Welcome to the May 2025 issue of Research Extracts. “The Extracts” is designed to keep busy practitioners and savvy consumers up to date on the latest research on diet, nutrients, botanicals, the microbiome, the environment, and lifestyle approaches to good health and wellness. Our medical team, including NDs, RDs, MS biology, MS chemistry, an LAc, and a Certified Specialist in Sports Dietetics (CSSD), summarizes the essence of several interesting recent studies. 

In this issue: (1) Movement Moment: sodium hyperhydration and exercise performance, (2) avocado consumption and infant food allergy, (3) high iron stores and aging, and (4) cardiorespiratory fitness and mortality. 

Movement Moment: Sodium Hyperhydration and Exercise Performance

Prolonged exercise in hot or humid environments can increase a person’s core temperature and heart rate beyond what athletes are used to, impairing endurance capacity and performance. And the effects of dehydration can exacerbate these symptoms if a person can’t hydrate enough to account for sweat losses. Females are at an increased risk of dehydration and poor performance related to the heat because of natural progesterone, which increases the body’s temperature when it's elevated, in addition to their lower sweat rates.  

Hyperhydrating with sodium before exercise, to increase total body water above a balanced hydration status, can delay dehydration and decrease the cardiovascular and thermal effects of the heat and even improve an athlete’s endurance capacity and performance. 

In a double-blinded, quasi-balanced, crossover, random order factorial designed study, 12 endurance-trained female cyclists and triathletes completed five total steady-state cycling sessions at 60% of their VO2 max and five time-trial sessions at 200kJ in a hyperhydrated state. These were conducted during the cooler months in Melbourne, Australia, to avoid any prior heat acclimatization and were completed across different phases of the menstrual cycle, including phase one, where both estrogen and progesterone are low, and phase four, where estrogen is typically moderate and progesterone is high.  

The researchers found that sodium hyperhydration improved cycling performance in a hot environment by 5%, reducing total completion time by 1.55 minutes, when compared to those who did not hyperhydrate with sodium before exercise. This technique was well tolerated, allowing athletes to work harder without significant changes in their core temperature or heart rate, and is a beneficial strategy for female athletes who will be competing in the heat. 

Note: With the summer months quickly approaching, try Thorne’s Daily Electrolytes or Catalyte before your next exercise session in the warmer weather.  

Contributed by: Maura Donovan, MS, RD, CSSD 

Reference

Avocado Intake During Pregnancy and Infant Food Allergy Risk

During pregnancy, nutritional and lifestyle modifications are often recommended to support the health of both mother and baby. From dietary supplements to alcohol consumption and exercise habits, these changes are believed to influence not only maternal well-being but also fetal development and long-term outcomes for the child. 

Now, research is starting to further explore how specific foods in the maternal diet may play a role in shaping early immune responses in infants. This prospective cohort study from the Kuopio Birth Cohort (KuBiCo) evaluated the relationship between avocado consumption during pregnancy and the development of allergic conditions in their children at age 12 months.

In this analysis, 2,272 mother-infant pairs were assessed based on maternal avocado intake during the first and/or third trimesters. Avocado consumers were defined as those who reported any avocado intake during either of those trimesters. Infant allergic outcomes were tracked via a 12-month follow-up questionnaire and included physician-diagnosed food allergy, eczema, rhinitis, and paroxysmal wheezing.

After adjusting for a comprehensive set of factors, such as maternal age at delivery, diet quality (measured by the Alternative Healthy Eating Index for Pregnancy), smoking status, mode of delivery, and breastfeeding duration, the data revealed that infants born to avocado consumers had 43.6% lower odds of developing food allergies compared to those whose mothers reported no avocado intake during pregnancy.

While no significant differences were observed in eczema or rhinitis, both the adjusted and unadjusted analyses suggest a potential reduction in paroxysmal wheezing, although this did not reach statistical significance after full adjustment.

