Vitamin D Deficiency
Low vitamin D levels can cause a range of problems in the body. One of the biggest risks is weaker bones. This can show up as bone pain, muscle weakness, or a higher chance of fractures. In children, not enough vitamin D can lead to rickets, which makes bones bend or bow. In adults, vitamin D deficiency raises the risk for thin, fragile bones that break more easily.
Vitamin D also plays a key role in maintaining proper muscle function. When levels are low, muscles may feel sore or weak, increasing the risk of falls and injuries, especially in older adults.
Who’s Most at Risk?
Certain groups face even more risks. For example:
| Group at Risk | Why the Risk is Higher |
|---|---|
| Older adults | Their bodies process and absorb vitamin D less efficiently. |
| Those with darker skin | More skin melanin means they produce less vitamin D from sunlight. |
| People with obesity | Their bodies store more vitamin D in fat cells, making it less available. |
| Those with Crohn’s or celiac disease | They absorb nutrients poorly, making it hard to get enough vitamin D. |
| Breastfed infants without supplements | Breast milk alone may not provide enough vitamin D. |
| People who avoid sun exposure | Less sunlight means they make less vitamin D. |
People who live in colder climates or areas with limited sunlight during the winter are also at increased risk, since sunlight is a key source of natural vitamin D. Vitamin D helps the body absorb calcium, which is key for strong bones. Without enough vitamin D, people can develop low blood calcium. This may cause muscle cramps or spasms.
In more severe cases, calcium imbalance caused by low vitamin D can lead to tingling sensations in the hands, feet, or around the mouth. Some may also experience difficulty concentrating or memory problems.
Connections to Chronic Illness
Some chronic illnesses link to low vitamin D. People with liver or kidney disease have a higher risk, since these organs process vitamin D. Low vitamin D may also connect to a higher chance of heart disease or some mental health issues such as depression and anxiety, though more research is needed.
Research has also explored possible links between low vitamin D levels and autoimmune conditions, including multiple sclerosis (MS) and type 1 diabetes. While the relationship isn’t fully understood, vitamin D may help regulate the immune system. Some individuals report mood changes or irritability with low vitamin D levels. This may be due to vitamin D’s influence on brain function and hormone regulation.
How to Get Enough Vitamin D
Getting too little vitamin D is more common in people with very little sun exposure, those who eat few foods rich in vitamin D, or people who have conditions that make it harder for their bodies to use or absorb this nutrient.
Foods that are naturally high in vitamin D include fatty fish like salmon, sardines, and trout. Some mushrooms also contain vitamin D, especially if exposed to ultraviolet (UV) light. Fortified foods are another common source. These include:
- Cow’s milk and yogurt
- Plant-based milks (such as soy, almond, or oat milk)
- Breakfast cereals
- Orange juice (if fortified)
- Margarine or spreads with added vitamin D
Egg yolks and beef liver also provide small amounts of vitamin D and may help contribute to daily intake. However, it’s often hard to meet daily needs through food alone. Sunlight remains one of the most efficient ways to produce vitamin D naturally. The skin makes vitamin D when exposed to UVB rays from the sun. But factors like sunscreen, time of day, season, skin tone, and age all affect how much vitamin D your body can make this way.
If you think you’re not getting enough vitamin D, consider discussing it with your healthcare provider. A blood test can measure your levels, and they may suggest a supplement. The recommended amount of vitamin D a day for adults is 600 international units (IU). For people older than age 70, the recommendation rises to 800 IU daily.
Your doctor might suggest a higher dose temporarily if your levels are especially low. However, taking too much vitamin D through supplements can lead to health issues like nausea, kidney problems, or calcium buildup in the blood. Always follow medical guidance on dosage.
