No single food can cure seasonal affective disorder or SAD. But some surprising foods may help boost mental health. This can be especially helpful because while the SAD treatment of antidepressant medication can affect people’s brains differently, some foods, like those rich in vitamin D and omega-3 fats can help everyone’s brain.

The National Institutes of Health estimates that millions of Americans experience SAD, described as seasonal depression or the “winter blues,” and that it often begins in young adulthood. Since it can occur year after year, it’s important to plan to avoid symptoms several months before they begin.

One of the most important things to know about eating an anti-SAD diet is to start eating it in September. In fact, most dietitians will tell you it’s good to have an eating pattern that’s good for mental health all year round. The Mediterranean Diet is a good place to start. In a randomized controlled study (the SMILES trial), scientists concluded that a Mediterranean-style diet (including three tablespoons of olive oil daily) may be an effective treatment strategy that is accessible to almost everyone — even those who don’t want to or are unable to take medications — for managing major depression.

For those affected by SAD, here are some of the foods that can help, and foods to avoid.

Omega-3 fatty acids are one of the most important nutrients to increase when struggling with SAD. Good fats are brain food. Omega-3 fats can improve blood flow to the brain and enhance the synthesis of healthy brain cells. Fatty fishes like salmon, sardines, tuna and trout are excellent sources of protein. Getting plenty of protein is also important for mental health; meat and fish contain the amino acid tryptophan which is needed for serotonin to cross into the brain. Researchers have found that people who have SAD have reduced levels of serotonin, the “good mood” hormone.

Nuts usually contain around 50 percent fat by (edible) weight, which is the richest source of fat in our diet after cooking oils. These healthy oils, along with fat-soluble antioxidants including vitamin E may be why eating nuts is so strongly associated with good blood circulation and decreased inflammation in the brain and the body. The brain needs good blood flow; this helps the brain have a proper response to stress. Include a variety of nuts. Walnuts contain omega-3 fats; pistachios are the only nut with a measurable amount of lutein, which is one of the most important antioxidants for mitigating stress in the brain.

Whole grains such as oatmeal, bulgur, barley and brown rice contain significant amounts of magnesium. Low levels of this nutrient is highly associated with higher stress levels. Magnesium is critical for relaying communications between the brain and the body, including hormones like cortisol. Whole grains are also high in fiber which improves gut health; a healthy gut can help improve brain and mental health because of the direct communication between the two in the gut-brain axis.

People with vitamin D deficiency may suffer from SAD because vitamin D is thought to promote serotonin activity. Mushrooms naturally contain a small amount of vitamin D, but some mushrooms are treated with special ultraviolet lights to make them rich in vitamin D. (Check the label for “rich in vitamin D” or “UV-treated.”) Vitamin D helps the immune system function properly, which directly links to mental health. Mushrooms also contain both soluble and insoluble fiber which is essential for improving gut health. Other foods containing vitamin D include milk, eggs, sardines, tuna and fortified breakfast cereals.

Whole seed spices like mustard seeds, black pepper, cumin and even everything-bagel-seasoning are rich in antioxidants. The bright color and bold flavors of ground spices are a clue that they also contain potent antioxidants; these include turmeric, red pepper and cinnamon. Some research suggests the curcumin in turmeric can slow down the natural and unnatural cell death from toxins and stress. Mustard seeds are rich in every component needed to become a whole plant, and their bold flavor signals the presence of strong polyphenols that fight stress to improve mood. Shop for whole-grain mustard to get more seed ‘power.’

While caffeine can increase serotonin, it’s generally not recommended that caffeine, especially high amounts of it, be consumed when struggling with mental health issues. The added sugar doesn’t help either. But drinking plenty of fluids is important. Hydration in the winter is tricky because we often don’t feel thirsty. But the brain can suffer from the effects of dehydration. If you like the fizz, seltzer can be just as hydrating as water.

While you can certainly find fresh and healthier food options at some fast food restaurants, most of it should be avoided. Sodium, ultra-processed ingredients and the lack of fiber (needed for a healthy gut-brain axis) are the reasons for avoidance. However, there’s one big caveat: if eating a ‘healthier’ fast food meal means eating with friends, enjoy it! Because eating with friends has such a strong connection to good mental health, it’s that important to enjoy sharing a meal with family or friends as much as possible.

It’s not a good idea to mix alcohol and symptoms of depression. This is a serious issue. But the good news is there are several excellent and enjoyable non-alcoholic options on the market. They may help us enjoy time with friends and family, which again, is good for helping with symptoms of SAD.