Gray days, long cold nights. It’s no wonder a lot of people get the blues during winter months. For most of us, the dark moods will come and go. But about 5 percent of Americans suffer from seasonal affective disorder (SAD), a more serious condition that can stress relationships, work, and general health.

“Nobody knows the actual cause of seasonal affective disorder, but it usually comes in the winter months when there is less light, especially in the northern climes,” says Amy Rothenberg, a naturopathic physician who practices in Enfield, Conn.

“The main symptoms are depression, lack of interest in doing things, withdrawing socially, carbohydrate cravings, gaining weight…there are all kinds of ways it manifests.”

Some experts believe SAD is triggered by the disruption of the circadian rhythm (sleep-wake cycle) from the shorter days and longer nights. That can affect the release of hormones, most notably sleep-inducing melatonin and mood-elevating serotonin.

Standard medical treatment for SAD includes using a full-spectrum light box to make up for lost daylight, cognitive behavioral and talk therapies, and antidepressants.

While many people opt for the ease of a pill, studies show that the most commonly used antidepressants have about the same effectiveness as a placebo. They also come with potential side effects including weight gain and loss of sex drive.

“I sidestep drugs if at all possible and try other approaches that work pretty darn well,” says Rothenberg, the American Association of Naturopathic Physicians (AANP) 2017 Physician of the Year. “These include lifestyle modifications, eating a healthy diet that includes a lot of fiber and some fermented foods that are good for the gut-brain connection, walking outside in the daylight and exercising regularly.”

Dietary supplements can also be effective in helping to fight the winter blues. Here are a few recommended by Rothenberg and other experts:

Vitamin D: The “sunshine” vitamin should be at the top of everyone’s list because people who live areas that get less daily sunlight tend to be deficient in this vital nutrient. “Vitamin D is involved with so many biological pathways that it affects almost every system of the body,” Rothenberg tells Newsmax Health. “We find that people with depression tend to have lower levels of vitamin D.”

B vitamins: These vitamins, especially folic acid and B6, can help with mild depression. Rothenberg notes that they also enhance the efficacy of prescription medications. “If your B vitamins are at good levels, you may be able to decrease the amount of antidepressants you take and still get a positive impact,” she says.

St. John’s Wort: This herbal remedy is commonly used to fight mood disorders, but it tends to work over the course of weeks, not days. Studies show it is as effective as many antidepressants. Just be aware that it can decrease the effectiveness of some medications – such as blood thinners, antivirals and birth control pills -- so make sure to consult your doctor before using it.

SAM-e (S-adenosyl-methionine): A natural compound vital to brain function, SAM-e optimizes levels of the “feel-good” hormones serotonin and dopamine, and also makes brain cells more sensitive to them. Studies consistently show that SAM-e supplementation not only outperforms placebos but also several medications in treating various types of depression, including SAD. It’s best when taken on an empty stomach in enteric-coated tablets or capsules.

Fish oil: Rothenberg calls the omega-3 fatty acids found in fish oil “my go-to supplement” for SAD. “They help to maintain emotional balance and are good for any neurologic complaint,” she adds. The fatty acids are beneficial to brain cell membranes, a vital element in maintaining healthy levels of serotonin and other neurotransmitters.

5-HTP: This neurotransmitter is a building block of serotonin. It’s so effective that Rothenberg says it shouldn’t be taken with antidepressants because that could be “too much.”

“While supplements may be a good tool in fighting seasonal affection disorder, people should start with diet, exercise and lifestyle modifications,” concludes Rothenberg. “It may also help to take a vacation in someplace sunny in the middle of the winter if you can.”