All posts by Frances Elizabeth Cates

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Does weather affect mood?

References to the connection between weather and emotion pervade our culture, whether it’s “sunshine on a cloudy day,” “singing in the rain,” “somewhere over the rainbow,” or “rainy day blues” (1). But does weather really affect mood? Let’s think twice.

Some people experience seasonal affective disorder (SAD), a type of depression that occurs most often during darker months in fall or winter (1). According to Johns Hopkins, chemical changes in the brain may be associated with symptoms of depression when the days are shorter and there is less daylight (5).

Regarding mood and weather, most of the experimental evidence suggests there is no relationship. A study of mood using data collected from participants’ online diaries and weather station data found that daily weather was not associated with mood (6). Another study collected questionnaire data from 97 participants regarding their current mood, activity level, and how much time they spent outside on the day they came to the lab and concluded that mood was not directly related to outside temperature or barometric pressure (7). A study of daily mood ratings and diary entries of 18 students analyzed the prevalence with which diary entries mentioned different types of weather and found no association between weather and mood (8). Another study used data from 14,478 people in a depression-screening program combined with meteorological data found no association between weather and mood (9).

Among the studies that found an association, one studied 497 people using 3 weather indicators from meteorological data and 3 self-reported mood indicators and identified four groups with a modest relationships between weather and mood: summer lovers, unaffected, summer haters, and rain haters (2). Another study that analyzed 38 million posts from 3 million users of a social media site and details regarding the weather during the time of the post in the region of the poster found that sentiments consistent with low mood were associated with weather conditions of high humidity, precipitation, fog, and temperature extremes below 50°F and above 70°F, while high mood was associated with clear skies, high atmospheric pressure, and sunlight temperatures between 50°F and 70°F (3). Because this study relied on time zone and location fields in users’ profiles, it is not certain whether the meteorological data they collected was accurate for all users. A third study that found an association recruited 4,548 people representative of the general population of Japan to complete baseline measures and keep a daily health record regarding physical and mental symptoms for a month and compared those with meteorological data found that self-reported agitation and anxiety were associated with higher temperatures, while depressed mood was associated with lower temperatures (4).

If there is a relationship between mood and weather it seems limited given the small magnitude when there is an association and the inconsistent detection of an association. Our perceived association between weather and mood may relate to cultural expressions and associations, automatic mental associations, or other factors. But it seems that the weather may not cause and perhaps cannot cure low mood.

1) Swaim, E. (2022, August 12). Yes, Weather Can Affect Mood and Energy- and So Can Climate Change. Healthline. https://www.healthline.com/health/mental-health/weather-and-mood#risk-factors

2) Klimstra, T. A., Frijns, T., Keijsers, L., Denissen, J. J., Raaijmakers, Q. A., van Aken, M. A., Koot, H. M., van Lier, P. A., & Meeus, W. H. (2011). Come rain or come shine: individual differences in how weather affects mood. Emotion (Washington, D.C.), 11(6), 1495–1499. https://doi.org/10.1037/a0024649

3) Gilette, H. (2024, April 26). Weather Can Affect Your Mood- but How? PsychCentral. https://ojs.aaai.org/index.php/ICWSM/article/view/14451/14300

4) Lee, M., Ohde, S., Urayama, K. Y., Takahashi, O., & Fukui, T. (2018). Weather and Health Symptoms. International journal of environmental research and public health, 15(8), 1670. https://doi.org/10.3390/ijerph15081670

5) Johns Hopkins. (n.d.). Seasonal Affective Disorder. https://www.hopkinsmedicine.org/health/conditions-and-diseases/seasonal-affective-disorder#:~:text=Seasonal%20affective%20disorder%20(SAD)%20is,antidepressants%20can%20help%20treat%20SAD.

