​Patients often wonder if there are any holistic remedies or natural supplements they can take to support their health. One of the most often asked about supplements are probiotics, or “good” bacteria (lactobacilli strains specifically), which are found naturally in fermented foods, such as yogurts, or in beverages like Kombucha. Probiotics are hypothesized to be beneficial for gut microbiota, GI symptoms, removing toxins, improving mood/cognitive function, and even reducing cholesterol levels and improving hypertension. One of the most important questions is, however, is there any benefit to probiotic supplementation in otherwise healthy individuals?

​Probiotics are well studied for gut health, specifically in terms of microbiome alterations and improving GI symptoms. Studies show that probiotic supplementation accelerates the transition of premature infant microbiome into mature microbiome and helps reduce inflammation. However, a review of seven randomized control trials (RCTs) studying the influence of probiotic supplementation found that probiotics actually did little to alter the microbiome- only one study found probiotics to significantly modify the overall diversity of the gut bacterial community. Various GI symptoms have been shown to improve with probiotic supplementation, including an RCT that demonstrated improved bloating, burping, and flatulence with 6 weeks of probiotic supplementation, and a review that GI symptoms improved in those with IBS and chronic constipation in those who took probiotics, though the exact mechanism of improved symptoms remains unclear.
 
There are also claims that probiotics improve mood/ cognitive function. A study of university badminton players found that six weeks of supplementation with probiotics led to decreased anxiety and stress levels and improved aerobic capacity. An RCT of older adults found that those assigned to the probiotic intervention group had improved mental flexibility and less stress after 12 weeks of supplementation. In another RCT, 30 adults with Alzheimer’s disease showed improved cognitive status via higher mini-mental status examination scores after 12 weeks of probiotic supplementation as compared to the control group. However, a meta-analysis of 10 studies of elderly adults found no significant overall alteration in cognition with probiotic supplementation. While the results are intriguing, more research is needed into the effects of probiotics on cognitive function, specifically the mechanism by which probiotics are theorized to improved mood and brain function.

In healthy adults, probiotics can be beneficial in improving gut microbiota concentration, immune system mediators, stool consistency and vaginal lactobacilli concentration, according to one review of 45 studies. They found there is not sufficient evidence to link probiotics to cardiovascular health or reduced lipid levels. The review concludes that if increasing bacterial concentrations is necessary for an individual to improve their health, then probiotic supplementation is likely helpful for them. The study does mention that bacteria levels are likely to return to what they were previously after supplementation is stopped.
 
Overall, my takeaway is that if you have GI distress or diarrhea, a probiotic may improve symptoms. If your gut microbiota is damaged, either from heavy antibiotic use, being elderly or a premature infant, probiotics are likely helpful for rebuilding the microbiome. Otherwise, if you are a healthy kid or adult, probiotics will probably not have adverse effects, but likely will not cause major positive effects either. More research is needed into the effect of probiotics on cognitive health, especially in terms of the mechanism by which memory and mood might be affected by probiotics. But if you don’t mind taking an additional pill every day, or even just eating more yogurt, why not?

​Olivia Kahn-Boesel is a fourth year medical student at Harvard Medical School. She is currently applying into internal medicine residencies and is interested in a career in gastroenterology. She previously attended Tufts University, where she studied biology and community health. She has interests in health equity, improving health outcomes for underserved populations, and medical education. In her free time she enjoys dancing, playing soccer, and exploring cities.

Yi Ying Ong, PhD ​

​Have you ever wondered, is faster growth in early life linked to faster brain development and smarter children? Undoubtedly, the brain undergoes remarkable growth during both fetal development and the early years of life, playing a role in the establishment of diverse cognitive processes. Poor fetal growth, stunting (too short), or wasting (too thin) have been consistently linked to poorer cognition. Healthy growth in early life is therefore important for brain growth and development. But is faster growth better in general? Conflicting findings from limited studies in high-income countries raise questions about whether we have reached the limits of biological intelligence that better growth can confer, and whether there are any negative impacts of excessive growth at specific early life periods on cognition. Our study aimed to address these questions.

