Now that you have your grocery shopping list in order, let's examine supplements.
- Melatonin: The neurotransmitter melatonin stabilizes your internal clock. That's why people with jet lag, for example, are advised to take a supplement or enjoy some melatonin-producing foods such as raspberries, tart cherries and almonds [source: Kasselik]. Some people also report that melatonin helps their depression symptoms, but others say the supplement actually makes their depression worse. This isn't one to try without talking to your doctor. What melatonin definitely does help with is insomnia, so if your sleep patterns are disturbed by seasonal affective disorder or depression, it may be helpful for you.
- Selenium: Low levels of the mineral selenium have been reported in people with depressive symptoms, but there is no clear correlation between the two -- and no evidence that low selenium actually causes mood disorders [source: Gao et al.]. But if you'd like to add a handful of Brazil nuts or a supplement to your diet to up your intake, it probably won't hurt.
- 5-HTP: Since it's believed that an imbalance in serotonin levels may be responsible for depression, scientists have been looking into factors that affect serotonin to find out how to influence its production. 5-HTP, which is made after you ingest tryptophan-rich foods like turkey, is converted into serotonin [source: University of Maryland Medical Center]. Can 5-HTP help depression in the same way antidepressants that affect serotonin do? Following our theme, the answer is unclear. There just isn't enough research to say.
- SAMe: You won't find it in foods, but the supplement SAMe has strong support. A 2002 analysis of available studies showed that SAMe provided symptom relief for depressed people. A more recent study, in 2010, showed that when SAMe was added to antidepressant treatment for people with major depression, there was clinically significant improvement [source: Nelson]. This is cheery news for people who don't respond well to antidepressant treatment alone.
What can we take from these findings? Modifying your diet to include more omega-3 rich foods and vitamin D, plus swapping out simple carbs for complex ones, may brighten your mood -- and it will definitely improve your health. And while there are high hopes for certain supplements, there hasn't been enough research done to justify their use, in many cases.
If you are dealing with seasonal affective disorder, talk to a health professional about what you can do. Even though supplements are naturally occurring substances, they can interact badly with certain medications and conditions, so make sure to bring them up if you use them.