6) Denissen, Jaap J A et al. “The effects of weather on daily mood: a multilevel approach.” Emotion (Washington, D.C.) vol. 8,5 (2008): 662-7. doi:10.1037/a0013497

7) Keller, M. C., Fredrickson, B. L., Ybarra, O., Côté, S., Johnson, K., Mikels, J., Conway, A., & Wager, T. (2005). A Warm Heart and a Clear Head: The Contingent Effects of Weather on Mood and Cognition. Psychological Science, 16(9), 724–731. https://doi.org/10.1111/j.1467-9280.2005.01602.x

8) Clark, L. A., & Watson, D. (1988). Mood and the mundane: Relations between daily life events and self-reported mood. Journal of Personality and Social Psychology, 54(2), 296–308. https://doi.org/10.1037/0022-3514.54.2.296

9) Huibers, Marcus J H et al. “Does the weather make us sad? Meteorological determinants of mood and depression in the general population.” Psychiatry research vol. 180,2-3 (2010): 143-6. doi:10.1016/j.psychres.2009.09.016

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Are plant-based milk alternatives as good for you as cow’s milk?

Plant-based milk alternatives, like almond, soy, and oat, have taken grocery stores by storm in recent years. With some people removing cow’s milk entirely from their diets, the question arises, does plant-based milk offer the same nutritional benefits as cow’s milk? Let’s think twice.

The nutritional value of plant-based (PB) milk alternatives is variable compared to cow’s milk, particularly in terms of protein. Research indicates that PB milk alternatives generally have lower protein content than cow’s milk. A 2022 systematic review of PB milk alternatives (1) found that only 7.7% of PB milks met USDA standards for protein. Furthermore, a 2021 study (2) reported that almond and soy milk provide less than half the protein content of cow’s milk.

Despite differences in protein content, PB milk alternatives can provide other nutrients, such as calcium, Vitamin A, and Vitamin D, and B12, in sufficient amounts. For example, the same 2021 study reported that almond milk contained the highest calcium content compared to oat, soy, goat’s, and cow’s milk (2). Fortification of PB milks with nutrients can help them meet the necessary standards (1). In a 2021 study by Johnson et al. (3,4), analysis of 233 PB milks revealed that half were fortified with vitamin D and 2/3 with calcium.

Additionally, some PB milk alternatives, especially almond milk, are desirable for their lower calories (5). For example, according to Baylor College of Medicine (6), almond milk is a lower-calorie option than cow’s milk due to its low protein and carbohydrate content, and it can provide small amounts of unsaturated fats.

Though fortification and other strategies can increase the nutrient content of PB milks, some research refutes their nutritional value. The same study by Johnson et al. found that only 12% of milk alternatives contained comparable or greater amounts of calcium, vitamin D, and protein when compared to cow’s milk (3). This result demonstrates a need for further research investigating nutritional outcomes of PB milks and the roles that the various key nutrients play.

While there is a long way to go before we fully understand the differences between milk products, it remains important to read milk labels and educate ourselves on the milks that are best for us.

References

Drewnowski A. (2022). Most Plant-Based Milk Alternatives in the USDA Branded Food Products Database Do Not Meet Proposed Nutrient Standards or Score Well on Nutrient Density Metrics. Nutrients, 14(22), 4767. https://doi.org/10.3390/nu14224767

Collard, K. M., & McCormick, D. P. (2021). A Nutritional Comparison of Cow’s Milk and Alternative Milk Products. Academic pediatrics, 21(6), 1067–1069. https://doi.org/10.1016/j.acap.2020.12.007

American Society for Nutrition (2023, July 4). Nutritional content of most milk alternatives doesn’t measure up to cow’s milk. https://nutrition.org/nutritional-content-of-most-milk-alternatives-doesnt-measure-up-to-cows-milk/#:~:text=Compared%20to%20cow’s%20milk%2C%20only,%2C%20vitamin%20D%2C%20and%20protein

