A few simple changes to your diet might help you not be so SAD this winter
The typical British weather is enough to get anyone down in the dumps, especially in the winter. But for 35-year-old Scot Jen Stocks, the seemingly endless grey skies affected her to the extent that she had to move to the other side of the world. "For days on end I was not get-ting enough light to trigger the body into feeling awake, which can actually cause your body to shut down, both physically and mental-ly," Jen explains. "I was basically depressed and it seemed to be coinciding with the winter months."
Jen was suffering with seasonal affective disorder-the mental-health condition with the all-too-apt acronym SAD. Thought to affect around two million people in the UK and more than 12 million across Northern Europe, SAD usually occurs at the same time each year, usually during winter. Symptoms vary from person to person, but Jen found she was constantly tearful, wanted to sleep all the time and had a lack of interest in outside life. Eventually Jen went to see a counsellor, who recommended she try a lamp specially designed for SAD sufferers to provide them with the light they're lacking. "I'd sit for half an hour looking into this lamp while eating breakfast and could feel my body waking up," she said.
But the lamp wasn't the answer for Jen. She realized that she'd had no symptoms of SAD when travelling in Australia a few years back, so she made the life-changing decision to emigrate. She now lives in Whangarei, New Zealand, and has no need for the SAD lamp. "Even in the winter here the light intensity is greater," Jen said. "I left my SAD lamp in my parents' attic and there's been no need to retrieve it." Jen's story shows just how much of an impact SAD can have on your life. Jen was willing to move halfway around the world to wave goodbye to her SAD symp-toms for good.
But such extremes aren't always necessary. Light therapy is the usual solution, though it doesn't work for everyone and can some-times be difficult to fit into your daily routine.
Happily, evidence suggests that just like non-seasonal depression, diet may have a major role to play in SAD. By knowing what foods to choose and what to avoid, you may be able to eat your way to a SAD-free life.
Fill up on fish
Scientists trying to figure out why some people get SAD and others don't got a surprise when they studied an Icelandic population they expected to have high rates of SAD due to the few hours of daylight they get in the winter.
The study actually found the opposite: there was no SAD in the 4,000 Icelanders they surveyed (Am J Psychiatry, 2000; 157: 234-8). A study of Canadians of wholly Icelandic descent had also shown low levels (Arch Gen Psychiatry, 1993; 50: 947-51). Despite greater exposures to sunlight in winter, most other countries, including the UK, the Netherlands and the US, have much higher rates of SAD.
While some have speculated that genetics might explain these strange findings-which are also contrary to SAD rates in other countries of a similar latitude to Iceland-others reckon that diet is the answer, namely fish.
In one published report, Drs Jerry Cott and Joseph Hibbeln, both interested in essential fatty acids (EFAs) and mental health, suggested that fish consumption could be the reason why Icelanders have such low rates of SAD (Am J Psychiatry, 2001; 158: 328).
Icelanders eat, on average, 225 lb of fish per person per year-more than five times the amount we eat in the UK and nine times the amount consumed by the Dutch. In Japan, another country with high fish intakes (147 lb per person per year), SAD rates are similarly low. Cott and Hibbeln believe that a high-fish diet may be protective against SAD because it's rich in omega-3 EFAs, which could help to lower depressive symptoms. In fact, the evidence shows that populations getting only small amounts of omega-3 fats have higher rates of depression. And people with depression tend to have lower levels of omega-3.
There are also clinical trials showing that supplementing with omega-3 fats can have antidepressant effects (Asia Pac J Clin Nutr, 2008; 17 Suppl 1: 151-7). SAD solution: Eat more fish-especially omega-3-rich ones like salmon, sardines, trout and herring-two or three times a week. If you don't like fish or are worried about mercury, take a good-quality supplement and aim for about 10 g/day of omega-3s. If you're a vegetarian or vegan, purslane is an excellent plant source of omega-3.
Cut down on carbs
One of the symptoms of SAD is craving carbohydrates, usually the bad 'simple' kind like sugar-laden cakes and sweets, white bread and processed snack foods (Compr Psychiatry, 1997; 38: 80-7). Although eating these energy-charged foods can give you a temporary mood boost, in the long run they may have a negative effect-and not just on your waistline.
According to a review looking at the evidence for food and mood by Professor Larry Christensen at the University of South Alabama, eating simple carbs may give you a short-term increase in energy, but the long-term effect is no energy and feelings of fatigue.
This means that SAD sufferers may well be stuck in a vicious cycle, bingeing on carbs for a quick fix, then eventually feeling worse and depressed, and craving more carbs again.
So instead of popping simple carbs as a form of self-medication, SAD sufferers should consider removing these foods completely from their diets for a longer-lasting improvement in mood and fatigue (Int J Eat Disord, 1993; 14: 171-83).
Studies have yet to be done on SAD patients in particular, but a trial of depressed individuals who cut sugar and caffeine from their diets found that their symptoms improved-and stayed that way for at least three months after the study ended. Further tests suggested that sugar was the biggest contributor to depression in these patients (Behav Ther, 1990; 21, 183-93).
SAD solution: Cut out simple carbs like sweets and processed foods, and go for unrefined 'complex' carbs instead. Oats, brown rice, quinoa, lentils, chickpeas, wholemeal pasta and root vegetables are good meal options (combined with an omega-3- or tryptophan-rich protein source-see above and below), while bananas, nuts and houmous with crudit'es make good simple snacks.
