Welcome to the October 2023 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, which includes 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) Mental Health Moment: alcohol consumption and dementia, (2) exposure to scents and cognitive function, (3) berries, leafy greens, and gestational diabetes, and (4) stress and insomnia increase risk for atrial fibrillation.

Mental Health Moment: Alcohol Consumption and Dementia 

Across the globe, more than 57 million people live with dementia. Alcohol consumption is one of many lifestyle behaviors that can influence dementia onset. The present study explored the effects of alcohol consumption and changes in the consumption pattern on dementia risk. This study examined data from the Korean National Health Insurance Service database of nearly 4 million participants ages 40 years and older. Questionnaires collected self-reported data on the average number of days per week that alcohol was consumed and number of standard drinks on each occasion. Assessments were repeated annually for seven years. 

The participants were divided into four groups based on their alcohol consumption: none, mild, moderate, or heavy. They also were grouped based on any changes in their alcohol consumption in subsequent yearly assessments: sustained non-drinkers, quitters, reducers, sustainers, and increasers. 

Comparing nondrinkers to drinkers, those who sustained mild or moderate alcohol consumption had a 21- and 17-percent lower risk of dementia, respectively, while sustained heavy drinkers had an 8-percent increased risk compared to nondrinkers. Compared to participants who sustained their alcohol consumption, participants who reduced their alcohol consumption from heavy to moderate amounts had a lower risk of dementia. Conversely, those who increased consumption of alcohol also increased their dementia risk. 

While this study found mild-to-moderate alcohol intake to have protective effects, there may be other factors at play that require further research. Overall, these results indicate that keeping alcohol intake controlled and within lower limits helps to reduce the risk of dementia. 

Contributed by Carly Duffy, MPH, RD

References

Exposure to Scents Improves Cognitive Function

The olfactory system (sense of smell) is directly connected to the brain’s learning and memory systems, so much so that decline in sense of smell can predict cognitive impairment and progression to Alzheimer’s disease in aging individuals. In both animal and human studies, exposure to scents helped restore sense of smell, which in turn improved cognition.

In this study, older adults, ages 60-85, with normal cognition and ability to smell odors, were randomized to control or exposure groups. The exposure group received exposure to essential oil scents via scent diffuser for two hours each night for six months. A single essential oil scent was used each night, and seven scents – rose, orange, eucalyptus, lemon, peppermint, rosemary, and lavender – were rotated, such that participants were exposed to a different scent nightly. The control group received exposure to only trace scents.

All participants were evaluated at baseline and after six months. Assessments included verbal learning, immediate and delayed recall, working memory, planning and attention switching, sense of smell, and mental health status. Participants in the exposure group experienced a 226-percent improvement on the verbal learning and memory assessment. The authors suggested this improvement was particularly of note because this study used only minimal scent exposure (one scent per day for two hours) compared to previous studies.

Note: In addition to investing in a diffuser, you could consider a Thorne supplement such as Memoractiv or Brain Factors to support cognitive function.*

Contributed by Jennifer L. Greer, ND, MEd

References

Daily Intake of Berries and Leafy Greens Improved Metabolic Markers in Gestational Diabetes

Gestational diabetes mellitus (GDM) affects nearly 10 percent of pregnancies in the United States and can lead to complications for both mother and baby. GDM arises during the second or third trimester of pregnancy and is diagnosed based on elevated blood sugar levels following a glucose tolerance test.

Thirty-eight pregnant women (ages 18-45) with a diagnosis of GDM were enrolled in a 12-week randomized controlled trial beginning at 24-28 weeks of gestation. All participants also had a previous diabetes diagnosis, either GDM during a prior pregnancy or type 2 diabetes.

Participants were randomized to either a “control” group (n=18) that received nutrition education based on the USDA Choose My Plate guidelines or a nutritional intervention group (n=20) that included specific recommendations to consume one cup of whole, fresh berries and one cup of leafy, green vegetables daily, as well as walking 15-30 minutes after meals. 

Blood samples were collected at the beginning and end of the study from all participants, and dietary and physical activities were recorded in daily logs. At the end of the study, physical activity had not differed significantly between groups; however, the group that consumed berries and leafy vegetables daily had a significantly higher intake of antioxidants and fiber. The intervention group consumed an average of 23 grams of fiber daily, compared to 15 grams in the control group. 

The group that consumed berries and leafy green vegetables also had significant improvements in several blood markers compared to the control group, including:

  • Decreased blood sugar tested randomly throughout the day
  • Increased HDL (often referred to as the “good cholesterol”)
  • Decreased serum IL-6 (a marker of inflammation)
  • Increased total serum antioxidant capacity

The researchers concluded that, because the addition of these functional foods appear to positively affect important metabolic markers, at least in part due to the increased intake of fiber and antioxidants, they should be considered a “must” for any pregnancies affected by GDM.

Note: In addition to a healthy diet that includes plenty of green leafy vegetables and berries, consider Basic Prenatal and Prenatal DHA to support a healthy pregnancy.*

Contributed by Carina Toledo, MS Clinical Nutrition, MHI

References

Atrial Fibrillation Can Be Caused by Stress

Atrial fibrillation (Afib) is a common heart arrhythmia. A person can either be born with it (congenital) or it can develop over time, and the incidence increases with age with approximately two percent of the U.S. adult population under 65 experiencing Afib; the incidence increases to nine percent in adults over age 65. 

What is Afib? Afib is an irregular heartbeat that also can cause the heart rate to increase to 100-175 beats a minute. It can be caused by problems within the heart, problems outside the heart such as hyperthyroidism or sleep apnea, genetics, or lifestyle factors like heavy caffeine, nicotine, or alcohol consumption. Because it causes blood turbulence in the heart, it can increase a person’s risk for blood clots, which can in turn increase the risk for a stroke or heart attack. 

This current retrospective study looked at Afib incidence in 83,736 postmenopausal women (average age 64) who participated in the Women’s Health Initiative. Over an average 10.5 years follow-up, there were 23,954 cases of Afib (which by the way looks to be significantly higher than the nine percent of the population over age 65 statistic). The purpose of the study was to examine psychosocial effects on Afib incidence. Questionnaires were used to assess psychosocial stressors at baseline. 

After adjusting for other Afib risk factors, analysis of psychosocial factors identified eight major factors associated with increased risk for Afib. These factors were assigned to two clusters – the Stress Cluster that included stressful life events, depressive symptoms, and insomnia; and the Strain Cluster that included optimism, social support, social strain, cynical hostility, and emotional expressiveness. Further analysis identified two factors from the Stress Cluster – insomnia and stressful life events – that were the most significantly related to Afib risk.

Note: If you want more insights into what might be causing your sleep issues or how your body is responding to stress, consider Thorne’s Sleep Test or Stress Test.

Contributed by Kathi Head, ND

References