Welcome to the April 2024 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, MDs, PhDs, RDs, an MS clinical nutrition, an MS biology, and an LAc, summarizes the essence of several interesting recent studies.

In this issue: (1) this month’s Mental Health Moment: how specific scents might benefit depression, (2) the connection between low calorie consumption and sleep quality in young rugby players, (3) protein intake and loss of muscle in menopause, and (4) CoQ10 for mitigating post-exercise muscle damage.

Mental Health Moment: Scent Recall Can Benefit Depression

Major depressive disorder (MDD) can have widespread adverse impacts on a person’s health and quality of life. A common cognitive function that is often difficult for individuals with MDD is autobiographical memory recall, even when their depressive symptoms are being managed. Individuals with MDD can have difficulty remembering specific events or over-generalize individual negative experiences as an entirely negative self-perception. Often, memories can be triggered by cues like words, images, and even smells. Odor cues are typically tied to more emotional experiences, making them vivid and memorable. This study assessed whether odor cues can trigger more direct memory retrieval and recall compared to word cues in individuals with MDD.

Adults ages 18-55 with a diagnosis of MDD were presented with cues and asked to recall a specific memory related to each cue. To evaluate recall, response times were measured. To compare odor cues versus word cues, all participants received both methods; 12 cues were received as odors and 12 cues as words. Participants also rated their memory’s associated emotion, arousal, vividness, and repetition. They also were asked to identify the odors they were presented to assess the influence of odor recognition accuracy.

This study found that odor cues resulted in more specific memory recall, while word cues were associated with more general categorical memory recall or no recall at all. Although the odor-recalled memories were associated with more arousal and vividness, they were more slowly recalled compared to word-cued memories. Even with incorrectly identifying the presented odor cue, these odors still produced more memory recall in this study population. This indicates that using odors to directly activate memory might be beneficial for individuals with MDD because of prefrontal processing deficits that make word cues less likely to elicit memory recall. Improving specific memory recall of positive experiences and memories might lead to improved autobiographical perspectives and less generalized negative self-image and other depressive symptoms. 

Note: To provide additional support for healthy mood, Thorne’s Emotion Balance Support can be of benefit.* The formula’s combination of nutrients and botanicals promotes healthy neurotransmitter and adrenal function to modulate stress and improve mood.*

Contributed by Carly Duffy, MPH, RD

Reference

Inadequate Caloric Intake Impairs Sleep Quality in Young Rugby Players

Low energy availability occurs when dietary energy intake is insufficient to meet daily energy needs. Although low energy availability is believed to affect sleep quality, previous studies have focused on subjective measures of sleep, rather than objective data. The following one-week study at a training center tracked the energy intake, expenditure, and sleep quality (using a wearable polysomnography sleep device) of 42 male rugby players (average age 16) with no prior sleep disorders. 

The participants could consume as much food as they desired for the entire seven days; alcohol was prohibited and caffeinated beverages were not allowed after noon. Food and drinks were weighed using an electronic food scale and recorded daily using a computerized nutrient analysis program to calculate caloric and macronutrient intake.

Training made up 15 hours for the week, and physical activity was monitored using accelerometry devices.

The participants were allotted a 9-hour window for sleep nightly (10:30 p.m. – 7:30 a.m.) and were not permitted to use electronic media devices during this time. On the last night of the 7-day trial, participants went to bed at 10 p.m., equipped with a wearable sleep device that measured total sleep time, sleep onset latency, wake after sleep onset, sleep efficiency, awakenings longer than 30 and 90 seconds, arousal index, and sleep architecture (stages: N1, N2, N3, and REM) based on the American Academy of Sleep Medicine recommendations.

At the end of the trial, participants were grouped into optimal, reduced, or low energy availability, based on their prior 7-day intake of 29.3 calories per kg of fat free mass daily, which was established as mean energy need.

