As a neurologist and herbalist with a passion for exploring the mind-body connection, I’ve seen firsthand over the years how certain everyday habits can impact our mood. You might be surprised to learn that your mood isn’t just tied to your thoughts; it’s also connected to biological factors related to your lifestyle. Everything from your sunlight exposure and movement routine (or lack thereof), to the food you eat and how much time you spend in nature affects whether you’d describe your mood as sunny and bright or down in the dumps. Here are six scientifically-backed reasons why your mood might be tanking—and what you can do to address them for a boost.
1. Not Enough Sunlight: The Vitamin D Deficiency Dilemma
If you’re feeling down, one of the first things I’d ask is: How much time do you spend outdoors? Studies show that a lack of sunlight can lead to lower levels of vitamin D, which is closely tied to mood regulation. Vitamin D, sometimes called the “sunshine vitamin,” influences the production of serotonin, a neurotransmitter that makes us feel happy and calm.
Read More: Ways To Boost And Balance The “Feel Good” Neurotransmitter Serotonin
But it’s more than that. Light exposure itself, regardless of your vitamin D levels, lifts mood and improves both memory and sleep issues by regulating your circadian rhythm. Morning light exposure is best, whereas artificial nighttime light can disrupt mood.
Lift Your Spirits: Try to spend at least 15 to 30 minutes outside with skin exposed daily, ideally in the morning when sunlight is optimal for vitamin D synthesis. If getting outdoors is tough, speak to a nutritionist about vitamin D supplements, especially during the winter. For most people, doses between 1,000 and 5,000 IU daily can offer great benefits.
2. Too Little Movement: Sedentary Lifestyle Blues
We all know that exercise is good for the body, but its benefits for the mind are equally impressive. Regular movement releases natural mood-boosting chemicals called endorphins. Meanwhile, when we’re inactive, those feel-good chemicals aren’t released as frequently, which can lead to what some researchers call the “sedentary blues”.
For example, a 2018 study published in The Lancet Psychiatry found that people who engaged in regular physical activity had 43 percent fewer days of poor mental health per month than those who didn’t.
Lift Your Spirits: You don’t have to hit the gym for hours to see the mood benefits of exercise. Moderate physical activity, like brisk walking, for 30 minutes five days a week can significantly improve your mood. Even exercise “snacks”—five- to 10-minute intervals of bouncing, walking, or some other physical movement that interrupts sitting—can lift your mood and vanquish the blues, research suggests. If your average day involves long periods sitting while working, try setting a timer to stretch, walk around, or do a mini workout for a few minutes each hour or so (ideally in addition to longer bouts of dedicated exercise time throughout the week). It’s your consistency, not intensity, that matters most.
3. Processed Foods: Fueling Up with the Wrong Stuff
Here’s a fact that might surprise you: The quality of the food you eat can directly impact your mood. Processed foods (think chips, packaged snacks, and ready-to-eat meals) are often low in essential nutrients and high in artificial additives. These foods can disrupt blood sugar levels and cause inflammation, which is now being linked to mood disorders. In fact, one 2019 study published in Nutrients linked high consumption of processed foods with an increased risk of depression.
Processed foods can create a vicious cycle in which you feel a quick “high” followed by a crash, leading to irritability, fatigue, and a gloomy mood. This happens, in part, because many processed foods are formulated to include specific levels of fat, sugar, and salt that produce an intense pleasure response in our brains when we eat them.
Another reason these foods cause mood problems is that they tend to be depleted of nutrients, especially vitamins and minerals necessary for balancing mood. Lean on processed foods too much and you’ll likely be walking around with lower levels of B vitamins, magnesium, omega-3 fatty acids, and other components necessary for supporting a healthy brain and balanced mood.
Lift Your Spirits: Try focusing on whole foods (vegetables, fruits, lean proteins, and whole grains) to provide your brain with the nutrients it needs to function at its best. These foods typically contain only a single ingredient (and if they contain more, each ingredient should be a simple food you recognize, such as dates or pumpkin seeds).
You might also consider incorporating a few supplements to ensure you’re well-stocked on nutrients that are pivotal for a healthy mood. A quality B vitamin complex, magnesium, zinc, and omega-3s are good places to start.
4. Too Much Sugar: The Blood Sugar Roller Coaster Mood Trap
Sugar can be tricky. While a sweet treat might make you feel good temporarily, too much sugar in your diet can lead to blood sugar spikes and crashes that can mess with your mood, even contributing to brain fog and anxiety. Studies have linked higher sugar intake, especially from sweetened beverages, with a greater risk of depression.
Read More: 6 Signs Your Blood Sugar Isn’t As Healthy As You Think
You see, when you consume sugar, your body releases insulin to balance your blood sugar levels. However, the higher your sugar intake, the harder your body has to work to keep things in check. Over time, the body can even become insulin resistant, a state that has been shown to have an inflammatory impact on the brain and contribute to cognitive health declines.
Lift Your Spirits: Opt for naturally sweet foods like fresh fruits, which contain fiber to slow down sugar absorption. Limit added sugars to keep your blood sugar—and mood—more stable throughout the day. For some people, daily supplements such as berberine, cinnamon, chromium, inositol, alpha lipoic acid, and apple cider vinegar can help calm the blood sugar roller coaster and balance your mood.
5. Poor Gut Health: Your ‘Second Brain’ Matters More Than You Think
The gut and brain are deeply connected through what’s known as the gut-brain axis—and a healthy gut produces neurotransmitters like serotonin, which helps regulate mood, sleep, and appetite. However, gut imbalances due to a diet high in processed foods, stress, or antibiotics, can contribute to poor mental health.
Research from JAMA Psychiatry has shown that people with poor gut health are more likely to experience anxiety and depression. This is, in part, because an imbalanced gut leads to an increase in pro-inflammatory molecules that can negatively affect the brain.
Lift Your Spirits: Regularly incorporating fiber-rich foods (especially those that contain prebiotics, like onions, garlic, and asparagus) and fermented foods (like yogurt, sauerkraut, and kimchi) can promote a healthy microbiome. These foods help produce and maintain a balanced gut environment, which can support better mood stability. Supplements like quality probiotics can also support your gut’s microbial diversity, which is an important factor in a healthy gut-brain axis and therefore mood.
6. Not Enough Time in Nature: The ‘Nature Deficit Disorder’ Phenomenon
Our ancestors spent the majority of their time outdoors, so it’s no wonder that we feel better when we’re in natural environments. Spending time in nature has been shown to reduce stress, lower blood pressure, boost focus, and improve mood. A landmark study published in Frontiers in Psychology found that even just 20 minutes in a park can reduce levels of cortisol (the stress hormone).
Being in nature can also help us disconnect from the constant stimulation of screens and noise, which can contribute to overstimulation and mental fatigue.
Lift Your Spirits: Make it a habit to get outdoors regularly, whether for a hike, a stroll in the park, or just to sit on a bench and take in your surroundings. Even brief outdoor breaks can work wonders for your mood and mental clarity.
The Bottom Line
Your mood is influenced by so much more than your thoughts alone. If you’re feeling low, it might be worth examining your daily habits and making small changes. Sunlight, movement, good nutrition, gut support, and time in nature all play vital roles in how we feel. The beauty is that by taking small steps—like adding more whole foods to your diet or spending a few more minutes outside each day—you can improve not only your mood but your overall health.
Dr. Shetreat is a neurologist, herbologist, and author of The Dirt Cure, in which she presents a nutritional plan for getting and keeping children healthy. She works and studies with indigenous communities and healers from around the world, and is the founder of the Terrain Institute, where she teaches earth-based programs for transformational healing.