Sunlight in the Shorter Days: Vitamin D, Mood, and God's Gift of Light

You leave for work and the sky is still gray. By the time you head home, the porch light is already on and supper is waiting in a dark kitchen. Many of us notice that our energy drops and our mood dips as the days shorten. If you have wondered whether that is more than your imagination, you are asking a good question.

Light is one of the first gifts God spoke into the world, and our bodies were made to respond to it. Sunlight helps the skin make vitamin D, it sets the rhythm of our sleep and waking, and for some people the loss of daylight is tied to real changes in mood. At the same time, too much sun carries its own risks, and not every skin type makes vitamin D the same way.

Below we look at what trusted health sources say about vitamin D in winter, plant based food sources, and seasonal mood changes. Then we open the Scriptures on light, keeping medical facts and spiritual lessons clearly separate. This is general wellness education, not medical advice, so please talk with your doctor about your own needs.

The short answer

Your body makes vitamin D when bare skin is exposed to the sun, and the National Institutes of Health notes that most people get at least some vitamin D this way. In fall and winter that becomes harder, because days are shorter, we spend more time indoors, and sunlight through a window does not count. The NIH Office of Dietary Supplements sets the Recommended Dietary Allowance at 600 IU (15 mcg) a day for most children and adults, and 800 IU (20 mcg) for adults over 70. Food can help close the gap, but the only reliable way to know your own level is a blood test ordered by your doctor.

Low mood in the darker months deserves attention too. Feeling a little sluggish is common, but seasonal affective disorder is a real form of depression. If sadness lingers, interferes with daily life, or includes thoughts of self harm, please reach out for professional help right away.

How sunlight helps your body make vitamin D

Vitamin D is a nutrient your body needs for strong bones, and the NIH explains that it helps your body absorb calcium. Harvard T.H. Chan School of Public Health calls vitamin D production in the skin the primary natural source of the vitamin. That process depends on a type of ultraviolet light called UVB reaching your skin, and Harvard notes that window glass completely blocks it. So a sunny room feels pleasant, but it does not raise your vitamin D level.

The NIH adds that clouds, smog, older age, and darker skin all reduce the amount of vitamin D your skin makes. Sunscreen matters as well, since Harvard reports that correctly applied sunscreen can reduce vitamin D absorption by more than 90 percent. Season and location also change how strong UVB rays are. Harvard gives the example that people in Boston cannot make enough vitamin D from sunlight for about 4 months of the year. North Texas sits much farther south, so our winter sun is stronger, but shorter days and long hours indoors still add up.

How much sun do you need for vitamin D?

The honest answer is that no single number fits everyone. Harvard notes that the amount of vitamin D the skin makes varies widely, depending on skin tone, age, season, location, and sunscreen use. Skin doctors also urge caution. The American Academy of Dermatology states that unprotected exposure to the sun's ultraviolet rays is a known risk factor for skin cancer, and it recommends that healthy adults get their vitamin D from food rather than from sun exposure or tanning. The wise path is to enjoy daylight while avoiding sunburn, and to rely on food and your doctor for vitamin D itself.

Darker skin and vitamin D: a word for Haitian families

Many families in our church have roots in Haiti, so this matters for us. The NIH puts it plainly: the darker your skin, the less vitamin D you make from sunlight exposure. Harvard explains that melanin, the pigment that gives skin its color, acts like a shade and reduces vitamin D production. Harvard also cites United States data showing that about 20 percent of White adults and about 75 percent of Black adults have blood levels of vitamin D below 50 nmol/L. This is not a reason for worry or shame, since the variety of skin God created is part of His design, but it is a good reason to ask your doctor about a vitamin D blood test, especially in winter.

Darker skin does not mean sun protection can be skipped, since the sun safety advice from health agencies is written for everyone. The CDC advises protecting your skin all year long by staying in the shade during midday hours, wearing clothing that covers your arms and legs, and using sunscreen with SPF 15 or higher that protects against both UVA and UVB rays. The goal for every family is balance: get outside, avoid burning, and pay attention to vitamin D through food and medical guidance.

How much vitamin D do you need?

The NIH Office of Dietary Supplements lists daily recommended amounts by age, counting vitamin D from all foods, beverages, and supplements together. These are a general guide for healthy people. Your doctor may advise differently based on your health and your blood test.

More is not always better. The NIH warns that getting too much vitamin D can be harmful, and that extremely high levels can cause kidney failure, irregular heartbeat, and even death. Please do not start high dose supplements on your own, and tell your doctor or pharmacist about any supplement you take.

Vitamin D foods for a plant based kitchen

Many Seventh-day Adventists eat a plant based or vegetarian diet, and this is where vitamin D needs a little planning. Harvard notes that people who do not eat milk, eggs, or fish, such as those following a vegan diet, are at higher risk of low vitamin D. Fortified foods do most of the work.

The NIH notes that almost all of the United States milk supply is fortified with about 3 mcg (120 IU) of vitamin D per cup, and that many plant based alternatives such as soy milk, almond milk, and oat milk are similarly fortified. Check the label, because fortification varies by brand. The NIH also explains that some mushrooms have been exposed to ultraviolet light to increase their vitamin D content.

In a Haitian kitchen this can look very natural. Oatmeal made with fortified soy or oat milk, or mushrooms folded into a vegetable legim beside your diri ak pwa, are simple ways to bring vitamin D foods to the table. If your diet still leaves you short, ask your doctor whether a supplement makes sense for you.

Morning light, sleep, and mood

Sunlight also shapes our daily rhythm. The National Institute of General Medical Sciences explains that circadian rhythms are the changes our bodies go through over a 24 hour cycle, and that light and dark have the biggest influence on them. In the evening, the brain's master clock signals the body to make more melatonin, which causes sleepiness.

