, I believe, claiming that it's giving them unwanted side effects in the form of depression, anxiety, insomnia, lack of libido and so forth. There's a claim that lion's man counteraccident enzyme called five alpha reductase, though to my knowledge there's no actual strong scientific evidence to suggest as much. Now it's not to say that some people may respond unfavorably to high-dose lion's man powder or extract. In fact, there's going to be a small percentage of the population that you'll find respond negatively or not at all to things where there's evidence to support people responding well to the very same things. This itself is not evidence or rationale against using something. So that's really important to understand for one. Likewise, I'm unable to take personal anecdotes from Reddit, especially from people who would appear to be using multiple questionable compounds alongside each other and then make sweeping, population-wide statements or recommendations to people. So there's that. Lastly, and especially as it comes to compounds with supposed cognitive effects in people, you absolutely cannot take a potential mechanism and then predict the effect that it's going to have in one person, let alone all people. To do so is to really lack an understanding of human biology and how that responds to certain compounds in the process through which science must go to understand how these compounds affect human physiology. So I say all that to inform you as a listener and help equip you all to think critically about blanket claims made that you hear on the internet.

Speaker 1: 10:19

Moving on to study number three, this one was published in the journal Pediatric Development, the results of which suggest that the use of acetaminophen, that's the active ingredient found in Tylenol, during pregnancy is linked to language delays in children. The title is examining the relationship of acetaminophen use during pregnancy with early language development in children. As a bit of background information, acetaminophen is the most common drug ingredient used in the United States and is found in over 600 different medications, including over-the-counter pain relievers, fever reducers, sleep aids, cough medicines and allergy medicines. To this point in time, acetaminophen is the only analgesic, that's, a pain medication, that's considered safe to use throughout pregnancy. Actually, both the American College of Obstetricians and gynecologists and the Society for Maternal Field Medicine recommended, as a first line, intervention for pain and fever during pregnancy. Research indicates that 50 to 65 percent of women in North America and Europe report taking medication that contains acetaminophen at least once during pregnancy. Although it's been considered safe to this point, there are very few clinical trials in pregnant women and research design here would be limited, because you wouldn't want to, or be able to give a pregnant person something that might be considered harmful to a developing fetus in a randomized controlled trial, for instance. Interestingly though, acetaminophen can cross the placenta and there has been growing interest in compounds like this that to this point, that we thought were safe but may potentially be affecting child development outcomes.

Speaker 1: 12:11

This particular study was conducted as part of the Illinois Kids Developmental Study, past. Research in this topic usually only asked pregnant women once per trimester about their acetaminophen use. For this work, the researchers actually met with the participants every four to six weeks during pregnancy and then within 24 hours of the child's birth. Language data was then collected later, when the children were between two and three years old. Well, when they were two and three years old, actually, the researchers chose two years as the age to begin collecting data on language outcomes, because this is a critical period during development, called the word explosion phase. This is when children are adding new words to their vocabulary daily. Now, as for the results, the study demonstrated that an increased use of acetaminophen, especially during the third trimester, was associated with smaller vocabularies and shorter length of uttered words when a child was two years old. At age three, more acetaminophen use was related to parents ranking their children as lower than their peers in learning ability. This result was primarily seen in the male children, not the female children. The most dramatic finding in this study was that if a person took acetaminophen 13 times, which would be equal to once a week, during pregnancy, her child would have a vocabulary that contained 26 fewer words at age two compared to their two year old counterparts.

Speaker 1: 13:41

The second and third trimesters are crucial periods for fetal development, especially the brain. Hearing and the auditory system really begin developing in the second trimester, but even brain centers at processed language begin developing in the third trimester, before the child is even born Hearing. The mechanism of action of acetaminophen is also helpful here, as is thought to produce its pain relieving effects through the endokinabinoid system, actually through interacting with CB1 receptors in a part of the brain called the rostral ventromedial medulla, which is a segment of the brainstem. This part of the brain interacts with other parts of the brain and the spinal cord to regulate the transmission of pain signals in the body. There's actually other research, mostly in rodents, that shows compounds that stimulate the endokinabinoid system during pregnancy, like THC from cannabis, for instance, can result in harm to developing fetus. Not to draw equivalence between those two compounds, that being acetaminophen and THC, but I do think that together it's suggestive that if any of these compounds that are in drug form or concentrated, as is the case here, with interacting with a developing fetus, that they would be exerting a super physiological stimulus to the developing system that they were interacting with and that stimulus may be harmful or lead to unfavorable effects in a still developing system.