We conducted our study in Project Viva, a large prospective cohort in the United States. We modeled height and BMI growth trajectories for 1,052 children and obtained their standardized growth rates in early infancy (0-4 months), late infancy (4-15 months), toddlerhood (15-37 months), and early childhood (37-84 months). We investigated the associations between growth rates and mid-childhood cognition – intelligence quotient (IQ), visual memory and learning, and visual motor ability. We adjusted for a comprehensive list of potential confounders including both parents’ education, height, child’s gestational age, size at birth, growth at preceding age periods, and other prenatal and sociodemographic confounders. Furthermore, we investigated if the association between postnatal growth and child cognition differed between children who had vs. had not experienced poor fetal growth (born small-for-gestational age).
 
We found that faster linear growth at any period from age 0-7 years did not provide consistent cognitive gains or deficits in mid-childhood. Our finding is consistent with previous studies in Project Viva and the Avon Longitudinal Study on Parents and Children (ALSPAC) which both found no associations between infant weight or length gain and child cognition. Unlike studies in low- and middle-income countries which found consistent associations between linear growth and cognition, there is almost no stunting/wasting occurring in our cohort, and most children were able to reach their growth potential.
While this overall finding suggested no overall relationship, we wanted to examine other outcomes and subgroups. And some associations emerged. We found that faster linear growth in early infancy (0-4 months) was significantly associated with higher visual motor ability (ability to copy/draw designs arranged in order of increasing difficulty). This is consistent with a prior study which found that better visual-motor integration seemed to be predominantly predicted by faster growth in infancy from 0-5 months. The importance of the early infancy period on visual motor skills might be linked to a rapid burst of synapse formation in the primary visual cortex between 2 to 4 months of age, with the primary visual cortex attaining adult size at around 4 months of age.
Additionally, we found that faster BMI gain, particularly at late infancy, was associated with slightly lower verbal IQ and design memory (draw geometric designs from memory) in mid-childhood. This finding is consistent with prior studies in the US which investigated weight-for-height or fat mass gain on child cognition. While the effect sizes are small, which might not warrant serious concern at this stage, the increasing prevalence of child obesity (nearly 20%) in the US might have small but significant influences on some types of cognition at a population-level. 

Finally, we found that faster linear growth, specifically in early infancy, was associated with higher non-verbal IQ among children who were small-for-gestational age. Our finding reveals the potential importance of early infancy compensatory (i.e., “catching up”) linear growth in this vulnerable group. Given that poor fetal growth occurs in nearly 10% of pregnancies in the US, our study highlights the need to consider both prenatal and postnatal growth trajectories in clinical practice.
Overall, these findings suggest some subtle connections between growth and some aspects of cognition for certain children. Vigilance to childhood growth, especially among those children gaining weight too quick or who were small-for-gestational age at birth, is critical to ensuring that children have healthy development. 

​Dr. Yi Ying Ong, PhD is a Research Fellow at the Harvard T.H. Chan School of Public Health. She received her undergraduate degree in Biomedical Sciences, and graduate degree in Epidemiology from the National University of Singapore. Her postdoctoral research focuses on the early life determinants of cognition, behavior, and puberty. In her free time, Yi Ying enjoys practicing yoga and playing tennis.

​One of the most popular child feeding “hacks” is sneaking vegetables into a more kid-friendly food so that the child will unwittingly them. Vegetables are one of the most universal sources of parental feeding angst. However, the typical rejection of vegetables can be easier to manage when parents recognize that this is just a normal kid thing. Here is a quick summary of what is going on:

​In general, kids will voluntarily eat 1) what they like and 2) what is familiar to them. “Liking” is the major factor for young babies, who will instinctively reject anything that tastes bitter, an innate way of protecting themselves from ingesting toxins. Many vegetables taste bitter so babies spit them out, and parents might stop offering them in favor of something that the baby seems to enjoy more. As the baby grows into a toddler, they hit the neophobic (“fear of new things”) stage, when they refuse to engage with the unfamiliar, including foods that they have not eaten regularly. The neophobic phase can last for a long time, and once kids are mostly past it (at around 6 years old), food preferences and eating habits are well-established and often don’t include vegetables. This is when it might be tempting to start “hiding” the vegetables, which might work for awhile. But let’s consider how this is impacting the child’s long-term relationship to vegetables and to food in general:

