Seasonal Affective Disorder (SAD) is a type of mood disorder recognised by depressive symptoms appearing, or being exacerbated, during specific seasons. It occurs most commonly during the autumn and winter months - when daylight hours are shorter[i].
Changes in natural light exposure, which can disrupt the body's internal clock and affect neurotransmitter levels, leading to symptoms such as low mood, fatigue or low energy, appetite changes and decreased motivation and enjoyment[ii]. Sleeping too long, or excessive sleepiness and feelings of lethargy are also commonly associated with SAD.
Geographical location: SAD is more common in places far away from the equator - where there are significant seasonal shifts in daylight hours[iii].
Gender: Women are more likely to experience SAD than men – hormonal constitution and differences in brain chemistry are thought to contribute[iv].
Depression: Those with a family history of other types of depression are at higher risk of developing the disorder[v].
Seasonal changes in routine: Disruption of daily routines due to seasonal changes, such as reduced outdoor activities and social activities during the winter months, may contribute to SAD[vi].
Nutritional therapy can play a supportive role in managing Seasonal Affective Disorder (SAD), helping to benefit overall brain health and neurotransmitter function[vii]. Neurotransmitters are messengers in your brain that help different nerve cells talk to each other. They are important in terms of mood disorders, because they help control things like how you feel, think, and behave.
Adequate intake of specific nutrients can influence mood, energy levels, and overall well-being (benefitting neurotransmitter function).
Serotonin production: Certain nutrients, such as tryptophan[viii], omega-3 fatty acids[ix], and B vitamins, are involved in the production and regulation of serotonin, a neurotransmitter that helps regulate mood. Increasing intake of these nutrients either in the diet or with supplementation can support healthy serotonin levels and potentially prevent depressive symptoms[x].
Vitamin D levels: Reduced sunlight exposure during the winter months can lead to lower vitamin D levels, which may be associated with SAD[xi]. Adequate vitamin D intake is important for overall mental health and well-being. Nutritional therapy can help to ensure sufficient vitamin D intake through dietary sources or supplementation. See our below section of vitamin D testing for more info. Liquid Vitamin D3 (1000IU per drop)
Omega-3 fatty acids: Omega-3 fatty acids have been shown to have mood-stabilising properties via their anti-inflammatory activity. Including omega-3-rich foods like fatty fish (salmon, mackerel), flaxseeds, and walnuts in the diet can support brain health and potentially improve SAD symptoms[xii]. Cytoplan Omega Balance (60 caps)
Blood sugar balance: Nutritional therapy can focus on maintaining stable blood sugar levels through balanced meals and snacks[xiii]. Fluctuations in blood sugar levels can affect energy levels and mood. Consuming complex carbohydrates, fibre-rich foods, and adequate intake of protein can help regulate blood sugar and sustain good energy levels throughout the day[xiv].
Light therapy: Light therapy involves exposure to bright artificial light that mimics natural sunlight. Daily sessions of light therapy, typically in the morning, can help regulate the body's internal clock and improve mood. Consult with a healthcare professional for guidance on the appropriate light therapy device and duration[xvii].
Increase sunlight exposure: Maximise exposure to natural sunlight during the day. Spend time outdoors, or make sure you open curtains or blinds to let in as much natural light as possible in daylight hours[xviii].
Exercise regularly: Engaging in regular physical activity, such as walking, jogging, or indoor workouts, can help boost mood and energy levels. Aim for at least 30 minutes of exercise most days of the week[xix].
Maintain a consistent routine: Establishing and maintaining a consistent daily routine can help regulate your body's internal clock and provide a sense of stability. Go to bed and wake up with consistent timing, eat meals at regular times, and structure your day with a good routine in mind.
Vitamin D levels: A blood test can measure your vitamin D levels. Since reduced sunlight exposure during the winter months can lead to lower vitamin D levels and may be associated with SAD, checking your vitamin D status can provide useful information[xx].
[i] Melrose S. Seasonal Affective Disorder: An Overview of Assessment and Treatment Approaches. Depress Res Treat. 2015;2015:178564.
[ii] Eastman CI, Young MA, Fogg LF, Liu L, & Meaden PM (1998). Bright light treatment of winter depression: a placebo-controlled trial. Arch Gen Psychiatry, 55(10), 883–889.
[iii] Rosen LN, Targum SD, Terman M, Bryant MJ, Hoffman H, Kasper SF, Hamovit JR, Docherty JP, Welch B, Rosenthal NE. Prevalence of seasonal affective disorder at four latitudes. Psychiatry Res. 1990 Feb;31(2):131-44.