Speaker 1: 15:16

Okay, so the big question should pregnant women swear off acetaminophen use altogether because of this one study? No, for one. This study was observational and it needs to be replicated on a larger scale. So until then, don't be afraid of acetaminophen when you really need it during pregnancy. Conditions like a high fever during pregnancy can be dangerous to both the mother and the developing fetus, and drugs like acetaminophen can be very helpful. As such, acetaminophen does remain a recommendation for serious pain and fever for women during pregnancy. There really are not other options available to pregnant women that would work as well as acetaminophen in many cases, especially more severe ones. However, if you are pregnant and just experiencing some minor discomfort, then some caution is probably warranted. That is what the researchers of this study do suggest.

Speaker 1: 16:16

The fourth article is the second one I referred to earlier that was published in the month of November. I chose this one because it pulled together 50 different studies, most of which were randomized controlled trials in humans, and it pulled them into a systematic review that looked at the effects of giving the amino acid glycine on several different health areas, including metabolic health, nervous system health and endocrine health, cardiovascular health and immune system health. This paper is titled the Effects of Glycine Administration on the Characteristics of Physiological Systems in Human Adults a Systematic Review, and it was published in the journal Geroscience. Now, for those of you that don't know the term, geroscience refers to a branch of science that's concerned with studying the intersection of three things aging, biology, chronic disease and health. Glycine is a compound of interest in this area because a lack of glycine in animal and human research has shown impeded growth, immune responses and metabolism.

Speaker 1: 17:23

No-transcript. There is some really interesting evidence again in animals and humans that giving extra glycine in the form of supplementation might protect against certain metabolic diseases. In some cases, an animal model, specifically glycine supplementation, has extended the life of roundworms by up to 33%, life of rats by up to 20% and the life of mice by up to 6%. So am I about to make a claim that it can do the same for humans. No, that's not why I cite those statistics. The point of the matter is that glycine seems to be a molecule that is generally protective in the body and, given that it's relatively inexpensive and safe for oral use, that studying its potential on health span is an important current topic of interest to many people.

Speaker 1: 18:12

Out of the 50 studies in the systematic review, 18 of which included healthy people, while the rest consisted of populations with a variety of different conditions. The ages of the people and the healthy populations ranged from 21 to 41 years old, so I assume that represents a large portion of the people listening to this podcast episode. For the populations with health conditions, ages range from 29 years old to 67 years old. When looking at all the studies, people were supplementing glycine orally between two days for all the way up to four months. The longer dosing durations were usually in people with different metabolic conditions that included insulin resistance, type 2 diabetes and high blood pressure. The most notable finding of this review was that glycine supplementation not only had benefit for conditioned populations, but also could benefit the nervous system of healthy individuals. There were three different studies included in the review suggesting that 3 grams of glycine 30 to 60 minutes before sleep, improved sleep quality, increased next day alertness and cognition, and decreased next day sleepiness and fatigue. The improvements in sleep even improved insulin responses in the healthy population.

Speaker 1: 19:33

The positive effects that glycine has on sleep are thought to be through its proposed mechanism, at the NMDA receptor in the suprachiasmatic nucleus brain region. This brain center is considered the master circadian pacemaker of the body that synchronizes cellular clocks to align with light dark cycles of the environment that we're in. The suprachiasmatic nucleus is also critical for promoting hypothermia and vasodilation. One of the ways in which the body prepares for sleep is by reducing core body temperature, and signaling within the suprachiasmatic nucleus plays a key role in this particular function.

Speaker 1: 20:15

The review paper highlights that glycine seemed to be most effective at improving nervous system characteristics like the ones I just mentioned, but also in psychiatric populations. There were actually 10 different studies that cited where oral glycine was used between 200 to 800 milligrams per kilogram body weight, usually as an adjunct treatment for 6 to 12 weeks, where it improved schizophrenic symptoms. In psychiatric populations, glycine at 3 grams twice daily, for a total of 6 grams a day for 4 weeks, improves sleep latency. That is, a shorter time to fall asleep. In people with overactive bladder disorder. Less surprisingly, but still relevant, outcomes of glycine supplementation in conditioned populations included improved insulin sensitivity, inflammatory markers and blood pressure when glycine was supplemented at 5 grams 3 times daily for at least 3 months. Of course, I do have to reiterate here that anyone listening to this podcast that becomes interested in the use of supplemental glycine for the purpose of improving symptoms of a specified condition must consult with their doctor before doing so. Glycine is safe. It is quite safe, but you do need your doctor's blessing just to be sure that there are no contraindications where someone will be put under the harm of supplementing something like glycine.

