These conditions can impact everything from our mood to our energy levels—but the good news is, there are a number of ways to combat the effects of SAD. Here’s what a neuroscientist recommends. “Those with SAD have difficulty regulating the neurotransmitter serotonin, which is responsible for balancing mood,” she notes. “There may also be an overproduction of melatonin, a hormone produced by the pineal gland. An increase in melatonin production can lead to feelings of sleepiness and lethargy.” And of course, a lack of sunlight means a lack of vitamin D, which is associated with depression2. Research shows that omega-3 polyunsaturated fatty acids have beneficial effects on depression, with dietary sources including wild salmon, mackerel, tuna, herring, sardines, oysters, anchovies, walnuts, flaxseed, hemp, sunflower, chia, and pumpkin seeds, Willeumier notes. This is another option that can be supplemented; check out these high-quality omega-3 supplements to start. “SSRIs can also be combined with light therapy to improve remission rate,” she adds, noting that serotonin-rich foods like sweet potatoes, avocados, plums, bananas, tomatoes, eggplant, walnuts, and pineapple can also help boost your serotonin levels.