1. Intrinsic vs. extrinsic motivation to eat: Research is pretty consistent in showing that children eat more vegetables (and just have a better relationship with food overall) when they have a sense of autonomy over their food intake. This means that they are deciding what and how much they are going to eat in response to their own preferences and internal feelings of hunger/fullness - they are eating something because they are intrinsically motivated. In contrast, children who are eating (or not eating) in response to pressure, restriction, or a desire for a reward are being extrinsically motivated.
2. Subtle messaging: eventually a child will probably discover that she is not eating a food that she has become familiar with, decided she likes, and voluntarily chosen to eat, but one that has been infiltrated by hidden vegetables. This establishes the vegetable as 1) something that is so undesirable that it needs to be hidden; 2) the evil thing that ruined a food she normally enjoyed; 3) something that someone else wants her to eat so much that they are willing to trick her into doing it. This pressure to eat the vegetable (a type of extrinsic motivation) can often have the opposite effect.
3. Children’s relationship with food: Meals and sharing food can be a wonderful source of joy and connection within a family. However, it is difficult to achieve these positive feelings when parents use food as a method of tricking or deceiving their child. How can children trust food if they don’t know what might be hiding in there?

These are not arguments again making spinach meatballs or zucchini muffins - the issue is the “hiding” or deception. “Flavor pairing” or pairing new or less-liked foods with other foods that a child does like, can sometimes increase acceptance of those foods. It can also be a way to provide positive exposures to vegetables, if done in a low-pressure and non-sneaky way.
If you’d like to read more about this and other topics related to child feeding and nutrition, you can check out my newsletter at https://justonebite.substack.com/.

​“You are not alone” is a phase I have used many times as a volunteer crisis counselor with the Crisis Text Line. This phrase rings especially true when I must use it with texters who struggle with body image or an eating disorder. While I have been in recovery for several years now, each time I get a texter who describes what they are going through, I feel as though I am reading my own diary. And it really is true; we are far from the only ones. The lifetime likelihood of developing an eating disorder for women is between 1.0% to 22.7% and though symptoms may vary in duration, severity, and type, they can impact all parts of a woman’s life. The American Psychiatric Association defines eating disorders as: “behavioral conditions characterized by severe and persistent disturbance in eating behaviors and associated distressing thoughts and emotions”. Anorexia, Bulimia, and Binge Eating disorder are the three most common, each having their own physical and nonphysical symptoms. Some symptoms of Anorexia are severely limiting food intake or a fear of gaining weight, Binge Eating Disorder symptoms includes consuming large amounts of food in a short period of time even after feeling and Bulimia symptoms includes inappropriate compensatory behaviors after an episode of binge eating. Eating disorders are linked to a decreased quality of life, with lower scores of overall, emotional, and psychological wellbeing compared to the general population. Comorbidity with other psychological conditions, such as depression and anxiety is common with eating disorders and can make the conditions worse. 

While the exact cause of eating disorders remains unknown, it is believed to be of a combination of genetics and social environmental causes. In females, puberty begins around 8 to 13 years old, and the mean age of eating disorder onset is 12.5. During puberty, the sudden rise of hormones causes the body to change rapidly, which may leave the adolescent feeling unhappy with their body. In a study on French school children, maturation during puberty in girls was shown to be related to a decrease in physical self-esteem associated with body fat. Since eating disorders tend to begin during this period of immense change, I began to wonder if eating disorder rates would also increase during perimenopause. Perimenopause is the transition that begins around the ages of 45 to 55 when circulating estrogen wanes and eventually ceases, which is then called menopause. As a research assistant collecting data from women in midlife (around age 50), I hear many women make negative comments about their bodies during measurements. Though some of these women play it off as a joke, these comments may display a trend- that this period of change may have a negative impact on body image.