Speaker 1: 21:48

The last study to be highlighted in this episode builds on the evidence piling up that suggests that the type of fiber that you consume can lead to different outcomes and that your gut microbiome, as it is now, will impact the fermentation of different types of fibers in your intestines, as different types of bacteria will preferentially metabolize different types of fibers. Fiber is a broad category of compounds that are structurally diverse, meaning that different kinds of fibers vary greatly in their monosaccharide composition and chemical bonds that hold them together. As such, fibers require a different repertoire of enzymes to be metabolized and broken down. These enzymes are dispersed across different fiber, degrading bacterial species and strains. Actually, different research from this past year did show. This past year, in 2023, did show that gut bacteria have encoded in them a genetic predisposition for targeting specific polysaccharide structures reflected by their enzyme expression, and that predisposition might hold constant within the same bacterial strains, regardless of whether that strand was coming from the guts of two separate people. That information, combined with this study I'm about to highlight here, are moving forward the concept of individualized nutrition as it pertains to fiber intake. We can look at someone's gut microbiome and figure out what kind, what kinds of fibers sorry, sorry, justin, I'm gonna start back in other words. In other words, can we look at someone's gut microbiome and figure out what kinds of fibers they would respond best to? Or could we take certain fibers that have been shown to result in different health outcomes or that help grow different types of favorable bacteria species and move someone's gut microbiome in a desired direction, for instance? These are the kinds of questions that studies like this are working toward answering.

Speaker 1: 24:04

The current study was published in the journal Gut Microbes and was titled functional profiling of gut microbial and immune responses toward different types of dietary fiber a step towards personalized dietary interventions. In this study, the researchers took three different types of dietary fiber, including inulin, which is a fructo-aligosaccharide, a supplement called fibermax, which is a mix of different kinds of fibers, and a supplement called vita fiber, which is an isomolto-aligosaccharide. All of these were given given at 15 grams per day for one week to 28 women, followed by a two-week washout period, and then the women switched conditions. So every participant tried every type of fiber at some point in the study. This is called a crossover study. This study did determine that taking one fiber at that concentration for one week was enough to see changes induced by that fiber. I know that'd be a likely question about the study if I didn't state it just now. Now I'm not going to get too deep into the different phyla that each fiber increased or decreased, because I think that's going to draw some people away from the primary message of this particular study.

Speaker 1: 25:18

One of the most notable findings here was that inulin increased bacterial species that are known for their ability to generate short-chain fatty acids, that these are generally anti-inflammatory and beneficial molecules produced and used by certain gut bacteria. Inulin did this better than the other two fibers. However, more so than the other fibers, inulin actually decreased bacterial diversity. Now, mainstream gut health enthusiasts would tell us that increased bacterial diversity is what we want. So what gives here? Well, it's true that increased bacterial diversity is often cited as beneficial, even in research. However, that might actually be context dependent.

Speaker 1: 26:00

Reduced bacterial diversity may not in fact, be an indicator of poor health. There's actually research in animals and humans that shows that a high fiber diet reduces bacterial diversity. One study from 2028 showed that a high fiber intervention improved glucose levels and responses to food in type 2 diabetics, despite decreasing their bacterial diversity. It turns out that high fiber intake will create an environment that selects for fiber metabolizing bacteria. Because this fiber acts as a resource for these bacteria. They essentially out-compete other bacteria in the environment and thus overall bacterial diversity would go down. While health outcomes might be positive, it would be the dose and type of fiber or fibers used that would result in increased or reduced bacterial diversity. But again, reduced diversity is not necessarily an indicator of poor health. Now, notably here, any effect that a fiber had on gut properties after one week of supplementation were essentially reversed after not taking the fiber for the two-week washout period, which shows that, although the gut microbiome is sensitive to change from an intervention. Bacterial communities are still quite stable and resilient toward these fiber induced changes. As such, continual fiber intake would be necessary to sustain changes to gut bacteria induced by eating fiber.

Speaker 1: 27:32

Okay, so that does wrap up this research review episode. It was quick. I hope this was informative for you in some way, and I do hope that I can earn your subscription to this podcast on whatever podcasting platform you're listening on. If you have not already, please go subscribe to my YouTube channel, as that would be the best place to go and place questions about these episodes, where you'd be most likely to get a response from me. Thank you for taking the time to listen and I do hope to see you again here soon.