Welcome to the December 2019 issue of Thorne’s Research Extracts – 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. Our medical team, which includes NDs, MDs, PhDs, RDs, and an MS, LAc, and CCN, has summarized the essence of several of the most interesting studies. 

Research summaries in this issue include (1) chocolate improves depression, (2) air pollution can cause brain tumors, (3) sleep reduces anxiety, and (4) fish can make you skinny.

Why chocolate can benefit you over the holidays

Because one in seven individuals suffers from depression, it touches nearly everyone directly or indirectly. Depression is a debilitating condition that adversely impacts sleep, appetite, weight, energy, cognitive function, self-worth, and risk of chronic disease. Scientists are continually searching not just for relief for those who suffer, but also for prevention. Enter chocolate. 

A recent published study in the journal Depression and Anxiety found that chocolate consumption, especially dark chocolate, might reduce the risk of developing depressive symptoms. Data from the dietary recalls of 13,626 individuals participating in the National Health and Nutrition Examination Survey (NHANES) was assessed to determine chocolate consumption and then compared to scores on the Patient Health Questionnaire, or PHQ-9, that assesses depressive symptoms. Unlike previous studies, however, this study looked at the type of chocolate consumed (dark or not) and the amount of chocolate eaten. Those who ate the most dark chocolate were 70-percent less likely to report symptoms of depression; no such association was found for eating non-dark chocolate.

Chocolate contains several potentially mood-elevating compounds, including phytocannabinoids and other important neuromodulators. Scientists speculate that these compounds, along with the flavanols in dark chocolate, may explain the mechanisms by which dark chocolate influences mood. For example, flavanols appear to have anti-inflammatory effects, one of the driving forces behind depression.

Contributed by Danielle Paciera, LDN, RD, CCN


  • Jackson S, Smith L, Firth J, et al. Is there a relationship between chocolate consumption and symptoms of depression? A cross?sectional survey of 13,626 U.S. adults. Depress Anxiety 2019;36(10):387-395.

Does air pollution contribute to brain tumor incidence?

Both outdoor air pollution and diesel exhaust are classified as known human carcinogens, based primarily on evidence related to lung cancer. Combustion processes in areas of high population concentration, including vehicle exhaust, are important sources of ambient ultrafine particles (UFPs). To date, only a small number of studies have examined the relationship of ambient UFPs to cancer. Although UFPs (particles <0.1 micrometer) can reach the human brain, to this point there were no studies that evaluated the relationship between ambient UFPs and the incidence of brain tumors. 

This study evaluated whether exposure to ambient UFPs in air pollution increased the incidence of brain tumors in 1.9 million exposed adults in multiple Canadian Census Cohorts. Assessment was made of within-city spatial variation in ambient UFPs across Montreal and Toronto. Cohort members were followed between 2001 and 2016.

During the follow-up period, 1,400 incidents of brain tumors were identified. Each 10,000/cmincrease in UFPs was positively associated with brain tumor incidence. After an indirect adjustment was made for cigarette smoking and body mass index (BMI), the relationship strengthened. The authors conclude that ambient UFPs are positively associated with brain tumor incidence, a previously unrecognized risk factor for brain tumors.

Contributed by Amanda Frick, ND, LAc


  • Weichenthal S, Olaniyan T, Christidis T, et al. Within-city spatial variations in ambient ultrafine particle concentrations and incident brain tumors in adults. Epidemiology November 2019. doi:10.1097/EDE.0000000000001137

Does deep sleep reduce symptoms of anxiety?

Restful sleep is vital to good health and lack of sleep can have a significant adverse impact on how we feel physically and emotionally. This study conducted at the University of California Berkeley strengthens our understanding of the relationship between sleep and mood. The 2-part study surveyed individuals about their perceived connection between sleep and anxiety and studied that connection in a controlled laboratory environment. The survey confirmed that even small negative changes in sleep (either amount of sleep or quality of sleep) predicted increased feelings of anxiety. In fact, poor sleep was shown to increase anxiety by as much as 30 percent.

In the laboratory portion of the study, the researchers showed that deep sleep exhibits a restorative effect on the part of the brain that regulates emotional control. The researchers suggest that this shows that deep sleep results in less emotional reactivity, thus decreasing anxiety. Obviously, this relationship is complex, because, in addition to the effect of poor sleep, anxiety itself can be a cause of decreased sleep quality and quantity. In any case, this data indicates that implementing lifestyle and other treatments that improve sleep could be critical to management of stress and anxiety. Consider taking a sleep test to better understand your sleep.

Contributed by Jacqueline Jacques, ND


Another good reason to eat fish?

Recent research conducted at Stanford University’s School of Medicine lends credence to the assertion that fish – specifically, the fat from the fish – might help keep the fat off of us. But first a little physiology. When the oceans were populated with one-celled organisms, these cells were propelled by numerous tiny hair-like cilia, but once on land, the cilia were no longer needed. However, many of our cells, including our fat cells, retained a remnant in the form of a tiny appendage called the primary cilium, which apparently acts like a sensing antenna. In this study, the researchers were looking at which molecules were being sensed by these tiny fat cell antennae.

To their surprise, they found omega-3 fatty acids have a specific effect on fat cells. When an omega-3 fatty acid molecule binds to a receptor on the cilium called FFAR4, it causes fat cells to replicate. Although you might think that is a bad thing – it’s not. Small cells are better repositories for storing energy, while larger fat cells are associated with insulin resistance, inflammation, and diabetes. The researchers said, "What you want is more small fat cells rather than fewer large fat cells. A large fat cell is not a healthy fat cell.

The center is farther away from an oxygen supply, it sends out bad signals, and it can burst and release toxic contents." The researchers went on to discover that, unlike omega-3 polyunsaturated fats, saturated fats blocked this signaling, which prevents the formation of new fat cells but contributes to more fat being added to existing cells. In summary, the researchers concluded, "We have provided a mechanism explaining why omega-3 fatty acids are critical for maintaining healthy fat balance and why saturated fats should be limited."

Contributed by Kathi Head, ND


So stave off depression with chocolate over the holidays, keep anxiety in check by getting plenty of sleep, and help maintain a healthy weight by eating fish. You might also consider one of Thorne’s suite of fish oil products. Don’t know which one to choose? Take our quick quiz.