NIGMS also notes that light from electronic devices at night can confuse our biological clocks. A short walk after breakfast, opening the curtains wide, or eating lunch outdoors on a mild Texas afternoon are gentle ways to give your body clear signals about day and night. Dimming screens in the evening completes the picture.

Winter blues or seasonal affective disorder?

Feeling a bit down when daylight shrinks is often called the winter blues. Seasonal affective disorder is different. NIMH describes it as a type of depression with a recurring seasonal pattern. Symptoms usually begin in late fall or early winter, ease in spring and summer, and last about 4 to 5 months a year.

According to NIMH, the winter pattern can include oversleeping, overeating with cravings for carbohydrates, weight gain, and pulling away from other people. Mayo Clinic adds low energy and notes that possible causes include reduced sunlight disrupting the body's internal clock, a drop in serotonin, and shifts in melatonin. It is diagnosed more often in women than in men and occurs more often in younger adults, and Mayo Clinic lists a low level of vitamin D among the risk factors.

There is real help available. NIMH describes four main types of treatment: light therapy, talk therapy, antidepressant medicine, and vitamin D. For light therapy, people typically sit in front of a special 10,000 lux light box for about 30 to 45 minutes a day, usually in the morning, and NIMH notes that vitamin D supplements may help some people, although studies have shown mixed results. These choices belong with a health professional.

Mayo Clinic advises seeing a health care provider when you feel down for days at a time and lose motivation for activities you usually enjoy, especially if sleep or appetite change. If you or someone you love is struggling or having thoughts of suicide, NIMH points to the 988 Suicide and Crisis Lifeline, which you can call or text at 988 in the United States. Asking for help is not a lack of faith but wisdom, and it is one way God brings healing through caring people.

What the Bible says about light

The Bible is not a nutrition textbook, and we should not read vitamin D into its pages. What Scripture gives us instead is a picture of light as a good gift from a loving Creator. Light was part of His design from the very first day.

"And God said, Let there be light: and there was light." Genesis 1:3, KJV

The next verse adds that "God saw the light, that it was good" (Genesis 1:4). Later in the same chapter God set lights in the sky "to divide the day from the night" (Genesis 1:14), giving our days and seasons their rhythm. The wise teacher of Ecclesiastes delighted in this gift, writing, "Truly the light is sweet, and a pleasant thing it is for the eyes to behold the sun" (Ecclesiastes 11:7). In the next verse he also tells us to remember "the days of darkness; for they shall be many" (Ecclesiastes 11:8), an honest admission that life includes darker seasons alongside the bright ones.

The Sun of righteousness and the Light of the world

Malachi used the image of sunrise to describe God's coming salvation, and Christians have long understood this promise as pointing to the Messiah. This is a spiritual picture, not a medical claim. Still, it speaks deeply to anyone walking through a gray season.

"But unto you that fear my name shall the Sun of righteousness arise with healing in his wings; and ye shall go forth, and grow up as calves of the stall." Malachi 4:2, KJV

Jesus made the image personal when He said, "I am the light of the world: he that followeth me shall not walk in darkness, but shall have the light of life" (John 8:12). The light our bodies need comes from the sun God made, but the light our souls need comes from the Son God sent. Both are gifts, and we are invited to receive both with gratitude.

Sunlight and the eight natural remedies

Seventh-day Adventists often speak of eight natural remedies for health: nutrition, exercise, water, sunlight, temperance, fresh air, rest, and trust in God. Sunlight is on that list, and so is temperance. Together they remind us that even good gifts are best enjoyed with balance, which is exactly the lesson of sun and skin.

The church's Fundamental Belief 22, Christian Behavior, teaches that "because our bodies are the temples of the Holy Spirit, we are to care for them intelligently." Paul asked the believers in Corinth, "know ye not that your body is the temple of the Holy Ghost which is in you" (1 Corinthians 6:19). Caring wisely for our bodies in winter, through food, daylight, rest, and medical care when needed, is one small way to honor the God who made us.

Reflection questions

Take these questions with you on a Sabbath afternoon walk. When you think about the darker seasons of your own life, where have you seen the light of Christ break through? What is one simple change you could make this winter to welcome more of God's daylight into your routine? Is there someone in your family or church who seems to be struggling as the days grow short, and how might you reach out to them with kindness?

A word of encouragement

If the shorter days have left you feeling heavy, you are not weak and you are not alone. God made our bodies to respond to light, so it makes sense that we feel the change when it fades. He has also given us food, rest, doctors, and a church family to help us through.

Every winter gives way to spring, and the psalmist wrote, "weeping may endure for a night, but joy cometh in the morning" (Psalm 30:5). Whatever season you are in, the Light of the world walks with you. His mercy has not grown dim.

A prayer

Father, thank You for the sun that warms our days and for the rhythm of seasons You set in motion. When the days grow short and our hearts feel heavy, help us to care wisely for the bodies You have given us. Shine the light of Jesus into every dark place in our lives, and give us courage to ask for help when we need it. In Jesus' name, Amen.

Your next step

If this season has been heavy, our church family would be honored to pray with you, so please share a prayer request. You are also warmly invited to join us for Sabbath School at 10:00 AM and Divine Service at 11:00 AM at 205 E Carver St in Alvarado, Texas, where we worship in Kreyòl and English. After the service we share a meal together, and there is always a place at the table for you.

"Truly the light is sweet, and a pleasant thing it is for the eyes to behold the sun:" Ecclesiastes 11:7, KJV