[iv] Chotai J, Smedh K, Johansson C, Nilsson LG, Adolfsson R. An epidemiological study on gender differences in self-reported seasonal changes in mood and behaviour in a general population of northern Sweden. Nord J Psychiatry. 2004;58(6):429-37.
[v] Fonte, A., Coutinho, B. Seasonal sensitivity and psychiatric morbidity: study about seasonal affective disorder. BMC Psychiatry 21, 317 (2021).
[vi] Roecklein KA, Rohan KJ. Seasonal affective disorder: an overview and update. Psychiatry (Edgmont). 2005 Jan;2(1):20-6. PMID: 21179639; PMCID: PMC3004726.
[vii] Levitan RD. The chronobiology and neurobiology of winter seasonal affective disorder. Dialogues Clin Neurosci. 2007;9(3):315-24
[viii] Lam RW, Zis AP, Grewal A, Delgado PL, Charney DS, Krystal JH. Effects of rapid tryptophan depletion in patients with seasonal affective disorder in remission after light therapy. Arch Gen Psychiatry. 1996 Jan;53(1):41-4.
[ix] van Strater AC, Bouvy PF. Omega-3-vetzuren bij de behandeling van stemmingsstoornissen. Een literatuuroverzicht [Omega-3 fatty acids in the treatment of affective disorders: an overview of the literature]. Tijdschr Psychiatr. 2007;49(2):85-94. Dutch. PMID: 17290337.
[x] Oren DA, Teicher MH, Schwartz PJ, Glod C, Turner EH, Ito YN, Sedway J, Rosenthal NE, Wehr TA. A controlled trial of cyanocobalamin (vitamin B12) in the treatment of winter seasonal affective disorder. J Affect Disord. 1994 Nov;32(3):197-200.
[xi] Penckofer S, Kouba J, Byrn M, Estwing Ferrans C. Vitamin D and depression: where is all the sunshine? Issues Ment Health Nurs. 2010 Jun;31(6):385-93.
[xii] Larrieu T, Layé S. Food for Mood: Relevance of Nutritional Omega-3 Fatty Acids for Depression and Anxiety. Front Physiol. 2018 Aug 6;9:1047. doi: 10.3389/fphys.2018.01047. PMID: 30127751; PMCID: PMC6087749.
[xiii] Penckofer S, Quinn L, Byrn M, Ferrans C, Miller M, Strange P. Does glycemic variability impact mood and quality of life? Diabetes Technol Ther. 2012 Apr;14(4):303-10.
[xiv] Russell WR, Baka A, Björck I, Delzenne N, Gao D, Griffiths HR, Hadjilucas E, Juvonen K, Lahtinen S, Lansink M, Loon LV, Mykkänen H, Östman E, Riccardi G, Vinoy S, Weickert MO. Impact of Diet Composition on Blood Glucose Regulation. Crit Rev Food Sci Nutr. 2016;56(4):541-90.
[xv] Riccardi G, Rivellese AA. Effects of dietary fiber and carbohydrate on glucose and lipoprotein metabolism in diabetic patients. Diabetes Care. 1991 Dec;14(12):1115-25
[xvi] Franz MJ. Protein: metabolism and effect on blood glucose levels. Diabetes Educ. 1997 Nov-Dec;23(6):643-6, 648, 650-1.
[xvii] Nussbaumer-Streit B, Forneris CA, Morgan LC, Van Noord MG, Gaynes BN, Greenblatt A, Wipplinger J, Lux LJ, Winkler D, Gartlehner G. Light therapy for preventing seasonal affective disorder. Cochrane Database Syst Rev. 2019 Mar 18;3(3):CD011269.
[xviii] Campbell PD, Miller AM, Woesner ME. Bright Light Therapy: Seasonal Affective Disorder and Beyond. Einstein J Biol Med. 2017;32:E13-E25. PMID: 31528147; PMCID: PMC6746555.
[xix] Drew EM, Hanson BL, Huo K. Seasonal affective disorder and engagement in physical activities among adults in Alaska. Int J Circumpolar Health. 2021 Dec;80(1):1906058.
[xx] Mathers CD, Loncar D. Projections of global mortality and burden of disease from 2002 to 2030. PLoS Med. 2006;3(11):e442.
Please note that the information contained within this website does not and should not replace medical advice, and is not intended to treat or diagnose. We always recommend you consult with your doctor. Our Nutritional Therapy team is highly trained and we offer one to one Nutritional Therapy Consultations, which are designed to be complementary to any medical treatment from a functional medicine approach, as well as offering a preventative & optimal health focus.