Avocados are a nutrient-dense fruit naturally rich in monounsaturated fats, fiber, folate, vitamin E, and several phytonutrients that may support immune development. These components have been previously studied for their potential to modulate inflammatory responses and promote healthy gut microbiomes, both of which play a role in immune health.

Although additional research is needed to confirm these findings, this study adds to the growing body of evidence suggesting that maternal diet, down to specific foods like avocado, may play a supportive role in early health and immune system development. Including nutrient-rich foods as part of a well-balanced prenatal diet may offer benefits that extend beyond pregnancy and into early childhood health.

Note: In addition to a healthy diet, nutrient gaps can be filled during pregnancy with the help of dietary supplements, including Thorne’s Basic Prenatal and Prenatal DHA.

Contributed By Ashley Huber, MS

Reference

Higher Ferritin Might be Associated with Faster Biological Aging in Women

Certain nutrients such as iron are essential for many bodily functions, but they can also be detrimental to health if blood levels are either too high or too low. In previous studies of telomere length (a way to measure biological aging), higher blood iron levels were associated with increased cellular senescence – a hallmark of aging in which cells stop dividing but don’t die. Other biological metrics of aging, such as DNA methylation, have less data related to iron status.

In a study of blood samples from 1,260 women ages 35-74, associations between blood levels of iron (ferritin, iron, and transferrin saturation) and methylation-based biological aging metrics were assessed. Increased ferritin (a protein that stores iron in the blood) was associated with increased biological aging across all three metrics. The authors noted this was the expected result considering that higher levels of ferritin are associated with increased oxidative stress and inflammation in the body, which in turn contribute to faster biological aging. 

However, one limitation of the study is that other blood iron markers (iron and transferrin saturation) were inversely associated with biological aging, a finding that is not consistent with the association between increased ferritin and increased biological aging. The authors suggested that this may be due to the choice of methylation-based markers of biological aging and that future research is needed to fully understand the role of iron in biological aging.

Note: Thorne’s Biological Age Health Panel analyzes the impact that lifestyle, nutrition, illness, and genetics have had on your body and provides insights so you can make changes that will improve your overall wellness and longevity.

Contributed by Jennifer L. Greer, ND, MEd

Reference

Cardiorespiratory Fitness vs BMI as a Predictor of CVD and Mortality

Overweight and obese body mass index (BMI) categories are often associated with cardiovascular disease (CVD) and all-cause mortality risk. Because of the continuous rise in obesity prevalence, weight loss has been a primary strategy for risk prevention, but weight regain is common. Alternately, cardiorespiratory fitness (CRF) may be a better indicator of health status, regardless of BMI.

This systematic review and meta-analysis explored the literature to quantify the relationship between CRF and BMI with CVD and all-cause mortality risk. The 20 included studies measured CRF using a maximal or VO2 peak exercise test which categorized participants into fit or unfit groups. Combined with BMI, comparison groups were established as normal weight-unfit, overweight-unfit, obese-unfit, overweight-fit, and obese-fit, using normal weight-fit as a reference group.

For all-cause mortality risk, the results showed that overweight-fit and obese-fit groups had no significantly increased risk compared to the normal-fit reference group. However, the normal-, overweight-, and obese-unfit groups had double the mortality risk compared to normal-weight fit. The population characteristics were also assessed, finding no differences between age, sex, chronic disease status, and the effects of cardiorespiratory fitness on all-cause mortality risk.

Similarly, in CVD mortality risk, there were no statistically significant increases in overweight- and obese-fit groups compared to normal weight-fit individuals, while the three unfit groups saw a significant two- to three-times increased risk. 

Overall, these results indicate that cardiorespiratory fitness is a stronger predictor of CVD and all-cause mortality risk compared to BMI, providing evidence for achieving health at any size with exercise-related improvements in metabolic function.

Note: To support healthy metabolic function, Thorne has a variety of supplements to choose from. Explore our product suite here. 

Contributed by Carly Duffy, MPH, RD

Reference