Nearly half – 47.6 percent – had low energy availability at the end of seven days, 35.7 percent had reduced energy, and only 16.7 percent were in optimal range. 

Sleep data indicated a direct correlation between low energy availability and dramatic declines in sleep quality. Participants with insufficient energy stores had more difficulty falling asleep, increased nighttime awakenings, and less time spent in deep sleep (N3 stage) than those with optimal energy intake.

This study highlights how difficult it can be for young athletes to satisfy energy needs during intensive training periods, and that sleep quality suffers when energy availability is low, further hindering proper recovery. 

Note: Thorne’s RecoveryPro® features several ingredients that support restful sleep and optimize nighttime muscle recovery, including whey protein, magnesium bisglycinate, tryptophan, and PharmaGABA®.*

Contributed by Carina Toledo, MS, MHI, CNS

Reference

Protein Intake and Loss of Muscle Mass in Menopausal Women

Estrogen has many positive effects on a woman’s body beyond maintaining reproductive health. It also has antioxidant properties, helps preserve muscle mass, maintains bone density, and protects cardiovascular health, among other functions. Thus, the loss of estrogen that accompanies menopause can trigger negative health effects throughout the body. Among them, loss of muscle mass can be balanced by adequate protein intake, and recent research suggests postmenopausal women can benefit from increased dietary protein.

In a cross-sectional study, women were divided into premenopausal and postmenopausal groups and screened for study exclusions – smoking, pregnancy, hormone replacement therapy, habitual exercise, and cardiometabolic disorders. The study measures included blood and urine samples, dietary analysis, muscle strength and endurance, body composition, and muscle quality.

In postmenopausal women, lower estrogen levels occurred alongside increased blood and urine markers that indicated higher levels of inflammation and increased loss of muscle protein. Compared to premenopausal women, muscle strength and muscle quality were also decreased in postmenopausal women. In addition, postmenopausal women consumed less dietary protein (0.81 g/kg/day) compared to premenopausal women (1.47 g/kg/day). 

Note: Learn more about the benefits of dietary protein intake from Thorne’s Take 5 Daily blog post Protein 101. Looking to supplement your diet with amino acids or a protein powder? Then consider Thorne’s Amino Complex, Whey Protein Isolate, or MediClear-SGS™.

Contributed by Jennifer L. Greer, ND, MEd

Reference

CoQ10 for Exercise-Induced Muscle Damage

Intense exercise increases the production of free radicals (reactive oxygen species), which have been implicated in exercise-induced muscle soreness and damage. Signs of muscle damage can be evaluated via various blood markers, including creatine kinase (CK), lactate dehydrogenase (LDH), and myoglobin (Mb). Malondialdehyde (MDA) is a marker of oxidative stress. 

Research on the use of CoQ10 for mitigating exercise-induced muscle damage has produced mixed results. Thus, the purpose of this meta-analysis was to evaluate pooled data to establish some clarity. A total of 28 randomized, controlled trials comprising 830 participants were used in the analysis.

Supplementation with CoQ10 resulted in significant decreases (assessed by weighted mean difference [WMD]) in CK, LDH, Mb, and MDA:

  • LDH (WMD: -52.10 IU/L)
  • CK (WMD: -50.64 IU/L)
  • Mb (WMD: -21.77 ng/mL)
  • MDA (WMD: -0.73 µmol/L)

The largest benefit of CoQ10 supplementation was its lowering of LDH; moderate decreases were seen in CK and MDA. When standardized to the same units of measure, the myoglobin difference was not statistically significant, nor was there a significant change in total antioxidant capacity.

The effect of CoQ10 was dose dependent with significantly greater biomarker decreases seen with every 100 mg of CoQ10. The authors report an optimal daily dose of 300-400 mg CoQ10. 

Note: Thorne’s CoQ10 product contains 100 mg of non-crystallized, optimally absorbed CoQ10 per gelcap.

Contributed by Kathi Head, ND

Reference