Lamotte, S. (2023, July 25). Good or bad? Plant-based and cow’s milk are not always nutritionally equal, study says. CNN. https://edition.cnn.com/2023/07/25/health/plant-milk-nutrition-labels-wellness/index.html

Vanga, S. K., & Raghavan, V. (2018). How well do plant based alternatives fare nutritionally compared to cow’s milk?. Journal of food science and technology, 55(1), 10–20. https://doi.org/10.1007/s13197-017-2915-y

Warren H. (2023, October 4). Cow milk vs. Alternative milk: what’s the best? Baylor College of Medicine. https://www.bcm.edu/news/cow-milk-vs-alternative-milk-whats-the-best#:~:text=Almond%20milk%20is%20a%20lower,with%20calcium%20and%20vitamin%20D.

All, Common Myths

Do pets reduce stress?

A quarter of pet owners want to make their pets famous on social media | Fox Business

IMG via Fox Business 

Are dogs really human’s best friend? Scientific research has tested the common belief that dogs and other pets can improve our quality of life. Let’s think twice: can our furry friends reduce stress?  

In one controlled trial of 82 university students (1), half watched videos of dogs, while the other half interacted with a dog directly. While both sets of students experienced decreased stress, the decrease was greater for students who interacted directly with the dogs. While the sample size is relatively small, it is sufficient to detect a large effect.  But the experimental groups were not randomly assigned, so other factors may account for the findings.  

A similar randomized control trial of university students and medical residents found that interacting with a dog reduced anxiety and negative mood more than viewing the dog or no exposure (2).   

A study of 53 adolescents diagnosed with post-traumatic stress disorder assigned 30 participants to a dog-training program and 23 to other training programs such as cooking and hairstyling according to their personal interests, (3). Researchers found that the individuals who worked with dogs experienced a greater alleviation in PTSD symptoms and lower depression severity compared to those not working with dogs. 

A study of military veterans and ex-first responders diagnosed with PTSD found that people with service dogs had significantly fewer PTSD-related symptoms, better sleep quality, and better wellbeing. There may be other factors (scientists call these confounders) associated with having a service or companion dog such as greater social support or agency, so a randomized trial is needed to confirm this finding.   

Many of us feel it’s obvious that dogs relieve stress.  But that’s exactly why good experimental science is needed to be certain.  Otherwise, we’ll just prove our bias.  To date, the evidence available does not adequately account for bias and potential confounders. Randomized trials with blinding of evaluators would help.  But it’s not clear what would constitute an adequate control for a live dog companion.  

 

References:

  1. Thelwell E. L. R. (2019). Paws for Thought: A Controlled Study Investigating the Benefits of Interacting with a House-Trained Dog on University Students Mood and Anxiety. Animals : an open access journal from MDPI, 9(10), 846. https://doi.org/10.3390/ani9100846  
  2. Crossman, M. K., Kazdin, A. E., Matijczak, A., Kitt, E. R., & Santos, L. R. (2020). The Influence of Interactions with Dogs on Affect, Anxiety, and Arousal in Children. Journal of clinical child and adolescent psychology : the official journal for the Society of Clinical Child and Adolescent Psychology, American Psychological Association, Division 53, 49(4), 535–548. https://doi.org/10.1080/15374416.2018.1520119 
  3. Maoz, I., Zubedat, S., Dolev, T., Aga-Mizrachi, S., Bloch, B., Michaeli, Y., Eshed, Y., Grinstein, D., & Avital, A. (2021). Dog training alleviates PTSD symptomatology by emotional and attentional regulation. European journal of psychotraumatology, 12(1), 1995264. https://doi.org/10.1080/20008198.2021.1995264 
  4. van Houtert, E. A. E., Rodenburg, T. B., Vermetten, E., & Endenburg, N. (2022). The Impact of Service Dogs on Military Veterans and (Ex) First Aid Responders With Post-traumatic Stress Disorder. Frontiers in psychiatry, 13, 834291. https://doi.org/10.3389/fpsyt.2022.834291