Top up your tryptophan
l-Tryptophan is an amino acid the body has to have to make serotonin-the so-called 'happy hormone' that some evidence suggests is involved in SAD (Int J Neuropsychopharmacol, 2001; 4: 409-20).
Supplements of l-tryptophan appear to have helped SAD sufferers. In one trial, SAD patients who responded poorly or not at all to light therapy were given 3 g/day of l-tryptophan for two weeks in addition to the light-box therapy. Nine out of 14 sufferers showed "very good clinical responses" to this combination treatment and only minor side-effects (Can J Psychiatry, 1997; 42: 303-6).
In another study, l-tryptophan was pitted against light therapy and a placebo in 13 SAD sufferers. Both l-tryptophan and light were equally effective at improving SAD symptoms-and both were better than placebo (J Clin Psychiatry, 1990; 51: 162-3). This means that a tryptophan-rich diet may be beneficial for SAD. However, according to nutritionist Natalie Savona in her book The Kitchen Shrink (Winchester, Hants, UK: Duncan Baird Publishers, 2003), for tryptophan in food to be converted to serotonin in the brain, you need a healthy supply of other nutrients like vitamins B3, B6 and C, folic acid and zinc. You also need a balance between carbs and protein, she says, as too much protein could mean tryptophan ends up competing with other amino acids to get to the brain.
SAD solution: Eat plenty of tryptophan-rich foods such as bananas, chicken, turkey, fish, sunflower seeds, oats, milk, dried dates, peanuts and cottage cheese, and select meals that are made up of balanced amounts of carbohydrates and protein.
It's also important to vary your diet to make sure you're getting the full spectrum of nutrients. (To make sure, you could take a multivitamin/mineral supple-ment.) If that doesn't work for you, consider taking supplements of l-tryptophan. Doses of 2 to 6 g/day have been used in various studies to good effect.
Don't worry, be happy
So before making any drastic life-changing decisions to deal with SAD or resigning yourself to a lifetime of light therapy, take a look at your diet to see whether a few simple tweaks can make you happier than usual this winter.
Let there be light
Bright-light therapy is the most researched treatment for SAD and it's a great option if you can stick with it. It has an overall positive treatment response of up to 70 per cent and rarely any side-effects (Altern Med Rev, 2005; 10: 5-13).
Treatment usually involves sitting in front of a 'light box', which gives off bright light that mimics natural outdoor light. Another form of light therapy that can be effective is 'dawn simulation', whereby a device such as the Lumie Bodyclock (www.lumie.com) gradually increases your bedside light in the morning. This form of light therapy may be easier to incorporate into your life than the traditional light boxes.
Another take on light therapy treatment is the Valkee brain stimulation headset (www.valkee.com), a device not unlike an iPod that channels bright light into the brain through the ear canal. It sounds like it can't possibly work, but the company actually has a clinical trial to back it up (Med Hypotheses, 2012; 78: 511-5).
Natural light-if you can get it-can also be an effective SAD-beater. A Swiss study showed that a daily one-hour walk outdoors in natural light was more effective than an artificial light box at improving SAD symptoms. The walking group also spent less time in bed, got up earlier and ate less carbs (J Affect Disord, 1996; 37: 109-20).
The herbal helper
St John's wort (Hypericum perforatum) has a long history of use for depression and a stack of studies reporting its success. Although only a few trials have looked specifically at its potential for treating SAD, the evidence so far is promising-suggesting it can improve depression, fatigue, anxiety, lethargy, sleep and other symptoms of SAD.
In one Viennese trial, 900 mg of St John's wort significantly improved SAD severity after just one month. Interestingly, when light therapy was added to the treatment, there wasn't much of any further improvement (Pharmacopsychiatry, 1997; 30 Suppl 2: 89-93).
D for depression
If SAD is triggered by a lack of sunlight, then the 'sunshine vitamin' D looks like an obvious solution. But does it work?
In one trial, SAD sufferers were given either one dose of 100,000 IU of vitamin D or two hours of bright-light therapy every day for a month. There was significant improvement in depression in the vitamin D group, but not in the light-therapy group (J Nutr Health Aging, 1999; 3: 5-7).
Another study looked at whether vitamin D3 supplements-or 'cholecalciferol', the same stuff your body makes from sunshine-would improve mood in healthy people during winter. The results showed that daily vitamin D3-whether 400 IU or 800 IU-was significantly more effective than no vitamin D3 (Psychopharmacology [Berl], 1998; 135: 319-23).
On the other hand, a much larger study of more than 2,000 healthy elderly women found that supplementing with vitamin D (800 IU daily) did not prevent the common winter-time mood slump (J Nutr Health Aging, 2006; 10: 151-3).
It may be that vitamin D only helps people with actual SAD and not the much milder forms of 'winter blues'. Or perhaps vitamin D only helps if its blood levels are initially low, as was the case with the above study of genuine SAD sufferers.
More research is needed on vitamin D and SAD, but as the supplements are good for your health overall-particularly in winter when there's often not enough sunlight to get a decent dose of D the natural way-there's little harm in giving it a go. Suggested dosage: For best results, consult a qualified practitioner to first find out if your vitamin D levels are low. If so, they can recommend a therapeutic dosage. Based on the research so far, a daily dose of 800-5000 IU of vitamin D3 may be your best bet.
WDDTY November 2012 vol 23 no 8