Scientific literature supports this hypothesis. The rates of eating disorders during menopause are statistically higher than the rates before or after menopause, and it is thought to be correlated with one specific hormone: estrogen. The activation of estrogen during puberty drives cellular and behavioral responses to the body during this time, which is shown to play a role in eating disorder development in twin studies. Similarly, body image and disordered eating behaviors vary throughout a woman’s menstrual cycle in parallel with estrogen. During perimenopause, the level of estrogen begins to fluctuate greatly and eventually decreases, which may help explain why eating disorders increase during this time. The fluctuation of hormones during the menopausal transition also causes body composition and weight to change, which could lead the woman wishing she looked like she did before.  

It is essential that clinicians, researchers, and women themselves are aware of this window of vulnerability. During this menopausal transition, eating disorders can develop and current eating disorders may worsen. Clinicians have the opportunity to prepare their pre-menopausal patients for these changes and provide support. Women entering midlife should be conscious of potential changes in thoughts around food and their bodies. If you are struggling, you are NEVER truly alone.

​Recovery is possible.
Visit the National Eating Disorder Association for more information: National Eating Disorders Association. If you are in a crisis and need help immediately, text their acronym “NEDA” to 741741 to speak with a trained crisis text line counselor or call (800) 931-2237.

Michelle is currently a research assistant at Project Viva. She graduated from Michigan State University in May ’22 with a BS in Human Biology and a minor in Bioethics. During her time at MSU, she worked as a Research Assistant and mentor at a pediatric/adolescent mental health clinic and as a phlebotomist at an outpatient lab. In her free time, she loves to go on road trips, go hiking and play tennis. 

Current data show Asian Americans have the lowest prevalence of obesity among U.S. racial and ethnic groups. At a relatively low 12%, this number is less than half that of those who identify as White (29%) and Black (40%). However, health data for Asian Americans are misleading; among that Asian American demographic, there are multiple ethnic groups, some with higher prevalence of chronic disease and obesity. Viewing Asian Americans as one monolithic group masks disparities within subgroups that would benefit from more targeted intervention, highlighting the importance of disaggregating Asian American data, especially when making policies.

Asian Americans include those who are ethnically Chinese, Vietnamese, Filipino, Japanese, Korean, and Indian, to name a few. A recent study by Shah and colleagues (2022) showed that the prevalence of obesity among these groups range from 6% (Vietnamese) to 17% (Filipino). But these numbers do not actually represent the percentage of people who are at an elevated risk for heart disease and diabetes because they use the standard BMI threshold of 30 kg/m2 to define obesity rather than the modified threshold of 27.5 kg/m2 for many Asian populations that the WHO has recommended. The modified threshold better reflects disease risk among a population that carries fat differently than non-Hispanic White populations. Using this modified cutoff, 29% of Filipinos and 27% of Japanese are obese, comparable to non-Hispanic Whites. When we view Asian Americans as one, or when we use inaccurate systems for classification, we mistakenly believe that resources and interventions to prevent excess weight gain do not need to target this population.

Given the disparities in the prevalence of obesity among Asian American subgroups, it should come as no surprise that disparities also exist for diet-related chronic diseases. Shah and colleagues (2022) additionally showed that the prevalence of Asian Americans with diabetes, history of cardiovascular disease, and hypertension are 8%, 4%, and 21%, respectively. However, the prevalence of diabetes is 14% among Filipino, heart disease is 7% among Japanese, and hypertension is 39% among Japanese—almost double the overall statistic for each condition, and comparable to those who identify as non-Hispanic Black. There is clearly heterogeneity among Asian subgroups, and resource allocation should reflect these disparities.

In recognition of the importance of collecting data on this fast-growing racial group, the National Health and Nutrition Examination Surveys (NHANES) started oversampling Asians in 2011 so that we could obtain reliable public health estimates from the survey. While this is a critical start, it is not enough, especially when researchers cannot easily access subgroup information for research. Health disparities among Asian Americans need to be properly addressed; to do so requires a bigger push toward data disaggregation and access to such data.

​Dr. Sophia Hua is a postdoctoral research fellow in the Department of Nutrition at the Harvard School of Public Health. Her research focuses on behavioral interventions to prevent diet-related chronic diseases and evaluations of nutrition policies. In her spare time, she enjoys reading and baking.