Seasonal affective disorder (SAD)
Why everything seems worse in the winter
Even though winter has a lot going for it – woolly hats, hot chocolate, curling up with a book, thick socks, a log fire and other things ‘hygge’ come to mind – something important is missing: light. At this time of year, you go to work before sunrise and come home after sunset, with very little exposure to natural light in between. This lack of light over months on end causes serious problems for many people.
What the experts have to say about SAD
According to experts, the ‘winter blues’, or seasonal affective disorder (SAD), affects about 3% of the population. Occurring every autumn like clockwork, it comes with a variety of symptoms, including low mood, listlessness, an increased need for sleep and cravings for sweets and carbohydrates – and therefore weight gain. It affects women more often than men, and particularly people who are on the verge of depression already.
What causes SAD
The exact cause of SAD is not yet properly understood, but it is thought that an imbalance of neurotransmitters is involved. Those are messenger substances in the brain needed for mental and physical performance, mood and sleep – melatonin and serotonin, among others. Melatonin – the sleep hormone – is made in the body from serotonin – the happy hormone. The lack of the neurotransmitter serotonin due to low levels of light can tip sensitive people over the edge. Serotonin is a brain chemical required to make you feel happy and content, for motivation and activity. Many common anti-depressants work by increasing serotonin levels in the brain.
Serotonin and SAD
While serotonin production requires light, the closely related neurotransmitter melatonin requires darkness. During the long nights of winter, more serotonin is converted into melatonin, further reducing the levels of our “happy” neurotransmitter. Melatonin is required for sleep, but too much of it may make you sleepy during the day, and in fact tiredness is a common symptom of SAD.
Vitamin D and SAD
Low vitamin D levels also affect mood. This vitamin is the only one your body can produce. It is made in the skin under the influence of sunlight, so of course we make less of it during the winter. No wonder then, that many of us are feeling low at this time of year. Sadly, there are not many good food sources of vitamin D. Foods naturally vitamin D-rich are oily fish (salmon, sardines, fresh tuna, trout, halibut, mackerel, et.), high-quality cod liver oil, egg yolks and liver. Mushrooms contain a form of vitamin D called D2 (ergocalciferol), what your body needs is D3 (cholecalciferol).
Research shows that D2 is less effective at raising levels of vitamin D in the blood. Also, do not be fooled into thinking foods fortified with vitamin D are the same or have similar benefits to animal foods. Fortified foods (like cereals, margarine and some yoghurts) contain D2, and usually even a synthetic one. It doesn’t cost much to get your vitamin D levels checked, and if yours is low, food is not going to cut it. You may have to get yourself a nutritional supplement of vitamin D3.
How can we counteract SAD
A promising way to counteract SAD is the use of a full-spectrum light source, either from a lightbox or light bulbs in the house. Sufferers of SAD respond well to full-spectrum light. About 70% report considerable improvement. For this beneficial effect, it is necessary to spend 30 minutes each day in front of a full-spectrum lightbox or six hours with artificial full-spectrum lighting in the house. 98% of light enters your body through the eyes, only 2% through the skin.
Looking out of a window doesn’t cut it, as glass blocks the ultraviolet light. Sunglasses won’t give you full-spectrum light either, so if you can, leave them off when you are out during the winter and the sun is not directly in your face.
Diet and SAD
Diet, too, can help coping with SAD, though not as efficiently as light treatment and exercise. The amino acid tryptophan is a precursor for serotonin. It is one of the eight essential amino acids – i.e. we have to ingest it, the body cannot make it –, and it is found in a variety of foods:
Dairy products, eggs, red meat, poultry, fish, chocolate, oats, dried dates, chickpeas, almonds, sunflower and pumpkin seeds, bananas, spirulina and peanuts all contain tryptophan. Although turkey is often advertised as an excellent source of tryptophan, it has no more of the amino acid than other poultry meats. So, chicken is fine if that’s what you prefer. Unfortunately, it is rather difficult for tryptophan to access the brain, but transport can be enhanced by combining tryptophan-rich foods with complex carbohydrates such as brown rice, brown pasta, wholegrain bread or oats.
Exercise and SAD
One of the best ways to combat SAD, however, is exercise, especially exercise outdoors. Exercise has been found to be effective in combating depression in any case. When your body feels better, so does the mind. It doesn’t really matter what you do as long as you are active.
If you don’t enjoy vigorous exercise, don’t worry: Even a 10-minute walk during your lunch break, getting off one bus stop early, walking to the shops instead of driving, taking the stairs instead of the escalators or lift is better than nothing.
Get out into nature and beat SAD
Ideally, get out into nature and visit your local park or forest. There’s no need to run, you can just walk. It all counts. Try and incorporate small changes like these and you may soon find that you are able to do more, walk further, or climb faster, which is a great incentive to keep going.
Remember that most of the light accesses the body through the eyes rather than the skin, and this is what triggers the synthesis of said vitamin D. Your body and mind would thank you if – despite the weather – you’d get outdoors for some exercise and to give your body the chance to soak up some light.